[PR,c++/85027] deal with baselink in save_expr in instantiate_type

Message ID or605e6m0n.fsf@lxoliva.fsfla.org
State New
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  • [PR,c++/85027] deal with baselink in save_expr in instantiate_type
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Commit Message

Alexandre Oliva March 30, 2018, 7:49 a.m.
We use SAVE_EXPRs in conditional expressions without the middle
operand, to evaluate the first operand only once.  When the conversion
of the first operand fails, we may call instantiate_type get a better
error message.  We have code to peel off the SAVE_EXPR there, but then
we may end up with a BASELINK, and we're past the code that deals with
BASELINKs.  Reorder the tests so that we expose the saved expr first,
and then deal with BASELINKs.

Regstrapped on i686- and x86_64-linux-gnu.  Ok to install?

for  gcc/cp/ChangeLog

	PR c++/85027
	* class.c (instantiate_type): Peel off SAVE_EXPR before
	BASELINK.

for  gcc/testsuite/ChangeLog

	PR c++/85027
	* g++.dg/pr85027.C: New.
---
 gcc/cp/class.c                 |   10 +++++-----
 gcc/testsuite/g++.dg/pr85027.C |    8 ++++++++
 2 files changed, 13 insertions(+), 5 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/pr85027.C



-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer

Comments

Jason Merrill March 30, 2018, 2:48 p.m. | #1
OK.

On Fri, Mar 30, 2018 at 3:49 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
> We use SAVE_EXPRs in conditional expressions without the middle

> operand, to evaluate the first operand only once.  When the conversion

> of the first operand fails, we may call instantiate_type get a better

> error message.  We have code to peel off the SAVE_EXPR there, but then

> we may end up with a BASELINK, and we're past the code that deals with

> BASELINKs.  Reorder the tests so that we expose the saved expr first,

> and then deal with BASELINKs.

>

> Regstrapped on i686- and x86_64-linux-gnu.  Ok to install?

>

> for  gcc/cp/ChangeLog

>

>         PR c++/85027

>         * class.c (instantiate_type): Peel off SAVE_EXPR before

>         BASELINK.

>

> for  gcc/testsuite/ChangeLog

>

>         PR c++/85027

>         * g++.dg/pr85027.C: New.

> ---

>  gcc/cp/class.c                 |   10 +++++-----

>  gcc/testsuite/g++.dg/pr85027.C |    8 ++++++++

>  2 files changed, 13 insertions(+), 5 deletions(-)

>  create mode 100644 gcc/testsuite/g++.dg/pr85027.C

>

> diff --git a/gcc/cp/class.c b/gcc/cp/class.c

> index debcaf21cf76..0427d1224f74 100644

> --- a/gcc/cp/class.c

> +++ b/gcc/cp/class.c

> @@ -7971,6 +7971,11 @@ instantiate_type (tree lhstype, tree rhs, tsubst_flags_t complain)

>         }

>      }

>

> +  /* If we instantiate a template, and it is a A ?: C expression

> +     with omitted B, look through the SAVE_EXPR.  */

> +  if (TREE_CODE (rhs) == SAVE_EXPR)

> +    rhs = TREE_OPERAND (rhs, 0);

> +

>    if (BASELINK_P (rhs))

>      {

>        access_path = BASELINK_ACCESS_BINFO (rhs);

> @@ -7986,11 +7991,6 @@ instantiate_type (tree lhstype, tree rhs, tsubst_flags_t complain)

>        return error_mark_node;

>      }

>

> -  /* If we instantiate a template, and it is a A ?: C expression

> -     with omitted B, look through the SAVE_EXPR.  */

> -  if (TREE_CODE (rhs) == SAVE_EXPR)

> -    rhs = TREE_OPERAND (rhs, 0);

> -

>    /* There are only a few kinds of expressions that may have a type

>       dependent on overload resolution.  */

>    gcc_assert (TREE_CODE (rhs) == ADDR_EXPR

> diff --git a/gcc/testsuite/g++.dg/pr85027.C b/gcc/testsuite/g++.dg/pr85027.C

> new file mode 100644

> index 000000000000..01b1b291aecd

> --- /dev/null

> +++ b/gcc/testsuite/g++.dg/pr85027.C

> @@ -0,0 +1,8 @@

> +// { dg-do compile }

> +

> +// Avoid -pedantic-error default

> +// { dg-options "" }

> +

> +struct A { static int a; };

> +

> +int t = A::A ? : 0; // { dg-error "cannot resolve" }

>

>

> --

> Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/

> You must be the change you wish to see in the world. -- Gandhi

> Be Free! -- http://FSFLA.org/   FSF Latin America board member

> Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer

Patch

diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index debcaf21cf76..0427d1224f74 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -7971,6 +7971,11 @@  instantiate_type (tree lhstype, tree rhs, tsubst_flags_t complain)
 	}
     }
 
+  /* If we instantiate a template, and it is a A ?: C expression
+     with omitted B, look through the SAVE_EXPR.  */
+  if (TREE_CODE (rhs) == SAVE_EXPR)
+    rhs = TREE_OPERAND (rhs, 0);
+
   if (BASELINK_P (rhs))
     {
       access_path = BASELINK_ACCESS_BINFO (rhs);
@@ -7986,11 +7991,6 @@  instantiate_type (tree lhstype, tree rhs, tsubst_flags_t complain)
       return error_mark_node;
     }
 
-  /* If we instantiate a template, and it is a A ?: C expression
-     with omitted B, look through the SAVE_EXPR.  */
-  if (TREE_CODE (rhs) == SAVE_EXPR)
-    rhs = TREE_OPERAND (rhs, 0);
-
   /* There are only a few kinds of expressions that may have a type
      dependent on overload resolution.  */
   gcc_assert (TREE_CODE (rhs) == ADDR_EXPR
diff --git a/gcc/testsuite/g++.dg/pr85027.C b/gcc/testsuite/g++.dg/pr85027.C
new file mode 100644