multi-range implementation for value_range (irange)

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  • multi-range implementation for value_range (irange)
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Bill Schmidt via Gcc-patches July 31, 2020, 9:44 p.m.
INTRO
=====

The following is the implementation of irange, our multi-range class 
that is API compatible with value_range.  It is meant to be a drop-in 
replacement for value_range that provides multi-ranges while peacefully 
coexisting with the existing implementation.

As Andrew previously mentioned, we have moved the representation of our 
multi-range class from wide-int to trees, and merged it with the 
value_range class.  There is now a base class which "recognizes" a 1 
sub-range case as a special legacy mode which supports ANTI_RANGE and 
incorporates the original value_range code.  Multi-range is fully 
interoperable with value_range code now and all existing code which uses 
value_range still operates exactly the same as it did.  It's just 
slightly different under the covers.

range-ops has been returned to working in multi-range mode now that it's 
compatible with value_range.  Any consumer working with ranges can 
switch to multi-range by switching to the multi-range API.  Basically if 
you pass a value_range to any of the existing range-ops folders, you get 
a low-precision result back, but if you pass a wider irange, you will 
get almost infinite precision back from the range-ops code, as well as 
the union and intersect, etc code.  More details below.

TESTING
=======

The code has been regression tested on x86-64, x86-32, aarch64, ppc64 
and ppc64le.  It has also gone through a complete fedora build (over 
9000 packages on x86_64).

We have also tested this patch on the ranger staging branch with the 
ranger, which makes full use of multi-ranges, as opposed to evrp/vrp 
which use value_ranges.

PERFORMANCE
===========

We benchmarked the code with 240 .ii files gathered from a GCC 
bootstrap.  The tests were run 3 times a piece and times were averaged 
in.  We measured performance with two approaches: one was user-time as 
reported by -ftime-report-details, and the other one was done with 
./cc1plus running under callgrind emulation.  We decided on callgrind, 
as the numbers are so small on evrp/vrp that the smallest difference in 
environment throws off the numbers.  Callgrind proved immensely useful 
in pin-pointing those last few percentage points.

For user-time, our difference was:

* evrp with irange is 2.04% slower than mainline.  In practice, this is 
a combined difference of 1.0425 seconds versus 1.0637 seconds (delta of 
0.0212 secs) over the 200+ files compiled.

* vrp with irange is 3.68% *FASTER* than mainline.  In practice, this is 
a difference of 5.5075 seconds versus 5.3050 seconds (delta of 0.2025 secs).

For callgrind, our difference was:

* evrp with irange is 5.76% slower than mainline.

* vrp with irange is 3.68% slower than mainline.

Reasons for the slowdown:

* A trivial amount of slowdown is expected by the additional ranges.

* Extra indirection in the base class (discussed below).

* Coexistence with legacy value_range's and their anti-ranges.  Copying 
between value_range and wider irange's involves a time and memory penalty.

Conclusion: We expect these differences to pretty much disappear as all 
users of value_range are converted to multi-ranges.

But seriously folks, it's a 0.02 second slowdown over 240 files on a 
uni-processor build.  Plus, we more than made up for that by making VRP 
0.2 seconds faster :-).

MEMORY LAYOUT
=============

irange is the base class, which contains no storage, but a pointer to 
the storage when it becomes available:

class irange
{
      unsigned char m_num_ranges;
      unsigned char m_max_ranges;
      ENUM_BITFIELD(value_range_kind) m_kind : 8;
      tree *m_base;
};

Irange is meant to be an abstract class that is only instantiated by the 
class with the actual storage (int_range<>):

template<unsigned N>
class int_range : public irange
{
      tree m_ranges[N*2];
};

In this world, value_range which is int_range<1>, is only one word 
larger than the original value_range structure (24 versus 32 bytes on 
x86-64).

USAGE
=====

Multi-ranges can be declared in three ways:

* int_range<N> where N is the number of sub-ranges.

* widest_irange.  This is a convenience typedef for int_range<255>, and 
is used throughout to hold temporaries to make sure things don't get 
squished down into a lower-precision while calculating intermediate 
results.  Originally we had infinite precision that grew like auto_vec<> 
but decided against it for performance reasons.  We also didn't see the 
need for sub-ranges larger than a couple dozen.  Simple tests showed 
that they mostly went unused.  I could dig up our original research on 
this, if folks are interested in what the ideal N is.  As it is, a 
widest_irange is about 4k on x86-64.

* value_range.  This is a convenience typedef for int_range<1> and is 
special in that it is implemented under the covers with all the 
VR_ANTI_RANGE nonsense.  It's legacy.  It's meant to go away.  Or 
rather, int_range<1> will eventually become just that... a bare range 
with two end-points, no anti-range business.

Note: Assignment between any combination works as expected.  You can 
copy a value_range into a multi-range, and vice-versa.  Obviously, 
copying a higher precision multi-range down to a value_range will 
frequently result in squishing of ranges and precision loss.

Note: range-ops (and the ranger) use the base class irange and are meant 
to work with anything you throw at it.

API
===

Nothing changes in the public API.

However, we have marked all the API methods that are slated to be 
deprecated by DEPRECATED in the header file.  Examples of these are 
kind(), min(), max(), symbolic_p(), etc.  We hope this makes it easier 
for contributors and reviewers to notice when deprecated API calls are 
slipping into the code base.

We encourage passes that use value_range to, at the very least, be 
converted away from these deprecated methods.  i.e. Don't depend on 
kind() and VR_ANTI_RANGE.  Instead re-frame your questions with 
intersect(), union(), contains_p(), and all the fancy clean API methods.

NOTES ON THE PATCH ITSELF
=========================

* Internally, a value_range is distinguished from a multi-range with the 
protected method legacy_mode_p().  If/when we get rid of value_range, 
all we have to do is search for this idiom and kill the legacy_mode_p 
code path.

* A good portion of the changes are in range-ops, primarily in the form 
of adjustments to make range-ops range agnostic (using the abstract 
irange, instead of value_range), as well as performance tweaks so we 
don't slow down unnecessarily.  However, there are a bunch of 
::op1_range and ::op2_range implementations for opcodes that were 
previously unimplemented.  The reviewer can safely ignore these, as the 
only consumer of these are in the ranger.  We're providing them (as we 
did in the original range-ops submission), as the range_operator classes 
are a package onto themselves.

* ipa-cp changes from vec<value_range> to std::vec<value_range>.

We are using std::vec to ensure constructors are run, which they aren't 
in our internal vec<> implementation.  Although we usually steer away 
from using std::vec because of interactions with our GC system, 
ipcp_param_lattices is only live within the pass and allocated with calloc.

* There is a one-line change to the gengtype lexer so it can handle the 
<N> in the int_range template.

* We found that caching of 0, 1, and MAX for pointers significantly 
speeds things up (vrp_val_max, ~[0,0] comparisons, etc).  This caching 
was added to the already present cache for common wide_ints in 
wide_int_to_tree_1.

Jeff approved this patch off-list.  I will re-run tests once again and 
commit by Monday.

Aldy and Andrew

Comments

Gerald Pfeifer Aug. 5, 2020, 2:27 p.m. | #1
Hi Aldy,

On Fri, 31 Jul 2020, Aldy Hernandez via Gcc-patches wrote:
> Jeff approved this patch off-list.  I will re-run tests once again and 

> commit by Monday.


I believe this has broken the bootstrap with clang (specifically
FreeBSD clang version 10.0.0):

In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/c/gimple-parser.c:44:
In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/tree-vrp.h:23:
/scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:347:1: error: static declaration of 'gt_ggc_mx' follows non-static declaration gt_ggc_mx (int_range<N> *x)
/scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:150:37: note: previous declaration is here
  template <unsigned X> friend void gt_ggc_mx (int_range<X> *);
                                    ^

/scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:358:1: error: static declaration of 'gt_pch_nx' follows non-static declaration gt_pch_nx (int_range<N> *x)
/scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:151:37: note: previous declaration is here
  template <unsigned X> friend void gt_pch_nx (int_range<X> *);
                                    ^

My daily tester started to 20200803T1640, so the root cause of this must 
have entered GCC trunk between Sunday 16:40 UTC and Monday 16:40 UTC.

Gerald
Martin Jambor Aug. 5, 2020, 3:09 p.m. | #2
On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:
>


[...]

>

> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>

> We are using std::vec to ensure constructors are run, which they aren't 

> in our internal vec<> implementation.  Although we usually steer away 

> from using std::vec because of interactions with our GC system, 

> ipcp_param_lattices is only live within the pass and allocated with calloc.

>


Ummm... I did not object but I will save the URL of this message in the
archive so that I can waive it in front of anyone complaining why I
don't use our internal vec's in IPA data structures.

But it actually raises a broader question: was this supposed to be an
exception, allowed only not to complicate the irange patch further, or
will this be generally accepted thing to do when someone wants to have a
vector of constructed items?

Thanks,

Martin
Bill Schmidt via Gcc-patches Aug. 5, 2020, 3:41 p.m. | #3
On 8/5/20 5:09 PM, Martin Jambor wrote:

> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>

> 

> [...]

> 

>>

>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>

>> We are using std::vec to ensure constructors are run, which they aren't

>> in our internal vec<> implementation.  Although we usually steer away

>> from using std::vec because of interactions with our GC system,

>> ipcp_param_lattices is only live within the pass and allocated with calloc.

>>

> 

> Ummm... I did not object but I will save the URL of this message in the

> archive so that I can waive it in front of anyone complaining why I

> don't use our internal vec's in IPA data structures.

> 

> But it actually raises a broader question: was this supposed to be an

> exception, allowed only not to complicate the irange patch further, or

> will this be generally accepted thing to do when someone wants to have a

> vector of constructed items?


I don't want to start a precedent without further discussion, so let's 
assume this was an exception.

Is there another objection to std::vec<> other than it doesn't play well 
with our GC?  Is GCC's vec<> that much faster/efficient than std::vec<>? 
  Does it matter?

I will note that an alternative would have been to rewrite our 
internal's vec<> implementation so that constructors are run.  We 
explored that, but it seemed like more work than it was worth.

Andrew, do you remember the details on the C++ness issues with GCC's 
vec<> implementation?

Aldy
Bill Schmidt via Gcc-patches Aug. 5, 2020, 3:45 p.m. | #4
On 8/5/20 4:27 PM, Gerald Pfeifer wrote:
> Hi Aldy,

> 

> On Fri, 31 Jul 2020, Aldy Hernandez via Gcc-patches wrote:

>> Jeff approved this patch off-list.  I will re-run tests once again and

>> commit by Monday.

> 

> I believe this has broken the bootstrap with clang (specifically

> FreeBSD clang version 10.0.0):

> 

> In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/c/gimple-parser.c:44:

> In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/tree-vrp.h:23:

> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:347:1: error: static declaration of 'gt_ggc_mx' follows non-static declaration gt_ggc_mx (int_range<N> *x)

> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:150:37: note: previous declaration is here

>    template <unsigned X> friend void gt_ggc_mx (int_range<X> *);

>                                      ^

> 

> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:358:1: error: static declaration of 'gt_pch_nx' follows non-static declaration gt_pch_nx (int_range<N> *x)

> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:151:37: note: previous declaration is here

>    template <unsigned X> friend void gt_pch_nx (int_range<X> *);

>                                      ^

> 

> My daily tester started to 20200803T1640, so the root cause of this must

> have entered GCC trunk between Sunday 16:40 UTC and Monday 16:40 UTC.


Yeah, this is definitely caused by the irange patch.

GTY makes my head spin, and it took forever to get these gt_* functions 
set up.  I can't claim I understand them entirely :).

Just a guess, does removing the static solve the problem?

diff --git a/gcc/value-range.h b/gcc/value-range.h
index e3282c4ad03..1ab39939703 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -343,7 +343,7 @@ range_includes_zero_p (const irange *vr)
  }

  template<unsigned N>
-static inline void
+inline void
  gt_ggc_mx (int_range<N> *x)
  {
    for (unsigned i = 0; i < N; ++i)
@@ -354,7 +354,7 @@ gt_ggc_mx (int_range<N> *x)
  }

  template<unsigned N>
-static inline void
+inline void
  gt_pch_nx (int_range<N> *x)
  {
    for (unsigned i = 0; i < N; ++i)
@@ -365,7 +365,7 @@ gt_pch_nx (int_range<N> *x)
  }

  template<unsigned N>
-static inline void
+inline void
  gt_pch_nx (int_range<N> *x, gt_pointer_operator op, void *cookie)
  {
    for (unsigned i = 0; i < N; ++i)
Bill Schmidt via Gcc-patches Aug. 5, 2020, 4:54 p.m. | #5
On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:
>On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>

>

>[...]

>

>>

>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>

>> We are using std::vec to ensure constructors are run, which they

>aren't 

>> in our internal vec<> implementation.  Although we usually steer away

>

>> from using std::vec because of interactions with our GC system, 

>> ipcp_param_lattices is only live within the pass and allocated with

>calloc.

>>

>

>Ummm... I did not object but I will save the URL of this message in the

>archive so that I can waive it in front of anyone complaining why I

>don't use our internal vec's in IPA data structures.

>

>But it actually raises a broader question: was this supposed to be an

>exception, allowed only not to complicate the irange patch further, or

>will this be generally accepted thing to do when someone wants to have

>a

>vector of constructed items?


It's definitely not what we want. You have to find another solution to this problem. 

Richard. 

>Thanks,

>

>Martin
Bill Schmidt via Gcc-patches Aug. 5, 2020, 4:55 p.m. | #6
On August 5, 2020 5:41:01 PM GMT+02:00, Aldy Hernandez via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
>On 8/5/20 5:09 PM, Martin Jambor wrote:

>

>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>>

>> 

>> [...]

>> 

>>>

>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>

>>> We are using std::vec to ensure constructors are run, which they

>aren't

>>> in our internal vec<> implementation.  Although we usually steer

>away

>>> from using std::vec because of interactions with our GC system,

>>> ipcp_param_lattices is only live within the pass and allocated with

>calloc.

>>>

>> 

>> Ummm... I did not object but I will save the URL of this message in

>the

>> archive so that I can waive it in front of anyone complaining why I

>> don't use our internal vec's in IPA data structures.

>> 

>> But it actually raises a broader question: was this supposed to be an

>> exception, allowed only not to complicate the irange patch further,

>or

>> will this be generally accepted thing to do when someone wants to

>have a

>> vector of constructed items?

>

>I don't want to start a precedent without further discussion, so let's 

>assume this was an exception.

>

>Is there another objection to std::vec<> other than it doesn't play

>well 

>with our GC?  Is GCC's vec<> that much faster/efficient than

>std::vec<>? 

>  Does it matter?

>

>I will note that an alternative would have been to rewrite our 

>internal's vec<> implementation so that constructors are run.  We 

>explored that, but it seemed like more work than it was worth.

>

>Andrew, do you remember the details on the C++ness issues with GCC's 

>vec<> implementation?


Note we generally want to avoid memory allocations per element so can't you use a value_range<1> or so to make it POD? 

Richard. 

>Aldy
Gerald Pfeifer Aug. 5, 2020, 10:43 p.m. | #7
[ Jeff, approval request below ]

On Wed, 5 Aug 2020, Aldy Hernandez wrote:
>> I believe this has broken the bootstrap with clang (specifically

>> FreeBSD clang version 10.0.0):

>>

>> In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/c/gimple-parser.c:44:

>> In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/tree-vrp.h:23:

>> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:347:1: error: static

>> declaration of 'gt_ggc_mx' follows non-static declaration gt_ggc_mx

>> (int_range<N> *x)

>> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:150:37: note: previous

>> declaration is here

>>    template <unsigned X> friend void gt_ggc_mx (int_range<X> *);

:
>> My daily tester started to 20200803T1640, so the root cause of this must

>> have entered GCC trunk between Sunday 16:40 UTC and Monday 16:40 UTC.

> Yeah, this is definitely caused by the irange patch.

> 

> GTY makes my head spin, and it took forever to get these gt_* functions 

> set up.  I can't claim I understand them entirely :).

> 

> Just a guess, does removing the static solve the problem?


Yes, that appears to solve this issue.  

Thank you, Aldy!  (And, yes, I ought to have thought of that myself. ;-)


Bootstrap still fails, but quite later (the log file is 13M as opposed 
to 0.8M) and related to something else ... also triggered by your patch, 
though, I'm afraid:

In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/ipa-fnsummary.c:85:
In file included from /usr/include/c++/v1/vector:274:
In file included from /usr/include/c++/v1/__bit_reference:15:
In file included from /usr/include/c++/v1/algorithm:643:
In file included from /usr/include/c++/v1/memory:653:
/usr/include/c++/v1/typeinfo:346:5: error: no member named 'fancy_abort' in namespace 'std::__1'; did you mean simply 'fancy_abort'?
    _VSTD::abort();
    ^~~~~~~
/usr/include/c++/v1/__config:782:15: note: expanded from macro '_VSTD'
#define _VSTD std::_LIBCPP_ABI_NAMESPACE
              ^
/scratch/tmp/gerald/GCC-HEAD/gcc/system.h:762:13: note: 'fancy_abort' declared here
extern void fancy_abort (const char *, int, const char *)
            ^

I believe this is due to the following:

diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index 55a0b272a96..49bab04524b 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -82,6 +82,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimplify.h"
 #include "stringpool.h"
 #include "attribs.h"
+#include <vector>
 #include "tree-into-ssa.h"
 
 /* Summaries.  */


This is nearly the only case in all of GCC where <vector> is included
directly; are you sure that's appropriate?

Digging a bit...

  2017-01-22  Dimitry Andric <dim@FreeBSD.org>

        * gcov.c (INCLUDE_ALGORITHM): Define.
        (INCLUDE_VECTOR): Define.
        No longer include <vector> and <algorithm> directly.

...makes me think this is a repeat of a similar situation around gcov
three years ago.

The patch below similarly uses INCLUDE_VECTOR and "system.h" and restores 
bootstrap.  Tested on i386-unknown-freebsd11.4 which uses clang 10.0.0 as 
system compiler.

Okay?

Gerald


2020-08-05  Gerald Pfeifer  <gerald@pfeifer.com> 
 
        * ipa-fnsummary.c (INCLUDE_VECTOR): Define. 
        Remove direct inclusion of <vector>. 

diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index 49bab04524b..59e52927151 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -52,6 +52,7 @@ along with GCC; see the file COPYING3.  If not see
    inlined performs analysis via its analyze_function method. */
 
 #include "config.h"
+#define INCLUDE_VECTOR
 #include "system.h"
 #include "coretypes.h"
 #include "backend.h"
@@ -82,7 +83,6 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimplify.h"
 #include "stringpool.h"
 #include "attribs.h"
-#include <vector>
 #include "tree-into-ssa.h"
 
 /* Summaries.  */
Bill Schmidt via Gcc-patches Aug. 6, 2020, 1:07 a.m. | #8
On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:
> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:

>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>> [...]

>>

>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>

>>> We are using std::vec to ensure constructors are run, which they

>> aren't

>>> in our internal vec<> implementation.  Although we usually steer away

>>> from using std::vec because of interactions with our GC system,

>>> ipcp_param_lattices is only live within the pass and allocated with

>> calloc.

>> Ummm... I did not object but I will save the URL of this message in the

>> archive so that I can waive it in front of anyone complaining why I

>> don't use our internal vec's in IPA data structures.

>>

>> But it actually raises a broader question: was this supposed to be an

>> exception, allowed only not to complicate the irange patch further, or

>> will this be generally accepted thing to do when someone wants to have

>> a

>> vector of constructed items?

> It's definitely not what we want. You have to find another solution to this problem.

>

> Richard.

>


Why isn't it what we want?

This is a small vector local to the pass so it doesn't interfere with 
our PITA GTY.
The class is pretty straightforward, but we do need a constructor to 
initialize the pointer and the max-size field.  There is no allocation 
done per element, so a small number of elements have a couple of fields 
initialized per element. We'd have to loop to do that anyway.

GCC's vec<> does not provide he ability to run a constructor, std::vec 
does.  I quizzed some libstdc++ folks, and there has been a lot of 
optimizations done on std::vec over the last few years,.. They think its 
pretty good now, and we were encouraged to use it.

We can visit the question tho...  What is the rationale for not using 
std::vec in the compiler?  We currently use std::swap, std:pair, 
std::map, std::sort, and a few others.
is there some aspect of using std::vec I am not aware of that makes it 
something we need to avoid?

Andrew
Richard Sandiford Aug. 6, 2020, 4 a.m. | #9
Gerald Pfeifer <gerald@pfeifer.com> writes:
> 2020-08-05  Gerald Pfeifer  <gerald@pfeifer.com> 

>  

>         * ipa-fnsummary.c (INCLUDE_VECTOR): Define. 

>         Remove direct inclusion of <vector>. 


OK, thanks.

Richard

> diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c

> index 49bab04524b..59e52927151 100644

> --- a/gcc/ipa-fnsummary.c

> +++ b/gcc/ipa-fnsummary.c

> @@ -52,6 +52,7 @@ along with GCC; see the file COPYING3.  If not see

>     inlined performs analysis via its analyze_function method. */

>  

>  #include "config.h"

> +#define INCLUDE_VECTOR

>  #include "system.h"

>  #include "coretypes.h"

>  #include "backend.h"

> @@ -82,7 +83,6 @@ along with GCC; see the file COPYING3.  If not see

>  #include "gimplify.h"

>  #include "stringpool.h"

>  #include "attribs.h"

> -#include <vector>

>  #include "tree-into-ssa.h"

>  

>  /* Summaries.  */
Richard Sandiford Aug. 6, 2020, 5:16 a.m. | #10
Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:

>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>> [...]

>>>

>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>>

>>>> We are using std::vec to ensure constructors are run, which they

>>> aren't

>>>> in our internal vec<> implementation.  Although we usually steer away

>>>> from using std::vec because of interactions with our GC system,

>>>> ipcp_param_lattices is only live within the pass and allocated with

>>> calloc.

>>> Ummm... I did not object but I will save the URL of this message in the

>>> archive so that I can waive it in front of anyone complaining why I

>>> don't use our internal vec's in IPA data structures.

>>>

>>> But it actually raises a broader question: was this supposed to be an

>>> exception, allowed only not to complicate the irange patch further, or

>>> will this be generally accepted thing to do when someone wants to have

>>> a

>>> vector of constructed items?

>> It's definitely not what we want. You have to find another solution to this problem.

>>

>> Richard.

>>

>

> Why isn't it what we want?

>

> This is a small vector local to the pass so it doesn't interfere with 

> our PITA GTY.

> The class is pretty straightforward, but we do need a constructor to 

> initialize the pointer and the max-size field.  There is no allocation 

> done per element, so a small number of elements have a couple of fields 

> initialized per element. We'd have to loop to do that anyway.

>

> GCC's vec<> does not provide he ability to run a constructor, std::vec 

> does.


I realise you weren't claiming otherwise, but: that could be fixed :-)

> I quizzed some libstdc++ folks, and there has been a lot of 

> optimizations done on std::vec over the last few years,.. They think its 

> pretty good now, and we were encouraged to use it.

>

> We can visit the question tho...  What is the rationale for not using 

> std::vec in the compiler?  We currently use std::swap, std:pair, 

> std::map, std::sort, and a few others.

> is there some aspect of using std::vec I am not aware of that makes it 

> something we need to avoid?


One reason to prefer vec<> for general interfaces is that it
works with auto_vec<…, N>, making it possible to pre-allocate a
reasonably-sized buffer on the stack without needing a round-trip
through the allocators.

FWIW, that isn't simply a GCC thing.  LLVM (which is obviously much
more C++-intensive than GCC) still makes heavy use of SmallVector for
automatic variables.  And the reason we have things like memory_block.h
is that malloc did used to show up high in profiles.

(FWIW, I'm not saying that's an argument in favour of avoiding
std::vector completely.  It's just a reason why it might not always
be the right choice.)

Thanks,
Richard
Bill Schmidt via Gcc-patches Aug. 6, 2020, 6:57 a.m. | #11
On Thu, Aug 6, 2020 at 3:07 AM Andrew MacLeod <amacleod@redhat.com> wrote:
>

> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

> > On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:

> >> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

> >> [...]

> >>

> >>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

> >>>

> >>> We are using std::vec to ensure constructors are run, which they

> >> aren't

> >>> in our internal vec<> implementation.  Although we usually steer away

> >>> from using std::vec because of interactions with our GC system,

> >>> ipcp_param_lattices is only live within the pass and allocated with

> >> calloc.

> >> Ummm... I did not object but I will save the URL of this message in the

> >> archive so that I can waive it in front of anyone complaining why I

> >> don't use our internal vec's in IPA data structures.

> >>

> >> But it actually raises a broader question: was this supposed to be an

> >> exception, allowed only not to complicate the irange patch further, or

> >> will this be generally accepted thing to do when someone wants to have

> >> a

> >> vector of constructed items?

> > It's definitely not what we want. You have to find another solution to this problem.

> >

> > Richard.

> >

>

> Why isn't it what we want?

>

> This is a small vector local to the pass so it doesn't interfere with

> our PITA GTY.

> The class is pretty straightforward, but we do need a constructor to

> initialize the pointer and the max-size field.  There is no allocation

> done per element, so a small number of elements have a couple of fields

> initialized per element. We'd have to loop to do that anyway.

>

> GCC's vec<> does not provide he ability to run a constructor, std::vec

> does.


Other places in the compiler use placement new here.  The only
complication is re-allocation which would require move CTORs which
up to a few weeks ago were not available.  But of course we want
our own re-allocation policy, thus vec<>, not std::vector.

Also you do

#include <vector>

inside ipa-fnsummary.c - you should know better to not include
system headers from .c files - they need to go in system.h.
You should do a

#define INCLUDE_VECTOR

before the system.h include in ipa-fnsummary.c instead.

I find it only mildly amusing that review & approval of this happened
behind the scenes ...

I scanned the code but didn't spot the point where you'd need to run
CTORs? Can you point me to that?

>  I quizzed some libstdc++ folks, and there has been a lot of

> optimizations done on std::vec over the last few years,.. They think its

> pretty good now, and we were encouraged to use it.

>

> We can visit the question tho...  What is the rationale for not using

> std::vec in the compiler?  We currently use std::swap, std:pair,

> std::map, std::sort, and a few others.


We're using std::swap and std::pair throughoug because those are lean.
One of the main motivations to not use the STL is because of TU
explosion when including lots of those large headers.  Bootstrap times
are still an issue.

There's also code size issues when we have both std::vector<tree>
and vec<tree> instantiations.  And as you say vec<> isn't going away
because there's no way to make std::vector & friends GC aware.

Then there's consistency across the code-base.  A big mess will
scare of new contributors.

Oh, and existing uses are mostly mistakes and are _not_ a reason
to add more "exceptions" - instead they are a reason to rectify those
mistakes.

Richard.

> is there some aspect of using std::vec I am not aware of that makes it

> something we need to avoid?

>

> Andrew

>

>

>

>

>
Bill Schmidt via Gcc-patches Aug. 6, 2020, 10:19 a.m. | #12
On 06/08/20 06:16 +0100, Richard Sandiford wrote:
>Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:

>>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>>> [...]

>>>>

>>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>>>

>>>>> We are using std::vec to ensure constructors are run, which they

>>>> aren't

>>>>> in our internal vec<> implementation.  Although we usually steer away

>>>>> from using std::vec because of interactions with our GC system,

>>>>> ipcp_param_lattices is only live within the pass and allocated with

>>>> calloc.

>>>> Ummm... I did not object but I will save the URL of this message in the

>>>> archive so that I can waive it in front of anyone complaining why I

>>>> don't use our internal vec's in IPA data structures.

>>>>

>>>> But it actually raises a broader question: was this supposed to be an

>>>> exception, allowed only not to complicate the irange patch further, or

>>>> will this be generally accepted thing to do when someone wants to have

>>>> a

>>>> vector of constructed items?

>>> It's definitely not what we want. You have to find another solution to this problem.

>>>

>>> Richard.

>>>

>>

>> Why isn't it what we want?

>>

>> This is a small vector local to the pass so it doesn't interfere with

>> our PITA GTY.

>> The class is pretty straightforward, but we do need a constructor to

>> initialize the pointer and the max-size field.  There is no allocation

>> done per element, so a small number of elements have a couple of fields

>> initialized per element. We'd have to loop to do that anyway.

>>

>> GCC's vec<> does not provide he ability to run a constructor, std::vec

>> does.

>

>I realise you weren't claiming otherwise, but: that could be fixed :-)


It really should be.

Artificial limitations like that are just a booby trap for the unwary.

>> I quizzed some libstdc++ folks, and there has been a lot of

>> optimizations done on std::vec over the last few years,.. They think its

>> pretty good now, and we were encouraged to use it.

>>

>> We can visit the question tho...  What is the rationale for not using

>> std::vec in the compiler?  We currently use std::swap, std:pair,

>> std::map, std::sort, and a few others.

>> is there some aspect of using std::vec I am not aware of that makes it

>> something we need to avoid?

>

>One reason to prefer vec<> for general interfaces is that it

>works with auto_vec<…, N>, making it possible to pre-allocate a

>reasonably-sized buffer on the stack without needing a round-trip

>through the allocators.

>

>FWIW, that isn't simply a GCC thing.  LLVM (which is obviously much

>more C++-intensive than GCC) still makes heavy use of SmallVector for

>automatic variables.  And the reason we have things like memory_block.h

>is that malloc did used to show up high in profiles.


Yes, LLVM's SmallVector is very useful. You can achieve a similar
thing with a custom allocator in std::vector, but it's more cumbersome
and it alters the type from std::vector<X> to std::vector<X, Y>.

The beauty of the LLVM design is the common base class for
SmallVector<T, N> is the same for all N, so you can pass it to APIs
that don't care about the size and just work with the base interface.

>(FWIW, I'm not saying that's an argument in favour of avoiding

>std::vector completely.  It's just a reason why it might not always

>be the right choice.)

>

>Thanks,

>Richard

>
Bill Schmidt via Gcc-patches Aug. 6, 2020, 10:23 a.m. | #13
On 06/08/20 08:57 +0200, Richard Biener wrote:
>On Thu, Aug 6, 2020 at 3:07 AM Andrew MacLeod <amacleod@redhat.com> wrote:

>>

>> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>> > On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:

>> >> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>> >> [...]

>> >>

>> >>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>> >>>

>> >>> We are using std::vec to ensure constructors are run, which they

>> >> aren't

>> >>> in our internal vec<> implementation.  Although we usually steer away

>> >>> from using std::vec because of interactions with our GC system,

>> >>> ipcp_param_lattices is only live within the pass and allocated with

>> >> calloc.

>> >> Ummm... I did not object but I will save the URL of this message in the

>> >> archive so that I can waive it in front of anyone complaining why I

>> >> don't use our internal vec's in IPA data structures.

>> >>

>> >> But it actually raises a broader question: was this supposed to be an

>> >> exception, allowed only not to complicate the irange patch further, or

>> >> will this be generally accepted thing to do when someone wants to have

>> >> a

>> >> vector of constructed items?

>> > It's definitely not what we want. You have to find another solution to this problem.

>> >

>> > Richard.

>> >

>>

>> Why isn't it what we want?

>>

>> This is a small vector local to the pass so it doesn't interfere with

>> our PITA GTY.

>> The class is pretty straightforward, but we do need a constructor to

>> initialize the pointer and the max-size field.  There is no allocation

>> done per element, so a small number of elements have a couple of fields

>> initialized per element. We'd have to loop to do that anyway.

>>

>> GCC's vec<> does not provide he ability to run a constructor, std::vec

>> does.

>

>Other places in the compiler use placement new here.  The only

>complication is re-allocation which would require move CTORs which

>up to a few weeks ago were not available.  But of course we want

>our own re-allocation policy, thus vec<>, not std::vector.

>

>Also you do

>

>#include <vector>

>

>inside ipa-fnsummary.c - you should know better to not include

>system headers from .c files - they need to go in system.h.

>You should do a

>

>#define INCLUDE_VECTOR

>

>before the system.h include in ipa-fnsummary.c instead.

>

>I find it only mildly amusing that review & approval of this happened

>behind the scenes ...

>

>I scanned the code but didn't spot the point where you'd need to run

>CTORs? Can you point me to that?

>

>>  I quizzed some libstdc++ folks, and there has been a lot of

>> optimizations done on std::vec over the last few years,.. They think its

>> pretty good now, and we were encouraged to use it.

>>

>> We can visit the question tho...  What is the rationale for not using

>> std::vec in the compiler?  We currently use std::swap, std:pair,

>> std::map, std::sort, and a few others.

>

>We're using std::swap and std::pair throughoug because those are lean.

>One of the main motivations to not use the STL is because of TU

>explosion when including lots of those large headers.  Bootstrap times

>are still an issue.

>

>There's also code size issues when we have both std::vector<tree>

>and vec<tree> instantiations.  And as you say vec<> isn't going away

>because there's no way to make std::vector & friends GC aware.

>

>Then there's consistency across the code-base.  A big mess will

>scare of new contributors.


So do weird types that don't run constructors and require manually
constructing things into buffers with placement new, or only using
types with trivial default construcrors. It's not 1994.

Containers should own and manage their contents. Maybe adding support
for non-trivial construction to vec and making it movable (and not
copyable) would make it more useful.

>Oh, and existing uses are mostly mistakes and are _not_ a reason

>to add more "exceptions" - instead they are a reason to rectify those

>mistakes.

>

>Richard.

>

>> is there some aspect of using std::vec I am not aware of that makes it

>> something we need to avoid?

>>

>> Andrew

>>

>>

>>

>>

>>

>
Bill Schmidt via Gcc-patches Aug. 6, 2020, 10:31 a.m. | #14
On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely <jwakely@redhat.com> wrote:
>

> On 06/08/20 06:16 +0100, Richard Sandiford wrote:

> >Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

> >> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

> >>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:

> >>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

> >>>> [...]

> >>>>

> >>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

> >>>>>

> >>>>> We are using std::vec to ensure constructors are run, which they

> >>>> aren't

> >>>>> in our internal vec<> implementation.  Although we usually steer away

> >>>>> from using std::vec because of interactions with our GC system,

> >>>>> ipcp_param_lattices is only live within the pass and allocated with

> >>>> calloc.

> >>>> Ummm... I did not object but I will save the URL of this message in the

> >>>> archive so that I can waive it in front of anyone complaining why I

> >>>> don't use our internal vec's in IPA data structures.

> >>>>

> >>>> But it actually raises a broader question: was this supposed to be an

> >>>> exception, allowed only not to complicate the irange patch further, or

> >>>> will this be generally accepted thing to do when someone wants to have

> >>>> a

> >>>> vector of constructed items?

> >>> It's definitely not what we want. You have to find another solution to this problem.

> >>>

> >>> Richard.

> >>>

> >>

> >> Why isn't it what we want?

> >>

> >> This is a small vector local to the pass so it doesn't interfere with

> >> our PITA GTY.

> >> The class is pretty straightforward, but we do need a constructor to

> >> initialize the pointer and the max-size field.  There is no allocation

> >> done per element, so a small number of elements have a couple of fields

> >> initialized per element. We'd have to loop to do that anyway.

> >>

> >> GCC's vec<> does not provide he ability to run a constructor, std::vec

> >> does.

> >

> >I realise you weren't claiming otherwise, but: that could be fixed :-)

>

> It really should be.

>

> Artificial limitations like that are just a booby trap for the unwary.


It's probably also historic because we couldn't even implement
the case of re-allocation correctly without std::move, could we?

> >> I quizzed some libstdc++ folks, and there has been a lot of

> >> optimizations done on std::vec over the last few years,.. They think its

> >> pretty good now, and we were encouraged to use it.

> >>

> >> We can visit the question tho...  What is the rationale for not using

> >> std::vec in the compiler?  We currently use std::swap, std:pair,

> >> std::map, std::sort, and a few others.

> >> is there some aspect of using std::vec I am not aware of that makes it

> >> something we need to avoid?

> >

> >One reason to prefer vec<> for general interfaces is that it

> >works with auto_vec<…, N>, making it possible to pre-allocate a

> >reasonably-sized buffer on the stack without needing a round-trip

> >through the allocators.

> >

> >FWIW, that isn't simply a GCC thing.  LLVM (which is obviously much

> >more C++-intensive than GCC) still makes heavy use of SmallVector for

> >automatic variables.  And the reason we have things like memory_block.h

> >is that malloc did used to show up high in profiles.

>

> Yes, LLVM's SmallVector is very useful. You can achieve a similar

> thing with a custom allocator in std::vector, but it's more cumbersome

> and it alters the type from std::vector<X> to std::vector<X, Y>.

>

> The beauty of the LLVM design is the common base class for

> SmallVector<T, N> is the same for all N, so you can pass it to APIs

> that don't care about the size and just work with the base interface.

>

> >(FWIW, I'm not saying that's an argument in favour of avoiding

> >std::vector completely.  It's just a reason why it might not always

> >be the right choice.)

> >

> >Thanks,

> >Richard

> >

>
Bill Schmidt via Gcc-patches Aug. 6, 2020, 10:48 a.m. | #15
On 06/08/20 12:31 +0200, Richard Biener wrote:
>On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely <jwakely@redhat.com> wrote:

>>

>> On 06/08/20 06:16 +0100, Richard Sandiford wrote:

>> >Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>> >> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>> >>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:

>> >>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>> >>>> [...]

>> >>>>

>> >>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>> >>>>>

>> >>>>> We are using std::vec to ensure constructors are run, which they

>> >>>> aren't

>> >>>>> in our internal vec<> implementation.  Although we usually steer away

>> >>>>> from using std::vec because of interactions with our GC system,

>> >>>>> ipcp_param_lattices is only live within the pass and allocated with

>> >>>> calloc.

>> >>>> Ummm... I did not object but I will save the URL of this message in the

>> >>>> archive so that I can waive it in front of anyone complaining why I

>> >>>> don't use our internal vec's in IPA data structures.

>> >>>>

>> >>>> But it actually raises a broader question: was this supposed to be an

>> >>>> exception, allowed only not to complicate the irange patch further, or

>> >>>> will this be generally accepted thing to do when someone wants to have

>> >>>> a

>> >>>> vector of constructed items?

>> >>> It's definitely not what we want. You have to find another solution to this problem.

>> >>>

>> >>> Richard.

>> >>>

>> >>

>> >> Why isn't it what we want?

>> >>

>> >> This is a small vector local to the pass so it doesn't interfere with

>> >> our PITA GTY.

>> >> The class is pretty straightforward, but we do need a constructor to

>> >> initialize the pointer and the max-size field.  There is no allocation

>> >> done per element, so a small number of elements have a couple of fields

>> >> initialized per element. We'd have to loop to do that anyway.

>> >>

>> >> GCC's vec<> does not provide he ability to run a constructor, std::vec

>> >> does.

>> >

>> >I realise you weren't claiming otherwise, but: that could be fixed :-)

>>

>> It really should be.

>>

>> Artificial limitations like that are just a booby trap for the unwary.

>

>It's probably also historic because we couldn't even implement

>the case of re-allocation correctly without std::move, could we?


I don't see why not. std::vector worked fine without std::move, it's
just more efficient with std::move, and can be used with a wider set
of element types.

When reallocating you can just copy each element to the new storage
and destroy the old element. If your type is non-copyable then you
need std::move, but I don't think the types I see used with vec<> are
non-copyable. Most of them are trivially-copyable.

I think the benefit of std::move to GCC is likely to be permitting
cheap copies to be made where previously they were banned for
performance reasons, but not because those copies were impossible.
Bill Schmidt via Gcc-patches Aug. 6, 2020, 11:03 a.m. | #16
On 8/6/20 8:57 AM, Richard Biener wrote:
> On Thu, Aug 6, 2020 at 3:07 AM Andrew MacLeod <amacleod@redhat.com> wrote:

>>

>> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor <mjambor@suse.cz> wrote:

>>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>>> [...]

>>>>

>>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>>>

>>>>> We are using std::vec to ensure constructors are run, which they

>>>> aren't

>>>>> in our internal vec<> implementation.  Although we usually steer away

>>>>> from using std::vec because of interactions with our GC system,

>>>>> ipcp_param_lattices is only live within the pass and allocated with

>>>> calloc.

>>>> Ummm... I did not object but I will save the URL of this message in the

>>>> archive so that I can waive it in front of anyone complaining why I

>>>> don't use our internal vec's in IPA data structures.

>>>>

>>>> But it actually raises a broader question: was this supposed to be an

>>>> exception, allowed only not to complicate the irange patch further, or

>>>> will this be generally accepted thing to do when someone wants to have

>>>> a

>>>> vector of constructed items?

>>> It's definitely not what we want. You have to find another solution to this problem.

>>>

>>> Richard.

>>>

>>

>> Why isn't it what we want?

>>

>> This is a small vector local to the pass so it doesn't interfere with

>> our PITA GTY.

>> The class is pretty straightforward, but we do need a constructor to

>> initialize the pointer and the max-size field.  There is no allocation

>> done per element, so a small number of elements have a couple of fields

>> initialized per element. We'd have to loop to do that anyway.

>>

>> GCC's vec<> does not provide he ability to run a constructor, std::vec

>> does.

> 

> Other places in the compiler use placement new here.  The only

> complication is re-allocation which would require move CTORs which

> up to a few weeks ago were not available.  But of course we want

> our own re-allocation policy, thus vec<>, not std::vector.

> 

> Also you do

> 

> #include <vector>

> 

> inside ipa-fnsummary.c - you should know better to not include

> system headers from .c files - they need to go in system.h.

> You should do a

> 

> #define INCLUDE_VECTOR

> 

> before the system.h include in ipa-fnsummary.c instead.


This has already been fixed by Gerald (thanks!).

Aldy
Bill Schmidt via Gcc-patches Aug. 6, 2020, 2:17 p.m. | #17
On 8/6/20 12:48 PM, Jonathan Wakely wrote:
> On 06/08/20 12:31 +0200, Richard Biener wrote:

>> On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely <jwakely@redhat.com> 

>> wrote:

>>>

>>> On 06/08/20 06:16 +0100, Richard Sandiford wrote:

>>> >Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>>> >> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>>> >>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor 

>>> <mjambor@suse.cz> wrote:

>>> >>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>> >>>> [...]

>>> >>>>

>>> >>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>> >>>>>

>>> >>>>> We are using std::vec to ensure constructors are run, which they

>>> >>>> aren't

>>> >>>>> in our internal vec<> implementation.  Although we usually 

>>> steer away

>>> >>>>> from using std::vec because of interactions with our GC system,

>>> >>>>> ipcp_param_lattices is only live within the pass and allocated 

>>> with

>>> >>>> calloc.

>>> >>>> Ummm... I did not object but I will save the URL of this message 

>>> in the

>>> >>>> archive so that I can waive it in front of anyone complaining why I

>>> >>>> don't use our internal vec's in IPA data structures.

>>> >>>>

>>> >>>> But it actually raises a broader question: was this supposed to 

>>> be an

>>> >>>> exception, allowed only not to complicate the irange patch 

>>> further, or

>>> >>>> will this be generally accepted thing to do when someone wants 

>>> to have

>>> >>>> a

>>> >>>> vector of constructed items?

>>> >>> It's definitely not what we want. You have to find another 

>>> solution to this problem.

>>> >>>

>>> >>> Richard.

>>> >>>

>>> >>

>>> >> Why isn't it what we want?

>>> >>

>>> >> This is a small vector local to the pass so it doesn't interfere with

>>> >> our PITA GTY.

>>> >> The class is pretty straightforward, but we do need a constructor to

>>> >> initialize the pointer and the max-size field.  There is no 

>>> allocation

>>> >> done per element, so a small number of elements have a couple of 

>>> fields

>>> >> initialized per element. We'd have to loop to do that anyway.

>>> >>

>>> >> GCC's vec<> does not provide he ability to run a constructor, 

>>> std::vec

>>> >> does.

>>> >

>>> >I realise you weren't claiming otherwise, but: that could be fixed :-)

>>>

>>> It really should be.

>>>

>>> Artificial limitations like that are just a booby trap for the unwary.

>>

>> It's probably also historic because we couldn't even implement

>> the case of re-allocation correctly without std::move, could we?

> 

> I don't see why not. std::vector worked fine without std::move, it's

> just more efficient with std::move, and can be used with a wider set

> of element types.

> 

> When reallocating you can just copy each element to the new storage

> and destroy the old element. If your type is non-copyable then you

> need std::move, but I don't think the types I see used with vec<> are

> non-copyable. Most of them are trivially-copyable.

> 

> I think the benefit of std::move to GCC is likely to be permitting

> cheap copies to be made where previously they were banned for

> performance reasons, but not because those copies were impossible.


For the record, neither value_range nor int_range<N> require any 
allocations.  The sub-range storage resides in the stack or wherever it 
was defined.  However, it is definitely not a POD.

Digging deeper, I notice that the original issue that caused us to use 
std::vector was not in-place new but the safe_grow_cleared.  The 
original code had:

> 	auto_vec<value_range, 32> known_value_ranges;

> ...

> ...

> 	if (!vr.undefined_p () && !vr.varying_p ())

>           {

>             if (!known_value_ranges.length ())

>               known_value_ranges.safe_grow_cleared (count);

>               known_value_ranges[i] = vr;

>           }


I would've gladly kept the auto_vec, had I been able to do call the 
constructor by doing an in-place new:

>                     if (!vr.undefined_p () && !vr.varying_p ())

>                       {

>                         if (!known_value_ranges.length ())

> -                         known_value_ranges.safe_grow_cleared (count);

> +                         {

> +                           known_value_ranges.safe_grow_cleared (count);

> +                           for (int i = 0; i < count; ++i)

> +                             new (&known_value_ranges[i]) value_range ();

> +                         }

>                         known_value_ranges[i] = vr;

>                       }

>                   }


But alas, compiling yields:

> In file included from /usr/include/wchar.h:35,

>                  from /usr/include/c++/10/cwchar:44,

>                  from /usr/include/c++/10/bits/postypes.h:40,

>                  from /usr/include/c++/10/iosfwd:40,

>                  from /usr/include/gmp-x86_64.h:34,

>                  from /usr/include/gmp.h:59,

>                  from /home/aldyh/src/gcc/gcc/system.h:687,

>                  from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

> /home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T = int_range<1>; A = va_heap; size_t = long unsigned int]’:

> /home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, bool) [with T = int_range<1>]’

> /home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

> /home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

> /home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

> /home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

> /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

> /home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’ within non-standard-layout type ‘vec_embedded’ {aka ‘vec<int_range<1>, va_heap, vl_embed>’} is conditionally-supported [-Winvalid-offsetof]

>  1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>       |                    ^


The attached patch reverts the functionality to auto_vec<>, but the 
in-place new doesn't work.  Does anyone have any suggestions?

Aldy
commit b508fee91fd473cdc82c7c6c404cd09cf06b5af7
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Thu Aug 6 15:32:28 2020 +0200

    in-place new on resized elements.
    
    fails with:
    
    g++  -fno-PIE -c   -g   -DIN_GCC     -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wno-error=format-diag -Wmissing-format-attribute -Woverloaded-virtual -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -fno-common  -DHAVE_CONFIG_H -I. -I. -I/home/aldyh/src/gcc/gcc -I/home/aldyh/src/gcc/gcc/. -I/home/aldyh/src/gcc/gcc/../include -I/home/aldyh/src/gcc/gcc/../libcpp/include  -I/home/aldyh/src/gcc/gcc/../libdecnumber -I/home/aldyh/src/gcc/gcc/../libdecnumber/bid -I../libdecnumber -I/home/aldyh/src/gcc/gcc/../libbacktrace   -o ipa-fnsummary.o -MT ipa-fnsummary.o -MMD -MP -MF ./.deps/ipa-fnsummary.TPo /home/aldyh/src/gcc/gcc/ipa-fnsummary.c
    In file included from /usr/include/wchar.h:35,
                     from /usr/include/c++/10/cwchar:44,
                     from /usr/include/c++/10/bits/postypes.h:40,
                     from /usr/include/c++/10/iosfwd:40,
                     from /usr/include/gmp-x86_64.h:34,
                     from /usr/include/gmp.h:59,
                     from /home/aldyh/src/gcc/gcc/system.h:687,
                     from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:
    /home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T = int_range<1>; A = va_heap; size_t = long unsigned int]’:
    /home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, bool) [with T = int_range<1>]’
    /home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’
    /home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’
    /home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’
    /home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’
    /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here
    /home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’ within non-standard-layout type ‘vec_embedded’ {aka ‘vec<int_range<1>, va_heap, vl_embed>’} is conditionally-supported [-Winvalid-offsetof]
     1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
          |                    ^

diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index 49bab04524b..4c6bc9f1877 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -82,7 +82,6 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimplify.h"
 #include "stringpool.h"
 #include "attribs.h"
-#include <vector>
 #include "tree-into-ssa.h"
 
 /* Summaries.  */
@@ -331,7 +330,7 @@ static void
 evaluate_conditions_for_known_args (struct cgraph_node *node,
 				    bool inline_p,
 				    vec<tree> known_vals,
-				    const std::vector<value_range> &known_value_ranges,
+				    vec<value_range> known_value_ranges,
 				    vec<ipa_agg_value_set> known_aggs,
 				    clause_t *ret_clause,
 				    clause_t *ret_nonspec_clause)
@@ -446,7 +445,7 @@ evaluate_conditions_for_known_args (struct cgraph_node *node,
 	      continue;
 	    }
 	}
-      if (c->operand_num < (int) known_value_ranges.size ()
+      if (c->operand_num < (int) known_value_ranges.length ()
 	  && !c->agg_contents
 	  && !known_value_ranges[c->operand_num].undefined_p ()
 	  && !known_value_ranges[c->operand_num].varying_p ()
@@ -555,7 +554,7 @@ evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 {
   struct cgraph_node *callee = e->callee->ultimate_alias_target ();
   class ipa_fn_summary *info = ipa_fn_summaries->get (callee);
-  std::vector<value_range> known_value_ranges (32);
+  auto_vec<value_range, 32> known_value_ranges;
   class ipa_edge_args *args;
 
   if (clause_ptr)
@@ -630,11 +629,11 @@ evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 								   i));
 		    if (!vr.undefined_p () && !vr.varying_p ())
 		      {
-			if (!known_value_ranges.size ())
+			if (!known_value_ranges.length ())
 			  {
-			    known_value_ranges.resize (count);
+			    known_value_ranges.safe_grow_cleared (count);
 			    for (int i = 0; i < count; ++i)
-			      known_value_ranges[i].set_undefined ();
+			      new (&known_value_ranges[i]) value_range ();
 			  }
 			known_value_ranges[i] = vr;
 		      }
@@ -808,7 +807,7 @@ ipa_fn_summary_t::duplicate (cgraph_node *src,
 	}
       evaluate_conditions_for_known_args (dst, false,
 					  known_vals,
-					  std::vector<value_range> (),
+					  vNULL,
 					  vNULL,
 					  &possible_truths,
 					  /* We are going to specialize,
@@ -3692,8 +3691,7 @@ estimate_ipcp_clone_size_and_time (struct cgraph_node *node,
   clause_t clause, nonspec_clause;
 
   /* TODO: Also pass known value ranges.  */
-  evaluate_conditions_for_known_args (node, false, known_vals,
-				      std::vector<value_range> (),
+  evaluate_conditions_for_known_args (node, false, known_vals, vNULL,
 				      known_aggs, &clause, &nonspec_clause);
   ipa_call_context ctx (node, clause, nonspec_clause,
 		        known_vals, known_contexts,
Bill Schmidt via Gcc-patches Aug. 6, 2020, 2:35 p.m. | #18
On Thu, Aug 6, 2020 at 4:17 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>

>

>

> On 8/6/20 12:48 PM, Jonathan Wakely wrote:

> > On 06/08/20 12:31 +0200, Richard Biener wrote:

> >> On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely <jwakely@redhat.com>

> >> wrote:

> >>>

> >>> On 06/08/20 06:16 +0100, Richard Sandiford wrote:

> >>> >Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

> >>> >> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

> >>> >>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor

> >>> <mjambor@suse.cz> wrote:

> >>> >>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

> >>> >>>> [...]

> >>> >>>>

> >>> >>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

> >>> >>>>>

> >>> >>>>> We are using std::vec to ensure constructors are run, which they

> >>> >>>> aren't

> >>> >>>>> in our internal vec<> implementation.  Although we usually

> >>> steer away

> >>> >>>>> from using std::vec because of interactions with our GC system,

> >>> >>>>> ipcp_param_lattices is only live within the pass and allocated

> >>> with

> >>> >>>> calloc.

> >>> >>>> Ummm... I did not object but I will save the URL of this message

> >>> in the

> >>> >>>> archive so that I can waive it in front of anyone complaining why I

> >>> >>>> don't use our internal vec's in IPA data structures.

> >>> >>>>

> >>> >>>> But it actually raises a broader question: was this supposed to

> >>> be an

> >>> >>>> exception, allowed only not to complicate the irange patch

> >>> further, or

> >>> >>>> will this be generally accepted thing to do when someone wants

> >>> to have

> >>> >>>> a

> >>> >>>> vector of constructed items?

> >>> >>> It's definitely not what we want. You have to find another

> >>> solution to this problem.

> >>> >>>

> >>> >>> Richard.

> >>> >>>

> >>> >>

> >>> >> Why isn't it what we want?

> >>> >>

> >>> >> This is a small vector local to the pass so it doesn't interfere with

> >>> >> our PITA GTY.

> >>> >> The class is pretty straightforward, but we do need a constructor to

> >>> >> initialize the pointer and the max-size field.  There is no

> >>> allocation

> >>> >> done per element, so a small number of elements have a couple of

> >>> fields

> >>> >> initialized per element. We'd have to loop to do that anyway.

> >>> >>

> >>> >> GCC's vec<> does not provide he ability to run a constructor,

> >>> std::vec

> >>> >> does.

> >>> >

> >>> >I realise you weren't claiming otherwise, but: that could be fixed :-)

> >>>

> >>> It really should be.

> >>>

> >>> Artificial limitations like that are just a booby trap for the unwary.

> >>

> >> It's probably also historic because we couldn't even implement

> >> the case of re-allocation correctly without std::move, could we?

> >

> > I don't see why not. std::vector worked fine without std::move, it's

> > just more efficient with std::move, and can be used with a wider set

> > of element types.

> >

> > When reallocating you can just copy each element to the new storage

> > and destroy the old element. If your type is non-copyable then you

> > need std::move, but I don't think the types I see used with vec<> are

> > non-copyable. Most of them are trivially-copyable.

> >

> > I think the benefit of std::move to GCC is likely to be permitting

> > cheap copies to be made where previously they were banned for

> > performance reasons, but not because those copies were impossible.

>

> For the record, neither value_range nor int_range<N> require any

> allocations.  The sub-range storage resides in the stack or wherever it

> was defined.  However, it is definitely not a POD.

>

> Digging deeper, I notice that the original issue that caused us to use

> std::vector was not in-place new but the safe_grow_cleared.  The

> original code had:

>

> >       auto_vec<value_range, 32> known_value_ranges;

> > ...

> > ...

> >       if (!vr.undefined_p () && !vr.varying_p ())

> >           {

> >             if (!known_value_ranges.length ())

> >               known_value_ranges.safe_grow_cleared (count);

> >               known_value_ranges[i] = vr;

> >           }

>

> I would've gladly kept the auto_vec, had I been able to do call the

> constructor by doing an in-place new:

>

> >                     if (!vr.undefined_p () && !vr.varying_p ())

> >                       {

> >                         if (!known_value_ranges.length ())

> > -                         known_value_ranges.safe_grow_cleared (count);

> > +                         {

> > +                           known_value_ranges.safe_grow_cleared (count);

> > +                           for (int i = 0; i < count; ++i)

> > +                             new (&known_value_ranges[i]) value_range ();


With your placement new loop you should only need .safe_grow (count)
which should then make it work(?)

> > +                         }

> >                         known_value_ranges[i] = vr;

> >                       }

> >                   }

>

> But alas, compiling yields:

>

> > In file included from /usr/include/wchar.h:35,

> >                  from /usr/include/c++/10/cwchar:44,

> >                  from /usr/include/c++/10/bits/postypes.h:40,

> >                  from /usr/include/c++/10/iosfwd:40,

> >                  from /usr/include/gmp-x86_64.h:34,

> >                  from /usr/include/gmp.h:59,

> >                  from /home/aldyh/src/gcc/gcc/system.h:687,

> >                  from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

> > /home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T = int_range<1>; A = va_heap; size_t = long unsigned int]’:

> > /home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, bool) [with T = int_range<1>]’

> > /home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

> > /home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

> > /home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

> > /home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

> > /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

> > /home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’ within non-standard-layout type ‘vec_embedded’ {aka ‘vec<int_range<1>, va_heap, vl_embed>’} is conditionally-supported [-Winvalid-offsetof]

> >  1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >       |                    ^

>

> The attached patch reverts the functionality to auto_vec<>, but the

> in-place new doesn't work.  Does anyone have any suggestions?


I'm not able to decipher the above but I wonder why we have vl_embed
here.  Does the error vanish
if you use auto_vec<value_range> instead of auto_vec<value_range, 32>
here?  I guess the issue
is

template<typename T, typename A>
inline size_t
vec<T, A, vl_embed>::embedded_size (unsigned alloc)
{
  typedef vec<T, A, vl_embed> vec_embedded;
  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
}

when T is not a std layout type even though its offset does not depend on the
layout of T ...  The record in question is

template<typename T, typename A>
struct GTY((user)) vec<T, A, vl_embed>
{
public:
...
  /* FIXME - These fields should be private, but we need to cater to
             compilers that have stricter notions of PODness for types.  */
  vec_prefix m_vecpfx;
  T m_vecdata[1];
};

and the intent is to count tail-padding for say 'char' where sizeof
(vec<>) would
cover 4 elements already.

Richard.

>

> Aldy
Bill Schmidt via Gcc-patches Aug. 6, 2020, 2:59 p.m. | #19
On 8/6/20 4:35 PM, Richard Biener wrote:
> On Thu, Aug 6, 2020 at 4:17 PM Aldy Hernandez <aldyh@redhat.com> wrote:

>>

>>

>>

>> On 8/6/20 12:48 PM, Jonathan Wakely wrote:

>>> On 06/08/20 12:31 +0200, Richard Biener wrote:

>>>> On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely <jwakely@redhat.com>

>>>> wrote:

>>>>>

>>>>> On 06/08/20 06:16 +0100, Richard Sandiford wrote:

>>>>>> Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>>>>>>> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>>>>>>>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor

>>>>> <mjambor@suse.cz> wrote:

>>>>>>>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>>>>>>>> [...]

>>>>>>>>>

>>>>>>>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>>>>>>>>

>>>>>>>>>> We are using std::vec to ensure constructors are run, which they

>>>>>>>>> aren't

>>>>>>>>>> in our internal vec<> implementation.  Although we usually

>>>>> steer away

>>>>>>>>>> from using std::vec because of interactions with our GC system,

>>>>>>>>>> ipcp_param_lattices is only live within the pass and allocated

>>>>> with

>>>>>>>>> calloc.

>>>>>>>>> Ummm... I did not object but I will save the URL of this message

>>>>> in the

>>>>>>>>> archive so that I can waive it in front of anyone complaining why I

>>>>>>>>> don't use our internal vec's in IPA data structures.

>>>>>>>>>

>>>>>>>>> But it actually raises a broader question: was this supposed to

>>>>> be an

>>>>>>>>> exception, allowed only not to complicate the irange patch

>>>>> further, or

>>>>>>>>> will this be generally accepted thing to do when someone wants

>>>>> to have

>>>>>>>>> a

>>>>>>>>> vector of constructed items?

>>>>>>>> It's definitely not what we want. You have to find another

>>>>> solution to this problem.

>>>>>>>>

>>>>>>>> Richard.

>>>>>>>>

>>>>>>>

>>>>>>> Why isn't it what we want?

>>>>>>>

>>>>>>> This is a small vector local to the pass so it doesn't interfere with

>>>>>>> our PITA GTY.

>>>>>>> The class is pretty straightforward, but we do need a constructor to

>>>>>>> initialize the pointer and the max-size field.  There is no

>>>>> allocation

>>>>>>> done per element, so a small number of elements have a couple of

>>>>> fields

>>>>>>> initialized per element. We'd have to loop to do that anyway.

>>>>>>>

>>>>>>> GCC's vec<> does not provide he ability to run a constructor,

>>>>> std::vec

>>>>>>> does.

>>>>>>

>>>>>> I realise you weren't claiming otherwise, but: that could be fixed :-)

>>>>>

>>>>> It really should be.

>>>>>

>>>>> Artificial limitations like that are just a booby trap for the unwary.

>>>>

>>>> It's probably also historic because we couldn't even implement

>>>> the case of re-allocation correctly without std::move, could we?

>>>

>>> I don't see why not. std::vector worked fine without std::move, it's

>>> just more efficient with std::move, and can be used with a wider set

>>> of element types.

>>>

>>> When reallocating you can just copy each element to the new storage

>>> and destroy the old element. If your type is non-copyable then you

>>> need std::move, but I don't think the types I see used with vec<> are

>>> non-copyable. Most of them are trivially-copyable.

>>>

>>> I think the benefit of std::move to GCC is likely to be permitting

>>> cheap copies to be made where previously they were banned for

>>> performance reasons, but not because those copies were impossible.

>>

>> For the record, neither value_range nor int_range<N> require any

>> allocations.  The sub-range storage resides in the stack or wherever it

>> was defined.  However, it is definitely not a POD.

>>

>> Digging deeper, I notice that the original issue that caused us to use

>> std::vector was not in-place new but the safe_grow_cleared.  The

>> original code had:

>>

>>>        auto_vec<value_range, 32> known_value_ranges;

>>> ...

>>> ...

>>>        if (!vr.undefined_p () && !vr.varying_p ())

>>>            {

>>>              if (!known_value_ranges.length ())

>>>                known_value_ranges.safe_grow_cleared (count);

>>>                known_value_ranges[i] = vr;

>>>            }

>>

>> I would've gladly kept the auto_vec, had I been able to do call the

>> constructor by doing an in-place new:

>>

>>>                      if (!vr.undefined_p () && !vr.varying_p ())

>>>                        {

>>>                          if (!known_value_ranges.length ())

>>> -                         known_value_ranges.safe_grow_cleared (count);

>>> +                         {

>>> +                           known_value_ranges.safe_grow_cleared (count);

>>> +                           for (int i = 0; i < count; ++i)

>>> +                             new (&known_value_ranges[i]) value_range ();

> 

> With your placement new loop you should only need .safe_grow (count)

> which should then make it work(?)


Ah yes, no cleared is necessary as the in-place new would initialize the 
chunk.  But as discussed below, the compiler still barfs.

> 

>>> +                         }

>>>                          known_value_ranges[i] = vr;

>>>                        }

>>>                    }

>>

>> But alas, compiling yields:

>>

>>> In file included from /usr/include/wchar.h:35,

>>>                   from /usr/include/c++/10/cwchar:44,

>>>                   from /usr/include/c++/10/bits/postypes.h:40,

>>>                   from /usr/include/c++/10/iosfwd:40,

>>>                   from /usr/include/gmp-x86_64.h:34,

>>>                   from /usr/include/gmp.h:59,

>>>                   from /home/aldyh/src/gcc/gcc/system.h:687,

>>>                   from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

>>> /home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T = int_range<1>; A = va_heap; size_t = long unsigned int]’:

>>> /home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, bool) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

>>> /home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’ within non-standard-layout type ‘vec_embedded’ {aka ‘vec<int_range<1>, va_heap, vl_embed>’} is conditionally-supported [-Winvalid-offsetof]

>>>   1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>>>        |                    ^

>>

>> The attached patch reverts the functionality to auto_vec<>, but the

>> in-place new doesn't work.  Does anyone have any suggestions?

> 

> I'm not able to decipher the above but I wonder why we have vl_embed

> here.  Does the error vanish

> if you use auto_vec<value_range> instead of auto_vec<value_range, 32>

> here?  I guess the issue


No.

Aldy
Bill Schmidt via Gcc-patches Aug. 6, 2020, 4:30 p.m. | #20
On 06/08/20 16:17 +0200, Aldy Hernandez wrote:
>

>

>On 8/6/20 12:48 PM, Jonathan Wakely wrote:

>>On 06/08/20 12:31 +0200, Richard Biener wrote:

>>>On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely 

>>><jwakely@redhat.com> wrote:

>>>>

>>>>On 06/08/20 06:16 +0100, Richard Sandiford wrote:

>>>>>Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>>>>>> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>>>>>>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor 

>>>><mjambor@suse.cz> wrote:

>>>>>>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>>>>>>> [...]

>>>>>>>>

>>>>>>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>>>>>>>

>>>>>>>>> We are using std::vec to ensure constructors are run, which they

>>>>>>>> aren't

>>>>>>>>> in our internal vec<> implementation.  Although we usually 

>>>>steer away

>>>>>>>>> from using std::vec because of interactions with our GC system,

>>>>>>>>> ipcp_param_lattices is only live within the pass and 

>>>>allocated with

>>>>>>>> calloc.

>>>>>>>> Ummm... I did not object but I will save the URL of this 

>>>>message in the

>>>>>>>> archive so that I can waive it in front of anyone complaining why I

>>>>>>>> don't use our internal vec's in IPA data structures.

>>>>>>>>

>>>>>>>> But it actually raises a broader question: was this 

>>>>supposed to be an

>>>>>>>> exception, allowed only not to complicate the irange patch 

>>>>further, or

>>>>>>>> will this be generally accepted thing to do when someone 

>>>>wants to have

>>>>>>>> a

>>>>>>>> vector of constructed items?

>>>>>>> It's definitely not what we want. You have to find another 

>>>>solution to this problem.

>>>>>>>

>>>>>>> Richard.

>>>>>>>

>>>>>>

>>>>>> Why isn't it what we want?

>>>>>>

>>>>>> This is a small vector local to the pass so it doesn't interfere with

>>>>>> our PITA GTY.

>>>>>> The class is pretty straightforward, but we do need a constructor to

>>>>>> initialize the pointer and the max-size field.  There is no 

>>>>allocation

>>>>>> done per element, so a small number of elements have a couple 

>>>>of fields

>>>>>> initialized per element. We'd have to loop to do that anyway.

>>>>>>

>>>>>> GCC's vec<> does not provide he ability to run a constructor, 

>>>>std::vec

>>>>>> does.

>>>>>

>>>>>I realise you weren't claiming otherwise, but: that could be fixed :-)

>>>>

>>>>It really should be.

>>>>

>>>>Artificial limitations like that are just a booby trap for the unwary.

>>>

>>>It's probably also historic because we couldn't even implement

>>>the case of re-allocation correctly without std::move, could we?

>>

>>I don't see why not. std::vector worked fine without std::move, it's

>>just more efficient with std::move, and can be used with a wider set

>>of element types.

>>

>>When reallocating you can just copy each element to the new storage

>>and destroy the old element. If your type is non-copyable then you

>>need std::move, but I don't think the types I see used with vec<> are

>>non-copyable. Most of them are trivially-copyable.

>>

>>I think the benefit of std::move to GCC is likely to be permitting

>>cheap copies to be made where previously they were banned for

>>performance reasons, but not because those copies were impossible.

>

>For the record, neither value_range nor int_range<N> require any 

>allocations.  The sub-range storage resides in the stack or wherever 

>it was defined.  However, it is definitely not a POD.

>

>Digging deeper, I notice that the original issue that caused us to use 

>std::vector was not in-place new but the safe_grow_cleared.  The 

>original code had:

>

>>	auto_vec<value_range, 32> known_value_ranges;

>>...

>>...

>>	if (!vr.undefined_p () && !vr.varying_p ())

>>          {

>>            if (!known_value_ranges.length ())

>>              known_value_ranges.safe_grow_cleared (count);

>>              known_value_ranges[i] = vr;

>>          }

>

>I would've gladly kept the auto_vec, had I been able to do call the 

>constructor by doing an in-place new:

>

>>                    if (!vr.undefined_p () && !vr.varying_p ())

>>                      {

>>                        if (!known_value_ranges.length ())

>>-                         known_value_ranges.safe_grow_cleared (count);

>>+                         {

>>+                           known_value_ranges.safe_grow_cleared (count);

>>+                           for (int i = 0; i < count; ++i)

>>+                             new (&known_value_ranges[i]) value_range ();

>>+                         }

>>                        known_value_ranges[i] = vr;

>>                      }

>>                  }

>

>But alas, compiling yields:

>

>>In file included from /usr/include/wchar.h:35,

>>                 from /usr/include/c++/10/cwchar:44,

>>                 from /usr/include/c++/10/bits/postypes.h:40,

>>                 from /usr/include/c++/10/iosfwd:40,

>>                 from /usr/include/gmp-x86_64.h:34,

>>                 from /usr/include/gmp.h:59,

>>                 from /home/aldyh/src/gcc/gcc/system.h:687,

>>                 from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

>>/home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T = int_range<1>; A = va_heap; size_t = long unsigned int]’:

>>/home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, bool) [with T = int_range<1>]’

>>/home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

>>/home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

>>/home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

>>/home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

>>/home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

>>/home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’ within non-standard-layout type ‘vec_embedded’ {aka ‘vec<int_range<1>, va_heap, vl_embed>’} is conditionally-supported [-Winvalid-offsetof]

>> 1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>>      |                    ^


Can we just avoid using offsetof there?

Untested ...

--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -1281,8 +1281,8 @@ template<typename T, typename A>
  inline size_t
  vec<T, A, vl_embed>::embedded_size (unsigned alloc)
  {
-  typedef vec<T, A, vl_embed> vec_embedded;
-  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
+  size_t offset = (char*)&m_vecdata - (char*)this;
+  return offset + alloc * sizeof (T);
  }
Bill Schmidt via Gcc-patches Aug. 6, 2020, 5:58 p.m. | #21
On 8/6/20 6:30 PM, Jonathan Wakely wrote:
> On 06/08/20 16:17 +0200, Aldy Hernandez wrote:

>>

>>

>> On 8/6/20 12:48 PM, Jonathan Wakely wrote:

>>> On 06/08/20 12:31 +0200, Richard Biener wrote:

>>>> On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely <jwakely@redhat.com> 

>>>> wrote:

>>>>>

>>>>> On 06/08/20 06:16 +0100, Richard Sandiford wrote:

>>>>>> Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>>>>>>> On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>>>>>>>> On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor 

>>>>> <mjambor@suse.cz> wrote:

>>>>>>>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>>>>>>>> [...]

>>>>>>>>>

>>>>>>>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>>>>>>>>

>>>>>>>>>> We are using std::vec to ensure constructors are run, which they

>>>>>>>>> aren't

>>>>>>>>>> in our internal vec<> implementation.  Although we usually 

>>>>> steer away

>>>>>>>>>> from using std::vec because of interactions with our GC system,

>>>>>>>>>> ipcp_param_lattices is only live within the pass and 

>>>>> allocated with

>>>>>>>>> calloc.

>>>>>>>>> Ummm... I did not object but I will save the URL of this 

>>>>> message in the

>>>>>>>>> archive so that I can waive it in front of anyone complaining 

>>>>>>>>> why I

>>>>>>>>> don't use our internal vec's in IPA data structures.

>>>>>>>>>

>>>>>>>>> But it actually raises a broader question: was this 

>>>>> supposed to be an

>>>>>>>>> exception, allowed only not to complicate the irange patch 

>>>>> further, or

>>>>>>>>> will this be generally accepted thing to do when someone 

>>>>> wants to have

>>>>>>>>> a

>>>>>>>>> vector of constructed items?

>>>>>>>> It's definitely not what we want. You have to find another 

>>>>> solution to this problem.

>>>>>>>>

>>>>>>>> Richard.

>>>>>>>>

>>>>>>>

>>>>>>> Why isn't it what we want?

>>>>>>>

>>>>>>> This is a small vector local to the pass so it doesn't interfere 

>>>>>>> with

>>>>>>> our PITA GTY.

>>>>>>> The class is pretty straightforward, but we do need a constructor to

>>>>>>> initialize the pointer and the max-size field.  There is no 

>>>>> allocation

>>>>>>> done per element, so a small number of elements have a couple 

>>>>> of fields

>>>>>>> initialized per element. We'd have to loop to do that anyway.

>>>>>>>

>>>>>>> GCC's vec<> does not provide he ability to run a constructor, 

>>>>> std::vec

>>>>>>> does.

>>>>>>

>>>>>> I realise you weren't claiming otherwise, but: that could be fixed 

>>>>>> :-)

>>>>>

>>>>> It really should be.

>>>>>

>>>>> Artificial limitations like that are just a booby trap for the unwary.

>>>>

>>>> It's probably also historic because we couldn't even implement

>>>> the case of re-allocation correctly without std::move, could we?

>>>

>>> I don't see why not. std::vector worked fine without std::move, it's

>>> just more efficient with std::move, and can be used with a wider set

>>> of element types.

>>>

>>> When reallocating you can just copy each element to the new storage

>>> and destroy the old element. If your type is non-copyable then you

>>> need std::move, but I don't think the types I see used with vec<> are

>>> non-copyable. Most of them are trivially-copyable.

>>>

>>> I think the benefit of std::move to GCC is likely to be permitting

>>> cheap copies to be made where previously they were banned for

>>> performance reasons, but not because those copies were impossible.

>>

>> For the record, neither value_range nor int_range<N> require any 

>> allocations.  The sub-range storage resides in the stack or wherever 

>> it was defined.  However, it is definitely not a POD.

>>

>> Digging deeper, I notice that the original issue that caused us to use 

>> std::vector was not in-place new but the safe_grow_cleared.  The 

>> original code had:

>>

>>>     auto_vec<value_range, 32> known_value_ranges;

>>> ...

>>> ...

>>>     if (!vr.undefined_p () && !vr.varying_p ())

>>>          {

>>>            if (!known_value_ranges.length ())

>>>              known_value_ranges.safe_grow_cleared (count);

>>>              known_value_ranges[i] = vr;

>>>          }

>>

>> I would've gladly kept the auto_vec, had I been able to do call the 

>> constructor by doing an in-place new:

>>

>>>                    if (!vr.undefined_p () && !vr.varying_p ())

>>>                      {

>>>                        if (!known_value_ranges.length ())

>>> -                         known_value_ranges.safe_grow_cleared (count);

>>> +                         {

>>> +                           known_value_ranges.safe_grow_cleared 

>>> (count);

>>> +                           for (int i = 0; i < count; ++i)

>>> +                             new (&known_value_ranges[i]) 

>>> value_range ();

>>> +                         }

>>>                        known_value_ranges[i] = vr;

>>>                      }

>>>                  }

>>

>> But alas, compiling yields:

>>

>>> In file included from /usr/include/wchar.h:35,

>>>                 from /usr/include/c++/10/cwchar:44,

>>>                 from /usr/include/c++/10/bits/postypes.h:40,

>>>                 from /usr/include/c++/10/iosfwd:40,

>>>                 from /usr/include/gmp-x86_64.h:34,

>>>                 from /usr/include/gmp.h:59,

>>>                 from /home/aldyh/src/gcc/gcc/system.h:687,

>>>                 from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

>>> /home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static size_t 

>>> vec<T, A, vl_embed>::embedded_size(unsigned int) [with T = 

>>> int_range<1>; A = va_heap; size_t = long unsigned int]’:

>>> /home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static void 

>>> va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, bool) 

>>> [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool 

>>> vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool 

>>> vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void 

>>> vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void 

>>> vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

>>> /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

>>> /home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’ within 

>>> non-standard-layout type ‘vec_embedded’ {aka ‘vec<int_range<1>, 

>>> va_heap, vl_embed>’} is conditionally-supported [-Winvalid-offsetof]

>>> 1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>>>      |                    ^

> 

> Can we just avoid using offsetof there?

> 

> Untested ...

> 

> --- a/gcc/vec.h

> +++ b/gcc/vec.h

> @@ -1281,8 +1281,8 @@ template<typename T, typename A>

>   inline size_t

>   vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>   {

> -  typedef vec<T, A, vl_embed> vec_embedded;

> -  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> +  size_t offset = (char*)&m_vecdata - (char*)this;

> +  return offset + alloc * sizeof (T);

>   }

> 

> 


Now we have:

In file included from /home/aldyh/src/gcc/gcc/rtl.h:30,
                  from /home/aldyh/src/gcc/gcc/genpreds.c:27:
/home/aldyh/src/gcc/gcc/vec.h: In static member function ‘static size_t 
vec<T, A, vl_embed>::embedded_size(unsigned int)’:
/home/aldyh/src/gcc/gcc/vec.h:1284:27: error: invalid use of member 
‘vec<T, A, vl_embed>::m_vecdata’ in static member function
  1284 |   size_t offset = (char*)&m_vecdata - (char*)this;
       |                           ^~~~~~~~~
/home/aldyh/src/gcc/gcc/vec.h:626:5: note: declared here
   626 |   T m_vecdata[1];
       |     ^~~~~~~~~
/home/aldyh/src/gcc/gcc/vec.h:1284:46: error: ‘this’ is unavailable for 
static member functions
  1284 |   size_t offset = (char*)&m_vecdata - (char*)this;
       |                                              ^~~~
Bill Schmidt via Gcc-patches Aug. 6, 2020, 7:24 p.m. | #22
On 06/08/20 19:58 +0200, Aldy Hernandez wrote:
>

>

>On 8/6/20 6:30 PM, Jonathan Wakely wrote:

>>On 06/08/20 16:17 +0200, Aldy Hernandez wrote:

>>>

>>>

>>>On 8/6/20 12:48 PM, Jonathan Wakely wrote:

>>>>On 06/08/20 12:31 +0200, Richard Biener wrote:

>>>>>On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely 

>>>>><jwakely@redhat.com> wrote:

>>>>>>

>>>>>>On 06/08/20 06:16 +0100, Richard Sandiford wrote:

>>>>>>>Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>>>>>>>>On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>>>>>>>>>On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor

>>>>>><mjambor@suse.cz> wrote:

>>>>>>>>>>On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>>>>>>>>>[...]

>>>>>>>>>>

>>>>>>>>>>>* ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>>>>>>>>>

>>>>>>>>>>>We are using std::vec to ensure constructors are run, which they

>>>>>>>>>>aren't

>>>>>>>>>>>in our internal vec<> implementation.  Although we 

>>>>>>>>>>>usually

>>>>>>steer away

>>>>>>>>>>>from using std::vec because of interactions with our GC system,

>>>>>>>>>>>ipcp_param_lattices is only live within the pass 

>>>>>>>>>>>and

>>>>>>allocated with

>>>>>>>>>>calloc.

>>>>>>>>>>Ummm... I did not object but I will save the URL of 

>>>>>>>>>>this

>>>>>>message in the

>>>>>>>>>>archive so that I can waive it in front of anyone 

>>>>>>>>>>complaining why I

>>>>>>>>>>don't use our internal vec's in IPA data structures.

>>>>>>>>>>

>>>>>>>>>>But it actually raises a broader question: was this

>>>>>>supposed to be an

>>>>>>>>>>exception, allowed only not to complicate the irange 

>>>>>>>>>>patch

>>>>>>further, or

>>>>>>>>>>will this be generally accepted thing to do when 

>>>>>>>>>>someone

>>>>>>wants to have

>>>>>>>>>>a

>>>>>>>>>>vector of constructed items?

>>>>>>>>>It's definitely not what we want. You have to find 

>>>>>>>>>another

>>>>>>solution to this problem.

>>>>>>>>>

>>>>>>>>>Richard.

>>>>>>>>>

>>>>>>>>

>>>>>>>>Why isn't it what we want?

>>>>>>>>

>>>>>>>>This is a small vector local to the pass so it doesn't 

>>>>>>>>interfere with

>>>>>>>>our PITA GTY.

>>>>>>>>The class is pretty straightforward, but we do need a constructor to

>>>>>>>>initialize the pointer and the max-size field.  There is 

>>>>>>>>no

>>>>>>allocation

>>>>>>>>done per element, so a small number of elements have a 

>>>>>>>>couple

>>>>>>of fields

>>>>>>>>initialized per element. We'd have to loop to do that anyway.

>>>>>>>>

>>>>>>>>GCC's vec<> does not provide he ability to run a 

>>>>>>>>constructor,

>>>>>>std::vec

>>>>>>>>does.

>>>>>>>

>>>>>>>I realise you weren't claiming otherwise, but: that could 

>>>>>>>be fixed :-)

>>>>>>

>>>>>>It really should be.

>>>>>>

>>>>>>Artificial limitations like that are just a booby trap for the unwary.

>>>>>

>>>>>It's probably also historic because we couldn't even implement

>>>>>the case of re-allocation correctly without std::move, could we?

>>>>

>>>>I don't see why not. std::vector worked fine without std::move, it's

>>>>just more efficient with std::move, and can be used with a wider set

>>>>of element types.

>>>>

>>>>When reallocating you can just copy each element to the new storage

>>>>and destroy the old element. If your type is non-copyable then you

>>>>need std::move, but I don't think the types I see used with vec<> are

>>>>non-copyable. Most of them are trivially-copyable.

>>>>

>>>>I think the benefit of std::move to GCC is likely to be permitting

>>>>cheap copies to be made where previously they were banned for

>>>>performance reasons, but not because those copies were impossible.

>>>

>>>For the record, neither value_range nor int_range<N> require any 

>>>allocations.  The sub-range storage resides in the stack or 

>>>wherever it was defined.  However, it is definitely not a POD.

>>>

>>>Digging deeper, I notice that the original issue that caused us to 

>>>use std::vector was not in-place new but the safe_grow_cleared.  

>>>The original code had:

>>>

>>>>    auto_vec<value_range, 32> known_value_ranges;

>>>>...

>>>>...

>>>>    if (!vr.undefined_p () && !vr.varying_p ())

>>>>         {

>>>>           if (!known_value_ranges.length ())

>>>>             known_value_ranges.safe_grow_cleared (count);

>>>>             known_value_ranges[i] = vr;

>>>>         }

>>>

>>>I would've gladly kept the auto_vec, had I been able to do call 

>>>the constructor by doing an in-place new:

>>>

>>>>                   if (!vr.undefined_p () && !vr.varying_p ())

>>>>                     {

>>>>                       if (!known_value_ranges.length ())

>>>>-                         known_value_ranges.safe_grow_cleared (count);

>>>>+                         {

>>>>+                           known_value_ranges.safe_grow_cleared 

>>>>(count);

>>>>+                           for (int i = 0; i < count; ++i)

>>>>+                             new (&known_value_ranges[i]) 

>>>>value_range ();

>>>>+                         }

>>>>                       known_value_ranges[i] = vr;

>>>>                     }

>>>>                 }

>>>

>>>But alas, compiling yields:

>>>

>>>>In file included from /usr/include/wchar.h:35,

>>>>                from /usr/include/c++/10/cwchar:44,

>>>>                from /usr/include/c++/10/bits/postypes.h:40,

>>>>                from /usr/include/c++/10/iosfwd:40,

>>>>                from /usr/include/gmp-x86_64.h:34,

>>>>                from /usr/include/gmp.h:59,

>>>>                from /home/aldyh/src/gcc/gcc/system.h:687,

>>>>                from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

>>>>/home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static 

>>>>size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T 

>>>>= int_range<1>; A = va_heap; size_t = long unsigned int]’:

>>>>/home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static 

>>>>void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, 

>>>>bool) [with T = int_range<1>]’

>>>>/home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool 

>>>>vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

>>>>/home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool 

>>>>vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

>>>>/home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void 

>>>>vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

>>>>/home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void 

>>>>vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

>>>>/home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

>>>>/home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’ 

>>>>within non-standard-layout type ‘vec_embedded’ {aka 

>>>>‘vec<int_range<1>, va_heap, vl_embed>’} is 

>>>>conditionally-supported [-Winvalid-offsetof]

>>>>1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>>>>     |                    ^

>>

>>Can we just avoid using offsetof there?

>>

>>Untested ...

>>

>>--- a/gcc/vec.h

>>+++ b/gcc/vec.h

>>@@ -1281,8 +1281,8 @@ template<typename T, typename A>

>>  inline size_t

>>  vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>>  {

>>-  typedef vec<T, A, vl_embed> vec_embedded;

>>-  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>>+  size_t offset = (char*)&m_vecdata - (char*)this;

>>+  return offset + alloc * sizeof (T);

>>  }

>>

>>

>

>Now we have:

>

>In file included from /home/aldyh/src/gcc/gcc/rtl.h:30,

>                 from /home/aldyh/src/gcc/gcc/genpreds.c:27:

>/home/aldyh/src/gcc/gcc/vec.h: In static member function ‘static 

>size_t vec<T, A, vl_embed>::embedded_size(unsigned int)’:

>/home/aldyh/src/gcc/gcc/vec.h:1284:27: error: invalid use of member 

>‘vec<T, A, vl_embed>::m_vecdata’ in static member function

> 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

>      |                           ^~~~~~~~~

>/home/aldyh/src/gcc/gcc/vec.h:626:5: note: declared here

>  626 |   T m_vecdata[1];

>      |     ^~~~~~~~~

>/home/aldyh/src/gcc/gcc/vec.h:1284:46: error: ‘this’ is unavailable 

>for static member functions

> 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

>      |                                              ^~~~

>

>


Oh sorry, I didn't realise it was static.
Bill Schmidt via Gcc-patches Aug. 7, 2020, 6:48 a.m. | #23
On Thu, Aug 6, 2020 at 9:24 PM Jonathan Wakely <jwakely@redhat.com> wrote:
>

> On 06/08/20 19:58 +0200, Aldy Hernandez wrote:

> >

> >

> >On 8/6/20 6:30 PM, Jonathan Wakely wrote:

> >>On 06/08/20 16:17 +0200, Aldy Hernandez wrote:

> >>>

> >>>

> >>>On 8/6/20 12:48 PM, Jonathan Wakely wrote:

> >>>>On 06/08/20 12:31 +0200, Richard Biener wrote:

> >>>>>On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely

> >>>>><jwakely@redhat.com> wrote:

> >>>>>>

> >>>>>>On 06/08/20 06:16 +0100, Richard Sandiford wrote:

> >>>>>>>Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

> >>>>>>>>On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

> >>>>>>>>>On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor

> >>>>>><mjambor@suse.cz> wrote:

> >>>>>>>>>>On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

> >>>>>>>>>>[...]

> >>>>>>>>>>

> >>>>>>>>>>>* ipa-cp changes from vec<value_range> to std::vec<value_range>.

> >>>>>>>>>>>

> >>>>>>>>>>>We are using std::vec to ensure constructors are run, which they

> >>>>>>>>>>aren't

> >>>>>>>>>>>in our internal vec<> implementation.  Although we

> >>>>>>>>>>>usually

> >>>>>>steer away

> >>>>>>>>>>>from using std::vec because of interactions with our GC system,

> >>>>>>>>>>>ipcp_param_lattices is only live within the pass

> >>>>>>>>>>>and

> >>>>>>allocated with

> >>>>>>>>>>calloc.

> >>>>>>>>>>Ummm... I did not object but I will save the URL of

> >>>>>>>>>>this

> >>>>>>message in the

> >>>>>>>>>>archive so that I can waive it in front of anyone

> >>>>>>>>>>complaining why I

> >>>>>>>>>>don't use our internal vec's in IPA data structures.

> >>>>>>>>>>

> >>>>>>>>>>But it actually raises a broader question: was this

> >>>>>>supposed to be an

> >>>>>>>>>>exception, allowed only not to complicate the irange

> >>>>>>>>>>patch

> >>>>>>further, or

> >>>>>>>>>>will this be generally accepted thing to do when

> >>>>>>>>>>someone

> >>>>>>wants to have

> >>>>>>>>>>a

> >>>>>>>>>>vector of constructed items?

> >>>>>>>>>It's definitely not what we want. You have to find

> >>>>>>>>>another

> >>>>>>solution to this problem.

> >>>>>>>>>

> >>>>>>>>>Richard.

> >>>>>>>>>

> >>>>>>>>

> >>>>>>>>Why isn't it what we want?

> >>>>>>>>

> >>>>>>>>This is a small vector local to the pass so it doesn't

> >>>>>>>>interfere with

> >>>>>>>>our PITA GTY.

> >>>>>>>>The class is pretty straightforward, but we do need a constructor to

> >>>>>>>>initialize the pointer and the max-size field.  There is

> >>>>>>>>no

> >>>>>>allocation

> >>>>>>>>done per element, so a small number of elements have a

> >>>>>>>>couple

> >>>>>>of fields

> >>>>>>>>initialized per element. We'd have to loop to do that anyway.

> >>>>>>>>

> >>>>>>>>GCC's vec<> does not provide he ability to run a

> >>>>>>>>constructor,

> >>>>>>std::vec

> >>>>>>>>does.

> >>>>>>>

> >>>>>>>I realise you weren't claiming otherwise, but: that could

> >>>>>>>be fixed :-)

> >>>>>>

> >>>>>>It really should be.

> >>>>>>

> >>>>>>Artificial limitations like that are just a booby trap for the unwary.

> >>>>>

> >>>>>It's probably also historic because we couldn't even implement

> >>>>>the case of re-allocation correctly without std::move, could we?

> >>>>

> >>>>I don't see why not. std::vector worked fine without std::move, it's

> >>>>just more efficient with std::move, and can be used with a wider set

> >>>>of element types.

> >>>>

> >>>>When reallocating you can just copy each element to the new storage

> >>>>and destroy the old element. If your type is non-copyable then you

> >>>>need std::move, but I don't think the types I see used with vec<> are

> >>>>non-copyable. Most of them are trivially-copyable.

> >>>>

> >>>>I think the benefit of std::move to GCC is likely to be permitting

> >>>>cheap copies to be made where previously they were banned for

> >>>>performance reasons, but not because those copies were impossible.

> >>>

> >>>For the record, neither value_range nor int_range<N> require any

> >>>allocations.  The sub-range storage resides in the stack or

> >>>wherever it was defined.  However, it is definitely not a POD.

> >>>

> >>>Digging deeper, I notice that the original issue that caused us to

> >>>use std::vector was not in-place new but the safe_grow_cleared.

> >>>The original code had:

> >>>

> >>>>    auto_vec<value_range, 32> known_value_ranges;

> >>>>...

> >>>>...

> >>>>    if (!vr.undefined_p () && !vr.varying_p ())

> >>>>         {

> >>>>           if (!known_value_ranges.length ())

> >>>>             known_value_ranges.safe_grow_cleared (count);

> >>>>             known_value_ranges[i] = vr;

> >>>>         }

> >>>

> >>>I would've gladly kept the auto_vec, had I been able to do call

> >>>the constructor by doing an in-place new:

> >>>

> >>>>                   if (!vr.undefined_p () && !vr.varying_p ())

> >>>>                     {

> >>>>                       if (!known_value_ranges.length ())

> >>>>-                         known_value_ranges.safe_grow_cleared (count);

> >>>>+                         {

> >>>>+                           known_value_ranges.safe_grow_cleared

> >>>>(count);

> >>>>+                           for (int i = 0; i < count; ++i)

> >>>>+                             new (&known_value_ranges[i])

> >>>>value_range ();

> >>>>+                         }

> >>>>                       known_value_ranges[i] = vr;

> >>>>                     }

> >>>>                 }

> >>>

> >>>But alas, compiling yields:

> >>>

> >>>>In file included from /usr/include/wchar.h:35,

> >>>>                from /usr/include/c++/10/cwchar:44,

> >>>>                from /usr/include/c++/10/bits/postypes.h:40,

> >>>>                from /usr/include/c++/10/iosfwd:40,

> >>>>                from /usr/include/gmp-x86_64.h:34,

> >>>>                from /usr/include/gmp.h:59,

> >>>>                from /home/aldyh/src/gcc/gcc/system.h:687,

> >>>>                from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

> >>>>/home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static

> >>>>size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T

> >>>>= int_range<1>; A = va_heap; size_t = long unsigned int]’:

> >>>>/home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static

> >>>>void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int,

> >>>>bool) [with T = int_range<1>]’

> >>>>/home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool

> >>>>vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

> >>>>/home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool

> >>>>vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

> >>>>/home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void

> >>>>vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

> >>>>/home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void

> >>>>vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

> >>>>/home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

> >>>>/home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’

> >>>>within non-standard-layout type ‘vec_embedded’ {aka

> >>>>‘vec<int_range<1>, va_heap, vl_embed>’} is

> >>>>conditionally-supported [-Winvalid-offsetof]

> >>>>1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >>>>     |                    ^

> >>

> >>Can we just avoid using offsetof there?

> >>

> >>Untested ...

> >>

> >>--- a/gcc/vec.h

> >>+++ b/gcc/vec.h

> >>@@ -1281,8 +1281,8 @@ template<typename T, typename A>

> >>  inline size_t

> >>  vec<T, A, vl_embed>::embedded_size (unsigned alloc)

> >>  {

> >>-  typedef vec<T, A, vl_embed> vec_embedded;

> >>-  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >>+  size_t offset = (char*)&m_vecdata - (char*)this;

> >>+  return offset + alloc * sizeof (T);

> >>  }

> >>

> >>

> >

> >Now we have:

> >

> >In file included from /home/aldyh/src/gcc/gcc/rtl.h:30,

> >                 from /home/aldyh/src/gcc/gcc/genpreds.c:27:

> >/home/aldyh/src/gcc/gcc/vec.h: In static member function ‘static

> >size_t vec<T, A, vl_embed>::embedded_size(unsigned int)’:

> >/home/aldyh/src/gcc/gcc/vec.h:1284:27: error: invalid use of member

> >‘vec<T, A, vl_embed>::m_vecdata’ in static member function

> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

> >      |                           ^~~~~~~~~

> >/home/aldyh/src/gcc/gcc/vec.h:626:5: note: declared here

> >  626 |   T m_vecdata[1];

> >      |     ^~~~~~~~~

> >/home/aldyh/src/gcc/gcc/vec.h:1284:46: error: ‘this’ is unavailable

> >for static member functions

> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

> >      |                                              ^~~~

> >

> >

>

> Oh sorry, I didn't realise it was static.


Yeah, we eventually have no object when we need the offset.  Does
offsetof refusing to operate on this mean that using a temporary
object on the stack like the following can yield a different answer
from the "real" object?  I guess examples where it breaks boil
down to virtual inheritance.  Anyway, so the following _should_ work ...

template<typename T, typename A>
inline size_t
vec<T, A, vl_embed>::embedded_size (unsigned alloc)
{
  typedef vec<T, A, vl_embed> vec_embedded;
  vec_embedded tem;
  return (char *)&tem.m_vecdata - (char *)&tem + alloc * sizeof (T);
}

?
Bill Schmidt via Gcc-patches Aug. 7, 2020, 7:57 a.m. | #24
On 07/08/20 08:48 +0200, Richard Biener wrote:
>On Thu, Aug 6, 2020 at 9:24 PM Jonathan Wakely <jwakely@redhat.com> wrote:

>>

>> On 06/08/20 19:58 +0200, Aldy Hernandez wrote:

>> >

>> >

>> >On 8/6/20 6:30 PM, Jonathan Wakely wrote:

>> >>On 06/08/20 16:17 +0200, Aldy Hernandez wrote:

>> >>>

>> >>>

>> >>>On 8/6/20 12:48 PM, Jonathan Wakely wrote:

>> >>>>On 06/08/20 12:31 +0200, Richard Biener wrote:

>> >>>>>On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely

>> >>>>><jwakely@redhat.com> wrote:

>> >>>>>>

>> >>>>>>On 06/08/20 06:16 +0100, Richard Sandiford wrote:

>> >>>>>>>Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>> >>>>>>>>On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>> >>>>>>>>>On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor

>> >>>>>><mjambor@suse.cz> wrote:

>> >>>>>>>>>>On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>> >>>>>>>>>>[...]

>> >>>>>>>>>>

>> >>>>>>>>>>>* ipa-cp changes from vec<value_range> to std::vec<value_range>.

>> >>>>>>>>>>>

>> >>>>>>>>>>>We are using std::vec to ensure constructors are run, which they

>> >>>>>>>>>>aren't

>> >>>>>>>>>>>in our internal vec<> implementation.  Although we

>> >>>>>>>>>>>usually

>> >>>>>>steer away

>> >>>>>>>>>>>from using std::vec because of interactions with our GC system,

>> >>>>>>>>>>>ipcp_param_lattices is only live within the pass

>> >>>>>>>>>>>and

>> >>>>>>allocated with

>> >>>>>>>>>>calloc.

>> >>>>>>>>>>Ummm... I did not object but I will save the URL of

>> >>>>>>>>>>this

>> >>>>>>message in the

>> >>>>>>>>>>archive so that I can waive it in front of anyone

>> >>>>>>>>>>complaining why I

>> >>>>>>>>>>don't use our internal vec's in IPA data structures.

>> >>>>>>>>>>

>> >>>>>>>>>>But it actually raises a broader question: was this

>> >>>>>>supposed to be an

>> >>>>>>>>>>exception, allowed only not to complicate the irange

>> >>>>>>>>>>patch

>> >>>>>>further, or

>> >>>>>>>>>>will this be generally accepted thing to do when

>> >>>>>>>>>>someone

>> >>>>>>wants to have

>> >>>>>>>>>>a

>> >>>>>>>>>>vector of constructed items?

>> >>>>>>>>>It's definitely not what we want. You have to find

>> >>>>>>>>>another

>> >>>>>>solution to this problem.

>> >>>>>>>>>

>> >>>>>>>>>Richard.

>> >>>>>>>>>

>> >>>>>>>>

>> >>>>>>>>Why isn't it what we want?

>> >>>>>>>>

>> >>>>>>>>This is a small vector local to the pass so it doesn't

>> >>>>>>>>interfere with

>> >>>>>>>>our PITA GTY.

>> >>>>>>>>The class is pretty straightforward, but we do need a constructor to

>> >>>>>>>>initialize the pointer and the max-size field.  There is

>> >>>>>>>>no

>> >>>>>>allocation

>> >>>>>>>>done per element, so a small number of elements have a

>> >>>>>>>>couple

>> >>>>>>of fields

>> >>>>>>>>initialized per element. We'd have to loop to do that anyway.

>> >>>>>>>>

>> >>>>>>>>GCC's vec<> does not provide he ability to run a

>> >>>>>>>>constructor,

>> >>>>>>std::vec

>> >>>>>>>>does.

>> >>>>>>>

>> >>>>>>>I realise you weren't claiming otherwise, but: that could

>> >>>>>>>be fixed :-)

>> >>>>>>

>> >>>>>>It really should be.

>> >>>>>>

>> >>>>>>Artificial limitations like that are just a booby trap for the unwary.

>> >>>>>

>> >>>>>It's probably also historic because we couldn't even implement

>> >>>>>the case of re-allocation correctly without std::move, could we?

>> >>>>

>> >>>>I don't see why not. std::vector worked fine without std::move, it's

>> >>>>just more efficient with std::move, and can be used with a wider set

>> >>>>of element types.

>> >>>>

>> >>>>When reallocating you can just copy each element to the new storage

>> >>>>and destroy the old element. If your type is non-copyable then you

>> >>>>need std::move, but I don't think the types I see used with vec<> are

>> >>>>non-copyable. Most of them are trivially-copyable.

>> >>>>

>> >>>>I think the benefit of std::move to GCC is likely to be permitting

>> >>>>cheap copies to be made where previously they were banned for

>> >>>>performance reasons, but not because those copies were impossible.

>> >>>

>> >>>For the record, neither value_range nor int_range<N> require any

>> >>>allocations.  The sub-range storage resides in the stack or

>> >>>wherever it was defined.  However, it is definitely not a POD.

>> >>>

>> >>>Digging deeper, I notice that the original issue that caused us to

>> >>>use std::vector was not in-place new but the safe_grow_cleared.

>> >>>The original code had:

>> >>>

>> >>>>    auto_vec<value_range, 32> known_value_ranges;

>> >>>>...

>> >>>>...

>> >>>>    if (!vr.undefined_p () && !vr.varying_p ())

>> >>>>         {

>> >>>>           if (!known_value_ranges.length ())

>> >>>>             known_value_ranges.safe_grow_cleared (count);

>> >>>>             known_value_ranges[i] = vr;

>> >>>>         }

>> >>>

>> >>>I would've gladly kept the auto_vec, had I been able to do call

>> >>>the constructor by doing an in-place new:

>> >>>

>> >>>>                   if (!vr.undefined_p () && !vr.varying_p ())

>> >>>>                     {

>> >>>>                       if (!known_value_ranges.length ())

>> >>>>-                         known_value_ranges.safe_grow_cleared (count);

>> >>>>+                         {

>> >>>>+                           known_value_ranges.safe_grow_cleared

>> >>>>(count);

>> >>>>+                           for (int i = 0; i < count; ++i)

>> >>>>+                             new (&known_value_ranges[i])

>> >>>>value_range ();

>> >>>>+                         }

>> >>>>                       known_value_ranges[i] = vr;

>> >>>>                     }

>> >>>>                 }

>> >>>

>> >>>But alas, compiling yields:

>> >>>

>> >>>>In file included from /usr/include/wchar.h:35,

>> >>>>                from /usr/include/c++/10/cwchar:44,

>> >>>>                from /usr/include/c++/10/bits/postypes.h:40,

>> >>>>                from /usr/include/c++/10/iosfwd:40,

>> >>>>                from /usr/include/gmp-x86_64.h:34,

>> >>>>                from /usr/include/gmp.h:59,

>> >>>>                from /home/aldyh/src/gcc/gcc/system.h:687,

>> >>>>                from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

>> >>>>/home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static

>> >>>>size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T

>> >>>>= int_range<1>; A = va_heap; size_t = long unsigned int]’:

>> >>>>/home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static

>> >>>>void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int,

>> >>>>bool) [with T = int_range<1>]’

>> >>>>/home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool

>> >>>>vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

>> >>>>/home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool

>> >>>>vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

>> >>>>/home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void

>> >>>>vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

>> >>>>/home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void

>> >>>>vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

>> >>>>/home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

>> >>>>/home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’

>> >>>>within non-standard-layout type ‘vec_embedded’ {aka

>> >>>>‘vec<int_range<1>, va_heap, vl_embed>’} is

>> >>>>conditionally-supported [-Winvalid-offsetof]

>> >>>>1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>> >>>>     |                    ^

>> >>

>> >>Can we just avoid using offsetof there?

>> >>

>> >>Untested ...

>> >>

>> >>--- a/gcc/vec.h

>> >>+++ b/gcc/vec.h

>> >>@@ -1281,8 +1281,8 @@ template<typename T, typename A>

>> >>  inline size_t

>> >>  vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>> >>  {

>> >>-  typedef vec<T, A, vl_embed> vec_embedded;

>> >>-  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>> >>+  size_t offset = (char*)&m_vecdata - (char*)this;

>> >>+  return offset + alloc * sizeof (T);

>> >>  }

>> >>

>> >>

>> >

>> >Now we have:

>> >

>> >In file included from /home/aldyh/src/gcc/gcc/rtl.h:30,

>> >                 from /home/aldyh/src/gcc/gcc/genpreds.c:27:

>> >/home/aldyh/src/gcc/gcc/vec.h: In static member function ‘static

>> >size_t vec<T, A, vl_embed>::embedded_size(unsigned int)’:

>> >/home/aldyh/src/gcc/gcc/vec.h:1284:27: error: invalid use of member

>> >‘vec<T, A, vl_embed>::m_vecdata’ in static member function

>> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

>> >      |                           ^~~~~~~~~

>> >/home/aldyh/src/gcc/gcc/vec.h:626:5: note: declared here

>> >  626 |   T m_vecdata[1];

>> >      |     ^~~~~~~~~

>> >/home/aldyh/src/gcc/gcc/vec.h:1284:46: error: ‘this’ is unavailable

>> >for static member functions

>> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

>> >      |                                              ^~~~

>> >

>> >

>>

>> Oh sorry, I didn't realise it was static.

>

>Yeah, we eventually have no object when we need the offset.  Does

>offsetof refusing to operate on this mean that using a temporary

>object on the stack like the following can yield a different answer

>from the "real" object?  I guess examples where it breaks boil

>down to virtual inheritance.  Anyway, so the following _should_ work ...

>

>template<typename T, typename A>

>inline size_t

>vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>{

>  typedef vec<T, A, vl_embed> vec_embedded;


This typedef is redundant, the name 'vec' in thos scope refers to the
current instantiation, so you can just say 'vec'.

>  vec_embedded tem;


i.e. 'vec tem;' here, and remove the typedef on the previous line.

>  return (char *)&tem.m_vecdata - (char *)&tem + alloc * sizeof (T);

>}

>

>?


Yes, that should work fine. In general you wouldn't want to create an
object just to do this, but creating and destroying a vec has no side
effects so is fine.
Bill Schmidt via Gcc-patches Aug. 7, 2020, 8:22 a.m. | #25
On Fri, Aug 7, 2020 at 9:57 AM Jonathan Wakely <jwakely@redhat.com> wrote:
>

> On 07/08/20 08:48 +0200, Richard Biener wrote:

> >On Thu, Aug 6, 2020 at 9:24 PM Jonathan Wakely <jwakely@redhat.com> wrote:

> >>

> >> On 06/08/20 19:58 +0200, Aldy Hernandez wrote:

> >> >

> >> >

> >> >On 8/6/20 6:30 PM, Jonathan Wakely wrote:

> >> >>On 06/08/20 16:17 +0200, Aldy Hernandez wrote:

> >> >>>

> >> >>>

> >> >>>On 8/6/20 12:48 PM, Jonathan Wakely wrote:

> >> >>>>On 06/08/20 12:31 +0200, Richard Biener wrote:

> >> >>>>>On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely

> >> >>>>><jwakely@redhat.com> wrote:

> >> >>>>>>

> >> >>>>>>On 06/08/20 06:16 +0100, Richard Sandiford wrote:

> >> >>>>>>>Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

> >> >>>>>>>>On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

> >> >>>>>>>>>On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor

> >> >>>>>><mjambor@suse.cz> wrote:

> >> >>>>>>>>>>On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

> >> >>>>>>>>>>[...]

> >> >>>>>>>>>>

> >> >>>>>>>>>>>* ipa-cp changes from vec<value_range> to std::vec<value_range>.

> >> >>>>>>>>>>>

> >> >>>>>>>>>>>We are using std::vec to ensure constructors are run, which they

> >> >>>>>>>>>>aren't

> >> >>>>>>>>>>>in our internal vec<> implementation.  Although we

> >> >>>>>>>>>>>usually

> >> >>>>>>steer away

> >> >>>>>>>>>>>from using std::vec because of interactions with our GC system,

> >> >>>>>>>>>>>ipcp_param_lattices is only live within the pass

> >> >>>>>>>>>>>and

> >> >>>>>>allocated with

> >> >>>>>>>>>>calloc.

> >> >>>>>>>>>>Ummm... I did not object but I will save the URL of

> >> >>>>>>>>>>this

> >> >>>>>>message in the

> >> >>>>>>>>>>archive so that I can waive it in front of anyone

> >> >>>>>>>>>>complaining why I

> >> >>>>>>>>>>don't use our internal vec's in IPA data structures.

> >> >>>>>>>>>>

> >> >>>>>>>>>>But it actually raises a broader question: was this

> >> >>>>>>supposed to be an

> >> >>>>>>>>>>exception, allowed only not to complicate the irange

> >> >>>>>>>>>>patch

> >> >>>>>>further, or

> >> >>>>>>>>>>will this be generally accepted thing to do when

> >> >>>>>>>>>>someone

> >> >>>>>>wants to have

> >> >>>>>>>>>>a

> >> >>>>>>>>>>vector of constructed items?

> >> >>>>>>>>>It's definitely not what we want. You have to find

> >> >>>>>>>>>another

> >> >>>>>>solution to this problem.

> >> >>>>>>>>>

> >> >>>>>>>>>Richard.

> >> >>>>>>>>>

> >> >>>>>>>>

> >> >>>>>>>>Why isn't it what we want?

> >> >>>>>>>>

> >> >>>>>>>>This is a small vector local to the pass so it doesn't

> >> >>>>>>>>interfere with

> >> >>>>>>>>our PITA GTY.

> >> >>>>>>>>The class is pretty straightforward, but we do need a constructor to

> >> >>>>>>>>initialize the pointer and the max-size field.  There is

> >> >>>>>>>>no

> >> >>>>>>allocation

> >> >>>>>>>>done per element, so a small number of elements have a

> >> >>>>>>>>couple

> >> >>>>>>of fields

> >> >>>>>>>>initialized per element. We'd have to loop to do that anyway.

> >> >>>>>>>>

> >> >>>>>>>>GCC's vec<> does not provide he ability to run a

> >> >>>>>>>>constructor,

> >> >>>>>>std::vec

> >> >>>>>>>>does.

> >> >>>>>>>

> >> >>>>>>>I realise you weren't claiming otherwise, but: that could

> >> >>>>>>>be fixed :-)

> >> >>>>>>

> >> >>>>>>It really should be.

> >> >>>>>>

> >> >>>>>>Artificial limitations like that are just a booby trap for the unwary.

> >> >>>>>

> >> >>>>>It's probably also historic because we couldn't even implement

> >> >>>>>the case of re-allocation correctly without std::move, could we?

> >> >>>>

> >> >>>>I don't see why not. std::vector worked fine without std::move, it's

> >> >>>>just more efficient with std::move, and can be used with a wider set

> >> >>>>of element types.

> >> >>>>

> >> >>>>When reallocating you can just copy each element to the new storage

> >> >>>>and destroy the old element. If your type is non-copyable then you

> >> >>>>need std::move, but I don't think the types I see used with vec<> are

> >> >>>>non-copyable. Most of them are trivially-copyable.

> >> >>>>

> >> >>>>I think the benefit of std::move to GCC is likely to be permitting

> >> >>>>cheap copies to be made where previously they were banned for

> >> >>>>performance reasons, but not because those copies were impossible.

> >> >>>

> >> >>>For the record, neither value_range nor int_range<N> require any

> >> >>>allocations.  The sub-range storage resides in the stack or

> >> >>>wherever it was defined.  However, it is definitely not a POD.

> >> >>>

> >> >>>Digging deeper, I notice that the original issue that caused us to

> >> >>>use std::vector was not in-place new but the safe_grow_cleared.

> >> >>>The original code had:

> >> >>>

> >> >>>>    auto_vec<value_range, 32> known_value_ranges;

> >> >>>>...

> >> >>>>...

> >> >>>>    if (!vr.undefined_p () && !vr.varying_p ())

> >> >>>>         {

> >> >>>>           if (!known_value_ranges.length ())

> >> >>>>             known_value_ranges.safe_grow_cleared (count);

> >> >>>>             known_value_ranges[i] = vr;

> >> >>>>         }

> >> >>>

> >> >>>I would've gladly kept the auto_vec, had I been able to do call

> >> >>>the constructor by doing an in-place new:

> >> >>>

> >> >>>>                   if (!vr.undefined_p () && !vr.varying_p ())

> >> >>>>                     {

> >> >>>>                       if (!known_value_ranges.length ())

> >> >>>>-                         known_value_ranges.safe_grow_cleared (count);

> >> >>>>+                         {

> >> >>>>+                           known_value_ranges.safe_grow_cleared

> >> >>>>(count);

> >> >>>>+                           for (int i = 0; i < count; ++i)

> >> >>>>+                             new (&known_value_ranges[i])

> >> >>>>value_range ();

> >> >>>>+                         }

> >> >>>>                       known_value_ranges[i] = vr;

> >> >>>>                     }

> >> >>>>                 }

> >> >>>

> >> >>>But alas, compiling yields:

> >> >>>

> >> >>>>In file included from /usr/include/wchar.h:35,

> >> >>>>                from /usr/include/c++/10/cwchar:44,

> >> >>>>                from /usr/include/c++/10/bits/postypes.h:40,

> >> >>>>                from /usr/include/c++/10/iosfwd:40,

> >> >>>>                from /usr/include/gmp-x86_64.h:34,

> >> >>>>                from /usr/include/gmp.h:59,

> >> >>>>                from /home/aldyh/src/gcc/gcc/system.h:687,

> >> >>>>                from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

> >> >>>>/home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static

> >> >>>>size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T

> >> >>>>= int_range<1>; A = va_heap; size_t = long unsigned int]’:

> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static

> >> >>>>void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int,

> >> >>>>bool) [with T = int_range<1>]’

> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool

> >> >>>>vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool

> >> >>>>vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void

> >> >>>>vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void

> >> >>>>vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

> >> >>>>/home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’

> >> >>>>within non-standard-layout type ‘vec_embedded’ {aka

> >> >>>>‘vec<int_range<1>, va_heap, vl_embed>’} is

> >> >>>>conditionally-supported [-Winvalid-offsetof]

> >> >>>>1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >> >>>>     |                    ^

> >> >>

> >> >>Can we just avoid using offsetof there?

> >> >>

> >> >>Untested ...

> >> >>

> >> >>--- a/gcc/vec.h

> >> >>+++ b/gcc/vec.h

> >> >>@@ -1281,8 +1281,8 @@ template<typename T, typename A>

> >> >>  inline size_t

> >> >>  vec<T, A, vl_embed>::embedded_size (unsigned alloc)

> >> >>  {

> >> >>-  typedef vec<T, A, vl_embed> vec_embedded;

> >> >>-  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >> >>+  size_t offset = (char*)&m_vecdata - (char*)this;

> >> >>+  return offset + alloc * sizeof (T);

> >> >>  }

> >> >>

> >> >>

> >> >

> >> >Now we have:

> >> >

> >> >In file included from /home/aldyh/src/gcc/gcc/rtl.h:30,

> >> >                 from /home/aldyh/src/gcc/gcc/genpreds.c:27:

> >> >/home/aldyh/src/gcc/gcc/vec.h: In static member function ‘static

> >> >size_t vec<T, A, vl_embed>::embedded_size(unsigned int)’:

> >> >/home/aldyh/src/gcc/gcc/vec.h:1284:27: error: invalid use of member

> >> >‘vec<T, A, vl_embed>::m_vecdata’ in static member function

> >> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

> >> >      |                           ^~~~~~~~~

> >> >/home/aldyh/src/gcc/gcc/vec.h:626:5: note: declared here

> >> >  626 |   T m_vecdata[1];

> >> >      |     ^~~~~~~~~

> >> >/home/aldyh/src/gcc/gcc/vec.h:1284:46: error: ‘this’ is unavailable

> >> >for static member functions

> >> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

> >> >      |                                              ^~~~

> >> >

> >> >

> >>

> >> Oh sorry, I didn't realise it was static.

> >

> >Yeah, we eventually have no object when we need the offset.  Does

> >offsetof refusing to operate on this mean that using a temporary

> >object on the stack like the following can yield a different answer

> >from the "real" object?  I guess examples where it breaks boil

> >down to virtual inheritance.  Anyway, so the following _should_ work ...

> >

> >template<typename T, typename A>

> >inline size_t

> >vec<T, A, vl_embed>::embedded_size (unsigned alloc)

> >{

> >  typedef vec<T, A, vl_embed> vec_embedded;

>

> This typedef is redundant, the name 'vec' in thos scope refers to the

> current instantiation, so you can just say 'vec'.

>

> >  vec_embedded tem;

>

> i.e. 'vec tem;' here, and remove the typedef on the previous line.

>

> >  return (char *)&tem.m_vecdata - (char *)&tem + alloc * sizeof (T);

> >}

> >

> >?

>

> Yes, that should work fine. In general you wouldn't want to create an

> object just to do this, but creating and destroying a vec has no side

> effects so is fine.


Now that you say it, vec has a T[1] member so depending on T
there might be a side-effect as invoking its CTOR?  Or it might
even not compile if there is no default CTOR available...  Ick :/

Richard.

>

>
Bill Schmidt via Gcc-patches Aug. 7, 2020, 8:34 a.m. | #26
On 07/08/20 10:22 +0200, Richard Biener wrote:
>On Fri, Aug 7, 2020 at 9:57 AM Jonathan Wakely <jwakely@redhat.com> wrote:

>>

>> On 07/08/20 08:48 +0200, Richard Biener wrote:

>> >On Thu, Aug 6, 2020 at 9:24 PM Jonathan Wakely <jwakely@redhat.com> wrote:

>> >>

>> >> On 06/08/20 19:58 +0200, Aldy Hernandez wrote:

>> >> >

>> >> >

>> >> >On 8/6/20 6:30 PM, Jonathan Wakely wrote:

>> >> >>On 06/08/20 16:17 +0200, Aldy Hernandez wrote:

>> >> >>>

>> >> >>>

>> >> >>>On 8/6/20 12:48 PM, Jonathan Wakely wrote:

>> >> >>>>On 06/08/20 12:31 +0200, Richard Biener wrote:

>> >> >>>>>On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely

>> >> >>>>><jwakely@redhat.com> wrote:

>> >> >>>>>>

>> >> >>>>>>On 06/08/20 06:16 +0100, Richard Sandiford wrote:

>> >> >>>>>>>Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

>> >> >>>>>>>>On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

>> >> >>>>>>>>>On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor

>> >> >>>>>><mjambor@suse.cz> wrote:

>> >> >>>>>>>>>>On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>> >> >>>>>>>>>>[...]

>> >> >>>>>>>>>>

>> >> >>>>>>>>>>>* ipa-cp changes from vec<value_range> to std::vec<value_range>.

>> >> >>>>>>>>>>>

>> >> >>>>>>>>>>>We are using std::vec to ensure constructors are run, which they

>> >> >>>>>>>>>>aren't

>> >> >>>>>>>>>>>in our internal vec<> implementation.  Although we

>> >> >>>>>>>>>>>usually

>> >> >>>>>>steer away

>> >> >>>>>>>>>>>from using std::vec because of interactions with our GC system,

>> >> >>>>>>>>>>>ipcp_param_lattices is only live within the pass

>> >> >>>>>>>>>>>and

>> >> >>>>>>allocated with

>> >> >>>>>>>>>>calloc.

>> >> >>>>>>>>>>Ummm... I did not object but I will save the URL of

>> >> >>>>>>>>>>this

>> >> >>>>>>message in the

>> >> >>>>>>>>>>archive so that I can waive it in front of anyone

>> >> >>>>>>>>>>complaining why I

>> >> >>>>>>>>>>don't use our internal vec's in IPA data structures.

>> >> >>>>>>>>>>

>> >> >>>>>>>>>>But it actually raises a broader question: was this

>> >> >>>>>>supposed to be an

>> >> >>>>>>>>>>exception, allowed only not to complicate the irange

>> >> >>>>>>>>>>patch

>> >> >>>>>>further, or

>> >> >>>>>>>>>>will this be generally accepted thing to do when

>> >> >>>>>>>>>>someone

>> >> >>>>>>wants to have

>> >> >>>>>>>>>>a

>> >> >>>>>>>>>>vector of constructed items?

>> >> >>>>>>>>>It's definitely not what we want. You have to find

>> >> >>>>>>>>>another

>> >> >>>>>>solution to this problem.

>> >> >>>>>>>>>

>> >> >>>>>>>>>Richard.

>> >> >>>>>>>>>

>> >> >>>>>>>>

>> >> >>>>>>>>Why isn't it what we want?

>> >> >>>>>>>>

>> >> >>>>>>>>This is a small vector local to the pass so it doesn't

>> >> >>>>>>>>interfere with

>> >> >>>>>>>>our PITA GTY.

>> >> >>>>>>>>The class is pretty straightforward, but we do need a constructor to

>> >> >>>>>>>>initialize the pointer and the max-size field.  There is

>> >> >>>>>>>>no

>> >> >>>>>>allocation

>> >> >>>>>>>>done per element, so a small number of elements have a

>> >> >>>>>>>>couple

>> >> >>>>>>of fields

>> >> >>>>>>>>initialized per element. We'd have to loop to do that anyway.

>> >> >>>>>>>>

>> >> >>>>>>>>GCC's vec<> does not provide he ability to run a

>> >> >>>>>>>>constructor,

>> >> >>>>>>std::vec

>> >> >>>>>>>>does.

>> >> >>>>>>>

>> >> >>>>>>>I realise you weren't claiming otherwise, but: that could

>> >> >>>>>>>be fixed :-)

>> >> >>>>>>

>> >> >>>>>>It really should be.

>> >> >>>>>>

>> >> >>>>>>Artificial limitations like that are just a booby trap for the unwary.

>> >> >>>>>

>> >> >>>>>It's probably also historic because we couldn't even implement

>> >> >>>>>the case of re-allocation correctly without std::move, could we?

>> >> >>>>

>> >> >>>>I don't see why not. std::vector worked fine without std::move, it's

>> >> >>>>just more efficient with std::move, and can be used with a wider set

>> >> >>>>of element types.

>> >> >>>>

>> >> >>>>When reallocating you can just copy each element to the new storage

>> >> >>>>and destroy the old element. If your type is non-copyable then you

>> >> >>>>need std::move, but I don't think the types I see used with vec<> are

>> >> >>>>non-copyable. Most of them are trivially-copyable.

>> >> >>>>

>> >> >>>>I think the benefit of std::move to GCC is likely to be permitting

>> >> >>>>cheap copies to be made where previously they were banned for

>> >> >>>>performance reasons, but not because those copies were impossible.

>> >> >>>

>> >> >>>For the record, neither value_range nor int_range<N> require any

>> >> >>>allocations.  The sub-range storage resides in the stack or

>> >> >>>wherever it was defined.  However, it is definitely not a POD.

>> >> >>>

>> >> >>>Digging deeper, I notice that the original issue that caused us to

>> >> >>>use std::vector was not in-place new but the safe_grow_cleared.

>> >> >>>The original code had:

>> >> >>>

>> >> >>>>    auto_vec<value_range, 32> known_value_ranges;

>> >> >>>>...

>> >> >>>>...

>> >> >>>>    if (!vr.undefined_p () && !vr.varying_p ())

>> >> >>>>         {

>> >> >>>>           if (!known_value_ranges.length ())

>> >> >>>>             known_value_ranges.safe_grow_cleared (count);

>> >> >>>>             known_value_ranges[i] = vr;

>> >> >>>>         }

>> >> >>>

>> >> >>>I would've gladly kept the auto_vec, had I been able to do call

>> >> >>>the constructor by doing an in-place new:

>> >> >>>

>> >> >>>>                   if (!vr.undefined_p () && !vr.varying_p ())

>> >> >>>>                     {

>> >> >>>>                       if (!known_value_ranges.length ())

>> >> >>>>-                         known_value_ranges.safe_grow_cleared (count);

>> >> >>>>+                         {

>> >> >>>>+                           known_value_ranges.safe_grow_cleared

>> >> >>>>(count);

>> >> >>>>+                           for (int i = 0; i < count; ++i)

>> >> >>>>+                             new (&known_value_ranges[i])

>> >> >>>>value_range ();

>> >> >>>>+                         }

>> >> >>>>                       known_value_ranges[i] = vr;

>> >> >>>>                     }

>> >> >>>>                 }

>> >> >>>

>> >> >>>But alas, compiling yields:

>> >> >>>

>> >> >>>>In file included from /usr/include/wchar.h:35,

>> >> >>>>                from /usr/include/c++/10/cwchar:44,

>> >> >>>>                from /usr/include/c++/10/bits/postypes.h:40,

>> >> >>>>                from /usr/include/c++/10/iosfwd:40,

>> >> >>>>                from /usr/include/gmp-x86_64.h:34,

>> >> >>>>                from /usr/include/gmp.h:59,

>> >> >>>>                from /home/aldyh/src/gcc/gcc/system.h:687,

>> >> >>>>                from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

>> >> >>>>/home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static

>> >> >>>>size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T

>> >> >>>>= int_range<1>; A = va_heap; size_t = long unsigned int]’:

>> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static

>> >> >>>>void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int,

>> >> >>>>bool) [with T = int_range<1>]’

>> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool

>> >> >>>>vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

>> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool

>> >> >>>>vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

>> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void

>> >> >>>>vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

>> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void

>> >> >>>>vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

>> >> >>>>/home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

>> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’

>> >> >>>>within non-standard-layout type ‘vec_embedded’ {aka

>> >> >>>>‘vec<int_range<1>, va_heap, vl_embed>’} is

>> >> >>>>conditionally-supported [-Winvalid-offsetof]

>> >> >>>>1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>> >> >>>>     |                    ^

>> >> >>

>> >> >>Can we just avoid using offsetof there?

>> >> >>

>> >> >>Untested ...

>> >> >>

>> >> >>--- a/gcc/vec.h

>> >> >>+++ b/gcc/vec.h

>> >> >>@@ -1281,8 +1281,8 @@ template<typename T, typename A>

>> >> >>  inline size_t

>> >> >>  vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>> >> >>  {

>> >> >>-  typedef vec<T, A, vl_embed> vec_embedded;

>> >> >>-  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>> >> >>+  size_t offset = (char*)&m_vecdata - (char*)this;

>> >> >>+  return offset + alloc * sizeof (T);

>> >> >>  }

>> >> >>

>> >> >>

>> >> >

>> >> >Now we have:

>> >> >

>> >> >In file included from /home/aldyh/src/gcc/gcc/rtl.h:30,

>> >> >                 from /home/aldyh/src/gcc/gcc/genpreds.c:27:

>> >> >/home/aldyh/src/gcc/gcc/vec.h: In static member function ‘static

>> >> >size_t vec<T, A, vl_embed>::embedded_size(unsigned int)’:

>> >> >/home/aldyh/src/gcc/gcc/vec.h:1284:27: error: invalid use of member

>> >> >‘vec<T, A, vl_embed>::m_vecdata’ in static member function

>> >> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

>> >> >      |                           ^~~~~~~~~

>> >> >/home/aldyh/src/gcc/gcc/vec.h:626:5: note: declared here

>> >> >  626 |   T m_vecdata[1];

>> >> >      |     ^~~~~~~~~

>> >> >/home/aldyh/src/gcc/gcc/vec.h:1284:46: error: ‘this’ is unavailable

>> >> >for static member functions

>> >> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

>> >> >      |                                              ^~~~

>> >> >

>> >> >

>> >>

>> >> Oh sorry, I didn't realise it was static.

>> >

>> >Yeah, we eventually have no object when we need the offset.  Does

>> >offsetof refusing to operate on this mean that using a temporary

>> >object on the stack like the following can yield a different answer

>> >from the "real" object?  I guess examples where it breaks boil

>> >down to virtual inheritance.  Anyway, so the following _should_ work ...

>> >

>> >template<typename T, typename A>

>> >inline size_t

>> >vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>> >{

>> >  typedef vec<T, A, vl_embed> vec_embedded;

>>

>> This typedef is redundant, the name 'vec' in thos scope refers to the

>> current instantiation, so you can just say 'vec'.

>>

>> >  vec_embedded tem;

>>

>> i.e. 'vec tem;' here, and remove the typedef on the previous line.

>>

>> >  return (char *)&tem.m_vecdata - (char *)&tem + alloc * sizeof (T);

>> >}

>> >

>> >?

>>

>> Yes, that should work fine. In general you wouldn't want to create an

>> object just to do this, but creating and destroying a vec has no side

>> effects so is fine.

>

>Now that you say it, vec has a T[1] member so depending on T

>there might be a side-effect as invoking its CTOR?  Or it might

>even not compile if there is no default CTOR available...  Ick :/


Right.

Does the GTY stuff add members to the struct, or otherwise alter its
layout?

If not, then I'd just assume that the m_vecdata offset is
sizeof(vec_prefix), and add a static assert in the vec constructor
(where you do have an object to take the address of) to verify it. If
there is some target where the assumption isn't true the static assert
will fail as soon as you try to use the type, and we can fix it then.
Bill Schmidt via Gcc-patches Aug. 7, 2020, 8:54 a.m. | #27
On Fri, Aug 7, 2020 at 10:34 AM Jonathan Wakely <jwakely@redhat.com> wrote:
>

> On 07/08/20 10:22 +0200, Richard Biener wrote:

> >On Fri, Aug 7, 2020 at 9:57 AM Jonathan Wakely <jwakely@redhat.com> wrote:

> >>

> >> On 07/08/20 08:48 +0200, Richard Biener wrote:

> >> >On Thu, Aug 6, 2020 at 9:24 PM Jonathan Wakely <jwakely@redhat.com> wrote:

> >> >>

> >> >> On 06/08/20 19:58 +0200, Aldy Hernandez wrote:

> >> >> >

> >> >> >

> >> >> >On 8/6/20 6:30 PM, Jonathan Wakely wrote:

> >> >> >>On 06/08/20 16:17 +0200, Aldy Hernandez wrote:

> >> >> >>>

> >> >> >>>

> >> >> >>>On 8/6/20 12:48 PM, Jonathan Wakely wrote:

> >> >> >>>>On 06/08/20 12:31 +0200, Richard Biener wrote:

> >> >> >>>>>On Thu, Aug 6, 2020 at 12:19 PM Jonathan Wakely

> >> >> >>>>><jwakely@redhat.com> wrote:

> >> >> >>>>>>

> >> >> >>>>>>On 06/08/20 06:16 +0100, Richard Sandiford wrote:

> >> >> >>>>>>>Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

> >> >> >>>>>>>>On 8/5/20 12:54 PM, Richard Biener via Gcc-patches wrote:

> >> >> >>>>>>>>>On August 5, 2020 5:09:19 PM GMT+02:00, Martin Jambor

> >> >> >>>>>><mjambor@suse.cz> wrote:

> >> >> >>>>>>>>>>On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

> >> >> >>>>>>>>>>[...]

> >> >> >>>>>>>>>>

> >> >> >>>>>>>>>>>* ipa-cp changes from vec<value_range> to std::vec<value_range>.

> >> >> >>>>>>>>>>>

> >> >> >>>>>>>>>>>We are using std::vec to ensure constructors are run, which they

> >> >> >>>>>>>>>>aren't

> >> >> >>>>>>>>>>>in our internal vec<> implementation.  Although we

> >> >> >>>>>>>>>>>usually

> >> >> >>>>>>steer away

> >> >> >>>>>>>>>>>from using std::vec because of interactions with our GC system,

> >> >> >>>>>>>>>>>ipcp_param_lattices is only live within the pass

> >> >> >>>>>>>>>>>and

> >> >> >>>>>>allocated with

> >> >> >>>>>>>>>>calloc.

> >> >> >>>>>>>>>>Ummm... I did not object but I will save the URL of

> >> >> >>>>>>>>>>this

> >> >> >>>>>>message in the

> >> >> >>>>>>>>>>archive so that I can waive it in front of anyone

> >> >> >>>>>>>>>>complaining why I

> >> >> >>>>>>>>>>don't use our internal vec's in IPA data structures.

> >> >> >>>>>>>>>>

> >> >> >>>>>>>>>>But it actually raises a broader question: was this

> >> >> >>>>>>supposed to be an

> >> >> >>>>>>>>>>exception, allowed only not to complicate the irange

> >> >> >>>>>>>>>>patch

> >> >> >>>>>>further, or

> >> >> >>>>>>>>>>will this be generally accepted thing to do when

> >> >> >>>>>>>>>>someone

> >> >> >>>>>>wants to have

> >> >> >>>>>>>>>>a

> >> >> >>>>>>>>>>vector of constructed items?

> >> >> >>>>>>>>>It's definitely not what we want. You have to find

> >> >> >>>>>>>>>another

> >> >> >>>>>>solution to this problem.

> >> >> >>>>>>>>>

> >> >> >>>>>>>>>Richard.

> >> >> >>>>>>>>>

> >> >> >>>>>>>>

> >> >> >>>>>>>>Why isn't it what we want?

> >> >> >>>>>>>>

> >> >> >>>>>>>>This is a small vector local to the pass so it doesn't

> >> >> >>>>>>>>interfere with

> >> >> >>>>>>>>our PITA GTY.

> >> >> >>>>>>>>The class is pretty straightforward, but we do need a constructor to

> >> >> >>>>>>>>initialize the pointer and the max-size field.  There is

> >> >> >>>>>>>>no

> >> >> >>>>>>allocation

> >> >> >>>>>>>>done per element, so a small number of elements have a

> >> >> >>>>>>>>couple

> >> >> >>>>>>of fields

> >> >> >>>>>>>>initialized per element. We'd have to loop to do that anyway.

> >> >> >>>>>>>>

> >> >> >>>>>>>>GCC's vec<> does not provide he ability to run a

> >> >> >>>>>>>>constructor,

> >> >> >>>>>>std::vec

> >> >> >>>>>>>>does.

> >> >> >>>>>>>

> >> >> >>>>>>>I realise you weren't claiming otherwise, but: that could

> >> >> >>>>>>>be fixed :-)

> >> >> >>>>>>

> >> >> >>>>>>It really should be.

> >> >> >>>>>>

> >> >> >>>>>>Artificial limitations like that are just a booby trap for the unwary.

> >> >> >>>>>

> >> >> >>>>>It's probably also historic because we couldn't even implement

> >> >> >>>>>the case of re-allocation correctly without std::move, could we?

> >> >> >>>>

> >> >> >>>>I don't see why not. std::vector worked fine without std::move, it's

> >> >> >>>>just more efficient with std::move, and can be used with a wider set

> >> >> >>>>of element types.

> >> >> >>>>

> >> >> >>>>When reallocating you can just copy each element to the new storage

> >> >> >>>>and destroy the old element. If your type is non-copyable then you

> >> >> >>>>need std::move, but I don't think the types I see used with vec<> are

> >> >> >>>>non-copyable. Most of them are trivially-copyable.

> >> >> >>>>

> >> >> >>>>I think the benefit of std::move to GCC is likely to be permitting

> >> >> >>>>cheap copies to be made where previously they were banned for

> >> >> >>>>performance reasons, but not because those copies were impossible.

> >> >> >>>

> >> >> >>>For the record, neither value_range nor int_range<N> require any

> >> >> >>>allocations.  The sub-range storage resides in the stack or

> >> >> >>>wherever it was defined.  However, it is definitely not a POD.

> >> >> >>>

> >> >> >>>Digging deeper, I notice that the original issue that caused us to

> >> >> >>>use std::vector was not in-place new but the safe_grow_cleared.

> >> >> >>>The original code had:

> >> >> >>>

> >> >> >>>>    auto_vec<value_range, 32> known_value_ranges;

> >> >> >>>>...

> >> >> >>>>...

> >> >> >>>>    if (!vr.undefined_p () && !vr.varying_p ())

> >> >> >>>>         {

> >> >> >>>>           if (!known_value_ranges.length ())

> >> >> >>>>             known_value_ranges.safe_grow_cleared (count);

> >> >> >>>>             known_value_ranges[i] = vr;

> >> >> >>>>         }

> >> >> >>>

> >> >> >>>I would've gladly kept the auto_vec, had I been able to do call

> >> >> >>>the constructor by doing an in-place new:

> >> >> >>>

> >> >> >>>>                   if (!vr.undefined_p () && !vr.varying_p ())

> >> >> >>>>                     {

> >> >> >>>>                       if (!known_value_ranges.length ())

> >> >> >>>>-                         known_value_ranges.safe_grow_cleared (count);

> >> >> >>>>+                         {

> >> >> >>>>+                           known_value_ranges.safe_grow_cleared

> >> >> >>>>(count);

> >> >> >>>>+                           for (int i = 0; i < count; ++i)

> >> >> >>>>+                             new (&known_value_ranges[i])

> >> >> >>>>value_range ();

> >> >> >>>>+                         }

> >> >> >>>>                       known_value_ranges[i] = vr;

> >> >> >>>>                     }

> >> >> >>>>                 }

> >> >> >>>

> >> >> >>>But alas, compiling yields:

> >> >> >>>

> >> >> >>>>In file included from /usr/include/wchar.h:35,

> >> >> >>>>                from /usr/include/c++/10/cwchar:44,

> >> >> >>>>                from /usr/include/c++/10/bits/postypes.h:40,

> >> >> >>>>                from /usr/include/c++/10/iosfwd:40,

> >> >> >>>>                from /usr/include/gmp-x86_64.h:34,

> >> >> >>>>                from /usr/include/gmp.h:59,

> >> >> >>>>                from /home/aldyh/src/gcc/gcc/system.h:687,

> >> >> >>>>                from /home/aldyh/src/gcc/gcc/ipa-fnsummary.c:55:

> >> >> >>>>/home/aldyh/src/gcc/gcc/vec.h: In instantiation of ‘static

> >> >> >>>>size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T

> >> >> >>>>= int_range<1>; A = va_heap; size_t = long unsigned int]’:

> >> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:288:58:   required from ‘static

> >> >> >>>>void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int,

> >> >> >>>>bool) [with T = int_range<1>]’

> >> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1746:20:   required from ‘bool

> >> >> >>>>vec<T>::reserve(unsigned int, bool) [with T = int_range<1>]’

> >> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1766:10:   required from ‘bool

> >> >> >>>>vec<T>::reserve_exact(unsigned int) [with T = int_range<1>]’

> >> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1894:3:   required from ‘void

> >> >> >>>>vec<T>::safe_grow(unsigned int) [with T = int_range<1>]’

> >> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1912:3:   required from ‘void

> >> >> >>>>vec<T>::safe_grow_cleared(unsigned int) [with T = int_range<1>]’

> >> >> >>>>/home/aldyh/src/gcc/gcc/ipa-fnsummary.c:634:51:   required from here

> >> >> >>>>/home/aldyh/src/gcc/gcc/vec.h:1285:20: warning: ‘offsetof’

> >> >> >>>>within non-standard-layout type ‘vec_embedded’ {aka

> >> >> >>>>‘vec<int_range<1>, va_heap, vl_embed>’} is

> >> >> >>>>conditionally-supported [-Winvalid-offsetof]

> >> >> >>>>1285 |   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >> >> >>>>     |                    ^

> >> >> >>

> >> >> >>Can we just avoid using offsetof there?

> >> >> >>

> >> >> >>Untested ...

> >> >> >>

> >> >> >>--- a/gcc/vec.h

> >> >> >>+++ b/gcc/vec.h

> >> >> >>@@ -1281,8 +1281,8 @@ template<typename T, typename A>

> >> >> >>  inline size_t

> >> >> >>  vec<T, A, vl_embed>::embedded_size (unsigned alloc)

> >> >> >>  {

> >> >> >>-  typedef vec<T, A, vl_embed> vec_embedded;

> >> >> >>-  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >> >> >>+  size_t offset = (char*)&m_vecdata - (char*)this;

> >> >> >>+  return offset + alloc * sizeof (T);

> >> >> >>  }

> >> >> >>

> >> >> >>

> >> >> >

> >> >> >Now we have:

> >> >> >

> >> >> >In file included from /home/aldyh/src/gcc/gcc/rtl.h:30,

> >> >> >                 from /home/aldyh/src/gcc/gcc/genpreds.c:27:

> >> >> >/home/aldyh/src/gcc/gcc/vec.h: In static member function ‘static

> >> >> >size_t vec<T, A, vl_embed>::embedded_size(unsigned int)’:

> >> >> >/home/aldyh/src/gcc/gcc/vec.h:1284:27: error: invalid use of member

> >> >> >‘vec<T, A, vl_embed>::m_vecdata’ in static member function

> >> >> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

> >> >> >      |                           ^~~~~~~~~

> >> >> >/home/aldyh/src/gcc/gcc/vec.h:626:5: note: declared here

> >> >> >  626 |   T m_vecdata[1];

> >> >> >      |     ^~~~~~~~~

> >> >> >/home/aldyh/src/gcc/gcc/vec.h:1284:46: error: ‘this’ is unavailable

> >> >> >for static member functions

> >> >> > 1284 |   size_t offset = (char*)&m_vecdata - (char*)this;

> >> >> >      |                                              ^~~~

> >> >> >

> >> >> >

> >> >>

> >> >> Oh sorry, I didn't realise it was static.

> >> >

> >> >Yeah, we eventually have no object when we need the offset.  Does

> >> >offsetof refusing to operate on this mean that using a temporary

> >> >object on the stack like the following can yield a different answer

> >> >from the "real" object?  I guess examples where it breaks boil

> >> >down to virtual inheritance.  Anyway, so the following _should_ work ...

> >> >

> >> >template<typename T, typename A>

> >> >inline size_t

> >> >vec<T, A, vl_embed>::embedded_size (unsigned alloc)

> >> >{

> >> >  typedef vec<T, A, vl_embed> vec_embedded;

> >>

> >> This typedef is redundant, the name 'vec' in thos scope refers to the

> >> current instantiation, so you can just say 'vec'.

> >>

> >> >  vec_embedded tem;

> >>

> >> i.e. 'vec tem;' here, and remove the typedef on the previous line.

> >>

> >> >  return (char *)&tem.m_vecdata - (char *)&tem + alloc * sizeof (T);

> >> >}

> >> >

> >> >?

> >>

> >> Yes, that should work fine. In general you wouldn't want to create an

> >> object just to do this, but creating and destroying a vec has no side

> >> effects so is fine.

> >

> >Now that you say it, vec has a T[1] member so depending on T

> >there might be a side-effect as invoking its CTOR?  Or it might

> >even not compile if there is no default CTOR available...  Ick :/

>

> Right.

>

> Does the GTY stuff add members to the struct, or otherwise alter its

> layout?


No.

> If not, then I'd just assume that the m_vecdata offset is

> sizeof(vec_prefix), and add a static assert in the vec constructor

> (where you do have an object to take the address of) to verify it. If

> there is some target where the assumption isn't true the static assert

> will fail as soon as you try to use the type, and we can fix it then.


The point of the exercise is to factor in the effects of alignment of T
on the m_vecdata member offset.  Just using sizeof(vec_prefix)
doesn't work there.  Of course ROUND_UP (sizeof (vec_prefix), alignof (T))
might work.  But then it's all less portable than what offsetof() intended to be
and we do know we're not dealing with any virtual inheritance or so thus
the FE telling us that offsetof is non-standard here is unhelpful :/
Now could we just use an uninitialized pointer / pointer to an
uninitialized object here?

vec *tem; // = XALLOCA (vec);
return (char *)&tem->m_vecdata - (char *)tem + alloc * sizeof (T);

it's going to look awfully like the old-school NULL pointer offsetof
implementation though.

Richard.

>
Bill Schmidt via Gcc-patches Aug. 7, 2020, 8:55 a.m. | #28
On Fri, Aug 07, 2020 at 09:34:38AM +0100, Jonathan Wakely via Gcc-patches wrote:
> > Now that you say it, vec has a T[1] member so depending on T

> > there might be a side-effect as invoking its CTOR?  Or it might

> > even not compile if there is no default CTOR available...  Ick :/

> 

> Right.

> 

> Does the GTY stuff add members to the struct, or otherwise alter its

> layout?


Or perhaps use offsetof on an alternate structure that should have the same
layout.
So instead of
  typedef vec<T, A, vl_embed> vec_embedded;
  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
use
  struct alignas (T) U { char data[sizeof (T)]; };
  typedef vec<U, A, vl_embed> vec_embedded;
  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
where vec_embedded should have the same offset of m_vecdata as vec.

Proof of concept:
template <typename T>
struct vec
{
  int a;
  T m_vecdata[1];
};

template <typename T>
int
foo (int alloc)
{
//  typedef vec<T> vec_embedded;
  struct alignas (T) U { char data[sizeof (T)]; };
  typedef vec<U> vec_embedded;
  return __builtin_offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
}

struct V { };
struct S : virtual V { long long l; S (); ~S (); };

int a = foo <S> (0);

	Jakub
Bill Schmidt via Gcc-patches Aug. 7, 2020, 9:17 a.m. | #29
On 07/08/20 10:55 +0200, Jakub Jelinek wrote:
>On Fri, Aug 07, 2020 at 09:34:38AM +0100, Jonathan Wakely via Gcc-patches wrote:

>> > Now that you say it, vec has a T[1] member so depending on T

>> > there might be a side-effect as invoking its CTOR?  Or it might

>> > even not compile if there is no default CTOR available...  Ick :/

>>

>> Right.

>>

>> Does the GTY stuff add members to the struct, or otherwise alter its

>> layout?

>

>Or perhaps use offsetof on an alternate structure that should have the same

>layout.


Yes that's what I was going to suggest next.

>So instead of

>  typedef vec<T, A, vl_embed> vec_embedded;

>  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>use

>  struct alignas (T) U { char data[sizeof (T)]; };

>  typedef vec<U, A, vl_embed> vec_embedded;


static_assert(sizeof(vec_embedded) == sizeof(vec), "");
static_assert(alignof(vec_embedded) == alignof(vec), "");

>  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>where vec_embedded should have the same offset of m_vecdata as vec.
Bill Schmidt via Gcc-patches Aug. 7, 2020, 6:04 p.m. | #30
Is the attached patch what y'all suggest?

The patch reverts the GCC vec<> usage in ipa-fnsummary.c and
implements the above suggestion.

Bootstraps, tests running...

If tests pass, is this OK?

Thanks.
Aldy

On Fri, Aug 7, 2020 at 11:17 AM Jonathan Wakely via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>

> On 07/08/20 10:55 +0200, Jakub Jelinek wrote:

> >On Fri, Aug 07, 2020 at 09:34:38AM +0100, Jonathan Wakely via Gcc-patches wrote:

> >> > Now that you say it, vec has a T[1] member so depending on T

> >> > there might be a side-effect as invoking its CTOR?  Or it might

> >> > even not compile if there is no default CTOR available...  Ick :/

> >>

> >> Right.

> >>

> >> Does the GTY stuff add members to the struct, or otherwise alter its

> >> layout?

> >

> >Or perhaps use offsetof on an alternate structure that should have the same

> >layout.

>

> Yes that's what I was going to suggest next.

>

> >So instead of

> >  typedef vec<T, A, vl_embed> vec_embedded;

> >  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >use

> >  struct alignas (T) U { char data[sizeof (T)]; };

> >  typedef vec<U, A, vl_embed> vec_embedded;

>

> static_assert(sizeof(vec_embedded) == sizeof(vec), "");

> static_assert(alignof(vec_embedded) == alignof(vec), "");

>

> >  return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> >where vec_embedded should have the same offset of m_vecdata as vec.

>
diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index 49bab04524b..d853ed8f075 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -82,7 +82,6 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimplify.h"
 #include "stringpool.h"
 #include "attribs.h"
-#include <vector>
 #include "tree-into-ssa.h"
 
 /* Summaries.  */
@@ -331,7 +330,7 @@ static void
 evaluate_conditions_for_known_args (struct cgraph_node *node,
 				    bool inline_p,
 				    vec<tree> known_vals,
-				    const std::vector<value_range> &known_value_ranges,
+				    vec<value_range> known_value_ranges,
 				    vec<ipa_agg_value_set> known_aggs,
 				    clause_t *ret_clause,
 				    clause_t *ret_nonspec_clause)
@@ -446,7 +445,7 @@ evaluate_conditions_for_known_args (struct cgraph_node *node,
 	      continue;
 	    }
 	}
-      if (c->operand_num < (int) known_value_ranges.size ()
+      if (c->operand_num < (int) known_value_ranges.length ()
 	  && !c->agg_contents
 	  && !known_value_ranges[c->operand_num].undefined_p ()
 	  && !known_value_ranges[c->operand_num].varying_p ()
@@ -555,7 +554,7 @@ evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 {
   struct cgraph_node *callee = e->callee->ultimate_alias_target ();
   class ipa_fn_summary *info = ipa_fn_summaries->get (callee);
-  std::vector<value_range> known_value_ranges (32);
+  auto_vec<value_range, 32> known_value_ranges;
   class ipa_edge_args *args;
 
   if (clause_ptr)
@@ -630,11 +629,11 @@ evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 								   i));
 		    if (!vr.undefined_p () && !vr.varying_p ())
 		      {
-			if (!known_value_ranges.size ())
+			if (!known_value_ranges.length ())
 			  {
-			    known_value_ranges.resize (count);
+			    known_value_ranges.safe_grow (count);
 			    for (int i = 0; i < count; ++i)
-			      known_value_ranges[i].set_undefined ();
+			      new (&known_value_ranges[i]) value_range ();
 			  }
 			known_value_ranges[i] = vr;
 		      }
@@ -808,7 +807,7 @@ ipa_fn_summary_t::duplicate (cgraph_node *src,
 	}
       evaluate_conditions_for_known_args (dst, false,
 					  known_vals,
-					  std::vector<value_range> (),
+					  vNULL,
 					  vNULL,
 					  &possible_truths,
 					  /* We are going to specialize,
@@ -3692,8 +3691,7 @@ estimate_ipcp_clone_size_and_time (struct cgraph_node *node,
   clause_t clause, nonspec_clause;
 
   /* TODO: Also pass known value ranges.  */
-  evaluate_conditions_for_known_args (node, false, known_vals,
-				      std::vector<value_range> (),
+  evaluate_conditions_for_known_args (node, false, known_vals, vNULL,
 				      known_aggs, &clause, &nonspec_clause);
   ipa_call_context ctx (node, clause, nonspec_clause,
 		        known_vals, known_contexts,
diff --git a/gcc/vec.h b/gcc/vec.h
index 3ad99b83690..01d7736c520 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -1281,7 +1281,10 @@ template<typename T, typename A>
 inline size_t
 vec<T, A, vl_embed>::embedded_size (unsigned alloc)
 {
-  typedef vec<T, A, vl_embed> vec_embedded;
+  struct alignas (T) U { char data[sizeof (T)]; };
+  typedef vec<U, A, vl_embed> vec_embedded;
+  static_assert(sizeof(vec_embedded) == sizeof(vec), "");
+  static_assert(alignof(vec_embedded) == alignof(vec), "");
   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
 }
Bill Schmidt via Gcc-patches Aug. 7, 2020, 6:33 p.m. | #31
On Fri, Aug 07, 2020 at 08:04:57PM +0200, Aldy Hernandez wrote:
> --- a/gcc/ipa-fnsummary.c

> +++ b/gcc/ipa-fnsummary.c

> @@ -82,7 +82,6 @@ along with GCC; see the file COPYING3.  If not see

>  #include "gimplify.h"

>  #include "stringpool.h"

>  #include "attribs.h"

> -#include <vector>

>  #include "tree-into-ssa.h"


This part won't apply (Gerald has changed it to #define INCLUDE_VECTOR
earlier I think).

> --- a/gcc/vec.h

> +++ b/gcc/vec.h

> @@ -1281,7 +1281,10 @@ template<typename T, typename A>

>  inline size_t

>  vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>  {

> -  typedef vec<T, A, vl_embed> vec_embedded;

> +  struct alignas (T) U { char data[sizeof (T)]; };

> +  typedef vec<U, A, vl_embed> vec_embedded;

> +  static_assert(sizeof(vec_embedded) == sizeof(vec), "");

> +  static_assert(alignof(vec_embedded) == alignof(vec), "");


s/(/ (/g on the above two lines please (GCC vs. libstdc++ coding
style differences).

I think it would be nice to see e.g. in -fdump-tree-gimple dump
on ipa-fnsummary.c what value_range ctors does it call for the auto_vec and
if that is what we want, other than that LGTM.

	Jakub
Martin Liška Aug. 10, 2020, 3:42 a.m. | #32
On 8/5/20 4:27 PM, Gerald Pfeifer wrote:
> Hi Aldy,

> 

> On Fri, 31 Jul 2020, Aldy Hernandez via Gcc-patches wrote:

>> Jeff approved this patch off-list.  I will re-run tests once again and

>> commit by Monday.

> 

> I believe this has broken the bootstrap with clang (specifically

> FreeBSD clang version 10.0.0):

> 

> In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/c/gimple-parser.c:44:

> In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/tree-vrp.h:23:

> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:347:1: error: static declaration of 'gt_ggc_mx' follows non-static declaration gt_ggc_mx (int_range<N> *x)

> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:150:37: note: previous declaration is here

>    template <unsigned X> friend void gt_ggc_mx (int_range<X> *);

>                                      ^

> 

> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:358:1: error: static declaration of 'gt_pch_nx' follows non-static declaration gt_pch_nx (int_range<N> *x)

> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:151:37: note: previous declaration is here

>    template <unsigned X> friend void gt_pch_nx (int_range<X> *);

>                                      ^

> 

> My daily tester started to 20200803T1640, so the root cause of this must

> have entered GCC trunk between Sunday 16:40 UTC and Monday 16:40 UTC.

> 

> Gerald

> 


Hey.

This one is still broken. Can you please Aldy take a look?
It's good that GCC code base can be compiled with clang ;)

Martin
Bill Schmidt via Gcc-patches Aug. 10, 2020, 7:44 a.m. | #33
On 8/10/20 5:42 AM, Martin Liška wrote:
> On 8/5/20 4:27 PM, Gerald Pfeifer wrote:

>> Hi Aldy,

>>

>> On Fri, 31 Jul 2020, Aldy Hernandez via Gcc-patches wrote:

>>> Jeff approved this patch off-list.  I will re-run tests once again and

>>> commit by Monday.

>>

>> I believe this has broken the bootstrap with clang (specifically

>> FreeBSD clang version 10.0.0):

>>

>> In file included from 

>> /scratch/tmp/gerald/GCC-HEAD/gcc/c/gimple-parser.c:44:

>> In file included from /scratch/tmp/gerald/GCC-HEAD/gcc/tree-vrp.h:23:

>> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:347:1: error: static 

>> declaration of 'gt_ggc_mx' follows non-static declaration gt_ggc_mx 

>> (int_range<N> *x)

>> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:150:37: note: previous 

>> declaration is here

>>    template <unsigned X> friend void gt_ggc_mx (int_range<X> *);

>>                                      ^

>>

>> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:358:1: error: static 

>> declaration of 'gt_pch_nx' follows non-static declaration gt_pch_nx 

>> (int_range<N> *x)

>> /scratch/tmp/gerald/GCC-HEAD/gcc/value-range.h:151:37: note: previous 

>> declaration is here

>>    template <unsigned X> friend void gt_pch_nx (int_range<X> *);

>>                                      ^

>>

>> My daily tester started to 20200803T1640, so the root cause of this must

>> have entered GCC trunk between Sunday 16:40 UTC and Monday 16:40 UTC.

>>

>> Gerald

>>

> 

> Hey.

> 

> This one is still broken. Can you please Aldy take a look?

> It's good that GCC code base can be compiled with clang ;)


My bad.  I thought Gerald had committed the inline fix as well.

OK pending tests?

gcc/ChangeLog:

	* value-range.h (gt_ggc_mx): Declare inline.
	(gt_pch_nx): Same.
---
  gcc/value-range.h | 6 +++---
  1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/gcc/value-range.h b/gcc/value-range.h
index e3282c4ad03..1ab39939703 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -343,7 +343,7 @@ range_includes_zero_p (const irange *vr)
  }

  template<unsigned N>
-static inline void
+inline void
  gt_ggc_mx (int_range<N> *x)
  {
    for (unsigned i = 0; i < N; ++i)
@@ -354,7 +354,7 @@ gt_ggc_mx (int_range<N> *x)
  }

  template<unsigned N>
-static inline void
+inline void
  gt_pch_nx (int_range<N> *x)
  {
    for (unsigned i = 0; i < N; ++i)
@@ -365,7 +365,7 @@ gt_pch_nx (int_range<N> *x)
  }

  template<unsigned N>
-static inline void
+inline void
  gt_pch_nx (int_range<N> *x, gt_pointer_operator op, void *cookie)
  {
    for (unsigned i = 0; i < N; ++i)
-- 
2.26.2
Gerald Pfeifer Aug. 10, 2020, 10:22 a.m. | #34
On Mon, 10 Aug 2020, Aldy Hernandez wrote:
> My bad.  I thought Gerald had committed the inline fix as well.


Oh, and I thought you were going to after my success report. :-)

(I did not run into problems because my own tester passed since I
still had your patch locally.9

> OK pending tests?

> 

> gcc/ChangeLog:

> 

> 	* value-range.h (gt_ggc_mx): Declare inline.

> 	(gt_pch_nx): Same.


If your test bootstraping with GCC passes, I think (especially as
the original author of this code) you can invoke the obvious rule
and go ahead.

Gerald
Martin Liška Aug. 10, 2020, 10:30 a.m. | #35
On 8/10/20 12:22 PM, Gerald Pfeifer wrote:
> If your test bootstraping with GCC passes, I think (especially as

> the original author of this code) you can invoke the obvious rule

> and go ahead.


Yes, I would also consider it an obvious change.

Martin
Bill Schmidt via Gcc-patches Aug. 10, 2020, 11:03 a.m. | #36
On 8/10/20 12:22 PM, Gerald Pfeifer wrote:
> On Mon, 10 Aug 2020, Aldy Hernandez wrote:

>> My bad.  I thought Gerald had committed the inline fix as well.

> 

> Oh, and I thought you were going to after my success report. :-)

> 

> (I did not run into problems because my own tester passed since I

> still had your patch locally.9

> 

>> OK pending tests?

>>

>> gcc/ChangeLog:

>>

>> 	* value-range.h (gt_ggc_mx): Declare inline.

>> 	(gt_pch_nx): Same.

> 

> If your test bootstraping with GCC passes, I think (especially as

> the original author of this code) you can invoke the obvious rule

> and go ahead.

> 

> Gerald

> 


Tests passed on ppc64le-linux.  Pushed.

Sorry for the delay.
Aldy
Bill Schmidt via Gcc-patches Aug. 10, 2020, 12:57 p.m. | #37
On 8/7/20 8:33 PM, Jakub Jelinek wrote:
> On Fri, Aug 07, 2020 at 08:04:57PM +0200, Aldy Hernandez wrote:

>> --- a/gcc/ipa-fnsummary.c

>> +++ b/gcc/ipa-fnsummary.c

>> @@ -82,7 +82,6 @@ along with GCC; see the file COPYING3.  If not see

>>   #include "gimplify.h"

>>   #include "stringpool.h"

>>   #include "attribs.h"

>> -#include <vector>

>>   #include "tree-into-ssa.h"

> 

> This part won't apply (Gerald has changed it to #define INCLUDE_VECTOR

> earlier I think).

> 

>> --- a/gcc/vec.h

>> +++ b/gcc/vec.h

>> @@ -1281,7 +1281,10 @@ template<typename T, typename A>

>>   inline size_t

>>   vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>>   {

>> -  typedef vec<T, A, vl_embed> vec_embedded;

>> +  struct alignas (T) U { char data[sizeof (T)]; };

>> +  typedef vec<U, A, vl_embed> vec_embedded;

>> +  static_assert(sizeof(vec_embedded) == sizeof(vec), "");

>> +  static_assert(alignof(vec_embedded) == alignof(vec), "");

> 

> s/(/ (/g on the above two lines please (GCC vs. libstdc++ coding

> style differences).

> 

> I think it would be nice to see e.g. in -fdump-tree-gimple dump

> on ipa-fnsummary.c what value_range ctors does it call for the auto_vec and

> if that is what we want, other than that LGTM.


I see the following in the dump:

evaluate_properties_for_edge()
{
...
   struct auto_vec known_value_ranges;
...
   try
     {
...
       auto_vec<int_range<1>, 32>::auto_vec (&known_value_ranges);
...

It looks like the auto_vec constructor is calling the int_range<1> 
constructor correctly:

auto_vec<int_range<1>, 32>::auto_vec (struct auto_vec * const this)
{
...
     int_range<1>::int_range (D.130911);


The int_range<1> constructor also looks correct:

int_range<1>::int_range (struct int_range * const this, const struct 
int_range & other)
{
   *this = {CLOBBER};
   {
     _1 = &this->D.92184;
     _2 = &this->m_ranges;
     irange::irange (_1, _2, 1);
     _3 = &this->D.92184;
     _4 = &other->D.92184;
     irange::operator= (_3, _4);
   }
}

If y'all agree, I will push the patch with Jakub's suggested changes.

Aldy
Bill Schmidt via Gcc-patches Aug. 10, 2020, 1:05 p.m. | #38
For the record.  The final patch (below) passes tests on ppc64le for 
both trunk, and the ranger-staging branch with ranger enabled.

Aldy

gcc/ChangeLog:

	* ipa-fnsummary.c (evaluate_conditions_for_known_args):
	(evaluate_properties_for_edge):
	(ipa_fn_summary_t::duplicate):
	(estimate_ipcp_clone_size_and_time):
	* vec.h (vl_embed>::embedded_size):
---
  gcc/ipa-fnsummary.c | 17 ++++++++---------
  gcc/vec.h           |  5 ++++-
  2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index 59e52927151..2cfab40156e 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -331,7 +331,7 @@ static void
  evaluate_conditions_for_known_args (struct cgraph_node *node,
  				    bool inline_p,
  				    vec<tree> known_vals,
-				    const std::vector<value_range> &known_value_ranges,
+				    vec<value_range> known_value_ranges,
  				    vec<ipa_agg_value_set> known_aggs,
  				    clause_t *ret_clause,
  				    clause_t *ret_nonspec_clause)
@@ -446,7 +446,7 @@ evaluate_conditions_for_known_args (struct 
cgraph_node *node,
  	      continue;
  	    }
  	}
-      if (c->operand_num < (int) known_value_ranges.size ()
+      if (c->operand_num < (int) known_value_ranges.length ()
  	  && !c->agg_contents
  	  && !known_value_ranges[c->operand_num].undefined_p ()
  	  && !known_value_ranges[c->operand_num].varying_p ()
@@ -555,7 +555,7 @@ evaluate_properties_for_edge (struct cgraph_edge *e, 
bool inline_p,
  {
    struct cgraph_node *callee = e->callee->ultimate_alias_target ();
    class ipa_fn_summary *info = ipa_fn_summaries->get (callee);
-  std::vector<value_range> known_value_ranges (32);
+  auto_vec<value_range, 32> known_value_ranges;
    class ipa_edge_args *args;

    if (clause_ptr)
@@ -630,11 +630,11 @@ evaluate_properties_for_edge (struct cgraph_edge 
*e, bool inline_p,
  								   i));
  		    if (!vr.undefined_p () && !vr.varying_p ())
  		      {
-			if (!known_value_ranges.size ())
+			if (!known_value_ranges.length ())
  			  {
-			    known_value_ranges.resize (count);
+			    known_value_ranges.safe_grow (count);
  			    for (int i = 0; i < count; ++i)
-			      known_value_ranges[i].set_undefined ();
+			      new (&known_value_ranges[i]) value_range ();
  			  }
  			known_value_ranges[i] = vr;
  		      }
@@ -808,7 +808,7 @@ ipa_fn_summary_t::duplicate (cgraph_node *src,
  	}
        evaluate_conditions_for_known_args (dst, false,
  					  known_vals,
-					  std::vector<value_range> (),
+					  vNULL,
  					  vNULL,
  					  &possible_truths,
  					  /* We are going to specialize,
@@ -3692,8 +3692,7 @@ estimate_ipcp_clone_size_and_time (struct 
cgraph_node *node,
    clause_t clause, nonspec_clause;

    /* TODO: Also pass known value ranges.  */
-  evaluate_conditions_for_known_args (node, false, known_vals,
-				      std::vector<value_range> (),
+  evaluate_conditions_for_known_args (node, false, known_vals, vNULL,
  				      known_aggs, &clause, &nonspec_clause);
    ipa_call_context ctx (node, clause, nonspec_clause,
  		        known_vals, known_contexts,
diff --git a/gcc/vec.h b/gcc/vec.h
index 3ad99b83690..db48e979d77 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -1281,7 +1281,10 @@ template<typename T, typename A>
  inline size_t
  vec<T, A, vl_embed>::embedded_size (unsigned alloc)
  {
-  typedef vec<T, A, vl_embed> vec_embedded;
+  struct alignas (T) U { char data[sizeof (T)]; };
+  typedef vec<U, A, vl_embed> vec_embedded;
+  static_assert (sizeof (vec_embedded) == sizeof(vec), "");
+  static_assert (alignof (vec_embedded) == alignof(vec), "");
    return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
  }

-- 
2.26.2
Bill Schmidt via Gcc-patches Aug. 10, 2020, 1:51 p.m. | #39
On Mon, Aug 10, 2020 at 02:57:31PM +0200, Aldy Hernandez wrote:
> > I think it would be nice to see e.g. in -fdump-tree-gimple dump

> > on ipa-fnsummary.c what value_range ctors does it call for the auto_vec and

> > if that is what we want, other than that LGTM.

> 

> I see the following in the dump:

> 

> evaluate_properties_for_edge()

> {

> ...

>   struct auto_vec known_value_ranges;

> ...

>   try

>     {

> ...

>       auto_vec<int_range<1>, 32>::auto_vec (&known_value_ranges);

> ...

> 

> It looks like the auto_vec constructor is calling the int_range<1>

> constructor correctly:

> 

> auto_vec<int_range<1>, 32>::auto_vec (struct auto_vec * const this)

> {

> ...

>     int_range<1>::int_range (D.130911);

> 

> 

> The int_range<1> constructor also looks correct:

> 

> int_range<1>::int_range (struct int_range * const this, const struct

> int_range & other)

> {

>   *this = {CLOBBER};

>   {

>     _1 = &this->D.92184;

>     _2 = &this->m_ranges;

>     irange::irange (_1, _2, 1);

>     _3 = &this->D.92184;

>     _4 = &other->D.92184;

>     irange::operator= (_3, _4);

>   }

> }

> 

> If y'all agree, I will push the patch with Jakub's suggested changes.


I believe even with that change vec doesn't work properly with (arbitrary)
non-PODs that need non-trivial construction or destruction.
I know you haven't introduced that yourself, but just would like to discuss
the semantics we want.

To test, I've tried:
--- vec.c.xx	2020-01-12 11:54:38.533381424 +0100
+++ vec.c	2020-08-10 15:33:40.600680476 +0200
@@ -544,9 +544,34 @@ test_auto_delete_vec ()
 
 /* Run all of the selftests within this file.  */
 
+struct SSXS
+{
+  SSXS () { __builtin_printf ("SSXS ()\n"); }
+  SSXS (const SSXS &) { __builtin_printf ("SSXS (const SSXS &)\n"); }
+  SSXS &operator= (const SSXS &) { __builtin_printf ("operator= (const SSXS &)\n"); }
+  ~SSXS () { __builtin_printf ("~SSXS ()\n"); }
+  int s;
+};
+
 void
 vec_c_tests ()
 {
+  {
+    auto_vec<SSXS, 8> ssxs;
+    __builtin_printf ("constructed\n");
+    SSXS ssxso;
+    __builtin_printf ("ssxso\n");
+    for (int i = 0; i < 16; i++)
+      {
+        __builtin_printf ("safe_push start\n");
+        {
+          ssxs.safe_push (ssxso);
+        }
+        __builtin_printf ("safe_push end\n");
+      }
+    __builtin_printf ("about to destruct\n");
+  }
+  __builtin_printf ("destructed\n");
   test_quick_push ();
   test_safe_push ();
   test_truncate ();

and I see following.  Let me add comments to that.

#So auto_vec constructor will default initialize all m_data
#elements (i.e. all the embedded objects):
SSXS ()
SSXS ()
SSXS ()
SSXS ()
SSXS ()
SSXS ()
SSXS ()
SSXS ()
constructed
#And now the extra object I've created.
SSXS ()
ssxso
# Now, 8 times we invoke an assignment operator, the objects
# are already constructed, so all is good.
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
# Now, 9th safe_push, we ran out of room in the embedded buffer.
# vec_copy_construct will now copy construct the 8 elements
# in the new array which will be used from now on.
safe_push start
SSXS (const SSXS &)
SSXS (const SSXS &)
SSXS (const SSXS &)
SSXS (const SSXS &)
SSXS (const SSXS &)
SSXS (const SSXS &)
SSXS (const SSXS &)
SSXS (const SSXS &)
# But important note, we do not construct the object at new m_vecdata[8],
# only call assignment operator on it.  That is invalid C++, isn't it?
operator= (const SSXS &)
safe_push end
safe_push start
# And again, and again ...
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
safe_push start
operator= (const SSXS &)
safe_push end
about to destruct
# Now we destruct the 8 embedded elts in auto_vec plus the variable
# I had there, but the 16 elts of the m_vecdata array, 8 of those
# were copy constructed and then operator= modified, while
# the other 8 were only operator= set, are not destructed ever.
~SSXS ()
~SSXS ()
~SSXS ()
~SSXS ()
~SSXS ()
~SSXS ()
~SSXS ()
~SSXS ()
~SSXS ()
destructed

So, for vec on types with non-trivial construction and/or destruction, the
question is, do we want to construct the elements whenever underlying
storage for those is allocated (i.e. as now let the embedded buffer have
constructed elements and whenever we allocate new memory for the vector,
next to the vec_copy_construct where we copy construct the oldsize elts,
we also default construct the remaining ones) and then destruct when
deallocating the memory and then just use assignment operator to push stuff
in, or do we want the memory uninitialized instead and only copy construct
during quick_push and destruct during pop etc., i.e. only the currently
active elts are constructed and nothing else?  E.g. auto_vec m_data would
then need to be a different type (e.g. char array with appropriate alignas
and size) which wouldn't need non-trivial construction and destruction.

For types with trivial construction/destruction, I'd like to keep current
behavior...

	Jakub
Bill Schmidt via Gcc-patches Aug. 10, 2020, 4:58 p.m. | #40
On August 10, 2020 3:51:28 PM GMT+02:00, Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
>On Mon, Aug 10, 2020 at 02:57:31PM +0200, Aldy Hernandez wrote:

>> > I think it would be nice to see e.g. in -fdump-tree-gimple dump

>> > on ipa-fnsummary.c what value_range ctors does it call for the

>auto_vec and

>> > if that is what we want, other than that LGTM.

>> 

>> I see the following in the dump:

>> 

>> evaluate_properties_for_edge()

>> {

>> ...

>>   struct auto_vec known_value_ranges;

>> ...

>>   try

>>     {

>> ...

>>       auto_vec<int_range<1>, 32>::auto_vec (&known_value_ranges);

>> ...

>> 

>> It looks like the auto_vec constructor is calling the int_range<1>

>> constructor correctly:

>> 

>> auto_vec<int_range<1>, 32>::auto_vec (struct auto_vec * const this)

>> {

>> ...

>>     int_range<1>::int_range (D.130911);

>> 

>> 

>> The int_range<1> constructor also looks correct:

>> 

>> int_range<1>::int_range (struct int_range * const this, const struct

>> int_range & other)

>> {

>>   *this = {CLOBBER};

>>   {

>>     _1 = &this->D.92184;

>>     _2 = &this->m_ranges;

>>     irange::irange (_1, _2, 1);

>>     _3 = &this->D.92184;

>>     _4 = &other->D.92184;

>>     irange::operator= (_3, _4);

>>   }

>> }

>> 

>> If y'all agree, I will push the patch with Jakub's suggested changes.

>

>I believe even with that change vec doesn't work properly with

>(arbitrary)

>non-PODs that need non-trivial construction or destruction.

>I know you haven't introduced that yourself, but just would like to

>discuss

>the semantics we want.

>

>To test, I've tried:

>--- vec.c.xx	2020-01-12 11:54:38.533381424 +0100

>+++ vec.c	2020-08-10 15:33:40.600680476 +0200

>@@ -544,9 +544,34 @@ test_auto_delete_vec ()

> 

> /* Run all of the selftests within this file.  */

> 

>+struct SSXS

>+{

>+  SSXS () { __builtin_printf ("SSXS ()\n"); }

>+  SSXS (const SSXS &) { __builtin_printf ("SSXS (const SSXS &)\n"); }

>+  SSXS &operator= (const SSXS &) { __builtin_printf ("operator= (const

>SSXS &)\n"); }

>+  ~SSXS () { __builtin_printf ("~SSXS ()\n"); }

>+  int s;

>+};

>+

> void

> vec_c_tests ()

> {

>+  {

>+    auto_vec<SSXS, 8> ssxs;

>+    __builtin_printf ("constructed\n");

>+    SSXS ssxso;

>+    __builtin_printf ("ssxso\n");

>+    for (int i = 0; i < 16; i++)

>+      {

>+        __builtin_printf ("safe_push start\n");

>+        {

>+          ssxs.safe_push (ssxso);

>+        }

>+        __builtin_printf ("safe_push end\n");

>+      }

>+    __builtin_printf ("about to destruct\n");

>+  }

>+  __builtin_printf ("destructed\n");

>   test_quick_push ();

>   test_safe_push ();

>   test_truncate ();

>

>and I see following.  Let me add comments to that.

>

>#So auto_vec constructor will default initialize all m_data

>#elements (i.e. all the embedded objects):

>SSXS ()

>SSXS ()

>SSXS ()

>SSXS ()

>SSXS ()

>SSXS ()

>SSXS ()

>SSXS ()

>constructed

>#And now the extra object I've created.

>SSXS ()

>ssxso

># Now, 8 times we invoke an assignment operator, the objects

># are already constructed, so all is good.

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

># Now, 9th safe_push, we ran out of room in the embedded buffer.

># vec_copy_construct will now copy construct the 8 elements

># in the new array which will be used from now on.

>safe_push start

>SSXS (const SSXS &)

>SSXS (const SSXS &)

>SSXS (const SSXS &)

>SSXS (const SSXS &)

>SSXS (const SSXS &)

>SSXS (const SSXS &)

>SSXS (const SSXS &)

>SSXS (const SSXS &)

># But important note, we do not construct the object at new

>m_vecdata[8],

># only call assignment operator on it.  That is invalid C++, isn't it?

>operator= (const SSXS &)

>safe_push end

>safe_push start

># And again, and again ...

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>safe_push start

>operator= (const SSXS &)

>safe_push end

>about to destruct

># Now we destruct the 8 embedded elts in auto_vec plus the variable

># I had there, but the 16 elts of the m_vecdata array, 8 of those

># were copy constructed and then operator= modified, while

># the other 8 were only operator= set, are not destructed ever.

>~SSXS ()

>~SSXS ()

>~SSXS ()

>~SSXS ()

>~SSXS ()

>~SSXS ()

>~SSXS ()

>~SSXS ()

>~SSXS ()

>destructed

>

>So, for vec on types with non-trivial construction and/or destruction,

>the

>question is, do we want to construct the elements whenever underlying

>storage for those is allocated (i.e. as now let the embedded buffer

>have

>constructed elements and whenever we allocate new memory for the

>vector,

>next to the vec_copy_construct where we copy construct the oldsize

>elts,

>we also default construct the remaining ones) and then destruct when

>deallocating the memory and then just use assignment operator to push

>stuff

>in, or do we want the memory uninitialized instead and only copy

>construct

>during quick_push and destruct during pop etc., i.e. only the currently

>active elts are constructed and nothing else?  E.g. auto_vec m_data

>would

>then need to be a different type (e.g. char array with appropriate

>alignas

>and size) which wouldn't need non-trivial construction and destruction.

>

>For types with trivial construction/destruction, I'd like to keep

>current

>behavior...


We want to construct / destruct on push/pop, not on allocation. We also want to use std::move upon reallocation (but then we can't use realloc, can we?) 

Richard. 

>	Jakub
Bill Schmidt via Gcc-patches Aug. 10, 2020, 5:18 p.m. | #41
On Mon, Aug 10, 2020 at 06:58:52PM +0200, Richard Biener wrote:
> We want to construct / destruct on push/pop, not on allocation.

> We also want to use std::move upon reallocation (but then we can't use realloc, can we?) 


I guess so, but we could stop using xrealloc or ggc_realloc only for types
which aren't trivially moveable using some template magic.

	Jakub
Bill Schmidt via Gcc-patches Aug. 10, 2020, 6:03 p.m. | #42
On Mon, Aug 10, 2020 at 03:05:26PM +0200, Aldy Hernandez wrote:
> For the record.  The final patch (below) passes tests on ppc64le for both

> trunk, and the ranger-staging branch with ranger enabled.

> 

> Aldy

> 

> gcc/ChangeLog:

> 

> 	* ipa-fnsummary.c (evaluate_conditions_for_known_args):

> 	(evaluate_properties_for_edge):

> 	(ipa_fn_summary_t::duplicate):

> 	(estimate_ipcp_clone_size_and_time):

> 	* vec.h (vl_embed>::embedded_size):


You didn't say what you've changed, supposedly for the first one
Revert 2020-08-?? change., then 3 times Likewise. and finally
something describing the actual change?

Anyway, this is ok for trunk, let's do the proper ctor/dtor/move handling
incrementally.

	Jakub
Tobias Burnus Aug. 13, 2020, 11:38 a.m. | #43
Hi,

I got a bit lost in this thread – but the
commit r11-2663-g82c4b78dbef6f03838e3040688c934360a09513f
"Replace std::vector<> usage in ipa-fnsummary.c with GCC's vec<>."

Causes here:

gcc-mainline/gcc/vec.h:1287:3: error: static assertion failed:
    static_assert (alignof (vec_embedded) == alignof(vec), "");
    ^
for a '--build=i686-pc-linux-gnu --host=powerpc64le-linux-gnu --target=nvptx-none'
build.

Tobias


On 8/7/20 8:04 PM, Aldy Hernandez via Gcc-patches wrote:

> Is the attached patch what y'all suggest?

>

> The patch reverts the GCC vec<> usage in ipa-fnsummary.c and

> implements the above suggestion.

>

> Bootstraps, tests running...

>

> If tests pass, is this OK?

>

> Thanks.

> Aldy

>

> On Fri, Aug 7, 2020 at 11:17 AM Jonathan Wakely via Gcc-patches

> <gcc-patches@gcc.gnu.org> wrote:

>> On 07/08/20 10:55 +0200, Jakub Jelinek wrote:

>>> On Fri, Aug 07, 2020 at 09:34:38AM +0100, Jonathan Wakely via Gcc-patches wrote:

>>>>> Now that you say it, vec has a T[1] member so depending on T

>>>>> there might be a side-effect as invoking its CTOR?  Or it might

>>>>> even not compile if there is no default CTOR available...  Ick :/

>>>> Right.

>>>>

>>>> Does the GTY stuff add members to the struct, or otherwise alter its

>>>> layout?

>>> Or perhaps use offsetof on an alternate structure that should have the same

>>> layout.

>> Yes that's what I was going to suggest next.

>>

>>> So instead of

>>>   typedef vec<T, A, vl_embed> vec_embedded;

>>>   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>>> use

>>>   struct alignas (T) U { char data[sizeof (T)]; };

>>>   typedef vec<U, A, vl_embed> vec_embedded;

>> static_assert(sizeof(vec_embedded) == sizeof(vec), "");

>> static_assert(alignof(vec_embedded) == alignof(vec), "");

>>

>>>   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>>> where vec_embedded should have the same offset of m_vecdata as vec.

-----------------
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Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Alexander Walter
Bill Schmidt via Gcc-patches Aug. 13, 2020, 11:52 a.m. | #44
On Thu, Aug 13, 2020 at 01:38:07PM +0200, Tobias Burnus wrote:
> Hi,

> 

> I got a bit lost in this thread – but the

> commit r11-2663-g82c4b78dbef6f03838e3040688c934360a09513f

> "Replace std::vector<> usage in ipa-fnsummary.c with GCC's vec<>."

> 

> Causes here:

> 

> gcc-mainline/gcc/vec.h:1287:3: error: static assertion failed:

>    static_assert (alignof (vec_embedded) == alignof(vec), "");

>    ^

> for a '--build=i686-pc-linux-gnu --host=powerpc64le-linux-gnu --target=nvptx-none'

> build.


On which instantiation it is and what is your system compiler?
Do you get when building the i686 native compiler, or i686 to powerpc64le cross-compiler
or powerpc64le to nvptx-none cross-compiler?

	Jakub
Tobias Burnus Aug. 13, 2020, 12:06 p.m. | #45
On 8/13/20 1:52 PM, Jakub Jelinek wrote:

> On Thu, Aug 13, 2020 at 01:38:07PM +0200, Tobias Burnus wrote:

>> I got a bit lost in this thread – but the

>> commit r11-2663-g82c4b78dbef6f03838e3040688c934360a09513f

>> "Replace std::vector<> usage in ipa-fnsummary.c with GCC's vec<>."

>>

>> Causes here:

>>

>> gcc-mainline/gcc/vec.h:1287:3: error: static assertion failed:

>>     static_assert (alignof (vec_embedded) == alignof(vec), "");

>>     ^

> On which instantiation it is and what is your system compiler?

> Do you get when building the i686 native compiler, or i686 to powerpc64le cross-compiler

> or powerpc64le to nvptx-none cross-compiler?


Build server is x86_64-gnu-linux, "i686-pc-linux-gnu-g++" is a native binary of GCC 5.2.0
[Don't ask why i686 and not x86_64 is used.]

Run command was:

i686-pc-linux-gnu-g++  -std=gnu++11 -c -DIN_GCC  -DCROSS_DIRECTORY_STRUCTURE    -DGENERATOR_FILE  -I. -Ibuild -I.../gcc-mainline/gcc -I.../gcc-mainline/gcc/build -I.../gcc-mainline/gcc/../include  -I.../gcc-mainline/gcc/../libcpp/include  \
         -o build/genemit.o .../gcc-mainline/gcc/genemit.c
In file included from .../gcc-mainline/gcc/rtl.h:30:0,
                  from .../gcc-mainline/gcc/genautomata.c:111:
.../gcc-mainline/gcc/vec.h: In instantiation of 'static size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T = long long int; A = va_heap; size_t = unsigned int]':
.../gcc-mainline/gcc/vec.h:288:58:   required from 'static void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, bool) [with T = long long int]'
.../gcc-mainline/gcc/vec.h:1749:20:   required from 'bool vec<T>::reserve(unsigned int, bool) [with T = long long int]'
.../gcc-mainline/gcc/vec.h:1858:11:   required from 'T* vec<T>::safe_push(const T&) [with T = long long int]'
.../gcc-mainline/gcc/genautomata.c:7454:40:   required from here
.../gcc-mainline/gcc/vec.h:1287:3: error: static assertion failed:
    static_assert (alignof (vec_embedded) == alignof(vec), "");
    ^
Makefile:2719: recipe for target 'build/genautomata.o' failed
make[1]: *** [build/genautomata.o] Error 1

Tobias

-----------------
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Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Alexander Walter
Bill Schmidt via Gcc-patches Aug. 13, 2020, 12:25 p.m. | #46
On Thu, Aug 13, 2020 at 02:06:21PM +0200, Tobias Burnus wrote:
> Build server is x86_64-gnu-linux, "i686-pc-linux-gnu-g++" is a native binary of GCC 5.2.0

> [Don't ask why i686 and not x86_64 is used.]


Ah, ok, so this boils down to:
int i = alignof (long long int);
struct TTT { char a; long long int b; };
int j = alignof (TTT);
ending up to be 8, 4 with -O2 -m32 in GCC 4.8 - 7.x and
only in GCC 8+ 4, 4.

So perhaps we want:
--- gcc/vec.h.jj	2020-08-12 12:45:58.410686880 +0200
+++ gcc/vec.h	2020-08-13 14:18:06.967041880 +0200
@@ -1281,10 +1281,11 @@ template<typename T, typename A>
 inline size_t
 vec<T, A, vl_embed>::embedded_size (unsigned alloc)
 {
-  struct alignas (T) U { char data[sizeof (T)]; };
+  struct V { char a; T b; };
+  struct alignas (V) U { char data[sizeof (T)]; };
   typedef vec<U, A, vl_embed> vec_embedded;
-  static_assert (sizeof (vec_embedded) == sizeof(vec), "");
-  static_assert (alignof (vec_embedded) == alignof(vec), "");
+  static_assert (sizeof (vec_embedded) == sizeof (vec), "");
+  static_assert (alignof (vec_embedded) == alignof (vec), "");
   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
 }

or
--- gcc/vec.h.jj	2020-08-12 12:45:58.410686880 +0200
+++ gcc/vec.h	2020-08-13 14:18:06.967041880 +0200
@@ -1281,10 +1281,11 @@ template<typename T, typename A>
 inline size_t
 vec<T, A, vl_embed>::embedded_size (unsigned alloc)
 {
-  struct alignas (T) U { char data[sizeof (T)]; };
+  struct V { char a; T b; } *v;
+  struct alignas (alignof (v->b)) U { char data[sizeof (T)]; };
   typedef vec<U, A, vl_embed> vec_embedded;
-  static_assert (sizeof (vec_embedded) == sizeof(vec), "");
-  static_assert (alignof (vec_embedded) == alignof(vec), "");
+  static_assert (sizeof (vec_embedded) == sizeof (vec), "");
+  static_assert (alignof (vec_embedded) == alignof (vec), "");
   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
 }
 
?

	Jakub
Bill Schmidt via Gcc-patches Aug. 13, 2020, 12:40 p.m. | #47
On Thu, Aug 13, 2020 at 02:25:42PM +0200, Jakub Jelinek via Gcc-patches wrote:
> --- gcc/vec.h.jj	2020-08-12 12:45:58.410686880 +0200

> +++ gcc/vec.h	2020-08-13 14:18:06.967041880 +0200

> @@ -1281,10 +1281,11 @@ template<typename T, typename A>

>  inline size_t

>  vec<T, A, vl_embed>::embedded_size (unsigned alloc)

>  {

> -  struct alignas (T) U { char data[sizeof (T)]; };

> +  struct V { char a; T b; } *v;

> +  struct alignas (alignof (v->b)) U { char data[sizeof (T)]; };

>    typedef vec<U, A, vl_embed> vec_embedded;

> -  static_assert (sizeof (vec_embedded) == sizeof(vec), "");

> -  static_assert (alignof (vec_embedded) == alignof(vec), "");

> +  static_assert (sizeof (vec_embedded) == sizeof (vec), "");

> +  static_assert (alignof (vec_embedded) == alignof (vec), "");

>    return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

>  }

>  


I guess this version is better.  Or maybe we should use the old
embedded_size version with offsetof for std::is_standard_layout (T)
and only use the new one (and in that case we don't need hacks like this
otherwise)?

	Jakub
Bill Schmidt via Gcc-patches Aug. 13, 2020, 12:46 p.m. | #48
Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:

> On Thu, Aug 13, 2020 at 02:06:21PM +0200, Tobias Burnus wrote:

>> Build server is x86_64-gnu-linux, "i686-pc-linux-gnu-g++" is a native  

>> binary of GCC 5.2.0

>> [Don't ask why i686 and not x86_64 is used.]

>

> Ah, ok, so this boils down to:

> int i = alignof (long long int);

> struct TTT { char a; long long int b; };

> int j = alignof (TTT);

> ending up to be 8, 4 with -O2 -m32 in GCC 4.8 - 7.x and

> only in GCC 8+ 4, 4.


Also the case for long long (darwin) and double (darwin, aix) where the  
embedded alignmen
is 4 and the natural aligment is 8 - as ABI (so in dependent of compiler  
version).
(which breaks bootstrap on all 32b Darwin hosts at least)

If the desired outcome is that the embedded vector is aligned to the  
natural alignment
of the type that could be forced on that field of the vec?

Iain


>

> So perhaps we want:

> --- gcc/vec.h.jj	2020-08-12 12:45:58.410686880 +0200

> +++ gcc/vec.h	2020-08-13 14:18:06.967041880 +0200

> @@ -1281,10 +1281,11 @@ template<typename T, typename A>

> inline size_t

> vec<T, A, vl_embed>::embedded_size (unsigned alloc)

> {

> -  struct alignas (T) U { char data[sizeof (T)]; };

> +  struct V { char a; T b; };

> +  struct alignas (V) U { char data[sizeof (T)]; };

>   typedef vec<U, A, vl_embed> vec_embedded;

> -  static_assert (sizeof (vec_embedded) == sizeof(vec), "");

> -  static_assert (alignof (vec_embedded) == alignof(vec), "");

> +  static_assert (sizeof (vec_embedded) == sizeof (vec), "");

> +  static_assert (alignof (vec_embedded) == alignof (vec), "");

>   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> }

>

> or

> --- gcc/vec.h.jj	2020-08-12 12:45:58.410686880 +0200

> +++ gcc/vec.h	2020-08-13 14:18:06.967041880 +0200

> @@ -1281,10 +1281,11 @@ template<typename T, typename A>

> inline size_t

> vec<T, A, vl_embed>::embedded_size (unsigned alloc)

> {

> -  struct alignas (T) U { char data[sizeof (T)]; };

> +  struct V { char a; T b; } *v;

> +  struct alignas (alignof (v->b)) U { char data[sizeof (T)]; };

>   typedef vec<U, A, vl_embed> vec_embedded;

> -  static_assert (sizeof (vec_embedded) == sizeof(vec), "");

> -  static_assert (alignof (vec_embedded) == alignof(vec), "");

> +  static_assert (sizeof (vec_embedded) == sizeof (vec), "");

> +  static_assert (alignof (vec_embedded) == alignof (vec), "");

>   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);

> }

>

> ?

>

> 	Jakub
Iain Sandoe Aug. 13, 2020, 12:55 p.m. | #49
Iain Sandoe via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:

> Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:

>

>> On Thu, Aug 13, 2020 at 02:06:21PM +0200, Tobias Burnus wrote:

>>> Build server is x86_64-gnu-linux, "i686-pc-linux-gnu-g++" is a native  

>>> binary of GCC 5.2.0

>>> [Don't ask why i686 and not x86_64 is used.]

>>

>> Ah, ok, so this boils down to:

>> int i = alignof (long long int);

>> struct TTT { char a; long long int b; };

>> int j = alignof (TTT);

>> ending up to be 8, 4 with -O2 -m32 in GCC 4.8 - 7.x and

>> only in GCC 8+ 4, 4.

>

> Also the case for long long (darwin) and double (darwin, aix) where the  

> embedded alignmen

> is 4 and the natural aligment is 8 - as ABI (so in dependent of compiler  

> version).

> (which breaks bootstrap on all 32b Darwin hosts at least)

>

> If the desired outcome is that the embedded vector is aligned to the  

> natural alignment

> of the type that could be forced on that field of the vec?


i.e:

diff --git a/gcc/vec.h b/gcc/vec.h
index db48e97..a8fca34 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -623,7 +623,7 @@ public:
    /* FIXME - These fields should be private, but we need to cater to
  	     compilers that have stricter notions of PODness for types.  */
    vec_prefix m_vecpfx;
-  T m_vecdata[1];
+  T m_vecdata[1] __attribute__((__aligned__(alignof(T))));
  };
Bill Schmidt via Gcc-patches Aug. 13, 2020, 1 p.m. | #50
On Thu, Aug 13, 2020 at 01:46:53PM +0100, Iain Sandoe wrote:
> Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:

> 

> > On Thu, Aug 13, 2020 at 02:06:21PM +0200, Tobias Burnus wrote:

> > > Build server is x86_64-gnu-linux, "i686-pc-linux-gnu-g++" is a

> > > native binary of GCC 5.2.0

> > > [Don't ask why i686 and not x86_64 is used.]

> > 

> > Ah, ok, so this boils down to:

> > int i = alignof (long long int);

> > struct TTT { char a; long long int b; };

> > int j = alignof (TTT);

> > ending up to be 8, 4 with -O2 -m32 in GCC 4.8 - 7.x and

> > only in GCC 8+ 4, 4.

> 

> Also the case for long long (darwin) and double (darwin, aix) where the

> embedded alignmen

> is 4 and the natural aligment is 8 - as ABI (so in dependent of compiler

> version).

> (which breaks bootstrap on all 32b Darwin hosts at least)

> 

> If the desired outcome is that the embedded vector is aligned to the natural

> alignment

> of the type that could be forced on that field of the vec?


The desired outcome is to get the offsetof value even for
vec with non-standard-layout type payload, and so in that case build

	Jakub
Bill Schmidt via Gcc-patches Aug. 13, 2020, 1:04 p.m. | #51
On Thu, Aug 13, 2020 at 01:55:40PM +0100, Iain Sandoe wrote:
> diff --git a/gcc/vec.h b/gcc/vec.h

> index db48e97..a8fca34 100644

> --- a/gcc/vec.h

> +++ b/gcc/vec.h

> @@ -623,7 +623,7 @@ public:

>    /* FIXME - These fields should be private, but we need to cater to

>  	     compilers that have stricter notions of PODness for types.  */

>    vec_prefix m_vecpfx;

> -  T m_vecdata[1];

> +  T m_vecdata[1] __attribute__((__aligned__(alignof(T))));


That uses an extension, so won't help us if the system compiler doesn't
support that extension, and will unnecessarily waste bytes in all the long
long (and some double?) vecs.

Perhaps even better we can just use vec itself rather than creating a new
artificial type, and just query the alignof the m_vecdata member in that
case:

--- gcc/vec.h.jj	2020-08-12 12:45:58.410686880 +0200
+++ gcc/vec.h	2020-08-13 15:03:15.823777382 +0200
@@ -1281,10 +1281,11 @@ template<typename T, typename A>
 inline size_t
 vec<T, A, vl_embed>::embedded_size (unsigned alloc)
 {
-  struct alignas (T) U { char data[sizeof (T)]; };
+  vec *v;
+  struct alignas (alignof (v->m_vecdata)) U { char data[sizeof (T)]; };
   typedef vec<U, A, vl_embed> vec_embedded;
-  static_assert (sizeof (vec_embedded) == sizeof(vec), "");
-  static_assert (alignof (vec_embedded) == alignof(vec), "");
+  static_assert (sizeof (vec_embedded) == sizeof (vec), "");
+  static_assert (alignof (vec_embedded) == alignof (vec), "");
   return offsetof (vec_embedded, m_vecdata) + alloc * sizeof (T);
 }
 


	Jakub
Bill Schmidt via Gcc-patches Aug. 24, 2020, 9:53 p.m. | #52
On Wed, 2020-08-05 at 17:41 +0200, Aldy Hernandez wrote:
> On 8/5/20 5:09 PM, Martin Jambor wrote:

> 

> > On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

> > 

> > [...]

> > 

> > > * ipa-cp changes from vec<value_range> to std::vec<value_range>.

> > > 

> > > We are using std::vec to ensure constructors are run, which they aren't

> > > in our internal vec<> implementation.  Although we usually steer away

> > > from using std::vec because of interactions with our GC system,

> > > ipcp_param_lattices is only live within the pass and allocated with calloc.

> > > 

> > 

> > Ummm... I did not object but I will save the URL of this message in the

> > archive so that I can waive it in front of anyone complaining why I

> > don't use our internal vec's in IPA data structures.

> > 

> > But it actually raises a broader question: was this supposed to be an

> > exception, allowed only not to complicate the irange patch further, or

> > will this be generally accepted thing to do when someone wants to have a

> > vector of constructed items?

> 

> I don't want to start a precedent without further discussion, so let's 

> assume this was an exception.

I'd characterize it as an exception too.  When I looked at the patch for Aldy, I
called out this code as well and asked him to justify it and convince me it was
safe, which he did.  I'd to the same for anything else adding use of a standard
C++ container to hold a GC-able object.

I'd certainly like to get to a place where we could be using more standard C++
library components.  But it'll take time to get there and consensus within the
project.

jeff
>
Bill Schmidt via Gcc-patches Aug. 24, 2020, 10:03 p.m. | #53
On 8/24/20 5:53 PM, Jeff Law wrote:
> On Wed, 2020-08-05 at 17:41 +0200, Aldy Hernandez wrote:

>> On 8/5/20 5:09 PM, Martin Jambor wrote:

>>

>>> On Fri, Jul 31 2020, Aldy Hernandez via Gcc-patches wrote:

>>>

>>> [...]

>>>

>>>> * ipa-cp changes from vec<value_range> to std::vec<value_range>.

>>>>

>>>> We are using std::vec to ensure constructors are run, which they aren't

>>>> in our internal vec<> implementation.  Although we usually steer away

>>>> from using std::vec because of interactions with our GC system,

>>>> ipcp_param_lattices is only live within the pass and allocated with calloc.

>>>>

>>> Ummm... I did not object but I will save the URL of this message in the

>>> archive so that I can waive it in front of anyone complaining why I

>>> don't use our internal vec's in IPA data structures.

>>>

>>> But it actually raises a broader question: was this supposed to be an

>>> exception, allowed only not to complicate the irange patch further, or

>>> will this be generally accepted thing to do when someone wants to have a

>>> vector of constructed items?

>> I don't want to start a precedent without further discussion, so let's

>> assume this was an exception.

> I'd characterize it as an exception too.  When I looked at the patch for Aldy, I

> called out this code as well and asked him to justify it and convince me it was

> safe, which he did.  I'd to the same for anything else adding use of a standard

> C++ container to hold a GC-able object.

>

> I'd certainly like to get to a place where we could be using more standard C++

> library components.  But it'll take time to get there and consensus within the

> project.

>

> jeff

I think there were adjustments made to gcc's vec, and the usage of 
std::vector is no longer present..

I also think it was not a long term perfect solution, but adequate for 
our needs at the moment.

Personally, I have no issue with std::vector when approriate.. too bad 
we can make it adequate for all our usage  :-P  That is a much bigger 
issue I am afraid.

Andrew

Patch

commit f6ec639a86fbf98055f3506cf16286d616dc18ce
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Thu Jul 30 11:30:18 2020 +0200

    Multi-range implementation for value_range (irange).
    
    Implement class irange, a generic multi-range implementation for
    value ranges.  This class is API compatible with value_range, and is meant
    to seamlessly coexist with it.
    
    gcc/ChangeLog:
    
            * Makefile.in (GTFILES): Move value-range.h up.
            * gengtype-lex.l: Set yylval to handle GTY markers on templates.
            * ipa-cp.c (initialize_node_lattices): Call value_range
            constructor.
            (ipcp_propagate_stage): Use in-place new so value_range construct
            is called.
            * ipa-fnsummary.c (evaluate_conditions_for_known_args): Use std
            vec instead of GCC's vec<>.
            (evaluate_properties_for_edge): Adjust for std vec.
            (ipa_fn_summary_t::duplicate): Same.
            (estimate_ipcp_clone_size_and_time): Same.
            * ipa-prop.c (ipa_get_value_range): Use in-place new for
            value_range.
            * ipa-prop.h (struct GTY): Remove class keyword for m_vr.
            * range-op.cc (empty_range_check): Rename to...
            (empty_range_varying): ...this and adjust for varying.
            (undefined_shift_range_check): Adjust for irange.
            (range_operator::wi_fold): Same.
            (range_operator::fold_range): Adjust for irange.  Special case
            single pairs for performance.
            (range_operator::op1_range): Adjust for irange.
            (range_operator::op2_range): Same.
            (value_range_from_overflowed_bounds): Same.
            (value_range_with_overflow): Same.
            (create_possibly_reversed_range): Same.
            (range_true): Same.
            (range_false): Same.
            (range_true_and_false): Same.
            (get_bool_state):  Adjust for irange and tweak for performance.
            (operator_equal::fold_range): Adjust for irange.
            (operator_equal::op1_range): Same.
            (operator_equal::op2_range): Same.
            (operator_not_equal::fold_range): Same.
            (operator_not_equal::op1_range): Same.
            (operator_not_equal::op2_range): Same.
            (build_lt): Same.
            (build_le): Same.
            (build_gt): Same.
            (build_ge): Same.
            (operator_lt::fold_range): Same.
            (operator_lt::op1_range): Same.
            (operator_lt::op2_range): Same.
            (operator_le::fold_range): Same.
            (operator_le::op1_range): Same.
            (operator_le::op2_range): Same.
            (operator_gt::fold_range): Same.
            (operator_gt::op1_range): Same.
            (operator_gt::op2_range): Same.
            (operator_ge::fold_range): Same.
            (operator_ge::op1_range): Same.
            (operator_ge::op2_range): Same.
            (operator_plus::wi_fold): Same.
            (operator_plus::op1_range): Same.
            (operator_plus::op2_range): Same.
            (operator_minus::wi_fold): Same.
            (operator_minus::op1_range): Same.
            (operator_minus::op2_range): Same.
            (operator_min::wi_fold): Same.
            (operator_max::wi_fold): Same.
            (cross_product_operator::wi_cross_product): Same.
            (operator_mult::op1_range): New.
            (operator_mult::op2_range): New.
            (operator_mult::wi_fold): Adjust for irange.
            (operator_div::wi_fold): Same.
            (operator_exact_divide::op1_range): Same.
            (operator_lshift::fold_range): Same.
            (operator_lshift::wi_fold): Same.
            (operator_lshift::op1_range): New.
            (operator_rshift::op1_range): New.
            (operator_rshift::fold_range): Adjust for irange.
            (operator_rshift::wi_fold): Same.
            (operator_cast::truncating_cast_p): Abstract out from
            operator_cast::fold_range.
            (operator_cast::fold_range): Adjust for irange and tweak for
            performance.
            (operator_cast::inside_domain_p): Abstract out from fold_range.
            (operator_cast::fold_pair): Same.
            (operator_cast::op1_range): Use abstracted methods above.  Adjust
            for irange and tweak for performance.
            (operator_logical_and::fold_range): Adjust for irange.
            (operator_logical_and::op1_range): Same.
            (operator_logical_and::op2_range): Same.
            (unsigned_singleton_p): New.
            (operator_bitwise_and::remove_impossible_ranges): New.
            (operator_bitwise_and::fold_range): New.
            (wi_optimize_and_or):  Adjust for irange.
            (operator_bitwise_and::wi_fold): Same.
            (set_nonzero_range_from_mask): New.
            (operator_bitwise_and::simple_op1_range_solver): New.
            (operator_bitwise_and::op1_range): Adjust for irange.
            (operator_bitwise_and::op2_range): Same.
            (operator_logical_or::fold_range): Same.
            (operator_logical_or::op1_range): Same.
            (operator_logical_or::op2_range): Same.
            (operator_bitwise_or::wi_fold): Same.
            (operator_bitwise_or::op1_range): Same.
            (operator_bitwise_or::op2_range): Same.
            (operator_bitwise_xor::wi_fold): Same.
            (operator_bitwise_xor::op1_range): New.
            (operator_bitwise_xor::op2_range): New.
            (operator_trunc_mod::wi_fold):  Adjust for irange.
            (operator_logical_not::fold_range): Same.
            (operator_logical_not::op1_range): Same.
            (operator_bitwise_not::fold_range): Same.
            (operator_bitwise_not::op1_range): Same.
            (operator_cst::fold_range): Same.
            (operator_identity::fold_range): Same.
            (operator_identity::op1_range): Same.
            (class operator_unknown): New.
            (operator_unknown::fold_range): New.
            (class operator_abs): Adjust for irange.
            (operator_abs::wi_fold): Same.
            (operator_abs::op1_range): Same.
            (operator_absu::wi_fold): Same.
            (class operator_negate): Same.
            (operator_negate::fold_range): Same.
            (operator_negate::op1_range): Same.
            (operator_addr_expr::fold_range): Same.
            (operator_addr_expr::op1_range): Same.
            (pointer_plus_operator::wi_fold): Same.
            (pointer_min_max_operator::wi_fold): Same.
            (pointer_and_operator::wi_fold): Same.
            (pointer_or_operator::op1_range): New.
            (pointer_or_operator::op2_range): New.
            (pointer_or_operator::wi_fold):  Adjust for irange.
            (integral_table::integral_table): Add entries for IMAGPART_EXPR
            and POINTER_DIFF_EXPR.
            (range_cast):  Adjust for irange.
            (build_range3): New.
            (range3_tests): New.
            (widest_irange_tests): New.
            (multi_precision_range_tests): New.
            (operator_tests): New.
            (range_tests): New.
            * range-op.h (class range_operator): Adjust for irange.
            (range_cast): Same.
            * tree-vrp.c (range_fold_binary_symbolics_p): Adjust for irange and
            tweak for performance.
            (range_fold_binary_expr): Same.
            (masked_increment): Change to extern.
            * tree-vrp.h (masked_increment): New.
            * tree.c (cache_wide_int_in_type_cache): New function abstracted
            out from wide_int_to_tree_1.
            (wide_int_to_tree_1): Cache 0, 1, and MAX for pointers.
            * value-range-equiv.cc (value_range_equiv::deep_copy): Use kind
            method.
            (value_range_equiv::move): Same.
            (value_range_equiv::check): Adjust for irange.
            (value_range_equiv::intersect): Same.
            (value_range_equiv::union_): Same.
            (value_range_equiv::dump): Same.
            * value-range.cc (irange::operator=): Same.
            (irange::maybe_anti_range): New.
            (irange::copy_legacy_range): New.
            (irange::set_undefined): Adjust for irange.
            (irange::swap_out_of_order_endpoints): Abstract out from set().
            (irange::set_varying): Adjust for irange.
            (irange::irange_set): New.
            (irange::irange_set_anti_range): New.
            (irange::set): Adjust for irange.
            (value_range::set_nonzero): Move to header file.
            (value_range::set_zero): Move to header file.
            (value_range::check): Rename to...
            (irange::verify_range): ...this.
            (value_range::num_pairs): Rename to...
            (irange::legacy_num_pairs): ...this, and adjust for irange.
            (value_range::lower_bound): Rename to...
            (irange::legacy_lower_bound): ...this, and adjust for irange.
            (value_range::upper_bound): Rename to...
            (irange::legacy_upper_bound): ...this, and adjust for irange.
            (value_range::equal_p): Rename to...
            (irange::legacy_equal_p): ...this.
            (value_range::operator==): Move to header file.
            (irange::equal_p): New.
            (irange::symbolic_p): Adjust for irange.
            (irange::constant_p): Same.
            (irange::singleton_p): Same.
            (irange::value_inside_range): Same.
            (irange::may_contain_p): Same.
            (irange::contains_p): Same.
            (irange::normalize_addresses): Same.
            (irange::normalize_symbolics): Same.
            (irange::legacy_intersect): Same.
            (irange::legacy_union): Same.
            (irange::union_): Same.
            (irange::intersect): Same.
            (irange::irange_union): New.
            (irange::irange_intersect): New.
            (subtract_one): New.
            (irange::invert): Adjust for irange.
            (dump_bound_with_infinite_markers): New.
            (irange::dump): Adjust for irange.
            (debug): Add irange versions.
            (range_has_numeric_bounds_p): Adjust for irange.
            (vrp_val_max): Move to header file.
            (vrp_val_min): Move to header file.
            (DEFINE_INT_RANGE_GC_STUBS): New.
            (DEFINE_INT_RANGE_INSTANCE): New.
            * value-range.h (class irange): New.
            (class int_range): New.
            (class value_range): Rename to a instantiation of int_range.
            (irange::legacy_mode_p): New.
            (value_range::value_range): Remove.
            (irange::kind): New.
            (irange::num_pairs): Adjust for irange.
            (irange::type): Adjust for irange.
            (irange::tree_lower_bound): New.
            (irange::tree_upper_bound): New.
            (irange::type): Adjust for irange.
            (irange::min): Same.
            (irange::max): Same.
            (irange::varying_p): Same.
            (irange::undefined_p): Same.
            (irange::zero_p): Same.
            (irange::nonzero_p): Same.
            (irange::supports_type_p): Same.
            (range_includes_zero_p): Same.
            (gt_ggc_mx): New.
            (gt_pch_nx): New.
            (irange::irange): New.
            (int_range::int_range): New.
            (int_range::operator=): New.
            (irange::set): Moved from value-range.cc and adjusted for irange.
            (irange::set_undefined): Same.
            (irange::set_varying): Same.
            (irange::operator==): Same.
            (irange::lower_bound): Same.
            (irange::upper_bound): Same.
            (irange::union_): Same.
            (irange::intersect): Same.
            (irange::set_nonzero): Same.
            (irange::set_zero): Same.
            (irange::normalize_min_max): New.
            (vrp_val_max): Move from value-range.cc.
            (vrp_val_min): Same.
            * vr-values.c (vr_values::get_lattice_entry): Call value_range
            constructor.

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 4208c6285b6..7251c007907 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -2628,13 +2628,13 @@  GTFILES = $(CPPLIB_H) $(srcdir)/input.h $(srcdir)/coretypes.h \
   $(srcdir)/tree-ssa-alias.h \
   $(srcdir)/tree-ssanames.h \
   $(srcdir)/tree-vrp.h \
+  $(srcdir)/value-range.h \
   $(srcdir)/ipa-prop.h \
   $(srcdir)/trans-mem.c \
   $(srcdir)/lto-streamer.h \
   $(srcdir)/target-globals.h \
   $(srcdir)/ipa-predicate.h \
   $(srcdir)/ipa-fnsummary.h \
-  $(srcdir)/value-range.h \
   $(srcdir)/vtable-verify.c \
   $(srcdir)/asan.c \
   $(srcdir)/ubsan.c \
diff --git a/gcc/gengtype-lex.l b/gcc/gengtype-lex.l
index a5e9d2b1de6..9bf6ffa73c4 100644
--- a/gcc/gengtype-lex.l
+++ b/gcc/gengtype-lex.l
@@ -125,7 +125,10 @@  CXX_KEYWORD inline|public:|private:|protected:|template|operator|friend|static|m
 "ptr_alias"/{EOID}	  	{ return PTR_ALIAS; }
 "nested_ptr"/{EOID}		{ return NESTED_PTR; }
 "user"/{EOID}			{ return USER_GTY; }
-[0-9]+				{ return NUM; }
+[0-9]+				{
+  *yylval = XDUPVAR (const char, yytext, yyleng, yyleng+1);
+  return NUM;
+}
 
 {IWORD}({WS}{IWORD})*/{EOID}		|
 "ENUM_BITFIELD"{WS}?"("{WS}?{ID}{WS}?")"	{
diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c
index fe010ff457c..10cc59509d5 100644
--- a/gcc/ipa-cp.c
+++ b/gcc/ipa-cp.c
@@ -1270,6 +1270,7 @@  initialize_node_lattices (struct cgraph_node *node)
 	  plats->ctxlat.set_to_bottom ();
 	  set_agg_lats_to_bottom (plats);
 	  plats->bits_lattice.set_to_bottom ();
+	  plats->m_value_range.m_vr = value_range ();
 	  plats->m_value_range.set_to_bottom ();
 	}
       else
@@ -3898,8 +3899,10 @@  ipcp_propagate_stage (class ipa_topo_info *topo)
       {
         class ipa_node_params *info = IPA_NODE_REF (node);
         determine_versionability (node, info);
-	info->lattices = XCNEWVEC (class ipcp_param_lattices,
-				   ipa_get_param_count (info));
+
+	unsigned nlattices = ipa_get_param_count (info);
+	void *chunk = XCNEWVEC (class ipcp_param_lattices, nlattices);
+	info->lattices = new (chunk) ipcp_param_lattices[nlattices];
 	initialize_node_lattices (node);
       }
     ipa_size_summary *s = ipa_size_summaries->get (node);
diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index 55a0b272a96..49bab04524b 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -82,6 +82,7 @@  along with GCC; see the file COPYING3.  If not see
 #include "gimplify.h"
 #include "stringpool.h"
 #include "attribs.h"
+#include <vector>
 #include "tree-into-ssa.h"
 
 /* Summaries.  */
@@ -330,7 +331,7 @@  static void
 evaluate_conditions_for_known_args (struct cgraph_node *node,
 				    bool inline_p,
 				    vec<tree> known_vals,
-				    vec<value_range> known_value_ranges,
+				    const std::vector<value_range> &known_value_ranges,
 				    vec<ipa_agg_value_set> known_aggs,
 				    clause_t *ret_clause,
 				    clause_t *ret_nonspec_clause)
@@ -445,7 +446,7 @@  evaluate_conditions_for_known_args (struct cgraph_node *node,
 	      continue;
 	    }
 	}
-      if (c->operand_num < (int) known_value_ranges.length ()
+      if (c->operand_num < (int) known_value_ranges.size ()
 	  && !c->agg_contents
 	  && !known_value_ranges[c->operand_num].undefined_p ()
 	  && !known_value_ranges[c->operand_num].varying_p ()
@@ -554,7 +555,7 @@  evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 {
   struct cgraph_node *callee = e->callee->ultimate_alias_target ();
   class ipa_fn_summary *info = ipa_fn_summaries->get (callee);
-  auto_vec<value_range, 32> known_value_ranges;
+  std::vector<value_range> known_value_ranges (32);
   class ipa_edge_args *args;
 
   if (clause_ptr)
@@ -629,8 +630,12 @@  evaluate_properties_for_edge (struct cgraph_edge *e, bool inline_p,
 								   i));
 		    if (!vr.undefined_p () && !vr.varying_p ())
 		      {
-			if (!known_value_ranges.length ())
-			  known_value_ranges.safe_grow_cleared (count);
+			if (!known_value_ranges.size ())
+			  {
+			    known_value_ranges.resize (count);
+			    for (int i = 0; i < count; ++i)
+			      known_value_ranges[i].set_undefined ();
+			  }
 			known_value_ranges[i] = vr;
 		      }
 		  }
@@ -803,7 +808,7 @@  ipa_fn_summary_t::duplicate (cgraph_node *src,
 	}
       evaluate_conditions_for_known_args (dst, false,
 					  known_vals,
-					  vNULL,
+					  std::vector<value_range> (),
 					  vNULL,
 					  &possible_truths,
 					  /* We are going to specialize,
@@ -3687,7 +3692,8 @@  estimate_ipcp_clone_size_and_time (struct cgraph_node *node,
   clause_t clause, nonspec_clause;
 
   /* TODO: Also pass known value ranges.  */
-  evaluate_conditions_for_known_args (node, false, known_vals, vNULL,
+  evaluate_conditions_for_known_args (node, false, known_vals,
+				      std::vector<value_range> (),
 				      known_aggs, &clause, &nonspec_clause);
   ipa_call_context ctx (node, clause, nonspec_clause,
 		        known_vals, known_contexts,
diff --git a/gcc/ipa-prop.c b/gcc/ipa-prop.c
index 71ac0e104d2..da50f0837fd 100644
--- a/gcc/ipa-prop.c
+++ b/gcc/ipa-prop.c
@@ -2059,7 +2059,7 @@  ipa_get_value_range (value_range *tmp)
   if (*slot)
     return *slot;
 
-  value_range *vr = ggc_alloc<value_range> ();
+  value_range *vr = new (ggc_alloc<value_range> ()) value_range;
   *vr = *tmp;
   *slot = vr;
 
diff --git a/gcc/ipa-prop.h b/gcc/ipa-prop.h
index 168c4c26443..23fcf905ef3 100644
--- a/gcc/ipa-prop.h
+++ b/gcc/ipa-prop.h
@@ -318,7 +318,7 @@  struct GTY (()) ipa_jump_func
   /* Information about value range, containing valid data only when vr_known is
      true.  The pointed to structure is shared betweed different jump
      functions.  Use ipa_set_jfunc_vr to set this field.  */
-  class value_range *m_vr;
+  value_range *m_vr;
 
   enum jump_func_type type;
   /* Represents a value of a jump function.  pass_through is used only in jump
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 5df075b15b5..c62e3977ce5 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -63,15 +63,17 @@  min_limit (const_tree type)
 }
 
 // If the range of either op1 or op2 is undefined, set the result to
-// undefined and return TRUE.
+// varying and return TRUE.  If the caller truely cares about a result,
+// they should pass in a varying if it has an undefined that it wants
+// treated as a varying.
 
 inline bool
-empty_range_check (value_range &r,
-		   const value_range &op1, const value_range & op2)
+empty_range_varying (irange &r, tree type,
+		     const irange &op1, const irange & op2)
 {
   if (op1.undefined_p () || op2.undefined_p ())
     {
-      r.set_undefined ();
+      r.set_varying (type);
       return true;
     }
   else
@@ -82,11 +84,11 @@  empty_range_check (value_range &r,
 // the appropriate range.
 
 static inline bool
-undefined_shift_range_check (value_range &r, tree type, const value_range op)
+undefined_shift_range_check (irange &r, tree type, const irange &op)
 {
   if (op.undefined_p ())
     {
-      r = value_range ();
+      r.set_undefined ();
       return true;
     }
 
@@ -98,7 +100,7 @@  undefined_shift_range_check (value_range &r, tree type, const value_range op)
       || wi::ge_p (op.upper_bound (),
 		   TYPE_PRECISION (type), TYPE_SIGN (op.type ())))
     {
-      r = value_range (type);
+      r.set_varying (type);
       return true;
     }
   return false;
@@ -125,32 +127,43 @@  wi_zero_p (tree type, const wide_int &wmin, const wide_int &wmax)
 // Default wide_int fold operation returns [MIN, MAX].
 
 void
-range_operator::wi_fold (value_range &r, tree type,
+range_operator::wi_fold (irange &r, tree type,
 			 const wide_int &lh_lb ATTRIBUTE_UNUSED,
 			 const wide_int &lh_ub ATTRIBUTE_UNUSED,
 			 const wide_int &rh_lb ATTRIBUTE_UNUSED,
 			 const wide_int &rh_ub ATTRIBUTE_UNUSED) const
 {
-  gcc_checking_assert (value_range::supports_type_p (type));
-  r = value_range (type);
+  gcc_checking_assert (irange::supports_type_p (type));
+  r.set_varying (type);
 }
 
 // The default for fold is to break all ranges into sub-ranges and
 // invoke the wi_fold method on each sub-range pair.
 
 bool
-range_operator::fold_range (value_range &r, tree type,
-			    const value_range &lh,
-			    const value_range &rh) const
+range_operator::fold_range (irange &r, tree type,
+			    const irange &lh,
+			    const irange &rh) const
 {
-  gcc_checking_assert (value_range::supports_type_p (type));
-  if (empty_range_check (r, lh, rh))
+  gcc_checking_assert (irange::supports_type_p (type));
+  if (empty_range_varying (r, type, lh, rh))
     return true;
 
-  value_range tmp;
+  unsigned num_lh = lh.num_pairs ();
+  unsigned num_rh = rh.num_pairs ();
+
+  // If both ranges are single pairs, fold directly into the result range.
+  if (num_lh == 1 && num_rh == 1)
+    {
+      wi_fold (r, type, lh.lower_bound (0), lh.upper_bound (0),
+	       rh.lower_bound (0), rh.upper_bound (0));
+      return true;
+    }
+
+  widest_irange tmp;
   r.set_undefined ();
-  for (unsigned x = 0; x < lh.num_pairs (); ++x)
-    for (unsigned y = 0; y < rh.num_pairs (); ++y)
+  for (unsigned x = 0; x < num_lh; ++x)
+    for (unsigned y = 0; y < num_rh; ++y)
       {
 	wide_int lh_lb = lh.lower_bound (x);
 	wide_int lh_ub = lh.upper_bound (x);
@@ -167,10 +180,10 @@  range_operator::fold_range (value_range &r, tree type,
 // The default for op1_range is to return false.
 
 bool
-range_operator::op1_range (value_range &r ATTRIBUTE_UNUSED,
+range_operator::op1_range (irange &r ATTRIBUTE_UNUSED,
 			   tree type ATTRIBUTE_UNUSED,
-			   const value_range &lhs ATTRIBUTE_UNUSED,
-			   const value_range &op2 ATTRIBUTE_UNUSED) const
+			   const irange &lhs ATTRIBUTE_UNUSED,
+			   const irange &op2 ATTRIBUTE_UNUSED) const
 {
   return false;
 }
@@ -178,10 +191,10 @@  range_operator::op1_range (value_range &r ATTRIBUTE_UNUSED,
 // The default for op2_range is to return false.
 
 bool
-range_operator::op2_range (value_range &r ATTRIBUTE_UNUSED,
+range_operator::op2_range (irange &r ATTRIBUTE_UNUSED,
 			   tree type ATTRIBUTE_UNUSED,
-			   const value_range &lhs ATTRIBUTE_UNUSED,
-			   const value_range &op1 ATTRIBUTE_UNUSED) const
+			   const irange &lhs ATTRIBUTE_UNUSED,
+			   const irange &op1 ATTRIBUTE_UNUSED) const
 {
   return false;
 }
@@ -191,7 +204,7 @@  range_operator::op2_range (value_range &r ATTRIBUTE_UNUSED,
 // to have overflowed (or underflowed).
 
 static void
-value_range_from_overflowed_bounds (value_range &r, tree type,
+value_range_from_overflowed_bounds (irange &r, tree type,
 				    const wide_int &wmin,
 				    const wide_int &wmax)
 {
@@ -214,9 +227,13 @@  value_range_from_overflowed_bounds (value_range &r, tree type,
   // Likewise if the anti-range bounds are outside of the types
   // values.
   if (covers || wi::cmp (tmin, tmax, sgn) > 0)
-    r = value_range (type);
+    r.set_varying (type);
   else
-    r = value_range (type, tmin, tmax, VR_ANTI_RANGE);
+    {
+      tree tree_min = wide_int_to_tree (type, tmin);
+      tree tree_max = wide_int_to_tree (type, tmax);
+      r.set (tree_min, tree_max, VR_ANTI_RANGE);
+    }
 }
 
 // Create and return a range from a pair of wide-ints.  MIN_OVF and
@@ -224,7 +241,7 @@  value_range_from_overflowed_bounds (value_range &r, tree type,
 // calculating WMIN and WMAX respectively.
 
 static void
-value_range_with_overflow (value_range &r, tree type,
+value_range_with_overflow (irange &r, tree type,
 			   const wide_int &wmin, const wide_int &wmax,
 			   wi::overflow_type min_ovf = wi::OVF_NONE,
 			   wi::overflow_type max_ovf = wi::OVF_NONE)
@@ -237,7 +254,7 @@  value_range_with_overflow (value_range &r, tree type,
   // values.
   if (prec == 1 && wi::ne_p (wmax, wmin))
     {
-      r = value_range (type);
+      r.set_varying (type);
       return;
     }
 
@@ -252,11 +269,12 @@  value_range_with_overflow (value_range &r, tree type,
 	  // If the limits are swapped, we wrapped around and cover
 	  // the entire range.
 	  if (wi::gt_p (tmin, tmax, sgn))
-	    r = value_range (type);
+	    r.set_varying (type);
 	  else
 	    // No overflow or both overflow or underflow.  The range
 	    // kind stays normal.
-	    r = value_range (type, tmin, tmax);
+	    r.set (wide_int_to_tree (type, tmin),
+		   wide_int_to_tree (type, tmax));
 	  return;
 	}
 
@@ -265,7 +283,7 @@  value_range_with_overflow (value_range &r, tree type,
 	value_range_from_overflowed_bounds (r, type, wmin, wmax);
       else
 	// Other underflow and/or overflow, drop to VR_VARYING.
-	r = value_range (type);
+	r.set_varying (type);
     }
   else
     {
@@ -285,7 +303,8 @@  value_range_with_overflow (value_range &r, tree type,
       else
         new_ub = wmax;
 
-      r = value_range (type, new_lb, new_ub);
+      r.set (wide_int_to_tree (type, new_lb),
+	     wide_int_to_tree (type, new_ub));
     }
 }
 
@@ -294,7 +313,7 @@  value_range_with_overflow (value_range &r, tree type,
 // [10,5] into [MIN,5][10,MAX].
 
 static inline void
-create_possibly_reversed_range (value_range &r, tree type,
+create_possibly_reversed_range (irange &r, tree type,
 				const wide_int &new_lb, const wide_int &new_ub)
 {
   signop s = TYPE_SIGN (type);
@@ -302,35 +321,35 @@  create_possibly_reversed_range (value_range &r, tree type,
   if (wi::gt_p (new_lb, new_ub, s))
     value_range_from_overflowed_bounds (r, type, new_lb, new_ub);
   else
-    // Otherwise its just a normal range.
-    r = value_range (type, new_lb, new_ub);
+    // Otherwise it's just a normal range.
+    r.set (wide_int_to_tree (type, new_lb), wide_int_to_tree (type, new_ub));
 }
 
-// Return a value_range instance that is a boolean TRUE.
+// Return an irange instance that is a boolean TRUE.
 
-static inline value_range
+static inline int_range<1>
 range_true (tree type)
 {
   unsigned prec = TYPE_PRECISION (type);
-  return value_range (type, wi::one (prec), wi::one (prec));
+  return int_range<1> (type, wi::one (prec), wi::one (prec));
 }
 
-// Return a value_range instance that is a boolean FALSE.
+// Return an irange instance that is a boolean FALSE.
 
-static inline value_range
+static inline int_range<1>
 range_false (tree type)
 {
   unsigned prec = TYPE_PRECISION (type);
-  return value_range (type, wi::zero (prec), wi::zero (prec));
+  return int_range<1> (type, wi::zero (prec), wi::zero (prec));
 }
 
-// Return a value_range that covers both true and false.
+// Return an irange that covers both true and false.
 
-static inline value_range
+static inline int_range<1>
 range_true_and_false (tree type)
 {
   unsigned prec = TYPE_PRECISION (type);
-  return value_range (type, wi::zero (prec), wi::one (prec));
+  return int_range<1> (type, wi::zero (prec), wi::one (prec));
 }
 
 enum bool_range_state { BRS_FALSE, BRS_TRUE, BRS_EMPTY, BRS_FULL };
@@ -341,7 +360,7 @@  enum bool_range_state { BRS_FALSE, BRS_TRUE, BRS_EMPTY, BRS_FULL };
 // the bool range.
 
 static bool_range_state
-get_bool_state (value_range &r, const value_range &lhs, tree val_type)
+get_bool_state (irange &r, const irange &lhs, tree val_type)
 {
   // If there is no result, then this is unexecutable.
   if (lhs.undefined_p ())
@@ -350,16 +369,16 @@  get_bool_state (value_range &r, const value_range &lhs, tree val_type)
       return BRS_EMPTY;
     }
 
-  // If the bounds aren't the same, then it's not a constant.
-  if (!wi::eq_p (lhs.upper_bound (), lhs.lower_bound ()))
+  if (lhs.zero_p ())
+    return BRS_FALSE;
+
+  // For TRUE, we can't just test for [1,1] because Ada can have
+  // multi-bit booleans, and TRUE values can be: [1, MAX], ~[0], etc.
+  if (lhs.contains_p (build_zero_cst (lhs.type ())))
     {
       r.set_varying (val_type);
       return BRS_FULL;
     }
-
-  if (lhs.zero_p ())
-    return BRS_FALSE;
-
   return BRS_TRUE;
 }
 
@@ -367,23 +386,23 @@  get_bool_state (value_range &r, const value_range &lhs, tree val_type)
 class operator_equal : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &val) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &val) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &val) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &val) const;
 } op_equal;
 
 bool
-operator_equal::fold_range (value_range &r, tree type,
-			    const value_range &op1,
-			    const value_range &op2) const
+operator_equal::fold_range (irange &r, tree type,
+			    const irange &op1,
+			    const irange &op2) const
 {
-  if (empty_range_check (r, op1, op2))
+  if (empty_range_varying (r, type, op1, op2))
     return true;
 
   // We can be sure the values are always equal or not if both ranges
@@ -411,9 +430,9 @@  operator_equal::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_equal::op1_range (value_range &r, tree type,
-			   const value_range &lhs,
-			   const value_range &op2) const
+operator_equal::op1_range (irange &r, tree type,
+			   const irange &lhs,
+			   const irange &op2) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -441,9 +460,9 @@  operator_equal::op1_range (value_range &r, tree type,
 }
 
 bool
-operator_equal::op2_range (value_range &r, tree type,
-			   const value_range &lhs,
-			   const value_range &op1) const
+operator_equal::op2_range (irange &r, tree type,
+			   const irange &lhs,
+			   const irange &op1) const
 {
   return operator_equal::op1_range (r, type, lhs, op1);
 }
@@ -452,23 +471,23 @@  operator_equal::op2_range (value_range &r, tree type,
 class operator_not_equal : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_not_equal;
 
 bool
-operator_not_equal::fold_range (value_range &r, tree type,
-				const value_range &op1,
-				const value_range &op2) const
+operator_not_equal::fold_range (irange &r, tree type,
+				const irange &op1,
+				const irange &op2) const
 {
-  if (empty_range_check (r, op1, op2))
+  if (empty_range_varying (r, type, op1, op2))
     return true;
 
   // We can be sure the values are always equal or not if both ranges
@@ -496,9 +515,9 @@  operator_not_equal::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_not_equal::op1_range (value_range &r, tree type,
-			       const value_range &lhs,
-			       const value_range &op2) const
+operator_not_equal::op1_range (irange &r, tree type,
+			       const irange &lhs,
+			       const irange &op2) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -527,9 +546,9 @@  operator_not_equal::op1_range (value_range &r, tree type,
 
 
 bool
-operator_not_equal::op2_range (value_range &r, tree type,
-			       const value_range &lhs,
-			       const value_range &op1) const
+operator_not_equal::op2_range (irange &r, tree type,
+			       const irange &lhs,
+			       const irange &op1) const
 {
   return operator_not_equal::op1_range (r, type, lhs, op1);
 }
@@ -537,7 +556,7 @@  operator_not_equal::op2_range (value_range &r, tree type,
 // (X < VAL) produces the range of [MIN, VAL - 1].
 
 static void
-build_lt (value_range &r, tree type, const wide_int &val)
+build_lt (irange &r, tree type, const wide_int &val)
 {
   wi::overflow_type ov;
   wide_int lim = wi::sub (val, 1, TYPE_SIGN (type), &ov);
@@ -546,21 +565,21 @@  build_lt (value_range &r, tree type, const wide_int &val)
   if (ov)
     r.set_undefined ();
   else
-    r = value_range (type, min_limit (type), lim);
+    r = int_range<1> (type, min_limit (type), lim);
 }
 
 // (X <= VAL) produces the range of [MIN, VAL].
 
 static void
-build_le (value_range &r, tree type, const wide_int &val)
+build_le (irange &r, tree type, const wide_int &val)
 {
-  r = value_range (type, min_limit (type), val);
+  r = int_range<1> (type, min_limit (type), val);
 }
 
 // (X > VAL) produces the range of [VAL + 1, MAX].
 
 static void
-build_gt (value_range &r, tree type, const wide_int &val)
+build_gt (irange &r, tree type, const wide_int &val)
 {
   wi::overflow_type ov;
   wide_int lim = wi::add (val, 1, TYPE_SIGN (type), &ov);
@@ -568,38 +587,38 @@  build_gt (value_range &r, tree type, const wide_int &val)
   if (ov)
     r.set_undefined ();
   else
-    r = value_range (type, lim, max_limit (type));
+    r = int_range<1> (type, lim, max_limit (type));
 }
 
 // (X >= val) produces the range of [VAL, MAX].
 
 static void
-build_ge (value_range &r, tree type, const wide_int &val)
+build_ge (irange &r, tree type, const wide_int &val)
 {
-  r = value_range (type, val, max_limit (type));
+  r = int_range<1> (type, val, max_limit (type));
 }
 
 
 class operator_lt :  public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_lt;
 
 bool
-operator_lt::fold_range (value_range &r, tree type,
-			 const value_range &op1,
-			 const value_range &op2) const
+operator_lt::fold_range (irange &r, tree type,
+			 const irange &op1,
+			 const irange &op2) const
 {
-  if (empty_range_check (r, op1, op2))
+  if (empty_range_varying (r, type, op1, op2))
     return true;
 
   signop sign = TYPE_SIGN (op1.type ());
@@ -615,9 +634,9 @@  operator_lt::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_lt::op1_range (value_range &r, tree type,
-			const value_range &lhs,
-			const value_range &op2) const
+operator_lt::op1_range (irange &r, tree type,
+			const irange &lhs,
+			const irange &op2) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -636,9 +655,9 @@  operator_lt::op1_range (value_range &r, tree type,
 }
 
 bool
-operator_lt::op2_range (value_range &r, tree type,
-			const value_range &lhs,
-			const value_range &op1) const
+operator_lt::op2_range (irange &r, tree type,
+			const irange &lhs,
+			const irange &op1) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -660,23 +679,23 @@  operator_lt::op2_range (value_range &r, tree type,
 class operator_le :  public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_le;
 
 bool
-operator_le::fold_range (value_range &r, tree type,
-			 const value_range &op1,
-			 const value_range &op2) const
+operator_le::fold_range (irange &r, tree type,
+			 const irange &op1,
+			 const irange &op2) const
 {
-  if (empty_range_check (r, op1, op2))
+  if (empty_range_varying (r, type, op1, op2))
     return true;
 
   signop sign = TYPE_SIGN (op1.type ());
@@ -692,9 +711,9 @@  operator_le::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_le::op1_range (value_range &r, tree type,
-			const value_range &lhs,
-			const value_range &op2) const
+operator_le::op1_range (irange &r, tree type,
+			const irange &lhs,
+			const irange &op2) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -713,9 +732,9 @@  operator_le::op1_range (value_range &r, tree type,
 }
 
 bool
-operator_le::op2_range (value_range &r, tree type,
-			const value_range &lhs,
-			const value_range &op1) const
+operator_le::op2_range (irange &r, tree type,
+			const irange &lhs,
+			const irange &op1) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -737,22 +756,22 @@  operator_le::op2_range (value_range &r, tree type,
 class operator_gt :  public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_gt;
 
 bool
-operator_gt::fold_range (value_range &r, tree type,
-			 const value_range &op1, const value_range &op2) const
+operator_gt::fold_range (irange &r, tree type,
+			 const irange &op1, const irange &op2) const
 {
-  if (empty_range_check (r, op1, op2))
+  if (empty_range_varying (r, type, op1, op2))
     return true;
 
   signop sign = TYPE_SIGN (op1.type ());
@@ -768,8 +787,8 @@  operator_gt::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_gt::op1_range (value_range &r, tree type,
-			const value_range &lhs, const value_range &op2) const
+operator_gt::op1_range (irange &r, tree type,
+			const irange &lhs, const irange &op2) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -788,9 +807,9 @@  operator_gt::op1_range (value_range &r, tree type,
 }
 
 bool
-operator_gt::op2_range (value_range &r, tree type,
-			const value_range &lhs,
-			const value_range &op1) const
+operator_gt::op2_range (irange &r, tree type,
+			const irange &lhs,
+			const irange &op1) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -812,23 +831,23 @@  operator_gt::op2_range (value_range &r, tree type,
 class operator_ge :  public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_ge;
 
 bool
-operator_ge::fold_range (value_range &r, tree type,
-			 const value_range &op1,
-			 const value_range &op2) const
+operator_ge::fold_range (irange &r, tree type,
+			 const irange &op1,
+			 const irange &op2) const
 {
-  if (empty_range_check (r, op1, op2))
+  if (empty_range_varying (r, type, op1, op2))
     return true;
 
   signop sign = TYPE_SIGN (op1.type ());
@@ -844,9 +863,9 @@  operator_ge::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_ge::op1_range (value_range &r, tree type,
-			const value_range &lhs,
-			const value_range &op2) const
+operator_ge::op1_range (irange &r, tree type,
+			const irange &lhs,
+			const irange &op2) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -865,9 +884,9 @@  operator_ge::op1_range (value_range &r, tree type,
 }
 
 bool
-operator_ge::op2_range (value_range &r, tree type,
-			const value_range &lhs,
-			const value_range &op1) const
+operator_ge::op2_range (irange &r, tree type,
+			const irange &lhs,
+			const irange &op1) const
 {
   switch (get_bool_state (r, lhs, type))
     {
@@ -889,13 +908,13 @@  operator_ge::op2_range (value_range &r, tree type,
 class operator_plus : public range_operator
 {
 public:
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
-  virtual void wi_fold (value_range &r, tree type,
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -903,7 +922,7 @@  public:
 } op_plus;
 
 void
-operator_plus::wi_fold (value_range &r, tree type,
+operator_plus::wi_fold (irange &r, tree type,
 			const wide_int &lh_lb, const wide_int &lh_ub,
 			const wide_int &rh_lb, const wide_int &rh_ub) const
 {
@@ -915,17 +934,17 @@  operator_plus::wi_fold (value_range &r, tree type,
 }
 
 bool
-operator_plus::op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const
+operator_plus::op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const
 {
   return range_op_handler (MINUS_EXPR, type)->fold_range (r, type, lhs, op2);
 }
 
 bool
-operator_plus::op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const
+operator_plus::op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const
 {
   return range_op_handler (MINUS_EXPR, type)->fold_range (r, type, lhs, op1);
 }
@@ -934,13 +953,13 @@  operator_plus::op2_range (value_range &r, tree type,
 class operator_minus : public range_operator
 {
 public:
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
-  virtual void wi_fold (value_range &r, tree type,
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -948,7 +967,7 @@  public:
 } op_minus;
 
 void 
-operator_minus::wi_fold (value_range &r, tree type,
+operator_minus::wi_fold (irange &r, tree type,
 			 const wide_int &lh_lb, const wide_int &lh_ub,
 			 const wide_int &rh_lb, const wide_int &rh_ub) const
 {
@@ -960,17 +979,17 @@  operator_minus::wi_fold (value_range &r, tree type,
 }
 
 bool
-operator_minus::op1_range (value_range &r, tree type,
-			   const value_range &lhs,
-			   const value_range &op2) const
+operator_minus::op1_range (irange &r, tree type,
+			   const irange &lhs,
+			   const irange &op2) const
 {
   return range_op_handler (PLUS_EXPR, type)->fold_range (r, type, lhs, op2);
 }
 
 bool
-operator_minus::op2_range (value_range &r, tree type,
-			   const value_range &lhs,
-			   const value_range &op1) const
+operator_minus::op2_range (irange &r, tree type,
+			   const irange &lhs,
+			   const irange &op1) const
 {
   return fold_range (r, type, op1, lhs);
 }
@@ -979,7 +998,7 @@  operator_minus::op2_range (value_range &r, tree type,
 class operator_min : public range_operator
 {
 public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -987,7 +1006,7 @@  public:
 } op_min;
 
 void
-operator_min::wi_fold (value_range &r, tree type,
+operator_min::wi_fold (irange &r, tree type,
 		       const wide_int &lh_lb, const wide_int &lh_ub,
 		       const wide_int &rh_lb, const wide_int &rh_ub) const
 {
@@ -1001,7 +1020,7 @@  operator_min::wi_fold (value_range &r, tree type,
 class operator_max : public range_operator
 {
 public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -1009,7 +1028,7 @@  public:
 } op_max;
 
 void
-operator_max::wi_fold (value_range &r, tree type,
+operator_max::wi_fold (irange &r, tree type,
 		       const wide_int &lh_lb, const wide_int &lh_ub,
 		       const wide_int &rh_lb, const wide_int &rh_ub) const
 {
@@ -1031,7 +1050,7 @@  public:
 				const wide_int &) const = 0;
 
   // Calculate the cross product of two sets of sub-ranges and return it.
-  void wi_cross_product (value_range &r, tree type,
+  void wi_cross_product (irange &r, tree type,
 			 const wide_int &lh_lb,
 			 const wide_int &lh_ub,
 			 const wide_int &rh_lb,
@@ -1052,7 +1071,7 @@  public:
 // figure the smallest and largest values to form the new range.
 
 void
-cross_product_operator::wi_cross_product (value_range &r, tree type,
+cross_product_operator::wi_cross_product (irange &r, tree type,
 					  const wide_int &lh_lb,
 					  const wide_int &lh_ub,
 					  const wide_int &rh_lb,
@@ -1060,7 +1079,7 @@  cross_product_operator::wi_cross_product (value_range &r, tree type,
 {
   wide_int cp1, cp2, cp3, cp4;
   // Default to varying.
-  r = value_range (type);
+  r.set_varying (type);
 
   // Compute the 4 cross operations, bailing if we get an overflow we
   // can't handle.
@@ -1096,15 +1115,46 @@  cross_product_operator::wi_cross_product (value_range &r, tree type,
 class operator_mult : public cross_product_operator
 {
 public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
 		        const wide_int &rh_ub) const;
   virtual bool wi_op_overflows (wide_int &res, tree type,
 				const wide_int &w0, const wide_int &w1) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_mult;
 
+bool
+operator_mult::op1_range (irange &r, tree type,
+			  const irange &lhs, const irange &op2) const
+{
+  tree offset;
+
+  // We can't solve 0 = OP1 * N by dividing by N with a wrapping type.
+  // For example: For 0 = OP1 * 2, OP1 could be 0, or MAXINT, whereas
+  // for 4 = OP1 * 2, OP1 could be 2 or 130 (unsigned 8-bit)
+  if (TYPE_OVERFLOW_WRAPS (type))
+    return false;
+
+  if (op2.singleton_p (&offset) && !integer_zerop (offset))
+    return range_op_handler (TRUNC_DIV_EXPR, type)->fold_range (r, type,
+								lhs, op2);
+  return false;
+}
+
+bool
+operator_mult::op2_range (irange &r, tree type,
+			  const irange &lhs, const irange &op1) const
+{
+  return operator_mult::op1_range (r, type, lhs, op1);
+}
+
 bool
 operator_mult::wi_op_overflows (wide_int &res, tree type,
 				const wide_int &w0, const wide_int &w1) const
@@ -1126,7 +1176,7 @@  operator_mult::wi_op_overflows (wide_int &res, tree type,
 }
 
 void 
-operator_mult::wi_fold (value_range &r, tree type,
+operator_mult::wi_fold (irange &r, tree type,
 			const wide_int &lh_lb, const wide_int &lh_ub,
 			const wide_int &rh_lb, const wide_int &rh_ub) const
 {
@@ -1195,7 +1245,7 @@  operator_mult::wi_fold (value_range &r, tree type,
   prod2 = prod3 - prod0;
   if (wi::geu_p (prod2, sizem1))
     // The range covers all values.
-    r = value_range (type);
+    r.set_varying (type);
   else
     {
       wide_int new_lb = wide_int::from (prod0, prec, sign);
@@ -1209,7 +1259,7 @@  class operator_div : public cross_product_operator
 {
 public:
   operator_div (enum tree_code c)  { code = c; }
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -1263,14 +1313,14 @@  operator_div::wi_op_overflows (wide_int &res, tree type,
 }
 
 void
-operator_div::wi_fold (value_range &r, tree type,
+operator_div::wi_fold (irange &r, tree type,
 		       const wide_int &lh_lb, const wide_int &lh_ub,
 		       const wide_int &rh_lb, const wide_int &rh_ub) const
 {
   // If we know we will divide by zero, return undefined.
   if (rh_lb == 0 && rh_ub == 0)
     {
-      r = value_range ();
+      r.set_undefined ();
       return;
     }
 
@@ -1293,14 +1343,14 @@  operator_div::wi_fold (value_range &r, tree type,
   // If flag_non_call_exceptions, we must not eliminate a division by zero.
   if (cfun->can_throw_non_call_exceptions)
     {
-      r = value_range (type);
+      r.set_varying (type);
       return;
     }
 
   // If we're definitely dividing by zero, there's nothing to do.
   if (wi_zero_p (type, divisor_min, divisor_max))
     {
-      r = value_range ();
+      r.set_undefined ();
       return;
     }
 
@@ -1312,12 +1362,12 @@  operator_div::wi_fold (value_range &r, tree type,
     wi_cross_product (r, type, dividend_min, dividend_max,
 		      divisor_min, wi::minus_one (prec));
   else
-    r = value_range ();
+    r.set_undefined ();
 
   // Then divide by the non-zero positive numbers, if any.
   if (wi::gt_p (divisor_max, wi::zero (prec), sign))
     {
-      value_range tmp;
+      widest_irange tmp;
       wi_cross_product (tmp, type, dividend_min, dividend_max,
 			wi::one (prec), divisor_max);
       r.union_ (tmp);
@@ -1336,16 +1386,16 @@  class operator_exact_divide : public operator_div
 {
 public:
   operator_exact_divide () : operator_div (TRUNC_DIV_EXPR) { }
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
 
 } op_exact_div;
 
 bool
-operator_exact_divide::op1_range (value_range &r, tree type,
-				  const value_range &lhs,
-				  const value_range &op2) const
+operator_exact_divide::op1_range (irange &r, tree type,
+				  const irange &lhs,
+				  const irange &op2) const
 {
   tree offset;
   // [2, 4] = op1 / [3,3]   since its exact divide, no need to worry about
@@ -1364,11 +1414,14 @@  operator_exact_divide::op1_range (value_range &r, tree type,
 class operator_lshift : public cross_product_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-
-  virtual void wi_fold (value_range &r, tree type,
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+
+  virtual void wi_fold (irange &r, tree type,
 			const wide_int &lh_lb, const wide_int &lh_ub,
 			const wide_int &rh_lb, const wide_int &rh_ub) const;
   virtual bool wi_op_overflows (wide_int &res,
@@ -1378,9 +1431,9 @@  public:
 } op_lshift;
 
 bool
-operator_lshift::fold_range (value_range &r, tree type,
-			     const value_range &op1,
-			     const value_range &op2) const
+operator_lshift::fold_range (irange &r, tree type,
+			     const irange &op1,
+			     const irange &op2) const
 {
   if (undefined_shift_range_check (r, type, op2))
     return true;
@@ -1390,15 +1443,14 @@  operator_lshift::fold_range (value_range &r, tree type,
     {
       unsigned shift = op2.lower_bound ().to_uhwi ();
       wide_int tmp = wi::set_bit_in_zero (shift, TYPE_PRECISION (type));
-      value_range mult (type, tmp, tmp);
+      int_range<1> mult (type, tmp, tmp);
 
       // Force wrapping multiplication.
       bool saved_flag_wrapv = flag_wrapv;
       bool saved_flag_wrapv_pointer = flag_wrapv_pointer;
       flag_wrapv = 1;
       flag_wrapv_pointer = 1;
-      bool b = range_op_handler (MULT_EXPR, type)->fold_range (r, type, op1,
-							       mult);
+      bool b = op_mult.fold_range (r, type, op1, mult);
       flag_wrapv = saved_flag_wrapv;
       flag_wrapv_pointer = saved_flag_wrapv_pointer;
       return b;
@@ -1409,7 +1461,7 @@  operator_lshift::fold_range (value_range &r, tree type,
 }
 
 void
-operator_lshift::wi_fold (value_range &r, tree type,
+operator_lshift::wi_fold (irange &r, tree type,
 			  const wide_int &lh_lb, const wide_int &lh_ub,
 			  const wide_int &rh_lb, const wide_int &rh_ub) const
 {
@@ -1465,7 +1517,7 @@  operator_lshift::wi_fold (value_range &r, tree type,
   if (in_bounds)
     wi_cross_product (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
   else
-   r = value_range (type);
+   r.set_varying (type);
 }
 
 bool
@@ -1485,14 +1537,56 @@  operator_lshift::wi_op_overflows (wide_int &res, tree type,
   return false;
 }
 
+bool
+operator_lshift::op1_range (irange &r,
+			    tree type,
+			    const irange &lhs,
+			    const irange &op2) const
+{
+  tree shift_amount;
+  if (op2.singleton_p (&shift_amount))
+    {
+      int_range<1> shifted (shift_amount, shift_amount), ub, lb;
+      const range_operator *rshift_op = range_op_handler (RSHIFT_EXPR, type);
+      rshift_op->fold_range (ub, type, lhs, shifted);
+      if (TYPE_UNSIGNED (type))
+	{
+	  r = ub;
+	  return true;
+	}
+      // For signed types, we can't just do an arithmetic rshift,
+      // because that will propagate the sign bit.
+      //
+      //  LHS
+      // 1110 = OP1 << 1
+      //
+      // Assuming a 4-bit signed integer, a right shift will result in
+      // OP1=1111, but OP1 could have also been 0111.  What we want is
+      // a range from 0111 to 1111.  That is, a range from the logical
+      // rshift (0111) to the arithmetic rshift (1111).
+      //
+      // Perform a logical rshift by doing the rshift as unsigned.
+      tree unsigned_type = unsigned_type_for (type);
+      widest_irange unsigned_lhs = lhs;
+      range_cast (unsigned_lhs, unsigned_type);
+      rshift_op = range_op_handler (RSHIFT_EXPR, unsigned_type);
+      rshift_op->fold_range (lb, unsigned_type, unsigned_lhs, shifted);
+      range_cast (lb, type);
+      r = lb;
+      r.union_ (ub);
+      return true;
+    }
+  return false;
+}
+
 
 class operator_rshift : public cross_product_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual void wi_fold (value_range &r, tree type,
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -1501,8 +1595,57 @@  public:
 				tree type,
 				const wide_int &w0,
 				const wide_int &w1) const;
+  virtual bool op1_range (irange &, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
 } op_rshift;
 
+bool
+operator_rshift::op1_range (irange &r,
+			    tree type,
+			    const irange &lhs,
+			    const irange &op2) const
+{
+  tree shift;
+  if (op2.singleton_p (&shift))
+    {
+      // Folding the original operation may discard some impossible
+      // ranges from the LHS.
+      widest_irange lhs_refined;
+      op_rshift.fold_range (lhs_refined, type, int_range<1> (type), op2);
+      lhs_refined.intersect (lhs);
+      if (lhs_refined.undefined_p ())
+	{
+	  r.set_undefined ();
+	  return true;
+	}
+      widest_irange shift_range (shift, shift);
+      widest_irange lb, ub;
+      op_lshift.fold_range (lb, type, lhs_refined, shift_range);
+      //    LHS
+      // 0000 0111 = OP1 >> 3
+      //
+      // OP1 is anything from 0011 1000 to 0011 1111.  That is, a
+      // range from LHS<<3 plus a mask of the 3 bits we shifted on the
+      // right hand side (0x07).
+      tree mask = fold_build1 (BIT_NOT_EXPR, type,
+			       fold_build2 (LSHIFT_EXPR, type,
+					    build_minus_one_cst (type),
+					    shift));
+      widest_irange mask_range (build_zero_cst (type), mask);
+      op_plus.fold_range (ub, type, lb, mask_range);
+      r = lb;
+      r.union_ (ub);
+      if (!lhs_refined.contains_p (build_zero_cst (type)))
+	{
+	  mask_range.invert ();
+	  r.intersect (mask_range);
+	}
+      return true;
+    }
+  return false;
+}
+
 bool
 operator_rshift::wi_op_overflows (wide_int &res,
 				  tree type,
@@ -1523,9 +1666,9 @@  operator_rshift::wi_op_overflows (wide_int &res,
 }
 
 bool
-operator_rshift::fold_range (value_range &r, tree type,
-			     const value_range &op1,
-			     const value_range &op2) const
+operator_rshift::fold_range (irange &r, tree type,
+			     const irange &op1,
+			     const irange &op2) const
 {
   // Invoke the generic fold routine if not undefined..
   if (undefined_shift_range_check (r, type, op2))
@@ -1535,7 +1678,7 @@  operator_rshift::fold_range (value_range &r, tree type,
 }
 
 void
-operator_rshift::wi_fold (value_range &r, tree type,
+operator_rshift::wi_fold (irange &r, tree type,
 			  const wide_int &lh_lb, const wide_int &lh_ub,
 			  const wide_int &rh_lb, const wide_int &rh_ub) const
 {
@@ -1546,139 +1689,180 @@  operator_rshift::wi_fold (value_range &r, tree type,
 class operator_cast: public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+private:
+  bool truncating_cast_p (const irange &inner, const irange &outer) const;
+  bool inside_domain_p (const wide_int &min, const wide_int &max,
+			const irange &outer) const;
+  void fold_pair (irange &r, unsigned index, const irange &inner,
+			   const irange &outer) const;
 } op_convert;
 
+// Return TRUE if casting from INNER to OUTER is a truncating cast.
+
+inline bool
+operator_cast::truncating_cast_p (const irange &inner,
+				  const irange &outer) const
+{
+  return TYPE_PRECISION (outer.type ()) < TYPE_PRECISION (inner.type ());
+}
+
+// Return TRUE if [MIN,MAX] is inside the domain of RANGE's type.
+
 bool
-operator_cast::fold_range (value_range &r, tree type ATTRIBUTE_UNUSED,
-			   const value_range &lh,
-			   const value_range &rh) const
+operator_cast::inside_domain_p (const wide_int &min,
+				const wide_int &max,
+				const irange &range) const
 {
-  if (empty_range_check (r, lh, rh))
-    return true;
-  
-  tree inner = lh.type ();
-  tree outer = rh.type ();
-  gcc_checking_assert (rh.varying_p ());
-  gcc_checking_assert (types_compatible_p (outer, type));
-  signop inner_sign = TYPE_SIGN (inner);
-  signop outer_sign = TYPE_SIGN (outer);
-  unsigned inner_prec = TYPE_PRECISION (inner);
-  unsigned outer_prec = TYPE_PRECISION (outer);
-
-  // Start with an empty range and add subranges.
-  r = value_range ();
-  for (unsigned x = 0; x < lh.num_pairs (); ++x)
-    {
-      wide_int lh_lb = lh.lower_bound (x);
-      wide_int lh_ub = lh.upper_bound (x);
-
-      // If the conversion is not truncating we can convert the min
-      // and max values and canonicalize the resulting range.
-      // Otherwise, we can do the conversion if the size of the range
-      // is less than what the precision of the target type can
-      // represent.
-      if (outer_prec >= inner_prec
-	  || wi::rshift (wi::sub (lh_ub, lh_lb),
-			 wi::uhwi (outer_prec, inner_prec),
-			 inner_sign) == 0)
+  wide_int domain_min = wi::to_wide (vrp_val_min (range.type ()));
+  wide_int domain_max = wi::to_wide (vrp_val_max (range.type ()));
+  signop domain_sign = TYPE_SIGN (range.type ());
+  return (wi::le_p (min, domain_max, domain_sign)
+	  && wi::le_p (max, domain_max, domain_sign)
+	  && wi::ge_p (min, domain_min, domain_sign)
+	  && wi::ge_p (max, domain_min, domain_sign));
+}
+
+
+// Helper for fold_range which work on a pair at a time.
+
+void
+operator_cast::fold_pair (irange &r, unsigned index,
+			   const irange &inner,
+			   const irange &outer) const
+{
+  tree inner_type = inner.type ();
+  tree outer_type = outer.type ();
+  signop inner_sign = TYPE_SIGN (inner_type);
+  unsigned outer_prec = TYPE_PRECISION (outer_type);
+
+  // check to see if casting from INNER to OUTER is a conversion that
+  // fits in the resulting OUTER type.
+  wide_int inner_lb = inner.lower_bound (index);
+  wide_int inner_ub = inner.upper_bound (index);
+  if (truncating_cast_p (inner, outer))
+    {
+      // We may be able to accomodate a truncating cast if the
+      // resulting range can be represented in the target type...
+      if (wi::rshift (wi::sub (inner_ub, inner_lb),
+		      wi::uhwi (outer_prec, TYPE_PRECISION (inner.type ())),
+				inner_sign) != 0)
 	{
-	  wide_int min = wide_int::from (lh_lb, outer_prec, inner_sign);
-	  wide_int max = wide_int::from (lh_ub, outer_prec, inner_sign);
-	  if (!wi::eq_p (min, wi::min_value (outer_prec, outer_sign))
-	      || !wi::eq_p (max, wi::max_value (outer_prec, outer_sign)))
-	    {
-	      value_range tmp;
-	      create_possibly_reversed_range (tmp, type, min, max);
-	      r.union_ (tmp);
-	      continue;
-	    }
+	  r.set_varying (outer_type);
+	  return;
 	}
-      r = value_range (type);
-      break;
+    }
+  // ...but we must still verify that the final range fits in the
+  // domain.  This catches -fstrict-enum restrictions where the domain
+  // range is smaller than what fits in the underlying type.
+  wide_int min = wide_int::from (inner_lb, outer_prec, inner_sign);
+  wide_int max = wide_int::from (inner_ub, outer_prec, inner_sign);
+  if (inside_domain_p (min, max, outer))
+    create_possibly_reversed_range (r, outer_type, min, max);
+  else
+    r.set_varying (outer_type);
+}
+
+
+bool
+operator_cast::fold_range (irange &r, tree type ATTRIBUTE_UNUSED,
+			   const irange &inner,
+			   const irange &outer) const
+{
+  if (empty_range_varying (r, type, inner, outer))
+    return true;
+
+  gcc_checking_assert (outer.varying_p ());
+  gcc_checking_assert (inner.num_pairs () > 0);
+
+  // Avoid a temporary by folding the first pair directly into the result.
+  fold_pair (r, 0, inner, outer);
+
+  // Then process any additonal pairs by unioning with their results.
+  for (unsigned x = 1; x < inner.num_pairs (); ++x)
+    {
+      widest_irange tmp;
+      fold_pair (tmp, x, inner, outer);
+      r.union_ (tmp);
+      if (r.varying_p ())
+	return true;
     }
   return true;
 }
 
 bool
-operator_cast::op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const
+operator_cast::op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const
 {
   tree lhs_type = lhs.type ();
-  value_range tmp;
   gcc_checking_assert (types_compatible_p (op2.type(), type));
 
-  // If the precision of the LHS is smaller than the precision of the
-  // RHS, then there would be truncation of the value on the RHS, and
-  // so we can tell nothing about it.
-  if (TYPE_PRECISION (lhs_type) < TYPE_PRECISION (type))
-    {
-      // If we've been passed an actual value for the RHS rather than
-      // the type, see if it fits the LHS, and if so, then we can allow
-      // it.
-      fold_range (r, lhs_type, op2, value_range (lhs_type));
-      fold_range (tmp, type, r, value_range (type));
-      if (tmp == op2)
+  if (truncating_cast_p (op2, lhs))
+    {
+      if (lhs.varying_p ())
+	r.set_varying (type);
+      else
         {
-	  // We know the value of the RHS fits in the LHS type, so
-	  // convert the LHS and remove any values that arent in OP2.
-	  fold_range (r, type, lhs, value_range (type));
-	  r.intersect (op2);
-	  return true;
-	}
-      // Special case if the LHS is a boolean.  A 0 means the RHS is
-      // zero, and a 1 means the RHS is non-zero.
-      if (TREE_CODE (lhs_type) == BOOLEAN_TYPE)
-	{
-	  // If the LHS is unknown, the result is whatever op2 already is.
-	  if (!lhs.singleton_p ())
-	    {
-	      r = op2;
-	      return true;
-	    }
-	  // Boolean casts are weird in GCC. It's actually an implied
-	  // mask with 0x01, so all that is known is whether the
-	  // rightmost bit is 0 or 1, which implies the only value
-	  // *not* in the RHS is 0 or -1.
-	  unsigned prec = TYPE_PRECISION (type);
-	  if (lhs.zero_p ())
-	    r = value_range (type, wi::minus_one (prec), wi::minus_one (prec),
-			     VR_ANTI_RANGE);
-	  else
-	    r = value_range (type, wi::zero (prec), wi::zero (prec),
-			     VR_ANTI_RANGE);
-	  // And intersect it with what we know about op2.
-	  r.intersect (op2);
+	  // We want to insert the LHS as an unsigned value since it
+	  // would not trigger the signed bit of the larger type.
+	  widest_irange converted_lhs = lhs;
+	  range_cast (converted_lhs, unsigned_type_for (lhs_type));
+	  range_cast (converted_lhs, type);
+	  // Start by building the positive signed outer range for the type.
+	  wide_int lim = wi::set_bit_in_zero (TYPE_PRECISION (lhs_type),
+					      TYPE_PRECISION (type));
+	  r = int_range<1> (type, lim, wi::max_value (TYPE_PRECISION (type),
+						      SIGNED));
+	  // For the signed part, we need to simply union the 2 ranges now.
+	  r.union_ (converted_lhs);
+
+	  // Create maximal negative number outside of LHS bits.
+	  lim = wi::mask (TYPE_PRECISION (lhs_type), true,
+			  TYPE_PRECISION (type));
+	  // Add this to the unsigned LHS range(s).
+	  widest_irange lim_range (type, lim, lim);
+	  widest_irange lhs_neg;
+	  range_op_handler (PLUS_EXPR, type)->fold_range (lhs_neg,
+							  type,
+							  converted_lhs,
+							  lim_range);
+	  // And union this with the entire outer types negative range.
+	  widest_irange neg (type,
+			     wi::min_value (TYPE_PRECISION (type),
+					    SIGNED),
+			     lim - 1);
+	  neg.union_ (lhs_neg);
+	  // And finally, munge the signed and unsigned portions.
+	  r.union_ (neg);
 	}
-      else
-	// Otherwise we'll have to assume it's whatever we know about op2.
-	r = op2;
+      // And intersect with any known value passed in the extra operand.
+      r.intersect (op2);
       return true;
     }
 
-  // If the LHS precision is greater than the rhs precision, the LHS
-  // range is restricted to the range of the RHS by this
-  // assignment.
-  if (TYPE_PRECISION (lhs_type) > TYPE_PRECISION (type))
+  widest_irange tmp;
+  if (TYPE_PRECISION (lhs_type) == TYPE_PRECISION (type))
+    tmp = lhs;
+  else
     {
+      // The cast is not truncating, and the range is restricted to
+      // the range of the RHS by this assignment.
+      //
       // Cast the range of the RHS to the type of the LHS.
-      fold_range (tmp, lhs_type, value_range (type), value_range (lhs_type));
-      // Intersect this with the LHS range will produce the range, which
-      // will be cast to the RHS type before returning.
+      fold_range (tmp, lhs_type, int_range<1> (type), int_range<1> (lhs_type));
+      // Intersect this with the LHS range will produce the range,
+      // which will be cast to the RHS type before returning.
       tmp.intersect (lhs);
     }
-  else
-    tmp = lhs;
 
   // Cast the calculated range to the type of the RHS.
-  fold_range (r, type, tmp, value_range (type));
+  fold_range (r, type, tmp, int_range<1> (type));
   return true;
 }
 
@@ -1686,24 +1870,24 @@  operator_cast::op1_range (value_range &r, tree type,
 class operator_logical_and : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &lh,
-			   const value_range &rh) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &lh,
+			   const irange &rh) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_logical_and;
 
 
 bool
-operator_logical_and::fold_range (value_range &r, tree type,
-				  const value_range &lh,
-				  const value_range &rh) const
+operator_logical_and::fold_range (irange &r, tree type,
+				  const irange &lh,
+				  const irange &rh) const
 {
-  if (empty_range_check (r, lh, rh))
+  if (empty_range_varying (r, type, lh, rh))
     return true;
 
   // 0 && anything is 0.
@@ -1721,9 +1905,9 @@  operator_logical_and::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_logical_and::op1_range (value_range &r, tree type,
-				 const value_range &lhs,
-				 const value_range &op2 ATTRIBUTE_UNUSED) const
+operator_logical_and::op1_range (irange &r, tree type,
+				 const irange &lhs,
+				 const irange &op2 ATTRIBUTE_UNUSED) const
 {
    switch (get_bool_state (r, lhs, type))
      {
@@ -1742,9 +1926,9 @@  operator_logical_and::op1_range (value_range &r, tree type,
 }
 
 bool
-operator_logical_and::op2_range (value_range &r, tree type,
-				 const value_range &lhs,
-				 const value_range &op1) const
+operator_logical_and::op2_range (irange &r, tree type,
+				 const irange &lhs,
+				 const irange &op1) const
 {
   return operator_logical_and::op1_range (r, type, lhs, op1);
 }
@@ -1753,19 +1937,106 @@  operator_logical_and::op2_range (value_range &r, tree type,
 class operator_bitwise_and : public range_operator
 {
 public:
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
-  virtual void wi_fold (value_range &r, tree type,
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &lh,
+			   const irange &rh) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
 		        const wide_int &rh_ub) const;
+private:
+  void simple_op1_range_solver (irange &r, tree type,
+				const irange &lhs,
+				const irange &op2) const;
+  void remove_impossible_ranges (irange &r, const irange &rh) const;
 } op_bitwise_and;
 
+static bool
+unsigned_singleton_p (const irange &op)
+{
+  tree mask;
+  if (op.singleton_p (&mask))
+    {
+      wide_int x = wi::to_wide (mask);
+      return wi::ge_p (x, 0, TYPE_SIGN (op.type ()));
+    }
+  return false;
+}
+
+// Remove any ranges from R that are known to be impossible when an
+// range is ANDed with MASK.
+
+void
+operator_bitwise_and::remove_impossible_ranges (irange &r,
+						const irange &rmask) const
+{
+  if (r.undefined_p () || !unsigned_singleton_p (rmask))
+    return;
+
+  wide_int mask = rmask.lower_bound ();
+  tree type = r.type ();
+  int prec = TYPE_PRECISION (type);
+  int leading_zeros = wi::clz (mask);
+  widest_irange impossible_ranges;
+
+  /* We know that starting at the most significant bit, any 0 in the
+     mask means the resulting range cannot contain a 1 in that same
+     position.  This means the following ranges are impossible:
+
+	x & 0b1001 1010
+			  IMPOSSIBLE RANGES
+	      01xx xxxx   [0100 0000, 0111 1111]
+	      001x xxxx   [0010 0000, 0011 1111]
+	      0000 01xx   [0000 0100, 0000 0111]
+	      0000 0001   [0000 0001, 0000 0001]
+  */
+  wide_int one = wi::one (prec);
+  for (int i = 0; i < prec - leading_zeros - 1; ++i)
+    if (wi::bit_and (mask, wi::lshift (one, wi::uhwi (i, prec))) == 0)
+      {
+	tree lb = fold_build2 (LSHIFT_EXPR, type,
+			       build_one_cst (type),
+			       build_int_cst (type, i));
+	tree ub_left = fold_build1 (BIT_NOT_EXPR, type,
+				    fold_build2 (LSHIFT_EXPR, type,
+						 build_minus_one_cst (type),
+						 build_int_cst (type, i)));
+	tree ub_right = fold_build2 (LSHIFT_EXPR, type,
+				     build_one_cst (type),
+				     build_int_cst (type, i));
+	tree ub = fold_build2 (BIT_IOR_EXPR, type, ub_left, ub_right);
+	impossible_ranges.union_ (int_range<1> (lb, ub));
+      }
+  if (!impossible_ranges.undefined_p ())
+    {
+      impossible_ranges.invert ();
+      r.intersect (impossible_ranges);
+    }
+}
+
+bool
+operator_bitwise_and::fold_range (irange &r, tree type,
+				  const irange &lh,
+				  const irange &rh) const
+{
+  if (range_operator::fold_range (r, type, lh, rh))
+    {
+      // FIXME: This is temporarily disabled because, though it
+      // generates better ranges, it's noticeably slower for evrp.
+      // remove_impossible_ranges (r, rh);
+      return true;
+    }
+  return false;
+}
+
+
 // Optimize BIT_AND_EXPR and BIT_IOR_EXPR in terms of a mask if
 // possible.  Basically, see if we can optimize:
 //
@@ -1777,7 +2048,7 @@  public:
 // return TRUE.
 
 static bool
-wi_optimize_and_or (value_range &r,
+wi_optimize_and_or (irange &r,
 		    enum tree_code code,
 		    tree type,
 		    const wide_int &lh_lb, const wide_int &lh_ub,
@@ -1886,7 +2157,7 @@  wi_set_zero_nonzero_bits (tree type,
 }
 
 void
-operator_bitwise_and::wi_fold (value_range &r, tree type,
+operator_bitwise_and::wi_fold (irange &r, tree type,
 			       const wide_int &lh_lb,
 			       const wide_int &lh_ub,
 			       const wide_int &rh_lb,
@@ -1938,29 +2209,128 @@  operator_bitwise_and::wi_fold (value_range &r, tree type,
     }
   // If the limits got swapped around, return varying.
   if (wi::gt_p (new_lb, new_ub,sign))
-    r = value_range (type);
+    r.set_varying (type);
   else
     value_range_with_overflow (r, type, new_lb, new_ub);
 }
 
+static void
+set_nonzero_range_from_mask (irange &r, tree type, const irange &lhs)
+{
+  if (!lhs.contains_p (build_zero_cst (type)))
+    r = range_nonzero (type);
+  else
+    r.set_varying (type);
+}
+
+// This was shamelessly stolen from register_edge_assert_for_2 and
+// adjusted to work with iranges.
+
+void
+operator_bitwise_and::simple_op1_range_solver (irange &r, tree type,
+					       const irange &lhs,
+					       const irange &op2) const
+{
+  if (!op2.singleton_p ())
+    {
+      set_nonzero_range_from_mask (r, type, lhs);
+      return;
+    }
+  unsigned int nprec = TYPE_PRECISION (type);
+  wide_int cst2v = op2.lower_bound ();
+  bool cst2n = wi::neg_p (cst2v, TYPE_SIGN (type));
+  wide_int sgnbit;
+  if (cst2n)
+    sgnbit = wi::set_bit_in_zero (nprec - 1, nprec);
+  else
+    sgnbit = wi::zero (nprec);
+
+  // Solve [lhs.lower_bound (), +INF] = x & MASK.
+  //
+  // Minimum unsigned value for >= if (VAL & CST2) == VAL is VAL and
+  // maximum unsigned value is ~0.  For signed comparison, if CST2
+  // doesn't have the most significant bit set, handle it similarly.  If
+  // CST2 has MSB set, the minimum is the same, and maximum is ~0U/2.
+  wide_int valv = lhs.lower_bound ();
+  wide_int minv = valv & cst2v, maxv;
+  bool we_know_nothing = false;
+  if (minv != valv)
+    {
+      // If (VAL & CST2) != VAL, X & CST2 can't be equal to VAL.
+      minv = masked_increment (valv, cst2v, sgnbit, nprec);
+      if (minv == valv)
+	{
+	  // If we can't determine anything on this bound, fall
+	  // through and conservatively solve for the other end point.
+	  we_know_nothing = true;
+	}
+    }
+  maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec);
+  if (we_know_nothing)
+    r.set_varying (type);
+  else
+    r = int_range<1> (type, minv, maxv);
+
+  // Solve [-INF, lhs.upper_bound ()] = x & MASK.
+  //
+  // Minimum unsigned value for <= is 0 and maximum unsigned value is
+  // VAL | ~CST2 if (VAL & CST2) == VAL.  Otherwise, find smallest
+  // VAL2 where
+  // VAL2 > VAL && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
+  // as maximum.
+  // For signed comparison, if CST2 doesn't have most significant bit
+  // set, handle it similarly.  If CST2 has MSB set, the maximum is
+  // the same and minimum is INT_MIN.
+  valv = lhs.upper_bound ();
+  minv = valv & cst2v;
+  if (minv == valv)
+    maxv = valv;
+  else
+    {
+      maxv = masked_increment (valv, cst2v, sgnbit, nprec);
+      if (maxv == valv)
+	{
+	  // If we couldn't determine anything on either bound, return
+	  // undefined.
+	  if (we_know_nothing)
+	    r.set_undefined ();
+	  return;
+	}
+      maxv -= 1;
+    }
+  maxv |= ~cst2v;
+  minv = sgnbit;
+  int_range<1> upper_bits (type, minv, maxv);
+  r.intersect (upper_bits);
+}
+
 bool
-operator_bitwise_and::op1_range (value_range &r, tree type,
-				 const value_range &lhs,
-				 const value_range &op2) const
+operator_bitwise_and::op1_range (irange &r, tree type,
+				 const irange &lhs,
+				 const irange &op2) const
 {
-  // If this is really a logical wi_fold, call that.
   if (types_compatible_p (type, boolean_type_node))
     return op_logical_and.op1_range (r, type, lhs, op2);
 
-  // For now do nothing with bitwise AND of value_range's.
-  r.set_varying (type);
+  r.set_undefined ();
+  for (unsigned i = 0; i < lhs.num_pairs (); ++i)
+    {
+      widest_irange chunk (lhs.type (),
+			   lhs.lower_bound (i),
+			   lhs.upper_bound (i));
+      widest_irange res;
+      simple_op1_range_solver (res, type, chunk, op2);
+      r.union_ (res);
+    }
+  if (r.undefined_p ())
+    set_nonzero_range_from_mask (r, type, lhs);
   return true;
 }
 
 bool
-operator_bitwise_and::op2_range (value_range &r, tree type,
-				 const value_range &lhs,
-				 const value_range &op1) const
+operator_bitwise_and::op2_range (irange &r, tree type,
+				 const irange &lhs,
+				 const irange &op1) const
 {
   return operator_bitwise_and::op1_range (r, type, lhs, op1);
 }
@@ -1969,23 +2339,23 @@  operator_bitwise_and::op2_range (value_range &r, tree type,
 class operator_logical_or : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &lh,
-			   const value_range &rh) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &lh,
+			   const irange &rh) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_logical_or;
 
 bool
-operator_logical_or::fold_range (value_range &r, tree type ATTRIBUTE_UNUSED,
-				 const value_range &lh,
-				 const value_range &rh) const
+operator_logical_or::fold_range (irange &r, tree type ATTRIBUTE_UNUSED,
+				 const irange &lh,
+				 const irange &rh) const
 {
-  if (empty_range_check (r, lh, rh))
+  if (empty_range_varying (r, type, lh, rh))
     return true;
 
   r = lh;
@@ -1994,9 +2364,9 @@  operator_logical_or::fold_range (value_range &r, tree type ATTRIBUTE_UNUSED,
 }
 
 bool
-operator_logical_or::op1_range (value_range &r, tree type,
-				const value_range &lhs,
-				const value_range &op2 ATTRIBUTE_UNUSED) const
+operator_logical_or::op1_range (irange &r, tree type,
+				const irange &lhs,
+				const irange &op2 ATTRIBUTE_UNUSED) const
 {
    switch (get_bool_state (r, lhs, type))
      {
@@ -2015,9 +2385,9 @@  operator_logical_or::op1_range (value_range &r, tree type,
 }
 
 bool
-operator_logical_or::op2_range (value_range &r, tree type,
-				const value_range &lhs,
-				const value_range &op1) const
+operator_logical_or::op2_range (irange &r, tree type,
+				const irange &lhs,
+				const irange &op1) const
 {
   return operator_logical_or::op1_range (r, type, lhs, op1);
 }
@@ -2026,13 +2396,13 @@  operator_logical_or::op2_range (value_range &r, tree type,
 class operator_bitwise_or : public range_operator
 {
 public:
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
-  virtual void wi_fold (value_range &r, tree type,
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -2040,7 +2410,7 @@  public:
 } op_bitwise_or;
 
 void
-operator_bitwise_or::wi_fold (value_range &r, tree type,
+operator_bitwise_or::wi_fold (irange &r, tree type,
 			      const wide_int &lh_lb,
 			      const wide_int &lh_ub,
 			      const wide_int &rh_lb,
@@ -2076,29 +2446,34 @@  operator_bitwise_or::wi_fold (value_range &r, tree type,
     new_lb = wi::max (new_lb, rh_lb, sign);
   // If the limits got swapped around, return varying.
   if (wi::gt_p (new_lb, new_ub,sign))
-    r = value_range (type);
+    r.set_varying (type);
   else
     value_range_with_overflow (r, type, new_lb, new_ub);
 }
 
 bool
-operator_bitwise_or::op1_range (value_range &r, tree type,
-				const value_range &lhs,
-				const value_range &op2) const
+operator_bitwise_or::op1_range (irange &r, tree type,
+				const irange &lhs,
+				const irange &op2) const
 {
   // If this is really a logical wi_fold, call that.
   if (types_compatible_p (type, boolean_type_node))
     return op_logical_or.op1_range (r, type, lhs, op2);
 
-  // For now do nothing with bitwise OR of value_range's.
+  if (lhs.zero_p ())
+    {
+      tree zero = build_zero_cst (type);
+      r = int_range<1> (zero, zero);
+      return true;
+    }
   r.set_varying (type);
   return true;
 }
 
 bool
-operator_bitwise_or::op2_range (value_range &r, tree type,
-				const value_range &lhs,
-				const value_range &op1) const
+operator_bitwise_or::op2_range (irange &r, tree type,
+				const irange &lhs,
+				const irange &op1) const
 {
   return operator_bitwise_or::op1_range (r, type, lhs, op1);
 }
@@ -2107,15 +2482,21 @@  operator_bitwise_or::op2_range (value_range &r, tree type,
 class operator_bitwise_xor : public range_operator
 {
 public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
 		        const wide_int &rh_ub) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 } op_bitwise_xor;
 
 void
-operator_bitwise_xor::wi_fold (value_range &r, tree type,
+operator_bitwise_xor::wi_fold (irange &r, tree type,
 			       const wide_int &lh_lb,
 			       const wide_int &lh_ub,
 			       const wide_int &rh_lb,
@@ -2142,14 +2523,55 @@  operator_bitwise_xor::wi_fold (value_range &r, tree type,
   if (wi::lt_p (new_lb, 0, sign) || wi::ge_p (new_ub, 0, sign))
     value_range_with_overflow (r, type, new_lb, new_ub);
   else
-    r = value_range (type);
+    r.set_varying (type);
+}
+
+bool
+operator_bitwise_xor::op1_range (irange &r, tree type,
+				 const irange &lhs,
+				 const irange &op2) const
+{
+  if (lhs.undefined_p () || lhs.varying_p ())
+    {
+      r = lhs;
+      return true;
+    }
+  if (types_compatible_p (type, boolean_type_node))
+    {
+      switch (get_bool_state (r, lhs, type))
+	{
+	case BRS_TRUE:
+	  if (op2.varying_p ())
+	    r.set_varying (type);
+	  else if (op2.zero_p ())
+	    r = range_true (type);
+	  else
+	    r = range_false (type);
+	  break;
+	case BRS_FALSE:
+	  r = op2;
+	  break;
+	default:
+	  gcc_unreachable ();
+	}
+      return true;
+    }
+  r.set_varying (type);
+  return true;
 }
 
+bool
+operator_bitwise_xor::op2_range (irange &r, tree type,
+				 const irange &lhs,
+				 const irange &op1) const
+{
+  return operator_bitwise_xor::op1_range (r, type, lhs, op1);
+}
 
 class operator_trunc_mod : public range_operator
 {
 public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -2157,7 +2579,7 @@  public:
 } op_trunc_mod;
 
 void
-operator_trunc_mod::wi_fold (value_range &r, tree type,
+operator_trunc_mod::wi_fold (irange &r, tree type,
 			     const wide_int &lh_lb,
 			     const wide_int &lh_ub,
 			     const wide_int &rh_lb,
@@ -2170,7 +2592,7 @@  operator_trunc_mod::wi_fold (value_range &r, tree type,
   // Mod 0 is undefined.  Return undefined.
   if (wi_zero_p (type, rh_lb, rh_ub))
     {
-      r = value_range ();
+      r.set_undefined ();
       return;
     }
 
@@ -2204,12 +2626,12 @@  operator_trunc_mod::wi_fold (value_range &r, tree type,
 class operator_logical_not : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &lh,
-			   const value_range &rh) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &lh,
+			   const irange &rh) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
 } op_logical_not;
 
 // Folding a logical NOT, oddly enough, involves doing nothing on the
@@ -2227,11 +2649,11 @@  public:
 //   which is the result we are looking for.. so.. pass it through.
 
 bool
-operator_logical_not::fold_range (value_range &r, tree type,
-				  const value_range &lh,
-				  const value_range &rh ATTRIBUTE_UNUSED) const
+operator_logical_not::fold_range (irange &r, tree type,
+				  const irange &lh,
+				  const irange &rh ATTRIBUTE_UNUSED) const
 {
-  if (empty_range_check (r, lh, rh))
+  if (empty_range_varying (r, type, lh, rh))
     return true;
 
   if (lh.varying_p () || lh.undefined_p ())
@@ -2246,10 +2668,10 @@  operator_logical_not::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_logical_not::op1_range (value_range &r,
+operator_logical_not::op1_range (irange &r,
 				 tree type ATTRIBUTE_UNUSED,
-				 const value_range &lhs,
-				 const value_range &op2 ATTRIBUTE_UNUSED) const
+				 const irange &lhs,
+				 const irange &op2 ATTRIBUTE_UNUSED) const
 {
   r = lhs;
   if (!lhs.varying_p () && !lhs.undefined_p ())
@@ -2261,33 +2683,33 @@  operator_logical_not::op1_range (value_range &r,
 class operator_bitwise_not : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &lh,
-			   const value_range &rh) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &lh,
+			   const irange &rh) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
 } op_bitwise_not;
 
 bool
-operator_bitwise_not::fold_range (value_range &r, tree type,
-				  const value_range &lh,
-				  const value_range &rh) const
+operator_bitwise_not::fold_range (irange &r, tree type,
+				  const irange &lh,
+				  const irange &rh) const
 {
-  if (empty_range_check (r, lh, rh))
+  if (empty_range_varying (r, type, lh, rh))
     return true;
 
   // ~X is simply -1 - X.
-  value_range minusone (type, wi::minus_one (TYPE_PRECISION (type)),
-			wi::minus_one (TYPE_PRECISION (type)));
+  int_range<1> minusone (type, wi::minus_one (TYPE_PRECISION (type)),
+			 wi::minus_one (TYPE_PRECISION (type)));
   return range_op_handler (MINUS_EXPR, type)->fold_range (r, type, minusone,
 							  lh);
 }
 
 bool
-operator_bitwise_not::op1_range (value_range &r, tree type,
-				 const value_range &lhs,
-				 const value_range &op2) const
+operator_bitwise_not::op1_range (irange &r, tree type,
+				 const irange &lhs,
+				 const irange &op2) const
 {
   // ~X is -1 - X and since bitwise NOT is involutary...do it again.
   return fold_range (r, type, lhs, op2);
@@ -2297,15 +2719,15 @@  operator_bitwise_not::op1_range (value_range &r, tree type,
 class operator_cst : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
 } op_integer_cst;
 
 bool
-operator_cst::fold_range (value_range &r, tree type ATTRIBUTE_UNUSED,
-			  const value_range &lh,
-			  const value_range &rh ATTRIBUTE_UNUSED) const
+operator_cst::fold_range (irange &r, tree type ATTRIBUTE_UNUSED,
+			  const irange &lh,
+			  const irange &rh ATTRIBUTE_UNUSED) const
 {
   r = lh;
   return true;
@@ -2315,48 +2737,66 @@  operator_cst::fold_range (value_range &r, tree type ATTRIBUTE_UNUSED,
 class operator_identity : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
 } op_identity;
 
 bool
-operator_identity::fold_range (value_range &r, tree type ATTRIBUTE_UNUSED,
-			       const value_range &lh,
-			       const value_range &rh ATTRIBUTE_UNUSED) const
+operator_identity::fold_range (irange &r, tree type ATTRIBUTE_UNUSED,
+			       const irange &lh,
+			       const irange &rh ATTRIBUTE_UNUSED) const
 {
   r = lh;
   return true;
 }
 
 bool
-operator_identity::op1_range (value_range &r, tree type ATTRIBUTE_UNUSED,
-			      const value_range &lhs,
-			      const value_range &op2 ATTRIBUTE_UNUSED) const
+operator_identity::op1_range (irange &r, tree type ATTRIBUTE_UNUSED,
+			      const irange &lhs,
+			      const irange &op2 ATTRIBUTE_UNUSED) const
 {
   r = lhs;
   return true;
 }
 
 
+class operator_unknown : public range_operator
+{
+public:
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+} op_unknown;
+
+bool
+operator_unknown::fold_range (irange &r, tree type,
+			      const irange &lh ATTRIBUTE_UNUSED,
+			      const irange &rh ATTRIBUTE_UNUSED) const
+{
+  r.set_varying (type);
+  return true;
+}
+
+
 class operator_abs : public range_operator
 {
  public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
 		        const wide_int &rh_ub) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
 } op_abs;
 
 void
-operator_abs::wi_fold (value_range &r, tree type,
+operator_abs::wi_fold (irange &r, tree type,
 		       const wide_int &lh_lb, const wide_int &lh_ub,
 		       const wide_int &rh_lb ATTRIBUTE_UNUSED,
 		       const wide_int &rh_ub ATTRIBUTE_UNUSED) const
@@ -2368,7 +2808,7 @@  operator_abs::wi_fold (value_range &r, tree type,
   // Pass through LH for the easy cases.
   if (sign == UNSIGNED || wi::ge_p (lh_lb, 0, sign))
     {
-      r = value_range (type, lh_lb, lh_ub);
+      r = int_range<1> (type, lh_lb, lh_ub);
       return;
     }
 
@@ -2378,7 +2818,7 @@  operator_abs::wi_fold (value_range &r, tree type,
   wide_int max_value = wi::max_value (prec, sign);
   if (!TYPE_OVERFLOW_UNDEFINED (type) && wi::eq_p (lh_lb, min_value))
     {
-      r = value_range (type);
+      r.set_varying (type);
       return;
     }
 
@@ -2416,15 +2856,15 @@  operator_abs::wi_fold (value_range &r, tree type,
       min = wi::zero (prec);
       max = max_value;
     }
-  r = value_range (type, min, max);
+  r = int_range<1> (type, min, max);
 }
 
 bool
-operator_abs::op1_range (value_range &r, tree type,
-			 const value_range &lhs,
-			 const value_range &op2) const
+operator_abs::op1_range (irange &r, tree type,
+			 const irange &lhs,
+			 const irange &op2) const
 {
-  if (empty_range_check (r, lhs, op2))
+  if (empty_range_varying (r, type, lhs, op2))
     return true;
   if (TYPE_UNSIGNED (type))
     {
@@ -2432,15 +2872,15 @@  operator_abs::op1_range (value_range &r, tree type,
       return true;
     }
   // Start with the positives because negatives are an impossible result.
-  value_range positives = range_positives (type);
+  widest_irange positives = range_positives (type);
   positives.intersect (lhs);
   r = positives;
   // Then add the negative of each pair:
   // ABS(op1) = [5,20] would yield op1 => [-20,-5][5,20].
   for (unsigned i = 0; i < positives.num_pairs (); ++i)
-    r.union_ (value_range (type,
-			   -positives.upper_bound (i),
-			   -positives.lower_bound (i)));
+    r.union_ (int_range<1> (type,
+			    -positives.upper_bound (i),
+			    -positives.lower_bound (i)));
   return true;
 }
 
@@ -2448,13 +2888,13 @@  operator_abs::op1_range (value_range &r, tree type,
 class operator_absu : public range_operator
 {
  public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 			const wide_int &lh_lb, const wide_int &lh_ub,
 			const wide_int &rh_lb, const wide_int &rh_ub) const;
 } op_absu;
 
 void
-operator_absu::wi_fold (value_range &r, tree type,
+operator_absu::wi_fold (irange &r, tree type,
 			const wide_int &lh_lb, const wide_int &lh_ub,
 			const wide_int &rh_lb ATTRIBUTE_UNUSED,
 			const wide_int &rh_ub ATTRIBUTE_UNUSED) const
@@ -2485,27 +2925,27 @@  operator_absu::wi_fold (value_range &r, tree type,
     }
 
   gcc_checking_assert (TYPE_UNSIGNED (type));
-  r = value_range (type, new_lb, new_ub);
+  r = int_range<1> (type, new_lb, new_ub);
 }
 
 
 class operator_negate : public range_operator
 {
  public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
 } op_negate;
 
 bool
-operator_negate::fold_range (value_range &r, tree type,
-			     const value_range &lh,
-			     const value_range &rh) const
+operator_negate::fold_range (irange &r, tree type,
+			     const irange &lh,
+			     const irange &rh) const
 {
-  if (empty_range_check (r, lh, rh))
+  if (empty_range_varying (r, type, lh, rh))
     return true;
   // -X is simply 0 - X.
   return range_op_handler (MINUS_EXPR, type)->fold_range (r, type,
@@ -2514,9 +2954,9 @@  operator_negate::fold_range (value_range &r, tree type,
 }
 
 bool
-operator_negate::op1_range (value_range &r, tree type,
-			    const value_range &lhs,
-			    const value_range &op2) const
+operator_negate::op1_range (irange &r, tree type,
+			    const irange &lhs,
+			    const irange &op2) const
 {
   // NEGATE is involutory.
   return fold_range (r, type, lhs, op2);
@@ -2526,20 +2966,20 @@  operator_negate::op1_range (value_range &r, tree type,
 class operator_addr_expr : public range_operator
 {
 public:
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &op1,
-			   const value_range &op2) const;
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &op1,
+			   const irange &op2) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
 } op_addr;
 
 bool
-operator_addr_expr::fold_range (value_range &r, tree type,
-				const value_range &lh,
-				const value_range &rh) const
+operator_addr_expr::fold_range (irange &r, tree type,
+				const irange &lh,
+				const irange &rh) const
 {
-  if (empty_range_check (r, lh, rh))
+  if (empty_range_varying (r, type, lh, rh))
     return true;
 
   // Return a non-null pointer of the LHS type (passed in op2).
@@ -2548,14 +2988,14 @@  operator_addr_expr::fold_range (value_range &r, tree type,
   else if (!lh.contains_p (build_zero_cst (lh.type ())))
     r = range_nonzero (type);
   else
-    r = value_range (type);
+    r.set_varying (type);
   return true;
 }
 
 bool
-operator_addr_expr::op1_range (value_range &r, tree type,
-			       const value_range &lhs,
-			       const value_range &op2) const
+operator_addr_expr::op1_range (irange &r, tree type,
+			       const irange &lhs,
+			       const irange &op2) const
 {
   return operator_addr_expr::fold_range (r, type, lhs, op2);
 }
@@ -2564,7 +3004,7 @@  operator_addr_expr::op1_range (value_range &r, tree type,
 class pointer_plus_operator : public range_operator
 {
 public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -2572,7 +3012,7 @@  public:
 } op_pointer_plus;
 
 void
-pointer_plus_operator::wi_fold (value_range &r, tree type,
+pointer_plus_operator::wi_fold (irange &r, tree type,
 				const wide_int &lh_lb,
 				const wide_int &lh_ub,
 				const wide_int &rh_lb,
@@ -2604,20 +3044,20 @@  pointer_plus_operator::wi_fold (value_range &r, tree type,
 	   && rh_lb == rh_ub && rh_lb == 0)
     r = range_zero (type);
   else
-   r = value_range (type);
+   r.set_varying (type);
 }
 
 
 class pointer_min_max_operator : public range_operator
 {
 public:
-  virtual void wi_fold (value_range & r, tree type,
+  virtual void wi_fold (irange & r, tree type,
 			const wide_int &lh_lb, const wide_int &lh_ub,
 			const wide_int &rh_lb, const wide_int &rh_ub) const;
 } op_ptr_min_max;
 
 void
-pointer_min_max_operator::wi_fold (value_range &r, tree type,
+pointer_min_max_operator::wi_fold (irange &r, tree type,
 				   const wide_int &lh_lb,
 				   const wide_int &lh_ub,
 				   const wide_int &rh_lb,
@@ -2633,20 +3073,20 @@  pointer_min_max_operator::wi_fold (value_range &r, tree type,
   else if (wi_zero_p (type, lh_lb, lh_ub) && wi_zero_p (type, rh_lb, rh_ub))
     r = range_zero (type);
   else
-    r = value_range (type);
+    r.set_varying (type);
 }
 
 
 class pointer_and_operator : public range_operator
 {
 public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 			const wide_int &lh_lb, const wide_int &lh_ub,
 			const wide_int &rh_lb, const wide_int &rh_ub) const;
 } op_pointer_and;
 
 void
-pointer_and_operator::wi_fold (value_range &r, tree type,
+pointer_and_operator::wi_fold (irange &r, tree type,
 			       const wide_int &lh_lb,
 			       const wide_int &lh_ub,
 			       const wide_int &rh_lb ATTRIBUTE_UNUSED,
@@ -2657,20 +3097,49 @@  pointer_and_operator::wi_fold (value_range &r, tree type,
   if (wi_zero_p (type, lh_lb, lh_ub) || wi_zero_p (type, lh_lb, lh_ub))
     r = range_zero (type);
   else 
-    r = value_range (type);
+    r.set_varying (type);
 }
 
 
 class pointer_or_operator : public range_operator
 {
 public:
-  virtual void wi_fold (value_range &r, tree type,
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
+  virtual void wi_fold (irange &r, tree type,
 			const wide_int &lh_lb, const wide_int &lh_ub,
 			const wide_int &rh_lb, const wide_int &rh_ub) const;
 } op_pointer_or;
 
+bool
+pointer_or_operator::op1_range (irange &r, tree type,
+				const irange &lhs,
+				const irange &op2 ATTRIBUTE_UNUSED) const
+{
+  if (lhs.zero_p ())
+    {
+      tree zero = build_zero_cst (type);
+      r = int_range<1> (zero, zero);
+      return true;
+    }
+  r.set_varying (type);
+  return true;
+}
+
+bool
+pointer_or_operator::op2_range (irange &r, tree type,
+				const irange &lhs,
+				const irange &op1) const
+{
+  return pointer_or_operator::op1_range (r, type, lhs, op1);
+}
+
 void
-pointer_or_operator::wi_fold (value_range &r, tree type,
+pointer_or_operator::wi_fold (irange &r, tree type,
 			      const wide_int &lh_lb,
 			      const wide_int &lh_ub,
 			      const wide_int &rh_lb,
@@ -2684,7 +3153,7 @@  pointer_or_operator::wi_fold (value_range &r, tree type,
   else if (wi_zero_p (type, lh_lb, lh_ub) && wi_zero_p (type, rh_lb, rh_ub))
     r = range_zero (type);
   else
-    r = value_range (type);
+    r.set_varying (type);
 }
 
 // This implements the range operator tables as local objects in this file.
@@ -2760,6 +3229,8 @@  integral_table::integral_table ()
   set (SSA_NAME, op_identity);
   set (PAREN_EXPR, op_identity);
   set (OBJ_TYPE_REF, op_identity);
+  set (IMAGPART_EXPR, op_unknown);
+  set (POINTER_DIFF_EXPR, op_unknown);
   set (ABS_EXPR, op_abs);
   set (ABSU_EXPR, op_absu);
   set (NEGATE_EXPR, op_negate);
@@ -2811,13 +3282,13 @@  range_op_handler (enum tree_code code, tree type)
 // Cast the range in R to TYPE.
 
 void
-range_cast (value_range &r, tree type)
+range_cast (irange &r, tree type)
 {
-  value_range tmp = r;
+  widest_irange tmp = r;
   range_operator *op = range_op_handler (CONVERT_EXPR, type);
   // Call op_convert, if it fails, the result is varying.
-  if (!op->fold_range (r, type, tmp, value_range (type)))
-    r = value_range (type);
+  if (!op->fold_range (r, type, tmp, int_range<1> (type)))
+    r.set_varying (type);
 }
 
 #if CHECKING_P
@@ -2836,37 +3307,280 @@  namespace selftest
 #define UCHAR(N) build_int_cstu (unsigned_char_type_node, (N))
 #define SCHAR(N) build_int_cst (signed_char_type_node, (N))
 
+static int_range<3>
+build_range3 (int a, int b, int c, int d, int e, int f)
+{
+  int_range<3> i1 (INT (a), INT (b));
+  int_range<3> i2 (INT (c), INT (d));
+  int_range<3> i3 (INT (e), INT (f));
+  i1.union_ (i2);
+  i1.union_ (i3);
+  return i1;
+}
+
+static void
+range3_tests ()
+{
+  typedef int_range<3> irange3;
+  irange3 r0, r1, r2;
+  irange3 i1, i2, i3;
+
+  // ([10,20] U [5,8]) U [1,3] ==> [1,3][5,8][10,20].
+  r0 = irange3 (INT (10), INT (20));
+  r1 = irange3 (INT (5), INT (8));
+  r0.union_ (r1);
+  r1 = irange3 (INT (1), INT (3));
+  r0.union_ (r1);
+  ASSERT_TRUE (r0 == build_range3 (1, 3, 5, 8, 10, 20));
+
+  // [1,3][5,8][10,20] U [-5,0] => [-5,3][5,8][10,20].
+  r1 = irange3 (INT (-5), INT (0));
+  r0.union_ (r1);
+  ASSERT_TRUE (r0 == build_range3 (-5, 3, 5, 8, 10, 20));
+
+  // [10,20][30,40] U [50,60] ==> [10,20][30,40][50,60].
+  r1 = irange3 (INT (50), INT (60));
+  r0 = irange3 (INT (10), INT (20));
+  r0.union_ (irange3 (INT (30), INT (40)));
+  r0.union_ (r1);
+  ASSERT_TRUE (r0 == build_range3 (10, 20, 30, 40, 50, 60));
+  // [10,20][30,40][50,60] U [70, 80] ==> [10,20][30,40][50,60][70,80].
+  r1 = irange3 (INT (70), INT (80));
+  r0.union_ (r1);
+
+  r2 = build_range3 (10, 20, 30, 40, 50, 60);
+  r2.union_ (irange3 (INT (70), INT (80)));
+  ASSERT_TRUE (r0 == r2);
+
+  // [10,20][30,40][50,60] U [6,35] => [6,40][50,60].
+  r0 = build_range3 (10, 20, 30, 40, 50, 60);
+  r1 = irange3 (INT (6), INT (35));
+  r0.union_ (r1);
+  r1 = irange3 (INT (6), INT (40));
+  r1.union_ (irange3 (INT (50), INT (60)));
+  ASSERT_TRUE (r0 == r1);
+
+  // [10,20][30,40][50,60] U [6,60] => [6,60].
+  r0 = build_range3 (10, 20, 30, 40, 50, 60);
+  r1 = irange3 (INT (6), INT (60));
+  r0.union_ (r1);
+  ASSERT_TRUE (r0 == irange3 (INT (6), INT (60)));
+
+  // [10,20][30,40][50,60] U [6,70] => [6,70].
+  r0 = build_range3 (10, 20, 30, 40, 50, 60);
+  r1 = irange3 (INT (6), INT (70));
+  r0.union_ (r1);
+  ASSERT_TRUE (r0 == irange3 (INT (6), INT (70)));
+
+  // [10,20][30,40][50,60] U [35,70] => [10,20][30,70].
+  r0 = build_range3 (10, 20, 30, 40, 50, 60);
+  r1 = irange3 (INT (35), INT (70));
+  r0.union_ (r1);
+  r1 = irange3 (INT (10), INT (20));
+  r1.union_ (irange3 (INT (30), INT (70)));
+  ASSERT_TRUE (r0 == r1);
+
+  // [10,20][30,40][50,60] U [15,35] => [10,40][50,60].
+  r0 = build_range3 (10, 20, 30, 40, 50, 60);
+  r1 = irange3 (INT (15), INT (35));
+  r0.union_ (r1);
+  r1 = irange3 (INT (10), INT (40));
+  r1.union_ (irange3 (INT (50), INT (60)));
+  ASSERT_TRUE (r0 == r1);
+
+  // [10,20][30,40][50,60] U [35,35] => [10,20][30,40][50,60].
+  r0 = build_range3 (10, 20, 30, 40, 50, 60);
+  r1 = irange3 (INT (35), INT (35));
+  r0.union_ (r1);
+  ASSERT_TRUE (r0 == build_range3 (10, 20, 30, 40, 50, 60));
+}
+
+static void
+widest_irange_tests ()
+{
+  widest_irange big;
+  unsigned int nrange;
+
+  // Build a huge multi-range range.
+  for (nrange = 0; nrange < 50; ++nrange)
+    {
+      int_range<1> tmp (INT (nrange*10), INT (nrange*10 + 5));
+      big.union_ (tmp);
+    }
+  ASSERT_TRUE (big.num_pairs () == nrange);
+
+  // Verify that we can copy it without loosing precision.
+  widest_irange copy (big);
+  ASSERT_TRUE (copy.num_pairs () == nrange);
+
+  // Inverting it should produce one more sub-range.
+  big.invert ();
+  ASSERT_TRUE (big.num_pairs () == nrange + 1);
+
+  int_range<1> tmp (INT (5), INT (37));
+  big.intersect (tmp);
+  ASSERT_TRUE (big.num_pairs () == 4);
+
+  // Test that [10,10][20,20] does NOT contain 15.
+  {
+    widest_irange i1 (build_int_cst (integer_type_node, 10),
+		      build_int_cst (integer_type_node, 10));
+    widest_irange i2 (build_int_cst (integer_type_node, 20),
+		      build_int_cst (integer_type_node, 20));
+    i1.union_ (i2);
+    ASSERT_FALSE (i1.contains_p (build_int_cst (integer_type_node, 15)));
+  }
+
+}
+
+static void
+multi_precision_range_tests ()
+{
+  // Test truncating copy to int_range<1>.
+  int_range<3> big = build_range3 (10, 20, 30, 40, 50, 60);
+  int_range<1> small = big;
+  ASSERT_TRUE (small == int_range<1> (INT (10), INT (60)));
+
+  // Test truncating copy to int_range<2>.
+  int_range<2> medium = big;
+  ASSERT_TRUE (!medium.undefined_p ());
+
+  // Test that a truncating copy of [MIN,20][22,40][80,MAX]
+  // ends up as a conservative anti-range of ~[21,21].
+  big = int_range<3> (vrp_val_min (integer_type_node), INT (20));
+  big.union_ (int_range<1> (INT (22), INT (40)));
+  big.union_ (int_range<1> (INT (80), vrp_val_max (integer_type_node)));
+  small = big;
+  ASSERT_TRUE (small == int_range<1> (INT (21), INT (21), VR_ANTI_RANGE));
+
+  range3_tests ();
+}
+
+static void
+operator_tests ()
+{
+  tree min = vrp_val_min (integer_type_node);
+  tree max = vrp_val_max (integer_type_node);
+  tree tiny = fold_build2 (PLUS_EXPR, integer_type_node, min,
+			   build_one_cst (integer_type_node));
+  widest_irange res;
+  widest_irange i1 (tiny, max);
+  widest_irange i2 (build_int_cst (integer_type_node, 255),
+		    build_int_cst (integer_type_node, 255));
+
+  // [MIN+1, MAX] = OP1 & 255: OP1 is VARYING
+  op_bitwise_and.op1_range (res, integer_type_node, i1, i2);
+  ASSERT_TRUE (res == int_range<1> (integer_type_node));
+
+  // VARYING = OP1 & 255: OP1 is VARYING
+  i1 = int_range<1> (integer_type_node);
+  op_bitwise_and.op1_range (res, integer_type_node, i1, i2);
+  ASSERT_TRUE (res == int_range<1> (integer_type_node));
+
+  // Test that 0x808.... & 0x8.... still contains 0x8....
+  // for a large set of numbers.
+  {
+    tree big_type = long_long_unsigned_type_node;
+    // big_num = 0x808,0000,0000,0000
+    tree big_num = fold_build2 (LSHIFT_EXPR, big_type,
+				build_int_cst (big_type, 0x808),
+				build_int_cst (big_type, 48));
+    op_bitwise_and.fold_range (res, big_type,
+			       int_range <1> (big_type),
+			       int_range <1> (big_num, big_num));
+    // val = 0x8,0000,0000,0000
+    tree val = fold_build2 (LSHIFT_EXPR, big_type,
+			    build_int_cst (big_type, 0x8),
+			    build_int_cst (big_type, 48));
+    ASSERT_TRUE (res.contains_p (val));
+  }
+
+  // unsigned: [3, MAX] = OP1 >> 1
+  {
+    widest_irange lhs (build_int_cst (unsigned_type_node, 3),
+		       TYPE_MAX_VALUE (unsigned_type_node));
+    widest_irange one (build_one_cst (unsigned_type_node),
+		       build_one_cst (unsigned_type_node));
+    widest_irange op1;
+    op_rshift.op1_range (op1, unsigned_type_node, lhs, one);
+    ASSERT_FALSE (op1.contains_p (UINT (3)));
+  }
+
+  // signed: [3, MAX] = OP1 >> 1
+  {
+    widest_irange lhs (INT (3), TYPE_MAX_VALUE (integer_type_node));
+    widest_irange one (INT (1), INT (1));
+    widest_irange op1;
+    op_rshift.op1_range (op1, integer_type_node, lhs, one);
+    ASSERT_FALSE (op1.contains_p (INT (-2)));
+  }
+
+  // This is impossible, so OP1 should be [].
+  // signed: [MIN, MIN] = OP1 >> 1
+  {
+    widest_irange lhs (TYPE_MIN_VALUE (integer_type_node),
+		       TYPE_MIN_VALUE (integer_type_node));
+    widest_irange one (INT (1), INT (1));
+    widest_irange op1;
+    op_rshift.op1_range (op1, integer_type_node, lhs, one);
+    ASSERT_TRUE (op1.undefined_p ());
+  }
+
+  // signed: ~[-1] = OP1 >> 31
+  {
+    widest_irange lhs (INT (-1), INT (-1), VR_ANTI_RANGE);
+    widest_irange shift (INT (31), INT (31));
+    widest_irange op1;
+    op_rshift.op1_range (op1, integer_type_node, lhs, shift);
+    widest_irange negatives = range_negatives (integer_type_node);
+    negatives.intersect (op1);
+    ASSERT_TRUE (negatives.undefined_p ());
+  }
+}
+
 // Run all of the selftests within this file.
 
 void
 range_tests ()
 {
   tree u128_type = build_nonstandard_integer_type (128, /*unsigned=*/1);
-  value_range i1, i2, i3;
-  value_range r0, r1, rold;
+  int_range<1> i1, i2, i3;
+  int_range<1> r0, r1, rold;
+
+  // Test 1-bit signed integer union.
+  // [-1,-1] U [0,0] = VARYING.
+  tree one_bit_type = build_nonstandard_integer_type (1, 0);
+  {
+    tree one_bit_min = vrp_val_min (one_bit_type);
+    tree one_bit_max = vrp_val_max (one_bit_type);
+    int_range<2> min (one_bit_min, one_bit_min);
+    int_range<2> max (one_bit_max, one_bit_max);
+    max.union_ (min);
+    ASSERT_TRUE (max.varying_p ());
+  }
 
   // Test that NOT(255) is [0..254] in 8-bit land.
-  value_range not_255 (UCHAR (255), UCHAR (255), VR_ANTI_RANGE);
-  ASSERT_TRUE (not_255 == value_range (UCHAR (0), UCHAR (254)));
+  int_range<1> not_255 (UCHAR (255), UCHAR (255), VR_ANTI_RANGE);
+  ASSERT_TRUE (not_255 == int_range<1> (UCHAR (0), UCHAR (254)));
 
   // Test that NOT(0) is [1..255] in 8-bit land.
-  value_range not_zero = range_nonzero (unsigned_char_type_node);
-  ASSERT_TRUE (not_zero == value_range (UCHAR (1), UCHAR (255)));
+  int_range<1> not_zero = range_nonzero (unsigned_char_type_node);
+  ASSERT_TRUE (not_zero == int_range<1> (UCHAR (1), UCHAR (255)));
 
   // Check that [0,127][0x..ffffff80,0x..ffffff]
   //  => ~[128, 0x..ffffff7f].
-  r0 = value_range (UINT128 (0), UINT128 (127));
+  r0 = int_range<1> (UINT128 (0), UINT128 (127));
   tree high = build_minus_one_cst (u128_type);
   // low = -1 - 127 => 0x..ffffff80.
   tree low = fold_build2 (MINUS_EXPR, u128_type, high, UINT128(127));
-  r1 = value_range (low, high); // [0x..ffffff80, 0x..ffffffff]
+  r1 = int_range<1> (low, high); // [0x..ffffff80, 0x..ffffffff]
   // r0 = [0,127][0x..ffffff80,0x..fffffff].
   r0.union_ (r1);
   // r1 = [128, 0x..ffffff7f].
-  r1 = value_range (UINT128(128),
-			 fold_build2 (MINUS_EXPR, u128_type,
-				      build_minus_one_cst (u128_type),
-				      UINT128(128)));
+  r1 = int_range<1> (UINT128(128),
+		     fold_build2 (MINUS_EXPR, u128_type,
+				  build_minus_one_cst (u128_type),
+				  UINT128(128)));
   r0.invert ();
   ASSERT_TRUE (r0 == r1);
 
@@ -2882,38 +3596,38 @@  range_tests ()
   tree maxuint = wide_int_to_tree (unsigned_type_node, r0.upper_bound ());
 
   // Check that ~[0,5] => [6,MAX] for unsigned int.
-  r0 = value_range (UINT (0), UINT (5));
+  r0 = int_range<1> (UINT (0), UINT (5));
   r0.invert ();
-  ASSERT_TRUE (r0 == value_range (UINT(6), maxuint));
+  ASSERT_TRUE (r0 == int_range<1> (UINT(6), maxuint));
 
   // Check that ~[10,MAX] => [0,9] for unsigned int.
-  r0 = value_range (UINT(10), maxuint);
+  r0 = int_range<1> (UINT(10), maxuint);
   r0.invert ();
-  ASSERT_TRUE (r0 == value_range (UINT (0), UINT (9)));
+  ASSERT_TRUE (r0 == int_range<1> (UINT (0), UINT (9)));
 
   // Check that ~[0,5] => [6,MAX] for unsigned 128-bit numbers.
-  r0 = value_range (UINT128 (0), UINT128 (5), VR_ANTI_RANGE);
-  r1 = value_range (UINT128(6), build_minus_one_cst (u128_type));
+  r0 = int_range<1> (UINT128 (0), UINT128 (5), VR_ANTI_RANGE);
+  r1 = int_range<1> (UINT128(6), build_minus_one_cst (u128_type));
   ASSERT_TRUE (r0 == r1);
 
   // Check that [~5] is really [-MIN,4][6,MAX].
-  r0 = value_range (INT (5), INT (5), VR_ANTI_RANGE);
-  r1 = value_range (minint, INT (4));
-  r1.union_ (value_range (INT (6), maxint));
+  r0 = int_range<1> (INT (5), INT (5), VR_ANTI_RANGE);
+  r1 = int_range<1> (minint, INT (4));
+  r1.union_ (int_range<1> (INT (6), maxint));
   ASSERT_FALSE (r1.undefined_p ());
   ASSERT_TRUE (r0 == r1);
 
-  r1 = value_range (INT (5), INT (5));
-  value_range r2 (r1);
+  r1 = int_range<1> (INT (5), INT (5));
+  int_range<1> r2 (r1);
   ASSERT_TRUE (r1 == r2);
 
-  r1 = value_range (INT (5), INT (10));
+  r1 = int_range<1> (INT (5), INT (10));
 
-  r1 = value_range (integer_type_node,
-	       wi::to_wide (INT (5)), wi::to_wide (INT (10)));
+  r1 = int_range<1> (integer_type_node,
+		     wi::to_wide (INT (5)), wi::to_wide (INT (10)));
   ASSERT_TRUE (r1.contains_p (INT (7)));
 
-  r1 = value_range (SCHAR (0), SCHAR (20));
+  r1 = int_range<1> (SCHAR (0), SCHAR (20));
   ASSERT_TRUE (r1.contains_p (SCHAR(15)));
   ASSERT_FALSE (r1.contains_p (SCHAR(300)));
 
@@ -2922,96 +3636,96 @@  range_tests ()
   if (TYPE_PRECISION (TREE_TYPE (maxint))
       > TYPE_PRECISION (short_integer_type_node))
     {
-      r1 = value_range (integer_zero_node, maxint);
+      r1 = int_range<1> (integer_zero_node, maxint);
       range_cast (r1, short_integer_type_node);
       ASSERT_TRUE (r1.lower_bound () == wi::to_wide (minshort)
 		   && r1.upper_bound() == wi::to_wide (maxshort));
     }
 
   // (unsigned char)[-5,-1] => [251,255].
-  r0 = rold = value_range (SCHAR (-5), SCHAR (-1));
+  r0 = rold = int_range<1> (SCHAR (-5), SCHAR (-1));
   range_cast (r0, unsigned_char_type_node);
-  ASSERT_TRUE (r0 == value_range (UCHAR (251), UCHAR (255)));
+  ASSERT_TRUE (r0 == int_range<1> (UCHAR (251), UCHAR (255)));
   range_cast (r0, signed_char_type_node);
   ASSERT_TRUE (r0 == rold);
 
   // (signed char)[15, 150] => [-128,-106][15,127].
-  r0 = rold = value_range (UCHAR (15), UCHAR (150));
+  r0 = rold = int_range<1> (UCHAR (15), UCHAR (150));
   range_cast (r0, signed_char_type_node);
-  r1 = value_range (SCHAR (15), SCHAR (127));
-  r2 = value_range (SCHAR (-128), SCHAR (-106));
+  r1 = int_range<1> (SCHAR (15), SCHAR (127));
+  r2 = int_range<1> (SCHAR (-128), SCHAR (-106));
   r1.union_ (r2);
   ASSERT_TRUE (r1 == r0);
   range_cast (r0, unsigned_char_type_node);
   ASSERT_TRUE (r0 == rold);
 
   // (unsigned char)[-5, 5] => [0,5][251,255].
-  r0 = rold = value_range (SCHAR (-5), SCHAR (5));
+  r0 = rold = int_range<1> (SCHAR (-5), SCHAR (5));
   range_cast (r0, unsigned_char_type_node);
-  r1 = value_range (UCHAR (251), UCHAR (255));
-  r2 = value_range (UCHAR (0), UCHAR (5));
+  r1 = int_range<1> (UCHAR (251), UCHAR (255));
+  r2 = int_range<1> (UCHAR (0), UCHAR (5));
   r1.union_ (r2);
   ASSERT_TRUE (r0 == r1);
   range_cast (r0, signed_char_type_node);
   ASSERT_TRUE (r0 == rold);
 
   // (unsigned char)[-5,5] => [0,5][251,255].
-  r0 = value_range (INT (-5), INT (5));
+  r0 = int_range<1> (INT (-5), INT (5));
   range_cast (r0, unsigned_char_type_node);
-  r1 = value_range (UCHAR (0), UCHAR (5));
-  r1.union_ (value_range (UCHAR (251), UCHAR (255)));
+  r1 = int_range<1> (UCHAR (0), UCHAR (5));
+  r1.union_ (int_range<1> (UCHAR (251), UCHAR (255)));
   ASSERT_TRUE (r0 == r1);
 
   // (unsigned char)[5U,1974U] => [0,255].
-  r0 = value_range (UINT (5), UINT (1974));
+  r0 = int_range<1> (UINT (5), UINT (1974));
   range_cast (r0, unsigned_char_type_node);
-  ASSERT_TRUE (r0 == value_range (UCHAR (0), UCHAR (255)));
+  ASSERT_TRUE (r0 == int_range<1> (UCHAR (0), UCHAR (255)));
   range_cast (r0, integer_type_node);
   // Going to a wider range should not sign extend.
-  ASSERT_TRUE (r0 == value_range (INT (0), INT (255)));
+  ASSERT_TRUE (r0 == int_range<1> (INT (0), INT (255)));
 
   // (unsigned char)[-350,15] => [0,255].
-  r0 = value_range (INT (-350), INT (15));
+  r0 = int_range<1> (INT (-350), INT (15));
   range_cast (r0, unsigned_char_type_node);
-  ASSERT_TRUE (r0 == (value_range
+  ASSERT_TRUE (r0 == (int_range<1>
 		      (TYPE_MIN_VALUE (unsigned_char_type_node),
 		       TYPE_MAX_VALUE (unsigned_char_type_node))));
 
   // Casting [-120,20] from signed char to unsigned short.
   // => [0, 20][0xff88, 0xffff].
-  r0 = value_range (SCHAR (-120), SCHAR (20));
+  r0 = int_range<1> (SCHAR (-120), SCHAR (20));
   range_cast (r0, short_unsigned_type_node);
-  r1 = value_range (UINT16 (0), UINT16 (20));
-  r2 = value_range (UINT16 (0xff88), UINT16 (0xffff));
+  r1 = int_range<1> (UINT16 (0), UINT16 (20));
+  r2 = int_range<1> (UINT16 (0xff88), UINT16 (0xffff));
   r1.union_ (r2);
   ASSERT_TRUE (r0 == r1);
   // A truncating cast back to signed char will work because [-120, 20]
   // is representable in signed char.
   range_cast (r0, signed_char_type_node);
-  ASSERT_TRUE (r0 == value_range (SCHAR (-120), SCHAR (20)));
+  ASSERT_TRUE (r0 == int_range<1> (SCHAR (-120), SCHAR (20)));
 
   // unsigned char -> signed short
   //	(signed short)[(unsigned char)25, (unsigned char)250]
   // => [(signed short)25, (signed short)250]
-  r0 = rold = value_range (UCHAR (25), UCHAR (250));
+  r0 = rold = int_range<1> (UCHAR (25), UCHAR (250));
   range_cast (r0, short_integer_type_node);
-  r1 = value_range (INT16 (25), INT16 (250));
+  r1 = int_range<1> (INT16 (25), INT16 (250));
   ASSERT_TRUE (r0 == r1);
   range_cast (r0, unsigned_char_type_node);
   ASSERT_TRUE (r0 == rold);
 
   // Test casting a wider signed [-MIN,MAX] to a nar`rower unsigned.
-  r0 = value_range (TYPE_MIN_VALUE (long_long_integer_type_node),
+  r0 = int_range<1> (TYPE_MIN_VALUE (long_long_integer_type_node),
 	       TYPE_MAX_VALUE (long_long_integer_type_node));
   range_cast (r0, short_unsigned_type_node);
-  r1 = value_range (TYPE_MIN_VALUE (short_unsigned_type_node),
+  r1 = int_range<1> (TYPE_MIN_VALUE (short_unsigned_type_node),
 	       TYPE_MAX_VALUE (short_unsigned_type_node));
   ASSERT_TRUE (r0 == r1);
 
   // NOT([10,20]) ==> [-MIN,9][21,MAX].
-  r0 = r1 = value_range (INT (10), INT (20));
-  r2 = value_range (minint, INT(9));
-  r2.union_ (value_range (INT(21), maxint));
+  r0 = r1 = int_range<1> (INT (10), INT (20));
+  r2 = int_range<1> (minint, INT(9));
+  r2.union_ (int_range<1> (INT(21), maxint));
   ASSERT_FALSE (r2.undefined_p ());
   r1.invert ();
   ASSERT_TRUE (r1 == r2);
@@ -3021,11 +3735,11 @@  range_tests ()
 
   // Test that booleans and their inverse work as expected.
   r0 = range_zero (boolean_type_node);
-  ASSERT_TRUE (r0 == value_range (build_zero_cst (boolean_type_node),
-				       build_zero_cst (boolean_type_node)));
+  ASSERT_TRUE (r0 == int_range<1> (build_zero_cst (boolean_type_node),
+				   build_zero_cst (boolean_type_node)));
   r0.invert ();
-  ASSERT_TRUE (r0 == value_range (build_one_cst (boolean_type_node),
-				       build_one_cst (boolean_type_node)));
+  ASSERT_TRUE (r0 == int_range<1> (build_one_cst (boolean_type_node),
+				   build_one_cst (boolean_type_node)));
 
   // Casting NONZERO to a narrower type will wrap/overflow so
   // it's just the entire range for the narrower type.
@@ -3038,8 +3752,8 @@  range_tests ()
     {
       r0 = range_nonzero (integer_type_node);
       range_cast (r0, short_integer_type_node);
-      r1 = value_range (TYPE_MIN_VALUE (short_integer_type_node),
-			     TYPE_MAX_VALUE (short_integer_type_node));
+      r1 = int_range<1> (TYPE_MIN_VALUE (short_integer_type_node),
+			 TYPE_MAX_VALUE (short_integer_type_node));
       ASSERT_TRUE (r0 == r1);
     }
 
@@ -3049,8 +3763,8 @@  range_tests ()
   // Converting this to 32-bits signed is [-MIN_16,-1][1, +MAX_16].
   r0 = range_nonzero (short_integer_type_node);
   range_cast (r0, integer_type_node);
-  r1 = value_range (INT (-32768), INT (-1));
-  r2 = value_range (INT (1), INT (32767));
+  r1 = int_range<1> (INT (-32768), INT (-1));
+  r2 = int_range<1> (INT (1), INT (32767));
   r1.union_ (r2);
   ASSERT_TRUE (r0 == r1);
 
@@ -3064,34 +3778,34 @@  range_tests ()
   ASSERT_TRUE (r0 == r1);
 
   // [10,20] U [15, 30] => [10, 30].
-  r0 = value_range (INT (10), INT (20));
-  r1 = value_range (INT (15), INT (30));
+  r0 = int_range<1> (INT (10), INT (20));
+  r1 = int_range<1> (INT (15), INT (30));
   r0.union_ (r1);
-  ASSERT_TRUE (r0 == value_range (INT (10), INT (30)));
+  ASSERT_TRUE (r0 == int_range<1> (INT (10), INT (30)));
 
   // [15,40] U [] => [15,40].
-  r0 = value_range (INT (15), INT (40));
+  r0 = int_range<1> (INT (15), INT (40));
   r1.set_undefined ();
   r0.union_ (r1);
-  ASSERT_TRUE (r0 == value_range (INT (15), INT (40)));
+  ASSERT_TRUE (r0 == int_range<1> (INT (15), INT (40)));
 
   // [10,20] U [10,10] => [10,20].
-  r0 = value_range (INT (10), INT (20));
-  r1 = value_range (INT (10), INT (10));
+  r0 = int_range<1> (INT (10), INT (20));
+  r1 = int_range<1> (INT (10), INT (10));
   r0.union_ (r1);
-  ASSERT_TRUE (r0 == value_range (INT (10), INT (20)));
+  ASSERT_TRUE (r0 == int_range<1> (INT (10), INT (20)));
 
   // [10,20] U [9,9] => [9,20].
-  r0 = value_range (INT (10), INT (20));
-  r1 = value_range (INT (9), INT (9));
+  r0 = int_range<1> (INT (10), INT (20));
+  r1 = int_range<1> (INT (9), INT (9));
   r0.union_ (r1);
-  ASSERT_TRUE (r0 == value_range (INT (9), INT (20)));
+  ASSERT_TRUE (r0 == int_range<1> (INT (9), INT (20)));
 
   // [10,20] ^ [15,30] => [15,20].
-  r0 = value_range (INT (10), INT (20));
-  r1 = value_range (INT (15), INT (30));
+  r0 = int_range<1> (INT (10), INT (20));
+  r1 = int_range<1> (INT (15), INT (30));
   r0.intersect (r1);
-  ASSERT_TRUE (r0 == value_range (INT (15), INT (20)));
+  ASSERT_TRUE (r0 == int_range<1> (INT (15), INT (20)));
 
   // Test the internal sanity of wide_int's wrt HWIs.
   ASSERT_TRUE (wi::max_value (TYPE_PRECISION (boolean_type_node),
@@ -3099,13 +3813,17 @@  range_tests ()
 	       == wi::uhwi (1, TYPE_PRECISION (boolean_type_node)));
 
   // Test zero_p().
-  r0 = value_range (INT (0), INT (0));
+  r0 = int_range<1> (INT (0), INT (0));
   ASSERT_TRUE (r0.zero_p ());
 
   // Test nonzero_p().
-  r0 = value_range (INT (0), INT (0));
+  r0 = int_range<1> (INT (0), INT (0));
   r0.invert ();
   ASSERT_TRUE (r0.nonzero_p ());
+
+  multi_precision_range_tests ();
+  widest_irange_tests ();
+  operator_tests ();
 }
 
 } // namespace selftest
diff --git a/gcc/range-op.h b/gcc/range-op.h
index 1311965f4f5..08f6bf9f73f 100644
--- a/gcc/range-op.h
+++ b/gcc/range-op.h
@@ -50,9 +50,9 @@  class range_operator
 {
 public:
   // Perform an operation between 2 ranges and return it.
-  virtual bool fold_range (value_range &r, tree type,
-			   const value_range &lh,
-			   const value_range &rh) const;
+  virtual bool fold_range (irange &r, tree type,
+			   const irange &lh,
+			   const irange &rh) const;
 
   // Return the range for op[12] in the general case.  LHS is the range for
   // the LHS of the expression, OP[12]is the range for the other
@@ -65,16 +65,16 @@  public:
   //
   // i.e.  [LHS] = ??? + OP2
   // is re-formed as R = [LHS] - OP2.
-  virtual bool op1_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op2) const;
-  virtual bool op2_range (value_range &r, tree type,
-			  const value_range &lhs,
-			  const value_range &op1) const;
+  virtual bool op1_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op2) const;
+  virtual bool op2_range (irange &r, tree type,
+			  const irange &lhs,
+			  const irange &op1) const;
 
 protected:
   // Perform an integral operation between 2 sub-ranges and return it.
-  virtual void wi_fold (value_range &r, tree type,
+  virtual void wi_fold (irange &r, tree type,
 		        const wide_int &lh_lb,
 		        const wide_int &lh_ub,
 		        const wide_int &rh_lb,
@@ -82,7 +82,7 @@  protected:
 };
 
 extern range_operator *range_op_handler (enum tree_code code, tree type);
-extern void range_cast (value_range &, tree type);
+extern void range_cast (irange &, tree type);
 extern void wi_set_zero_nonzero_bits (tree type,
 				      const wide_int &, const wide_int &,
 				      wide_int &maybe_nonzero,
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 7193ca4ad5e..de84c1d505d 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -1151,25 +1151,29 @@  static bool
 range_fold_binary_symbolics_p (value_range *vr,
 			       tree_code code,
 			       tree expr_type,
-			       const value_range *vr0, const value_range *vr1)
+			       const value_range *vr0_,
+			       const value_range *vr1_)
 {
-  if (vr0->symbolic_p () || vr1->symbolic_p ())
+  if (vr0_->symbolic_p () || vr1_->symbolic_p ())
     {
+      value_range vr0 = drop_undefines_to_varying (vr0_, expr_type);
+      value_range vr1 = drop_undefines_to_varying (vr1_, expr_type);
       if ((code == PLUS_EXPR || code == MINUS_EXPR))
 	{
-	  extract_range_from_plus_minus_expr (vr, code, expr_type, vr0, vr1);
+	  extract_range_from_plus_minus_expr (vr, code, expr_type,
+					      &vr0, &vr1);
 	  return true;
 	}
       if (POINTER_TYPE_P (expr_type) && code == POINTER_PLUS_EXPR)
 	{
-	  extract_range_from_pointer_plus_expr (vr, code, expr_type, vr0, vr1);
+	  extract_range_from_pointer_plus_expr (vr, code, expr_type,
+						&vr0, &vr1);
 	  return true;
 	}
       const range_operator *op = get_range_op_handler (vr, code, expr_type);
-      value_range vr0_cst (*vr0), vr1_cst (*vr1);
-      vr0_cst.normalize_symbolics ();
-      vr1_cst.normalize_symbolics ();
-      return op->fold_range (*vr, expr_type, vr0_cst, vr1_cst);
+      vr0.normalize_symbolics ();
+      vr1.normalize_symbolics ();
+      return op->fold_range (*vr, expr_type, vr0, vr1);
     }
   return false;
 }
@@ -1225,11 +1229,15 @@  range_fold_binary_expr (value_range *vr,
   if (!op)
     return;
 
-  value_range vr0 = drop_undefines_to_varying (vr0_, expr_type);
-  value_range vr1 = drop_undefines_to_varying (vr1_, expr_type);
-  if (range_fold_binary_symbolics_p (vr, code, expr_type, &vr0, &vr1))
+  if (range_fold_binary_symbolics_p (vr, code, expr_type, vr0_, vr1_))
     return;
 
+  value_range vr0 (*vr0_);
+  value_range vr1 (*vr1_);
+  if (vr0.undefined_p ())
+    vr0.set_varying (expr_type);
+  if (vr1.undefined_p ())
+    vr1.set_varying (expr_type);
   vr0.normalize_addresses ();
   vr1.normalize_addresses ();
   op->fold_range (*vr, expr_type, vr0, vr1);
@@ -1637,7 +1645,7 @@  extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
    (to transform signed values into unsigned) and at the end xor
    SGNBIT back.  */
 
-static wide_int
+wide_int
 masked_increment (const wide_int &val_in, const wide_int &mask,
 		  const wide_int &sgnbit, unsigned int prec)
 {
diff --git a/gcc/tree-vrp.h b/gcc/tree-vrp.h
index b3d187ffdf1..371e58aa0ea 100644
--- a/gcc/tree-vrp.h
+++ b/gcc/tree-vrp.h
@@ -62,5 +62,7 @@  extern bool overflow_comparison_p (tree_code, tree, tree, bool, tree *);
 extern tree get_single_symbol (tree, bool *, tree *);
 extern void maybe_set_nonzero_bits (edge, tree);
 extern value_range_kind determine_value_range (tree, wide_int *, wide_int *);
+extern wide_int masked_increment (const wide_int &val_in, const wide_int &mask,
+				  const wide_int &sgnbit, unsigned int prec);
 
 #endif /* GCC_TREE_VRP_H */
diff --git a/gcc/tree.c b/gcc/tree.c
index 6522a089ddf..01a342c5b92 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -1483,6 +1483,31 @@  int_cst_hasher::equal (tree x, tree y)
   return true;
 }
 
+/* Cache wide_int CST into the TYPE_CACHED_VALUES cache for TYPE.
+   SLOT is the slot entry to store it in, and MAX_SLOTS is the maximum
+   number of slots that can be cached for the type.  */
+
+static inline tree
+cache_wide_int_in_type_cache (tree type, const wide_int &cst,
+			      int slot, int max_slots)
+{
+  gcc_checking_assert (slot >= 0);
+  /* Initialize cache.  */
+  if (!TYPE_CACHED_VALUES_P (type))
+    {
+      TYPE_CACHED_VALUES_P (type) = 1;
+      TYPE_CACHED_VALUES (type) = make_tree_vec (max_slots);
+    }
+  tree t = TREE_VEC_ELT (TYPE_CACHED_VALUES (type), slot);
+  if (!t)
+    {
+      /* Create a new shared int.  */
+      t = build_new_int_cst (type, cst);
+      TREE_VEC_ELT (TYPE_CACHED_VALUES (type), slot) = t;
+    }
+  return t;
+}
+
 /* Create an INT_CST node of TYPE and value CST.
    The returned node is always shared.  For small integers we use a
    per-type vector cache, for larger ones we use a single hash table.
@@ -1515,6 +1540,28 @@  wide_int_to_tree_1 (tree type, const wide_int_ref &pcst)
   wide_int cst = wide_int::from (pcst, prec, sgn);
   unsigned int ext_len = get_int_cst_ext_nunits (type, cst);
 
+  enum tree_code code = TREE_CODE (type);
+  if (code == POINTER_TYPE || code == REFERENCE_TYPE)
+    {
+      /* Cache NULL pointer and zero bounds.  */
+      if (cst == 0)
+	ix = 0;
+      /* Cache upper bounds of pointers.  */
+      else if (cst == wi::max_value (prec, sgn))
+	ix = 1;
+      /* Cache 1 which is used for a non-zero range.  */
+      else if (cst == 1)
+	ix = 2;
+
+      if (ix >= 0)
+	{
+	  t = cache_wide_int_in_type_cache (type, cst, ix, 3);
+	  /* Make sure no one is clobbering the shared constant.  */
+	  gcc_checking_assert (TREE_TYPE (t) == type
+			       && cst == wi::to_wide (t));
+	  return t;
+	}
+    }
   if (ext_len == 1)
     {
       /* We just need to store a single HOST_WIDE_INT.  */
@@ -1524,7 +1571,7 @@  wide_int_to_tree_1 (tree type, const wide_int_ref &pcst)
       else
 	hwi = cst.to_shwi ();
 
-      switch (TREE_CODE (type))
+      switch (code)
 	{
 	case NULLPTR_TYPE:
 	  gcc_assert (hwi == 0);
@@ -1532,12 +1579,7 @@  wide_int_to_tree_1 (tree type, const wide_int_ref &pcst)
 
 	case POINTER_TYPE:
 	case REFERENCE_TYPE:
-	  /* Cache NULL pointer and zero bounds.  */
-	  if (hwi == 0)
-	    {
-	      limit = 1;
-	      ix = 0;
-	    }
+	  /* Ignore pointers, as they were already handled above.  */
 	  break;
 
 	case BOOLEAN_TYPE:
@@ -1574,27 +1616,14 @@  wide_int_to_tree_1 (tree type, const wide_int_ref &pcst)
 
       if (ix >= 0)
 	{
-	  /* Look for it in the type's vector of small shared ints.  */
-	  if (!TYPE_CACHED_VALUES_P (type))
-	    {
-	      TYPE_CACHED_VALUES_P (type) = 1;
-	      TYPE_CACHED_VALUES (type) = make_tree_vec (limit);
-	    }
-
-	  t = TREE_VEC_ELT (TYPE_CACHED_VALUES (type), ix);
-	  if (t)
-	    /* Make sure no one is clobbering the shared constant.  */
-	    gcc_checking_assert (TREE_TYPE (t) == type
-				 && TREE_INT_CST_NUNITS (t) == 1
-				 && TREE_INT_CST_OFFSET_NUNITS (t) == 1
-				 && TREE_INT_CST_EXT_NUNITS (t) == 1
-				 && TREE_INT_CST_ELT (t, 0) == hwi);
-	  else
-	    {
-	      /* Create a new shared int.  */
-	      t = build_new_int_cst (type, cst);
-	      TREE_VEC_ELT (TYPE_CACHED_VALUES (type), ix) = t;
-	    }
+	  t = cache_wide_int_in_type_cache (type, cst, ix, limit);
+	  /* Make sure no one is clobbering the shared constant.  */
+	  gcc_checking_assert (TREE_TYPE (t) == type
+			       && TREE_INT_CST_NUNITS (t) == 1
+			       && TREE_INT_CST_OFFSET_NUNITS (t) == 1
+			       && TREE_INT_CST_EXT_NUNITS (t) == 1
+			       && TREE_INT_CST_ELT (t, 0) == hwi);
+	  return t;
 	}
       else
 	{
diff --git a/gcc/value-range-equiv.cc b/gcc/value-range-equiv.cc
index 24132e3546e..7dc10b876e0 100644
--- a/gcc/value-range-equiv.cc
+++ b/gcc/value-range-equiv.cc
@@ -90,13 +90,13 @@  value_range_equiv::update (tree min, tree max, value_range_kind kind)
 void
 value_range_equiv::deep_copy (const value_range_equiv *from)
 {
-  set (from->min (), from->max (), from->m_equiv, from->m_kind);
+  set (from->min (), from->max (), from->m_equiv, from->kind ());
 }
 
 void
 value_range_equiv::move (value_range_equiv *from)
 {
-  set (from->min (), from->max (), NULL, from->m_kind);
+  set (from->min (), from->max (), NULL, from->kind ());
   m_equiv = from->m_equiv;
   from->m_equiv = NULL;
 }
@@ -127,8 +127,8 @@  value_range_equiv::set_equiv (bitmap equiv)
 void
 value_range_equiv::check ()
 {
-  value_range::check ();
-  switch (m_kind)
+  value_range::verify_range ();
+  switch (kind ())
     {
     case VR_UNDEFINED:
     case VR_VARYING:
@@ -206,8 +206,9 @@  value_range_equiv::intersect (const value_range_equiv *other)
     this->deep_copy (other);
   else
     {
-      value_range tem = intersect_helper (this, other);
-      this->update (tem.min (), tem.max (), tem.kind ());
+      legacy_intersect (this, other);
+      if (varying_p () || undefined_p ())
+	equiv_clear ();
 
       /* If the result is VR_UNDEFINED there is no need to mess with
 	 equivalencies.  */
@@ -254,8 +255,9 @@  value_range_equiv::union_ (const value_range_equiv *other)
     this->deep_copy (other);
   else
     {
-      value_range tem = union_helper (this, other);
-      this->update (tem.min (), tem.max (), tem.kind ());
+      legacy_union (this, other);
+      if (varying_p () || undefined_p ())
+	equiv_clear ();
 
       /* The resulting set of equivalences is always the intersection of
 	 the two sets.  */
@@ -277,7 +279,7 @@  void
 value_range_equiv::dump (FILE *file) const
 {
   value_range::dump (file);
-  if ((m_kind == VR_RANGE || m_kind == VR_ANTI_RANGE)
+  if ((kind () == VR_RANGE || kind () == VR_ANTI_RANGE)
       && m_equiv)
     {
       bitmap_iterator bi;
diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index bc4b061da57..93164b7e2e2 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -1,5 +1,7 @@ 
 /* Support routines for value ranges.
    Copyright (C) 2019-2020 Free Software Foundation, Inc.
+   Major hacks by Aldy Hernandez <aldyh@redhat.com> and
+   Andrew MacLeod <amacleod@redhat.com>.
 
 This file is part of GCC.
 
@@ -27,45 +29,168 @@  along with GCC; see the file COPYING3.  If not see
 #include "tree-pretty-print.h"
 #include "fold-const.h"
 
-value_range::value_range (tree min, tree max, value_range_kind kind)
+// Here we copy between any two irange's.  The ranges can be legacy or
+// multi-ranges, and copying between any combination works correctly.
+
+irange &
+irange::operator= (const irange &src)
+{
+  if (legacy_mode_p () != src.legacy_mode_p ())
+    {
+      copy_legacy_range (src);
+      return *this;
+    }
+  if (legacy_mode_p ())
+    {
+      gcc_checking_assert (src.legacy_mode_p ());
+      m_num_ranges = src.m_num_ranges;
+      m_base[0] = src.m_base[0];
+      m_base[1] = src.m_base[1];
+      m_kind = src.m_kind;
+      return *this;
+    }
+
+  unsigned x;
+  unsigned lim = src.m_num_ranges;
+  if (lim > m_max_ranges)
+    lim = m_max_ranges;
+
+  for (x = 0; x < lim * 2; ++x)
+    m_base[x] = src.m_base[x];
+
+  // If the range didn't fit, the last range should cover the rest.
+  if (lim != src.m_num_ranges)
+    m_base[x - 1] = src.m_base[src.m_num_ranges * 2 - 1];
+
+  m_num_ranges = lim;
+  return *this;
+}
+
+// Return TRUE if range is a multi-range that can be represented as a
+// VR_ANTI_RANGE.
+
+bool
+irange::maybe_anti_range () const
 {
-  set (min, max, kind);
+  tree ttype = type ();
+  unsigned int precision = TYPE_PRECISION (ttype);
+  signop sign = TYPE_SIGN (ttype);
+  return (num_pairs () > 1
+	  && precision > 1
+	  && lower_bound () == wi::min_value (precision, sign)
+	  && upper_bound () == wi::max_value (precision, sign));
 }
 
-value_range::value_range (tree type)
+// Copy between a legacy and a multi-range, or vice-versa.
+
+void
+irange::copy_legacy_range (const irange &src)
 {
-  set_varying (type);
+  gcc_checking_assert (src.legacy_mode_p () != legacy_mode_p ());
+  if (src.undefined_p ())
+    set_undefined ();
+  else if (src.varying_p ())
+    set_varying (src.type ());
+  else if (src.kind () == VR_ANTI_RANGE)
+    set (src.min (), src.max (), VR_ANTI_RANGE);
+  else if (legacy_mode_p () && src.maybe_anti_range ())
+    {
+      int_range<3> tmp (src);
+      tmp.invert ();
+      set (tmp.min (), wide_int_to_tree (src.type (), tmp.upper_bound (0)),
+	   VR_ANTI_RANGE);
+    }
+  else
+    set (src.min (), src.max (), VR_RANGE);
 }
 
-value_range::value_range (tree type,
-			  const wide_int &wmin, const wide_int &wmax,
-			  enum value_range_kind kind)
+// Swap min/max if they are out of order.  Return TRUE if further
+// processing of the range is necessary, FALSE otherwise.
+
+bool
+irange::swap_out_of_order_endpoints (tree &min, tree &max,
+					  value_range_kind &kind)
 {
-  tree min = wide_int_to_tree (type, wmin);
-  tree max = wide_int_to_tree (type, wmax);
-  gcc_checking_assert (kind == VR_RANGE || kind == VR_ANTI_RANGE);
-  set (min, max, kind);
+  /* Wrong order for min and max, to swap them and the VR type we need
+     to adjust them.  */
+  if (tree_int_cst_lt (max, min))
+    {
+      tree one, tmp;
+
+      /* For one bit precision if max < min, then the swapped
+	 range covers all values, so for VR_RANGE it is varying and
+	 for VR_ANTI_RANGE empty range, so drop to varying as well.  */
+      if (TYPE_PRECISION (TREE_TYPE (min)) == 1)
+	{
+	  set_varying (TREE_TYPE (min));
+	  return false;
+	}
+
+      one = build_int_cst (TREE_TYPE (min), 1);
+      tmp = int_const_binop (PLUS_EXPR, max, one);
+      max = int_const_binop (MINUS_EXPR, min, one);
+      min = tmp;
+
+      /* There's one corner case, if we had [C+1, C] before we now have
+	 that again.  But this represents an empty value range, so drop
+	 to varying in this case.  */
+      if (tree_int_cst_lt (max, min))
+	{
+	  set_varying (TREE_TYPE (min));
+	  return false;
+	}
+      kind = kind == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
+    }
+  return true;
 }
 
 void
-value_range::set_undefined ()
+irange::irange_set (tree min, tree max)
 {
-  m_kind = VR_UNDEFINED;
-  m_min = m_max = NULL;
+  gcc_checking_assert (!POLY_INT_CST_P (min));
+  gcc_checking_assert (!POLY_INT_CST_P (max));
+
+  m_base[0] = min;
+  m_base[1] = max;
+  m_num_ranges = 1;
+  if (flag_checking)
+    verify_range ();
 }
 
 void
-value_range::set_varying (tree type)
+irange::irange_set_anti_range (tree min, tree max)
 {
-  m_kind = VR_VARYING;
-  if (supports_type_p (type))
+  gcc_checking_assert (!POLY_INT_CST_P (min));
+  gcc_checking_assert (!POLY_INT_CST_P (max));
+
+  // set an anti-range
+  tree type = TREE_TYPE (min);
+  signop sign = TYPE_SIGN (type);
+  int_range<2> type_range (type);
+  // Calculate INVERSE([I,J]) as [-MIN, I-1][J+1, +MAX].
+  m_num_ranges = 0;
+  wi::overflow_type ovf;
+
+  wide_int w_min = wi::to_wide (min);
+  if (wi::ne_p (w_min, type_range.lower_bound ()))
     {
-      m_min = vrp_val_min (type);
-      m_max = vrp_val_max (type);
+      wide_int lim1 = wi::sub (w_min, 1, sign, &ovf);
+      gcc_checking_assert (ovf != wi::OVF_OVERFLOW);
+      m_base[0] = type_range.tree_lower_bound (0);
+      m_base[1] = wide_int_to_tree (type, lim1);
+      m_num_ranges = 1;
     }
-  else
-    /* We can't do anything range-wise with these types.  */
-    m_min = m_max = error_mark_node;
+  wide_int w_max = wi::to_wide (max);
+  if (wi::ne_p (w_max, type_range.upper_bound ()))
+    {
+      wide_int lim2 = wi::add (w_max, 1, sign, &ovf);
+      gcc_checking_assert (ovf != wi::OVF_OVERFLOW);
+      m_base[m_num_ranges * 2] = wide_int_to_tree (type, lim2);
+      m_base[m_num_ranges * 2 + 1] = type_range.tree_upper_bound (0);
+      ++m_num_ranges;
+    }
+  if (flag_checking)
+    verify_range ();
 }
 
 /* Set value range to the canonical form of {VRTYPE, MIN, MAX, EQUIV}.
@@ -78,15 +203,24 @@  value_range::set_varying (tree type)
    extract ranges from var + CST op limit.  */
 
 void
-value_range::set (tree min, tree max, value_range_kind kind)
+irange::set (tree min, tree max, value_range_kind kind)
 {
-  /* Use the canonical setters for VR_UNDEFINED and VR_VARYING.  */
+  if (!legacy_mode_p ())
+    {
+      if (kind == VR_RANGE)
+	irange_set (min, max);
+      else
+	{
+	  gcc_checking_assert (kind == VR_ANTI_RANGE);
+	  irange_set_anti_range (min, max);
+	}
+      return;
+    }
   if (kind == VR_UNDEFINED)
     {
       set_undefined ();
       return;
     }
-
   if (kind == VR_RANGE)
     {
       /* Convert POLY_INT_CST bounds into worst-case INTEGER_CST bounds.  */
@@ -109,68 +243,30 @@  value_range::set (tree min, tree max, value_range_kind kind)
     }
   else if (kind != VR_VARYING)
     {
-      if (POLY_INT_CST_P (min) || POLY_INT_CST_P (max))
-	kind = VR_VARYING;
+     if (POLY_INT_CST_P (min) || POLY_INT_CST_P (max))
+       kind = VR_VARYING;
     }
-
   if (kind == VR_VARYING)
     {
-      gcc_assert (TREE_TYPE (min) == TREE_TYPE (max));
-      tree typ = TREE_TYPE (min);
-      if (supports_type_p (typ))
-	{
-	  gcc_assert (vrp_val_min (typ));
-	  gcc_assert (vrp_val_max (typ));
-	}
-      set_varying (typ);
+      set_varying (TREE_TYPE (min));
       return;
     }
 
-  /* Nothing to canonicalize for symbolic ranges.  */
+  tree type = TREE_TYPE (min);
+  // Nothing to canonicalize for symbolic ranges.
   if (TREE_CODE (min) != INTEGER_CST
       || TREE_CODE (max) != INTEGER_CST)
     {
       m_kind = kind;
-      m_min = min;
-      m_max = max;
+      m_base[0] = min;
+      m_base[1] = max;
+      m_num_ranges = 1;
       return;
     }
+  if (!swap_out_of_order_endpoints (min, max, kind))
+    goto cleanup_set;
 
-  /* Wrong order for min and max, to swap them and the VR type we need
-     to adjust them.  */
-  if (tree_int_cst_lt (max, min))
-    {
-      tree one, tmp;
-
-      /* For one bit precision if max < min, then the swapped
-	 range covers all values, so for VR_RANGE it is varying and
-	 for VR_ANTI_RANGE empty range, so drop to varying as well.  */
-      if (TYPE_PRECISION (TREE_TYPE (min)) == 1)
-	{
-	  set_varying (TREE_TYPE (min));
-	  return;
-	}
-
-      one = build_int_cst (TREE_TYPE (min), 1);
-      tmp = int_const_binop (PLUS_EXPR, max, one);
-      max = int_const_binop (MINUS_EXPR, min, one);
-      min = tmp;
-
-      /* There's one corner case, if we had [C+1, C] before we now have
-	 that again.  But this represents an empty value range, so drop
-	 to varying in this case.  */
-      if (tree_int_cst_lt (max, min))
-	{
-	  set_varying (TREE_TYPE (min));
-	  return;
-	}
-
-      kind = kind == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
-    }
-
-  tree type = TREE_TYPE (min);
-
-  /* Anti-ranges that can be represented as ranges should be so.  */
+  // Anti-ranges that can be represented as ranges should be so.
   if (kind == VR_ANTI_RANGE)
     {
       /* For -fstrict-enums we may receive out-of-range ranges so consider
@@ -211,109 +307,90 @@  value_range::set (tree min, tree max, value_range_kind kind)
 	  kind = VR_RANGE;
         }
     }
+  else if (!swap_out_of_order_endpoints (min, max, kind))
+    goto cleanup_set;
 
-  /* Normalize [MIN, MAX] into VARYING and ~[MIN, MAX] into UNDEFINED.
+  /* Do not drop [-INF(OVF), +INF(OVF)] to varying.  (OVF) has to be sticky
+     to make sure VRP iteration terminates, otherwise we can get into
+     oscillations.  */
+  if (!normalize_min_max (type, min, max, kind))
+    {
+      m_kind = kind;
+      m_base[0] = min;
+      m_base[1] = max;
+      m_num_ranges = 1;
+      if (flag_checking)
+	verify_range ();
+    }
 
-     Avoid using TYPE_{MIN,MAX}_VALUE because -fstrict-enums can
-     restrict those to a subset of what actually fits in the type.
-     Instead use the extremes of the type precision which will allow
-     compare_range_with_value() to check if a value is inside a range,
-     whereas if we used TYPE_*_VAL, said function would just punt
-     upon seeing a VARYING.  */
+ cleanup_set:
+  // Avoid using TYPE_{MIN,MAX}_VALUE because -fstrict-enums can
+  // restrict those to a subset of what actually fits in the type.
+  // Instead use the extremes of the type precision
   unsigned prec = TYPE_PRECISION (type);
   signop sign = TYPE_SIGN (type);
   if (wi::eq_p (wi::to_wide (min), wi::min_value (prec, sign))
       && wi::eq_p (wi::to_wide (max), wi::max_value (prec, sign)))
-    {
-      if (kind == VR_RANGE)
-	set_varying (type);
-      else if (kind == VR_ANTI_RANGE)
-	set_undefined ();
-      else
-	gcc_unreachable ();
-      return;
-    }
-
-  /* Do not drop [-INF(OVF), +INF(OVF)] to varying.  (OVF) has to be sticky
-     to make sure VRP iteration terminates, otherwise we can get into
-     oscillations.  */
-
-  m_kind = kind;
-  m_min = min;
-  m_max = max;
+    m_kind = VR_VARYING;
+  else if (undefined_p ())
+    m_kind = VR_UNDEFINED;
   if (flag_checking)
-    check ();
-}
-
-void
-value_range::set (tree val)
-{
-  gcc_assert (TREE_CODE (val) == SSA_NAME || is_gimple_min_invariant (val));
-  if (TREE_OVERFLOW_P (val))
-    val = drop_tree_overflow (val);
-  set (val, val);
-}
-
-/* Set value range VR to a nonzero range of type TYPE.  */
-
-void
-value_range::set_nonzero (tree type)
-{
-  tree zero = build_int_cst (type, 0);
-  set (zero, zero, VR_ANTI_RANGE);
-}
-
-/* Set value range VR to a ZERO range of type TYPE.  */
-
-void
-value_range::set_zero (tree type)
-{
-  set (build_int_cst (type, 0));
+    verify_range ();
 }
 
 /* Check the validity of the range.  */
 
 void
-value_range::check ()
+irange::verify_range ()
 {
-  switch (m_kind)
+  if (!legacy_mode_p ())
     {
-    case VR_RANGE:
-    case VR_ANTI_RANGE:
-      {
-	gcc_assert (m_min && m_max);
-	gcc_assert (!TREE_OVERFLOW_P (m_min) && !TREE_OVERFLOW_P (m_max));
-
-	/* Creating ~[-MIN, +MAX] is stupid because that would be
-	   the empty set.  */
-	if (INTEGRAL_TYPE_P (TREE_TYPE (m_min)) && m_kind == VR_ANTI_RANGE)
-	  gcc_assert (!vrp_val_is_min (m_min) || !vrp_val_is_max (m_max));
+      gcc_checking_assert (m_kind == VR_RANGE);
+      for (unsigned i = 0; i < m_num_ranges; ++i)
+	{
+	  tree lb = tree_lower_bound (i);
+	  tree ub = tree_upper_bound (i);
+	  int c = compare_values (lb, ub);
+	  gcc_assert (c == 0 || c == -1);
+	}
+      return;
+    }
 
-	int cmp = compare_values (m_min, m_max);
-	gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
-	break;
-      }
+  switch (m_kind)
+    {
     case VR_UNDEFINED:
-      gcc_assert (!min () && !max ());
+      gcc_assert (m_num_ranges == 0);
       break;
+
     case VR_VARYING:
-      gcc_assert (m_min && m_max);
+      gcc_assert (m_num_ranges == 1);
       break;
+
+    case VR_ANTI_RANGE:
+    case VR_RANGE:
+      {
+	gcc_assert (m_num_ranges == 1);
+	int cmp = compare_values (tree_lower_bound (0), tree_upper_bound (0));
+	gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
+	return;
+      }
+
     default:
       gcc_unreachable ();
     }
 }
 
-/* Return the number of sub-ranges in a range.  */
-
 unsigned
-value_range::num_pairs () const
+irange::legacy_num_pairs () const
 {
+  gcc_checking_assert (legacy_mode_p ());
+
   if (undefined_p ())
     return 0;
   if (varying_p ())
     return 1;
-  if (symbolic_p ())
+  // Inlined symbolic_p for performance:
+  if (!is_gimple_min_invariant (min ()) || !is_gimple_min_invariant (max ()))
     {
       value_range numeric_range (*this);
       numeric_range.normalize_symbolics ();
@@ -323,111 +400,124 @@  value_range::num_pairs () const
     {
       // ~[MIN, X] has one sub-range of [X+1, MAX], and
       // ~[X, MAX] has one sub-range of [MIN, X-1].
-      if (vrp_val_is_min (m_min) || vrp_val_is_max (m_max))
+      if (vrp_val_is_min (min ()) || vrp_val_is_max (max ()))
 	return 1;
       return 2;
     }
+  gcc_checking_assert (m_num_ranges == 1);
   return 1;
 }
 
-/* Return the lower bound for a sub-range.  PAIR is the sub-range in
-   question.  */
+// Return the lower bound for a sub-range.  PAIR is the sub-range in
+// question.
 
 wide_int
-value_range::lower_bound (unsigned pair) const
+irange::legacy_lower_bound (unsigned pair) const
 {
+  gcc_checking_assert (legacy_mode_p ());
   if (symbolic_p ())
     {
       value_range numeric_range (*this);
       numeric_range.normalize_symbolics ();
-      return numeric_range.lower_bound (pair);
+      return numeric_range.legacy_lower_bound (pair);
     }
-
   gcc_checking_assert (!undefined_p ());
   gcc_checking_assert (pair + 1 <= num_pairs ());
-  tree t = NULL;
   if (m_kind == VR_ANTI_RANGE)
     {
-      tree typ = type ();
-      if (pair == 1 || vrp_val_is_min (m_min))
-	t = wide_int_to_tree (typ, wi::to_wide (m_max) + 1);
+      tree typ = type (), t;
+      if (pair == 1 || vrp_val_is_min (min ()))
+	t = wide_int_to_tree (typ, wi::to_wide (max ()) + 1);
       else
 	t = vrp_val_min (typ);
+      return wi::to_wide (t);
     }
-  else
-    t = m_min;
-  return wi::to_wide (t);
+ return wi::to_wide (tree_lower_bound (pair));
 }
 
-/* Return the upper bound for a sub-range.  PAIR is the sub-range in
-   question.  */
+// Return the upper bound for a sub-range.  PAIR is the sub-range in
+// question.
 
 wide_int
-value_range::upper_bound (unsigned pair) const
+irange::legacy_upper_bound (unsigned pair) const
 {
+  gcc_checking_assert (legacy_mode_p ());
   if (symbolic_p ())
     {
       value_range numeric_range (*this);
       numeric_range.normalize_symbolics ();
-      return numeric_range.upper_bound (pair);
+      return numeric_range.legacy_upper_bound (pair);
     }
-
   gcc_checking_assert (!undefined_p ());
   gcc_checking_assert (pair + 1 <= num_pairs ());
-  tree t = NULL;
   if (m_kind == VR_ANTI_RANGE)
     {
-      tree typ = type ();
-      if (pair == 1 || vrp_val_is_min (m_min))
+      tree typ = type (), t;
+      if (pair == 1 || vrp_val_is_min (min ()))
 	t = vrp_val_max (typ);
       else
-	t = wide_int_to_tree (typ, wi::to_wide (m_min) - 1);
+	t = wide_int_to_tree (typ, wi::to_wide (min ()) - 1);
+      return wi::to_wide (t);
     }
-  else
-    t = m_max;
-  return wi::to_wide (t);
-}
-
-/* Return the highest bound in a range.  */
-
-wide_int
-value_range::upper_bound () const
-{
-  unsigned pairs = num_pairs ();
-  gcc_checking_assert (pairs > 0);
-  return upper_bound (pairs - 1);
+  return wi::to_wide (tree_upper_bound (pair));
 }
 
 bool
-value_range::equal_p (const value_range &other) const
+irange::legacy_equal_p (const irange &other) const
 {
-  /* Ignore types for undefined.  All undefines are equal.  */
-  if (undefined_p ())
-    return m_kind == other.m_kind;
+  gcc_checking_assert (legacy_mode_p () && other.legacy_mode_p ());
 
-  return (m_kind == other.m_kind
-	  && vrp_operand_equal_p (m_min, other.m_min)
-	  && vrp_operand_equal_p (m_max, other.m_max));
+  if (m_kind != other.m_kind)
+   return false;
+  if (m_kind == VR_UNDEFINED || m_kind == VR_VARYING)
+    return true;
+  return (vrp_operand_equal_p (tree_lower_bound (0),
+			       other.tree_lower_bound (0))
+	  && vrp_operand_equal_p (tree_upper_bound (0),
+				  other.tree_upper_bound (0)));
 }
 
 bool
-value_range::operator== (const value_range &r) const
+irange::equal_p (const irange &other) const
 {
-  return equal_p (r);
+  if (legacy_mode_p ())
+    {
+      if (other.legacy_mode_p ())
+	return legacy_equal_p (other);
+      value_range tmp (other);
+      return legacy_equal_p (tmp);
+    }
+  if (other.legacy_mode_p ())
+    {
+      value_range tmp2 (*this);
+      return tmp2.legacy_equal_p (other);
+    }
+
+  if (m_num_ranges != other.m_num_ranges)
+    return false;
+
+  for (unsigned i = 0; i < m_num_ranges; ++i)
+    {
+      tree lb = tree_lower_bound (i);
+      tree ub = tree_upper_bound (i);
+      tree lb_other = other.tree_lower_bound (i);
+      tree ub_other = other.tree_upper_bound (i);
+      if (!operand_equal_p (lb, lb_other, 0)
+	  || !operand_equal_p (ub, ub_other, 0))
+	return false;
+    }
+  return true;
 }
 
-/* If range is a singleton, place it in RESULT and return TRUE.
-   Note: A singleton can be any gimple invariant, not just constants.
-   So, [&x, &x] counts as a singleton.  */
 /* Return TRUE if this is a symbolic range.  */
 
 bool
-value_range::symbolic_p () const
+irange::symbolic_p () const
 {
   return (!varying_p ()
 	  && !undefined_p ()
-	  && (!is_gimple_min_invariant (m_min)
-	      || !is_gimple_min_invariant (m_max)));
+	  && (!is_gimple_min_invariant (min ())
+	      || !is_gimple_min_invariant (max ())));
 }
 
 /* NOTE: This is not the inverse of symbolic_p because the range
@@ -436,17 +526,32 @@  value_range::symbolic_p () const
    constants would be represented as [-MIN, +MAX].  */
 
 bool
-value_range::constant_p () const
+irange::constant_p () const
 {
   return (!varying_p ()
 	  && !undefined_p ()
-	  && TREE_CODE (m_min) == INTEGER_CST
-	  && TREE_CODE (m_max) == INTEGER_CST);
+	  && TREE_CODE (min ()) == INTEGER_CST
+	  && TREE_CODE (max ()) == INTEGER_CST);
 }
 
+/* If range is a singleton, place it in RESULT and return TRUE.
+   Note: A singleton can be any gimple invariant, not just constants.
+   So, [&x, &x] counts as a singleton.  */
+
 bool
-value_range::singleton_p (tree *result) const
+irange::singleton_p (tree *result) const
 {
+  if (!legacy_mode_p ())
+    {
+      if (num_pairs () == 1 && (wi::to_wide (tree_lower_bound ())
+				== wi::to_wide (tree_upper_bound ())))
+	{
+	  if (result)
+	    *result = tree_lower_bound ();
+	  return true;
+	}
+      return false;
+    }
   if (m_kind == VR_ANTI_RANGE)
     {
       if (nonzero_p ())
@@ -454,7 +559,7 @@  value_range::singleton_p (tree *result) const
 	  if (TYPE_PRECISION (type ()) == 1)
 	    {
 	      if (result)
-		*result = m_max;
+		*result = max ();
 	      return true;
 	    }
 	  return false;
@@ -462,10 +567,11 @@  value_range::singleton_p (tree *result) const
       if (num_pairs () == 1)
 	{
 	  value_range vr0, vr1;
-	  ranges_from_anti_range (this, &vr0, &vr1);
+	  ranges_from_anti_range ((const value_range *) this, &vr0, &vr1);
 	  return vr0.singleton_p (result);
 	}
     }
+  // Catches non-numeric extremes as well.
   if (m_kind == VR_RANGE
       && vrp_operand_equal_p (min (), max ())
       && is_gimple_min_invariant (min ()))
@@ -478,30 +584,31 @@  value_range::singleton_p (tree *result) const
 }
 
 /* Return 1 if VAL is inside value range.
-          0 if VAL is not inside value range.
+	  0 if VAL is not inside value range.
 	 -2 if we cannot tell either way.
 
    Benchmark compile/20001226-1.c compilation time after changing this
    function.  */
 
 int
-value_range::value_inside_range (tree val) const
+irange::value_inside_range (tree val) const
 {
-  int cmp1, cmp2;
-
   if (varying_p ())
     return 1;
 
   if (undefined_p ())
     return 0;
 
-  cmp1 = operand_less_p (val, m_min);
+  if (!legacy_mode_p () && TREE_CODE (val) == INTEGER_CST)
+    return contains_p (val);
+
+  int cmp1 = operand_less_p (val, min ());
   if (cmp1 == -2)
     return -2;
   if (cmp1 == 1)
     return m_kind != VR_RANGE;
 
-  cmp2 = operand_less_p (m_max, val);
+  int cmp2 = operand_less_p (max (), val);
   if (cmp2 == -2)
     return -2;
 
@@ -514,30 +621,56 @@  value_range::value_inside_range (tree val) const
 /* Return TRUE if it is possible that range contains VAL.  */
 
 bool
-value_range::may_contain_p (tree val) const
+irange::may_contain_p (tree val) const
 {
   return value_inside_range (val) != 0;
 }
 
 /* Return TRUE if range contains INTEGER_CST.  */
+/* Return 1 if VAL is inside value range.
+	  0 if VAL is not inside value range.
+
+   Benchmark compile/20001226-1.c compilation time after changing this
+   function.  */
+
 
 bool
-value_range::contains_p (tree cst) const
+irange::contains_p (tree cst) const
 {
+  if (undefined_p ())
+    return false;
+
+  if (legacy_mode_p ())
+    {
+      gcc_checking_assert (TREE_CODE (cst) == INTEGER_CST);
+      if (symbolic_p ())
+	{
+	  value_range numeric_range (*this);
+	  numeric_range.normalize_symbolics ();
+	  return numeric_range.contains_p (cst);
+	}
+      return value_inside_range (cst) == 1;
+    }
+
   gcc_checking_assert (TREE_CODE (cst) == INTEGER_CST);
-  if (symbolic_p ())
+  signop sign = TYPE_SIGN (TREE_TYPE (cst));
+  wide_int v = wi::to_wide (cst);
+  for (unsigned r = 0; r < m_num_ranges; ++r)
     {
-      value_range numeric_range (*this);
-      numeric_range.normalize_symbolics ();
-      return numeric_range.contains_p (cst);
+      if (wi::lt_p (v, lower_bound (r), sign))
+	return false;
+      if (wi::le_p (v, upper_bound (r), sign))
+	return true;
     }
-  return value_inside_range (cst) == 1;
+
+  return false;
 }
 
+
 /* Normalize addresses into constants.  */
 
 void
-value_range::normalize_addresses ()
+irange::normalize_addresses ()
 {
   if (undefined_p ())
     return;
@@ -547,8 +680,8 @@  value_range::normalize_addresses ()
 
   if (!range_includes_zero_p (this))
     {
-      gcc_checking_assert (TREE_CODE (m_min) == ADDR_EXPR
-			   || TREE_CODE (m_max) == ADDR_EXPR);
+      gcc_checking_assert (TREE_CODE (min ()) == ADDR_EXPR
+			   || TREE_CODE (max ()) == ADDR_EXPR);
       set_nonzero (type ());
       return;
     }
@@ -558,7 +691,7 @@  value_range::normalize_addresses ()
 /* Normalize symbolics and addresses into constants.  */
 
 void
-value_range::normalize_symbolics ()
+irange::normalize_symbolics ()
 {
   if (varying_p () || undefined_p ())
     return;
@@ -939,45 +1072,64 @@  intersect_ranges (enum value_range_kind *vr0type,
 }
 
 /* Helper for the intersection operation for value ranges.  Given two
-   value ranges VR0 and VR1, return the intersection of the two
-   ranges.  This may not be the smallest possible such range.  */
+   ranges VR0 and VR1, set VR0 to the intersection of both ranges.
+   This may not be the smallest possible such range.  */
 
-value_range
-value_range::intersect_helper (const value_range *vr0, const value_range *vr1)
+void
+irange::legacy_intersect (irange *vr0, const irange *vr1)
 {
   /* If either range is VR_VARYING the other one wins.  */
   if (vr1->varying_p ())
-    return *vr0;
+    return;
   if (vr0->varying_p ())
-    return *vr1;
+    {
+      /* Avoid the full copy if we already know both sides are simple
+	 and can be trivially copied.  */
+      if (vr1->legacy_mode_p ())
+	{
+	  vr0->set (vr1->min (), vr1->max (), vr1->kind ());
+	  return;
+	}
+      *vr0 = *vr1;
+      return;
+    }
 
   /* When either range is VR_UNDEFINED the resulting range is
      VR_UNDEFINED, too.  */
   if (vr0->undefined_p ())
-    return *vr0;
+    return;
   if (vr1->undefined_p ())
-    return *vr1;
+    {
+      vr0->set_undefined ();
+      return;
+    }
 
   value_range_kind vr0kind = vr0->kind ();
   tree vr0min = vr0->min ();
   tree vr0max = vr0->max ();
-  intersect_ranges (&vr0kind, &vr0min, &vr0max,
-		    vr1->kind (), vr1->min (), vr1->max ());
+  /* Handle multi-ranges that can be represented as anti-ranges.  */
+  if (!vr1->legacy_mode_p () && vr1->maybe_anti_range ())
+    {
+      int_range<3> tmp (*vr1);
+      tmp.invert ();
+      intersect_ranges (&vr0kind, &vr0min, &vr0max,
+			VR_ANTI_RANGE, tmp.min (), tmp.max ());
+    }
+  else
+    intersect_ranges (&vr0kind, &vr0min, &vr0max,
+		      vr1->kind (), vr1->min (), vr1->max ());
+
   /* Make sure to canonicalize the result though as the inversion of a
-     VR_RANGE can still be a VR_RANGE.  Work on a temporary so we can
-     fall back to vr0 when this turns things to varying.  */
-  value_range tem;
+     VR_RANGE can still be a VR_RANGE.  */
   if (vr0kind == VR_UNDEFINED)
-    tem.set_undefined ();
+    vr0->set_undefined ();
   else if (vr0kind == VR_VARYING)
-    tem.set_varying (vr0->type ());
+    {
+      /* If we failed, use the original VR0.  */
+      return;
+    }
   else
-    tem.set (vr0min, vr0max, vr0kind);
-  /* If that failed, use the saved original VR0.  */
-  if (tem.varying_p ())
-    return *vr0;
-
-  return tem;
+    vr0->set (vr0min, vr0max, vr0kind);
 }
 
 /* Union the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and
@@ -1253,50 +1405,67 @@  give_up:
   *vr0max = NULL_TREE;
 }
 
-/* Helper for meet operation for value ranges.  Given two value ranges VR0 and
-   VR1, return a range that contains both VR0 and VR1.  This may not be the
+/* Helper for meet operation for value ranges.  Given two ranges VR0
+   and VR1, set VR0 to the union of both ranges.  This may not be the
    smallest possible such range.  */
 
-value_range
-value_range::union_helper (const value_range *vr0, const value_range *vr1)
+void
+irange::legacy_union (irange *vr0, const irange *vr1)
 {
   /* VR0 has the resulting range if VR1 is undefined or VR0 is varying.  */
   if (vr1->undefined_p ()
       || vr0->varying_p ())
-    return *vr0;
+    return;
 
   /* VR1 has the resulting range if VR0 is undefined or VR1 is varying.  */
-  if (vr0->undefined_p ()
-      || vr1->varying_p ())
-    return *vr1;
+  if (vr0->undefined_p ())
+    {
+      /* Avoid the full copy if we already know both sides are simple
+	 and can be trivially copied.  */
+      if (vr1->legacy_mode_p ())
+	{
+	  vr0->set (vr1->min (), vr1->max (), vr1->kind ());
+	  return;
+	}
+      *vr0 = *vr1;
+      return;
+    }
+  if (vr1->varying_p ())
+    {
+      vr0->set_varying (vr1->type ());
+      return;
+    }
 
   value_range_kind vr0kind = vr0->kind ();
   tree vr0min = vr0->min ();
   tree vr0max = vr0->max ();
-  union_ranges (&vr0kind, &vr0min, &vr0max,
-		vr1->kind (), vr1->min (), vr1->max ());
+  /* Handle multi-ranges that can be represented as anti-ranges.  */
+  if (!vr1->legacy_mode_p () && vr1->maybe_anti_range ())
+    {
+      int_range<3> tmp (*vr1);
+      tmp.invert ();
+      union_ranges (&vr0kind, &vr0min, &vr0max,
+		    VR_ANTI_RANGE, tmp.min (), tmp.max ());
+    }
+  else
+    union_ranges (&vr0kind, &vr0min, &vr0max,
+		  vr1->kind (), vr1->min (), vr1->max ());
 
-  /* Work on a temporary so we can still use vr0 when union returns varying.  */
-  value_range tem;
   if (vr0kind == VR_UNDEFINED)
-    tem.set_undefined ();
+    vr0->set_undefined ();
   else if (vr0kind == VR_VARYING)
-    tem.set_varying (vr0->type ());
-  else
-    tem.set (vr0min, vr0max, vr0kind);
-
-  /* Failed to find an efficient meet.  Before giving up and setting
-     the result to VARYING, see if we can at least derive a useful
-     anti-range.  */
-  if (tem.varying_p ()
-      && range_includes_zero_p (vr0) == 0
-      && range_includes_zero_p (vr1) == 0)
     {
-      tem.set_nonzero (vr0->type ());
-      return tem;
+      /* Failed to find an efficient meet.  Before giving up and
+	 setting the result to VARYING, see if we can at least derive
+	 a non-zero range.  */
+      if (range_includes_zero_p (vr0) == 0
+	  && range_includes_zero_p (vr1) == 0)
+	vr0->set_nonzero (vr0->type ());
+      else
+	vr0->set_varying (vr0->type ());
     }
-
-  return tem;
+  else
+    vr0->set (vr0min, vr0max, vr0kind);
 }
 
 /* Meet operation for value ranges.  Given two value ranges VR0 and
@@ -1304,161 +1473,495 @@  value_range::union_helper (const value_range *vr0, const value_range *vr1)
    may not be the smallest possible such range.  */
 
 void
-value_range::union_ (const value_range *other)
+irange::union_ (const irange *other)
 {
-  if (dump_file && (dump_flags & TDF_DETAILS))
+  if (legacy_mode_p ())
     {
-      fprintf (dump_file, "Meeting\n  ");
-      dump_value_range (dump_file, this);
-      fprintf (dump_file, "\nand\n  ");
-      dump_value_range (dump_file, other);
-      fprintf (dump_file, "\n");
-    }
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "Meeting\n  ");
+	  dump_value_range (dump_file, this);
+	  fprintf (dump_file, "\nand\n  ");
+	  dump_value_range (dump_file, other);
+	  fprintf (dump_file, "\n");
+	}
 
-  *this = union_helper (this, other);
+      legacy_union (this, other);
 
-  if (dump_file && (dump_flags & TDF_DETAILS))
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "to\n  ");
+	  dump_value_range (dump_file, this);
+	  fprintf (dump_file, "\n");
+	}
+      return;
+    }
+
+  if (other->legacy_mode_p ())
     {
-      fprintf (dump_file, "to\n  ");
-      dump_value_range (dump_file, this);
-      fprintf (dump_file, "\n");
+      int_range<2> wider;
+      wider = *other;
+      irange_union (wider);
     }
+  else
+    irange_union (*other);
 }
 
-/* Range union, but for references.  */
-
 void
-value_range::union_ (const value_range &r)
+irange::intersect (const irange *other)
 {
-  /* Disable details for now, because it makes the ranger dump
-     unnecessarily verbose.  */
-  bool details = dump_flags & TDF_DETAILS;
-  if (details)
-    dump_flags &= ~TDF_DETAILS;
-  union_ (&r);
-  if (details)
-    dump_flags |= TDF_DETAILS;
+  if (legacy_mode_p ())
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "Intersecting\n  ");
+	  dump_value_range (dump_file, this);
+	  fprintf (dump_file, "\nand\n  ");
+	  dump_value_range (dump_file, other);
+	  fprintf (dump_file, "\n");
+	}
+
+      legacy_intersect (this, other);
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "to\n  ");
+	  dump_value_range (dump_file, this);
+	  fprintf (dump_file, "\n");
+	}
+      return;
+    }
+
+  if (other->legacy_mode_p ())
+    {
+      int_range<2> wider;
+      wider = *other;
+      irange_intersect (wider);
+    }
+  else
+    irange_intersect (*other);
 }
 
+// union_ for multi-ranges.
+
 void
-value_range::intersect (const value_range *other)
+irange::irange_union (const irange &r)
 {
-  if (dump_file && (dump_flags & TDF_DETAILS))
+  gcc_checking_assert (!legacy_mode_p () && !r.legacy_mode_p ());
+
+  if (r.undefined_p () || varying_p ())
+    return;
+
+  if (undefined_p () || r.varying_p ())
     {
-      fprintf (dump_file, "Intersecting\n  ");
-      dump_value_range (dump_file, this);
-      fprintf (dump_file, "\nand\n  ");
-      dump_value_range (dump_file, other);
-      fprintf (dump_file, "\n");
+      operator= (r);
+      return;
     }
 
-  *this = intersect_helper (this, other);
+  // Do not worry about merging and such by reserving twice as many
+  // pairs as needed, and then simply sort the 2 ranges into this
+  // intermediate form.
+  //
+  // The intermediate result will have the property that the beginning
+  // of each range is <= the beginning of the next range.  There may
+  // be overlapping ranges at this point.  I.e. this would be valid
+  // [-20, 10], [-10, 0], [0, 20], [40, 90] as it satisfies this
+  // contraint : -20 < -10 < 0 < 40.  When the range is rebuilt into r,
+  // the merge is performed.
+  //
+  // [Xi,Yi]..[Xn,Yn]  U  [Xj,Yj]..[Xm,Ym]   -->  [Xk,Yk]..[Xp,Yp]
+  tree ttype = r.type ();
+  signop sign = TYPE_SIGN (ttype);
+
+  auto_vec<tree, 20> res;
+  wide_int u1 ;
+  wi::overflow_type ovf;
+  unsigned i = 0, j = 0, k = 0;
+
+  while (i < m_num_ranges * 2 && j < r.m_num_ranges * 2)
+    {
+      // lower of Xi and Xj is the lowest point.
+      if (wi::le_p (wi::to_wide (m_base[i]), wi::to_wide (r.m_base[j]), sign))
+	{
+	  res.safe_push (m_base[i]);
+	  res.safe_push (m_base[i + 1]);
+	  k += 2;
+	  i += 2;
+	}
+      else
+	{
+	  res.safe_push (r.m_base[j]);
+	  res.safe_push (r.m_base[j + 1]);
+	  k += 2;
+	  j += 2;
+	}
+    }
+  for ( ; i < m_num_ranges * 2; i += 2)
+    {
+      res.safe_push (m_base[i]);
+      res.safe_push (m_base[i + 1]);
+      k += 2;
+    }
+  for ( ; j < r.m_num_ranges * 2; j += 2)
+    {
+      res.safe_push (r.m_base[j]);
+      res.safe_push (r.m_base[j + 1]);
+      k += 2;
+    }
 
-  if (dump_file && (dump_flags & TDF_DETAILS))
+  // Now normalize the vector removing any overlaps.
+  i = 2;
+  int prec = TYPE_PRECISION (ttype);
+  wide_int max_val = wi::max_value (prec, sign);
+  for (j = 2; j < k ; j += 2)
     {
-      fprintf (dump_file, "to\n  ");
-      dump_value_range (dump_file, this);
-      fprintf (dump_file, "\n");
+      wide_int val_im1 = wi::to_wide (res[i - 1]);
+      if (val_im1 == max_val)
+	break;
+      u1 = wi::add (val_im1, 1, sign, &ovf);
+
+      // Overflow indicates we are at MAX already.
+      // A wide int bug requires the previous max_val check
+      // trigger: gcc.c-torture/compile/pr80443.c  with -O3
+      if (ovf == wi::OVF_OVERFLOW)
+	break;
+
+      wide_int val_j = wi::to_wide (res[j]);
+      wide_int val_jp1 = wi::to_wide (res[j+1]);
+      // Current upper+1 is >= lower bound next pair, then we merge ranges.
+      if (wi::ge_p (u1, val_j, sign))
+	{
+	  // New upper bounds is greater of current or the next one.
+	  if (wi::gt_p (val_jp1, val_im1, sign))
+	    res [i - 1] = res[j + 1];
+	}
+      else
+	{
+	  // This is a new distinct range, but no point in copying it
+	  // if it is already in the right place.
+	  if (i != j)
+	    {
+	      res[i++] = res[j];
+	      res[i++] = res[j + 1];
+	    }
+	  else
+	    i += 2;
+	}
     }
+
+  // At this point, the vector should have i ranges, none overlapping.
+  // Now it simply needs to be copied, and if there are too many
+  // ranges, merge some.  We wont do any analysis as to what the
+  // "best" merges are, simply combine the final ranges into one.
+  if (i > m_max_ranges * 2)
+    {
+      res[m_max_ranges * 2 - 1] = res[i - 1];
+      i = m_max_ranges * 2;
+    }
+
+  for (j = 0; j < i ; j++)
+    m_base[j] = res [j];
+  m_num_ranges = i / 2;
+
+  if (flag_checking)
+    verify_range ();
 }
 
-/* Range intersect, but for references.  */
+// intersect for multi-ranges.
 
 void
-value_range::intersect (const value_range &r)
+irange::irange_intersect (const irange &r)
+{
+  gcc_checking_assert (!legacy_mode_p () && !r.legacy_mode_p ());
+
+  if (undefined_p () || r.varying_p ())
+    return;
+  if (r.undefined_p ())
+    {
+      set_undefined ();
+      return;
+    }
+  if (varying_p ())
+    {
+      operator= (r);
+      return;
+    }
+
+  signop sign = TYPE_SIGN (TREE_TYPE(m_base[0]));
+  unsigned bld_pair = 0;
+  unsigned bld_lim = m_max_ranges;
+  widest_irange r2 (*this);
+  unsigned r2_lim = r2.num_pairs ();
+  unsigned i2 = 0;
+  for (unsigned i = 0; i < r.num_pairs (); )
+    {
+      // If r1's upper is < r2's lower, we can skip r1's pair.
+      tree ru = r.m_base[i * 2 + 1];
+      tree r2l = r2.m_base[i2 * 2];
+      if (wi::lt_p (wi::to_wide (ru), wi::to_wide (r2l), sign))
+	{
+	  i++;
+	  continue;
+	}
+      // Likewise, skip r2's pair if its excluded.
+      tree r2u = r2.m_base[i2 * 2 + 1];
+      tree rl = r.m_base[i * 2];
+      if (wi::lt_p (wi::to_wide (r2u), wi::to_wide (rl), sign))
+	{
+	  i2++;
+	  if (i2 < r2_lim)
+	    continue;
+	  // No more r2, break.
+	  break;
+	}
+
+      // Must be some overlap.  Find the highest of the lower bounds,
+      // and set it, unless the build limits lower bounds is already
+      // set.
+      if (bld_pair < bld_lim)
+	{
+	  if (wi::ge_p (wi::to_wide (rl), wi::to_wide (r2l), sign))
+	    m_base[bld_pair * 2] = rl;
+	  else
+	    m_base[bld_pair * 2] = r2l;
+	}
+      else
+	// Decrease and set a new upper.
+	bld_pair--;
+
+      // ...and choose the lower of the upper bounds.
+      if (wi::le_p (wi::to_wide (ru), wi::to_wide (r2u), sign))
+	{
+	  m_base[bld_pair * 2 + 1] = ru;
+	  bld_pair++;
+	  // Move past the r1 pair and keep trying.
+	  i++;
+	  continue;
+	}
+      else
+	{
+	  m_base[bld_pair * 2 + 1] = r2u;
+	  bld_pair++;
+	  i2++;
+	  if (i2 < r2_lim)
+	    continue;
+	  // No more r2, break.
+	  break;
+	}
+      // r2 has the higher lower bound.
+    }
+
+  // At the exit of this loop, it is one of 2 things:
+  // ran out of r1, or r2, but either means we are done.
+  m_num_ranges = bld_pair;
+  if (flag_checking)
+    verify_range ();
+}
+
+static wide_int inline
+subtract_one (const wide_int &x, tree type, wi::overflow_type &overflow)
 {
-  /* Disable details for now, because it makes the ranger dump
-     unnecessarily verbose.  */
-  bool details = dump_flags & TDF_DETAILS;
-  if (details)
-    dump_flags &= ~TDF_DETAILS;
-  intersect (&r);
-  if (details)
-    dump_flags |= TDF_DETAILS;
+  // A signed 1-bit bit-field, has a range of [-1,0] so subtracting +1
+  // overflows, since +1 is unrepresentable.  This is why we have an
+  // addition of -1 here.
+  if (TYPE_SIGN (type) == SIGNED)
+    return wi::add (x, -1 , SIGNED, &overflow);
+  else
+    return wi::sub (x, 1, UNSIGNED, &overflow);
 }
 
 /* Return the inverse of a range.  */
 
 void
-value_range::invert ()
+irange::invert ()
 {
-  /* We can't just invert VR_RANGE and VR_ANTI_RANGE because we may
-     create non-canonical ranges.  Use the constructors instead.  */
-  if (m_kind == VR_RANGE)
-    *this = value_range (m_min, m_max, VR_ANTI_RANGE);
-  else if (m_kind == VR_ANTI_RANGE)
-    *this = value_range (m_min, m_max);
+  if (legacy_mode_p ())
+    {
+      // We can't just invert VR_RANGE and VR_ANTI_RANGE because we may
+      // create non-canonical ranges.  Use the constructors instead.
+      if (m_kind == VR_RANGE)
+	*this = value_range (min (), max (), VR_ANTI_RANGE);
+      else if (m_kind == VR_ANTI_RANGE)
+	*this = value_range (min (), max ());
+      else
+	gcc_unreachable ();
+      return;
+    }
+
+  gcc_assert (!undefined_p () && !varying_p ());
+
+  // We always need one more set of bounds to represent an inverse, so
+  // if we're at the limit, we can't properly represent things.
+  //
+  // For instance, to represent the inverse of a 2 sub-range set
+  // [5, 10][20, 30], we would need a 3 sub-range set
+  // [-MIN, 4][11, 19][31, MAX].
+  //
+  // In this case, return the most conservative thing.
+  //
+  // However, if any of the extremes of the range are -MIN/+MAX, we
+  // know we will not need an extra bound.  For example:
+  //
+  // 	INVERT([-MIN,20][30,40]) => [21,29][41,+MAX]
+  // 	INVERT([-MIN,20][30,MAX]) => [21,29]
+  tree ttype = type ();
+  unsigned prec = TYPE_PRECISION (ttype);
+  signop sign = TYPE_SIGN (ttype);
+  wide_int type_min = wi::min_value (prec, sign);
+  wide_int type_max = wi::max_value (prec, sign);
+  if (m_num_ranges == m_max_ranges
+      && lower_bound () != type_min
+      && upper_bound () != type_max)
+    {
+      m_base[1] = wide_int_to_tree (ttype, type_max);
+      m_num_ranges = 1;
+      return;
+    }
+  // The algorithm is as follows.  To calculate INVERT ([a,b][c,d]), we
+  // generate [-MIN, a-1][b+1, c-1][d+1, MAX].
+  //
+  // If there is an over/underflow in the calculation for any
+  // sub-range, we eliminate that subrange.  This allows us to easily
+  // calculate INVERT([-MIN, 5]) with: [-MIN, -MIN-1][6, MAX].  And since
+  // we eliminate the underflow, only [6, MAX] remains.
+  unsigned i = 0;
+  wi::overflow_type ovf;
+  // Construct leftmost range.
+  widest_irange orig_range (*this);
+  unsigned nitems = 0;
+  wide_int tmp;
+  // If this is going to underflow on the MINUS 1, don't even bother
+  // checking.  This also handles subtracting one from an unsigned 0,
+  // which doesn't set the underflow bit.
+  if (type_min != orig_range.lower_bound ())
+    {
+      m_base[nitems++] = wide_int_to_tree (ttype, type_min);
+      tmp = subtract_one (orig_range.lower_bound (), ttype, ovf);
+      m_base[nitems++] = wide_int_to_tree (ttype, tmp);
+      if (ovf)
+	nitems = 0;
+    }
+  i++;
+  // Construct middle ranges if applicable.
+  if (orig_range.num_pairs () > 1)
+    {
+      unsigned j = i;
+      for (; j < (orig_range.num_pairs () * 2) - 1; j += 2)
+	{
+	  // The middle ranges cannot have MAX/MIN, so there's no need
+	  // to check for unsigned overflow on the +1 and -1 here.
+	  tmp = wi::add (wi::to_wide (orig_range.m_base[j]), 1, sign, &ovf);
+	  m_base[nitems++] = wide_int_to_tree (ttype, tmp);
+	  tmp = subtract_one (wi::to_wide (orig_range.m_base[j + 1]),
+			      ttype, ovf);
+	  m_base[nitems++] = wide_int_to_tree (ttype, tmp);
+	  if (ovf)
+	    nitems -= 2;
+	}
+      i = j;
+    }
+  // Construct rightmost range.
+  //
+  // However, if this will overflow on the PLUS 1, don't even bother.
+  // This also handles adding one to an unsigned MAX, which doesn't
+  // set the overflow bit.
+  if (type_max != wi::to_wide (orig_range.m_base[i]))
+    {
+      tmp = wi::add (wi::to_wide (orig_range.m_base[i]), 1, sign, &ovf);
+      m_base[nitems++] = wide_int_to_tree (ttype, tmp);
+      m_base[nitems++] = wide_int_to_tree (ttype, type_max);
+      if (ovf)
+	nitems -= 2;
+    }
+  m_num_ranges = nitems / 2;
+
+  if (flag_checking)
+    verify_range ();
+}
+
+static void
+dump_bound_with_infinite_markers (FILE *file, tree bound)
+{
+  tree type = TREE_TYPE (bound);
+  if (INTEGRAL_TYPE_P (type)
+      && !TYPE_UNSIGNED (type)
+      && vrp_val_is_min (bound)
+      && TYPE_PRECISION (type) != 1)
+    fprintf (file, "-INF");
+  else if (vrp_val_is_max (bound)
+	   && TYPE_PRECISION (type) != 1)
+    fprintf (file, "+INF");
   else
-    gcc_unreachable ();
+    print_generic_expr (file, bound);
 }
 
 void
-value_range::dump (FILE *file) const
+irange::dump (FILE *file) const
 {
   if (undefined_p ())
-    fprintf (file, "UNDEFINED");
-  else if (m_kind == VR_RANGE || m_kind == VR_ANTI_RANGE)
     {
-      tree ttype = type ();
-
-      print_generic_expr (file, ttype);
-      fprintf (file, " ");
-
+      fprintf (file, "UNDEFINED");
+      return;
+    }
+  print_generic_expr (file, type ());
+  fprintf (file, " ");
+  if (varying_p ())
+    {
+      fprintf (file, "VARYING");
+      return;
+    }
+ if (legacy_mode_p ())
+    {
       fprintf (file, "%s[", (m_kind == VR_ANTI_RANGE) ? "~" : "");
-
-      if (INTEGRAL_TYPE_P (ttype)
-	  && !TYPE_UNSIGNED (ttype)
-	  && vrp_val_is_min (min ())
-	  && TYPE_PRECISION (ttype) != 1)
-	fprintf (file, "-INF");
-      else
-	print_generic_expr (file, min ());
-
+      dump_bound_with_infinite_markers (file, min ());
       fprintf (file, ", ");
-
-      if (supports_type_p (ttype)
-	  && vrp_val_is_max (max ())
-	  && TYPE_PRECISION (ttype) != 1)
-	fprintf (file, "+INF");
-      else
-	print_generic_expr (file, max ());
-
+      dump_bound_with_infinite_markers (file, max ());
       fprintf (file, "]");
+      return;
     }
-  else if (varying_p ())
+  for (unsigned i = 0; i < m_num_ranges; ++i)
     {
-      print_generic_expr (file, type ());
-      fprintf (file, " VARYING");
+      tree lb = m_base[i * 2];
+      tree ub = m_base[i * 2 + 1];
+      fprintf (file, "[");
+      dump_bound_with_infinite_markers (file, lb);
+      fprintf (file, ", ");
+      dump_bound_with_infinite_markers (file, ub);
+      fprintf (file, "]");
     }
-  else
-    gcc_unreachable ();
 }
 
 void
-value_range::dump () const
+dump_value_range (FILE *file, const irange *vr)
 {
-  dump (stderr);
+  vr->dump (file);
 }
 
-void
-dump_value_range (FILE *file, const value_range *vr)
+DEBUG_FUNCTION void
+debug (const irange *vr)
 {
-  if (!vr)
-    fprintf (file, "[]");
-  else
-    vr->dump (file);
+  dump_value_range (stderr, vr);
+  fprintf (stderr, "\n");
+}
+
+DEBUG_FUNCTION void
+debug (const irange &vr)
+{
+  debug (&vr);
 }
 
 DEBUG_FUNCTION void
 debug (const value_range *vr)
 {
   dump_value_range (stderr, vr);
+  fprintf (stderr, "\n");
 }
 
 DEBUG_FUNCTION void
 debug (const value_range &vr)
 {
   dump_value_range (stderr, &vr);
+  fprintf (stderr, "\n");
 }
 
 /* Create two value-ranges in *VR0 and *VR1 from the anti-range *AR
@@ -1501,40 +2004,13 @@  ranges_from_anti_range (const value_range *ar,
 }
 
 bool
-range_has_numeric_bounds_p (const value_range *vr)
+range_has_numeric_bounds_p (const irange *vr)
 {
-  return (vr->min ()
+  return (!vr->undefined_p ()
 	  && TREE_CODE (vr->min ()) == INTEGER_CST
 	  && TREE_CODE (vr->max ()) == INTEGER_CST);
 }
 
-/* Return the maximum value for TYPE.  */
-
-tree
-vrp_val_max (const_tree type)
-{
-  if (INTEGRAL_TYPE_P (type))
-    return TYPE_MAX_VALUE (type);
-  if (POINTER_TYPE_P (type))
-    {
-      wide_int max = wi::max_value (TYPE_PRECISION (type), TYPE_SIGN (type));
-      return wide_int_to_tree (const_cast<tree> (type), max);
-    }
-  return NULL_TREE;
-}
-
-/* Return the minimum value for TYPE.  */
-
-tree
-vrp_val_min (const_tree type)
-{
-  if (INTEGRAL_TYPE_P (type))
-    return TYPE_MIN_VALUE (type);
-  if (POINTER_TYPE_P (type))
-    return build_zero_cst (const_cast<tree> (type));
-  return NULL_TREE;
-}
-
 /* Return whether VAL is equal to the maximum value of its type.
    We can't do a simple equality comparison with TYPE_MAX_VALUE because
    C typedefs and Ada subtypes can produce types whose TYPE_MAX_VALUE
@@ -1571,3 +2047,41 @@  vrp_operand_equal_p (const_tree val1, const_tree val2)
     return false;
   return true;
 }
+
+#define DEFINE_INT_RANGE_GC_STUBS(N)		\
+  void						\
+  gt_pch_nx (int_range<N> *&x)			\
+  {						\
+    for (unsigned i = 0; i < N; ++i)		\
+      {						\
+	gt_pch_nx (x->m_ranges[i * 2]);		\
+	gt_pch_nx (x->m_ranges[i * 2 + 1]);	\
+      }		  		       		\
+  }						\
+						\
+  void						\
+  gt_ggc_mx (int_range<N> *&x)			\
+  {	    	       				\
+    for (unsigned i = 0; i < N; ++i)		\
+      {						\
+	  gt_ggc_mx (x->m_ranges[i * 2]);	\
+	  gt_ggc_mx (x->m_ranges[i * 2 + 1]);	\
+      }						\
+  }
+
+#define DEFINE_INT_RANGE_INSTANCE(N)					\
+  template int_range<N>::int_range(tree, tree, value_range_kind);	\
+  template int_range<N>::int_range(tree_node *,				\
+				   const wide_int &,			\
+				   const wide_int &,			\
+				   value_range_kind);			\
+  template int_range<N>::int_range(tree);				\
+  template int_range<N>::int_range(const irange &);		\
+  template int_range<N>::int_range(const int_range &);			\
+  template int_range<N>& int_range<N>::operator= (const int_range &);
+
+DEFINE_INT_RANGE_INSTANCE(1)
+DEFINE_INT_RANGE_INSTANCE(2)
+DEFINE_INT_RANGE_INSTANCE(3)
+DEFINE_INT_RANGE_INSTANCE(255)
+DEFINE_INT_RANGE_GC_STUBS(1)
diff --git a/gcc/value-range.h b/gcc/value-range.h
index 0a9dc6f151f..e3282c4ad03 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -1,5 +1,7 @@ 
 /* Support routines for value ranges.
    Copyright (C) 2019-2020 Free Software Foundation, Inc.
+   Contributed by Aldy Hernandez <aldyh@redhat.com> and
+   Andrew Macleod <amacleod@redhat.com>.
 
 This file is part of GCC.
 
@@ -20,7 +22,7 @@  along with GCC; see the file COPYING3.  If not see
 #ifndef GCC_VALUE_RANGE_H
 #define GCC_VALUE_RANGE_H
 
-/* Types of value ranges.  */
+// Types of value ranges.
 enum value_range_kind
 {
   /* Empty range.  */
@@ -36,164 +38,292 @@  enum value_range_kind
 };
 
 // Range of values that can be associated with an SSA_NAME.
+//
+// This is the base class without any storage.
 
-class GTY((for_user)) value_range
+class irange
 {
 public:
-  value_range ();
-  value_range (tree, tree, value_range_kind = VR_RANGE);
-  value_range (tree type, const wide_int &, const wide_int &,
-	       value_range_kind = VR_RANGE);
-  value_range (tree type);
-
+  // In-place setters.
   void set (tree, tree, value_range_kind = VR_RANGE);
-  void set (tree);
   void set_nonzero (tree);
   void set_zero (tree);
-
-  enum value_range_kind kind () const;
-  tree min () const;
-  tree max () const;
-
-  /* Types of value ranges.  */
-  bool symbolic_p () const;
-  bool constant_p () const;
-  bool undefined_p () const;
-  bool varying_p () const;
   void set_varying (tree type);
   void set_undefined ();
 
-  void union_ (const value_range *);
-  void intersect (const value_range *);
-  void union_ (const value_range &);
-  void intersect (const value_range &);
-
-  bool operator== (const value_range &) const;
-  bool operator!= (const value_range &) const /* = delete */;
-  bool equal_p (const value_range &) const;
-
-  /* Misc methods.  */
-  tree type () const;
-  bool may_contain_p (tree) const;
-  bool zero_p () const;
-  bool nonzero_p () const;
-  bool singleton_p (tree *result = NULL) const;
-  void dump (FILE *) const;
-  void dump () const;
-
+  // Range types.
   static bool supports_type_p (tree);
-  void normalize_symbolics ();
-  void normalize_addresses ();
+  tree type () const;
 
-  static const unsigned int m_max_pairs = 2;
-  bool contains_p (tree) const;
+  // Iteration over sub-ranges.
   unsigned num_pairs () const;
   wide_int lower_bound (unsigned = 0) const;
   wide_int upper_bound (unsigned) const;
   wide_int upper_bound () const;
+
+  // Predicates.
+  bool zero_p () const;
+  bool nonzero_p () const;
+  bool undefined_p () const;
+  bool varying_p () const;
+  bool singleton_p (tree *result = NULL) const;
+  bool contains_p (tree) const;
+
+  // In-place operators.
+  void union_ (const irange &);
+  void intersect (const irange &);
   void invert ();
 
+  // Operator overloads.
+  irange& operator= (const irange &);
+  bool operator== (const irange &) const;
+  bool operator!= (const irange &r) const { return !(*this == r); }
+
+  // Misc methods.
+  void dump (FILE * = stderr) const;
+
+  // Deprecated legacy public methods.
+  enum value_range_kind kind () const;		// DEPRECATED
+  tree min () const;				// DEPRECATED
+  tree max () const;				// DEPRECATED
+  bool symbolic_p () const;			// DEPRECATED
+  bool constant_p () const;			// DEPRECATED
+  void normalize_symbolics ();			// DEPRECATED
+  void normalize_addresses ();			// DEPRECATED
+  bool may_contain_p (tree) const;		// DEPRECATED
+  void set (tree);				// DEPRECATED
+  bool equal_p (const irange &) const;		// DEPRECATED
+  void union_ (const class irange *);		// DEPRECATED
+  void intersect (const irange *);		// DEPRECATED
+
 protected:
-  void check ();
-  static value_range union_helper (const value_range *, const value_range *);
-  static value_range intersect_helper (const value_range *,
-				       const value_range *);
-
-  friend void gt_ggc_mx_value_range (void *);
-  friend void gt_pch_p_11value_range (void *, void *,
-				      gt_pointer_operator, void *);
-  friend void gt_pch_nx_value_range (void *);
-  friend void gt_ggc_mx (value_range &);
-  friend void gt_ggc_mx (value_range *&);
-  friend void gt_pch_nx (value_range &);
-  friend void gt_pch_nx (value_range *, gt_pointer_operator, void *);
-
-  enum value_range_kind m_kind;
-  tree m_min;
-  tree m_max;
+  irange (tree *, unsigned);
+  // potential promotion to public?
+  tree tree_lower_bound (unsigned = 0) const;
+  tree tree_upper_bound (unsigned) const;
+  tree tree_upper_bound () const;
+
+   // In-place operators.
+  void irange_union (const irange &);
+  void irange_intersect (const irange &);
+  void irange_set (tree, tree);
+  void irange_set_anti_range (tree, tree);
+
+  bool swap_out_of_order_endpoints (tree &min, tree &max, value_range_kind &);
+  bool normalize_min_max (tree type, tree min, tree max, value_range_kind);
+
+  bool legacy_mode_p () const;
+  bool legacy_equal_p (const irange &) const;
+  void legacy_union (irange *, const irange *);
+  void legacy_intersect (irange *, const irange *);
+  void verify_range ();
+  unsigned legacy_num_pairs () const;
+  wide_int legacy_lower_bound (unsigned = 0) const;
+  wide_int legacy_upper_bound (unsigned) const;
+  int value_inside_range (tree) const;
+  bool maybe_anti_range () const;
+  void copy_legacy_range (const irange &);
 
 private:
-  int value_inside_range (tree) const;
+  unsigned char m_num_ranges;
+  unsigned char m_max_ranges;
+  ENUM_BITFIELD(value_range_kind) m_kind : 8;
+  tree *m_base;
 };
 
-extern bool range_has_numeric_bounds_p (const value_range *);
+// Here we describe an irange with N pairs of ranges.  The storage for
+// the pairs is embedded in the class as an array.
+
+template<unsigned N>
+class GTY((user)) int_range : public irange
+{
+public:
+  int_range ();
+  int_range (tree, tree, value_range_kind = VR_RANGE);
+  int_range (tree type, const wide_int &, const wide_int &,
+	     value_range_kind = VR_RANGE);
+  int_range (tree type);
+  int_range (const int_range &);
+  int_range (const irange &);
+  int_range& operator= (const int_range &);
+private:
+  template <unsigned X> friend void gt_ggc_mx (int_range<X> *);
+  template <unsigned X> friend void gt_pch_nx (int_range<X> *);
+  template <unsigned X> friend void gt_pch_nx (int_range<X> *,
+					       gt_pointer_operator, void *);
+  // ?? hash-traits.h has its own extern for these, which is causing
+  // them to never be picked up by the templates.  For now, define
+  // elsewhere.
+  //template<unsigned X> friend void gt_ggc_mx (int_range<X> *&);
+  //template<unsigned X> friend void gt_pch_nx (int_range<X> *&);
+  friend void gt_ggc_mx (int_range<1> *&);
+  friend void gt_pch_nx (int_range<1> *&);
+
+  tree m_ranges[N*2];
+};
+
+// This is a special int_range<1> with only one pair, plus
+// VR_ANTI_RANGE magic to describe slightly more than can be described
+// in one pair.  It is described in the code as a "legacy range" (as
+// opposed to multi-ranges which have multiple sub-ranges).  It is
+// provided for backward compatibility with code that has not been
+// converted to multi-range irange's.
+//
+// There are copy operators to seamlessly copy to/fro multi-ranges.
+typedef int_range<1> value_range;
+
+// This is an "infinite" precision irange for use in temporary
+// calculations.
+typedef int_range<255> widest_irange;
+
+// Returns true for an old-school value_range as described above.
+inline bool
+irange::legacy_mode_p () const
+{
+  return m_max_ranges == 1;
+}
+
+extern bool range_has_numeric_bounds_p (const irange *);
 extern bool ranges_from_anti_range (const value_range *,
 				    value_range *, value_range *);
-extern void dump_value_range (FILE *, const value_range *);
+extern void dump_value_range (FILE *, const irange *);
 extern bool vrp_val_is_min (const_tree);
 extern bool vrp_val_is_max (const_tree);
-extern tree vrp_val_min (const_tree);
-extern tree vrp_val_max (const_tree);
 extern bool vrp_operand_equal_p (const_tree, const_tree);
 
-inline
-value_range::value_range ()
+inline value_range_kind
+irange::kind () const
+{
+  if (legacy_mode_p ())
+    return m_kind;
+
+  if (undefined_p ())
+    return VR_UNDEFINED;
+
+  if (varying_p ())
+    return VR_VARYING;
+
+  return VR_RANGE;
+}
+
+// Number of sub-ranges in a range.
+
+inline unsigned
+irange::num_pairs () const
 {
-  m_kind = VR_UNDEFINED;
-  m_min = m_max = NULL;
+  if (!legacy_mode_p ())
+    return m_num_ranges;
+  else
+    return legacy_num_pairs ();
 }
 
-inline value_range_kind
-value_range::kind () const
+inline tree
+irange::type () const
+{
+  gcc_checking_assert (!undefined_p ());
+  return TREE_TYPE (m_base[0]);
+}
+
+// Return the lower bound of a sub-range expressed as a tree.  PAIR is
+// the sub-range in question.
+
+inline tree
+irange::tree_lower_bound (unsigned pair) const
+{
+  return m_base[pair * 2];
+}
+
+// Return the upper bound of a sub-range expressed as a tree.  PAIR is
+// the sub-range in question.
+
+inline tree
+irange::tree_upper_bound (unsigned pair) const
 {
-  return m_kind;
+  return m_base[pair * 2 + 1];
 }
 
+// Return the highest bound of a range expressed as a tree.
+
 inline tree
-value_range::type () const
+irange::tree_upper_bound () const
 {
-  return TREE_TYPE (min ());
+  gcc_checking_assert (m_num_ranges);
+  return tree_upper_bound (m_num_ranges - 1);
 }
 
 inline tree
-value_range::min () const
+irange::min () const
 {
-  return m_min;
+  return tree_lower_bound (0);
 }
 
 inline tree
-value_range::max () const
+irange::max () const
 {
-  return m_max;
+  if (m_num_ranges)
+    return tree_upper_bound ();
+  else
+    return NULL;
 }
 
 inline bool
-value_range::varying_p () const
+irange::varying_p () const
 {
-  return m_kind == VR_VARYING;
+  if (legacy_mode_p ())
+    return m_kind == VR_VARYING;
+
+  if (m_num_ranges != 1)
+    return false;
+
+  tree l = m_base[0];
+  tree u = m_base[1];
+  tree t = TREE_TYPE (l);
+  if (INTEGRAL_TYPE_P (t))
+    return l == TYPE_MIN_VALUE (t) && u == TYPE_MAX_VALUE (t);
+  if (POINTER_TYPE_P (t))
+    return wi::to_wide (l) == 0
+	   && wi::to_wide (u) == wi::max_value (TYPE_PRECISION (t),
+						TYPE_SIGN (t));
+  return true;
+
 }
 
 inline bool
-value_range::undefined_p () const
+irange::undefined_p () const
 {
+  if (!legacy_mode_p ())
+    return m_num_ranges == 0;
+
+  if (CHECKING_P && legacy_mode_p ())
+    {
+      if (m_kind == VR_UNDEFINED)
+	gcc_checking_assert (m_num_ranges == 0);
+      else
+	gcc_checking_assert (m_num_ranges != 0);
+    }
   return m_kind == VR_UNDEFINED;
 }
 
 inline bool
-value_range::zero_p () const
+irange::zero_p () const
 {
-  return (m_kind == VR_RANGE
-	  && integer_zerop (m_min)
-	  && integer_zerop (m_max));
+  return (m_kind == VR_RANGE && m_num_ranges == 1
+	  && integer_zerop (tree_lower_bound (0))
+	  && integer_zerop (tree_upper_bound (0)));
 }
 
 inline bool
-value_range::nonzero_p () const
+irange::nonzero_p () const
 {
-  if (m_kind == VR_ANTI_RANGE
-      && !TYPE_UNSIGNED (type ())
-      && integer_zerop (m_min)
-      && integer_zerop (m_max))
-    return true;
+  if (undefined_p ())
+    return false;
 
-  return (m_kind == VR_RANGE
-	  && TYPE_UNSIGNED (type ())
-	  && integer_onep (m_min)
-	  && vrp_val_is_max (m_max));
+  tree zero = build_zero_cst (type ());
+  return *this == int_range<1> (zero, zero, VR_ANTI_RANGE);
 }
 
 inline bool
-value_range::supports_type_p (tree type)
+irange::supports_type_p (tree type)
 {
   if (type && (INTEGRAL_TYPE_P (type) || POINTER_TYPE_P (type)))
     return type;
@@ -201,7 +331,7 @@  value_range::supports_type_p (tree type)
 }
 
 inline bool
-range_includes_zero_p (const value_range *vr)
+range_includes_zero_p (const irange *vr)
 {
   if (vr->undefined_p ())
     return false;
@@ -212,4 +342,281 @@  range_includes_zero_p (const value_range *vr)
   return vr->may_contain_p (build_zero_cst (vr->type ()));
 }
 
+template<unsigned N>
+static inline void
+gt_ggc_mx (int_range<N> *x)
+{
+  for (unsigned i = 0; i < N; ++i)
+    {
+      gt_ggc_mx (x->m_ranges[i * 2]);
+      gt_ggc_mx (x->m_ranges[i * 2 + 1]);
+    }
+}
+
+template<unsigned N>
+static inline void
+gt_pch_nx (int_range<N> *x)
+{
+  for (unsigned i = 0; i < N; ++i)
+    {
+      gt_pch_nx (x->m_ranges[i * 2]);
+      gt_pch_nx (x->m_ranges[i * 2 + 1]);
+    }
+}
+
+template<unsigned N>
+static inline void
+gt_pch_nx (int_range<N> *x, gt_pointer_operator op, void *cookie)
+{
+  for (unsigned i = 0; i < N; ++i)
+    {
+      op (&x->m_ranges[i * 2], cookie);
+      op (&x->m_ranges[i * 2 + 1], cookie);
+    }
+}
+
+// Constructors for irange
+
+inline
+irange::irange (tree *base, unsigned nranges)
+{
+  m_base = base;
+  m_num_ranges = 0;
+  m_max_ranges = nranges;
+  if (legacy_mode_p ())
+    m_kind = VR_UNDEFINED;
+  else
+    m_kind = VR_RANGE;
+}
+
+// Constructors for int_range<>.
+
+template<unsigned N>
+inline
+int_range<N>::int_range ()
+  : irange (m_ranges, N)
+{
+}
+
+template<unsigned N>
+int_range<N>::int_range (const int_range &other)
+  : irange (m_ranges, N)
+{
+  irange::operator= (other);
+}
+
+template<unsigned N>
+int_range<N>::int_range (tree min, tree max, value_range_kind kind)
+  : irange (m_ranges, N)
+{
+  irange::set (min, max, kind);
+}
+
+template<unsigned N>
+int_range<N>::int_range (tree type)
+  : irange (m_ranges, N)
+{
+  set_varying (type);
+}
+
+template<unsigned N>
+int_range<N>::int_range (tree type, const wide_int &wmin, const wide_int &wmax,
+			 value_range_kind kind)
+  : irange (m_ranges, N)
+{
+  tree min = wide_int_to_tree (type, wmin);
+  tree max = wide_int_to_tree (type, wmax);
+  set (min, max, kind);
+}
+
+template<unsigned N>
+int_range<N>::int_range (const irange &other)
+  : irange (m_ranges, N)
+{
+  irange::operator= (other);
+}
+
+template<unsigned N>
+int_range<N>&
+int_range<N>::operator= (const int_range &src)
+{
+  irange::operator= (src);
+  return *this;
+}
+
+inline void
+irange::set (tree val)
+{
+  set (val, val);
+}
+
+inline void
+irange::set_undefined ()
+{
+  m_num_ranges = 0;
+  if (legacy_mode_p ())
+    m_kind = VR_UNDEFINED;
+}
+
+inline void
+irange::set_varying (tree type)
+{
+  if (legacy_mode_p ())
+    m_kind = VR_VARYING;
+
+  m_num_ranges = 1;
+  if (INTEGRAL_TYPE_P (type))
+    {
+      m_base[0] = TYPE_MIN_VALUE (type);
+      m_base[1] = TYPE_MAX_VALUE (type);
+    }
+  else if (POINTER_TYPE_P (type))
+    {
+      m_base[0] = build_int_cst (type, 0);
+      m_base[1] = build_int_cst (type, -1);
+    }
+  else
+    m_base[0] = m_base[1] = error_mark_node;
+}
+
+inline bool
+irange::operator== (const irange &r) const
+{
+  return equal_p (r);
+}
+
+// Return the lower bound of a sub-range.  PAIR is the sub-range in
+// question.
+
+inline wide_int
+irange::lower_bound (unsigned pair) const
+{
+  if (legacy_mode_p ())
+    return legacy_lower_bound (pair);
+  gcc_checking_assert (!undefined_p ());
+  gcc_checking_assert (pair + 1 <= num_pairs ());
+  return wi::to_wide (tree_lower_bound (pair));
+}
+
+// Return the upper bound of a sub-range.  PAIR is the sub-range in
+// question.
+
+inline wide_int
+irange::upper_bound (unsigned pair) const
+{
+  if (legacy_mode_p ())
+    return legacy_upper_bound (pair);
+  gcc_checking_assert (!undefined_p ());
+  gcc_checking_assert (pair + 1 <= num_pairs ());
+  return wi::to_wide (tree_upper_bound (pair));
+}
+
+// Return the highest bound of a range.
+
+inline wide_int
+irange::upper_bound () const
+{
+  unsigned pairs = num_pairs ();
+  gcc_checking_assert (pairs > 0);
+  return upper_bound (pairs - 1);
+}
+
+inline void
+irange::union_ (const irange &r)
+{
+  dump_flags_t m_flags = dump_flags;
+  dump_flags &= ~TDF_DETAILS;
+  irange::union_ (&r);
+  dump_flags = m_flags;
+}
+
+inline void
+irange::intersect (const irange &r)
+{
+  dump_flags_t m_flags = dump_flags;
+  dump_flags &= ~TDF_DETAILS;
+  irange::intersect (&r);
+  dump_flags = m_flags;
+}
+
+// Set value range VR to a nonzero range of type TYPE.
+
+inline void
+irange::set_nonzero (tree type)
+{
+  tree zero = build_int_cst (type, 0);
+  if (legacy_mode_p ())
+    set (zero, zero, VR_ANTI_RANGE);
+  else
+    irange_set_anti_range (zero, zero);
+}
+
+// Set value range VR to a ZERO range of type TYPE.
+
+inline void
+irange::set_zero (tree type)
+{
+  tree z = build_int_cst (type, 0);
+  if (legacy_mode_p ())
+    set (z);
+  else
+    irange_set (z, z);
+}
+
+// Normalize [MIN, MAX] into VARYING and ~[MIN, MAX] into UNDEFINED.
+//
+// Avoid using TYPE_{MIN,MAX}_VALUE because -fstrict-enums can
+// restrict those to a subset of what actually fits in the type.
+// Instead use the extremes of the type precision which will allow
+// compare_range_with_value() to check if a value is inside a range,
+// whereas if we used TYPE_*_VAL, said function would just punt upon
+// seeing a VARYING.
+
+inline bool
+irange::normalize_min_max (tree type, tree min, tree max,
+			   value_range_kind kind)
+{
+  unsigned prec = TYPE_PRECISION (type);
+  signop sign = TYPE_SIGN (type);
+  if (wi::eq_p (wi::to_wide (min), wi::min_value (prec, sign))
+      && wi::eq_p (wi::to_wide (max), wi::max_value (prec, sign)))
+    {
+      if (kind == VR_RANGE)
+	set_varying (type);
+      else if (kind == VR_ANTI_RANGE)
+	set_undefined ();
+      else
+	gcc_unreachable ();
+      return true;
+    }
+  return false;
+}
+
+// Return the maximum value for TYPE.
+
+inline tree
+vrp_val_max (const_tree type)
+{
+  if (INTEGRAL_TYPE_P (type))
+    return TYPE_MAX_VALUE (type);
+  if (POINTER_TYPE_P (type))
+    {
+      wide_int max = wi::max_value (TYPE_PRECISION (type), TYPE_SIGN (type));
+      return wide_int_to_tree (const_cast<tree> (type), max);
+    }
+  return NULL_TREE;
+}
+
+// Return the minimum value for TYPE.
+
+inline tree
+vrp_val_min (const_tree type)
+{
+  if (INTEGRAL_TYPE_P (type))
+    return TYPE_MIN_VALUE (type);
+  if (POINTER_TYPE_P (type))
+    return build_zero_cst (const_cast<tree> (type));
+  return NULL_TREE;
+}
+
 #endif // GCC_VALUE_RANGE_H
diff --git a/gcc/vr-values.c b/gcc/vr-values.c
index d0303599002..609375c072e 100644
--- a/gcc/vr-values.c
+++ b/gcc/vr-values.c
@@ -92,7 +92,8 @@  vr_values::get_lattice_entry (const_tree var)
     return vr;
 
   /* Create a default value range.  */
-  vr_value[ver] = vr = vrp_value_range_pool.allocate ();
+  vr = new (vrp_value_range_pool.allocate ()) value_range_equiv;
+  vr_value[ver] = vr;
 
   /* After propagation finished return varying.  */
   if (values_propagated)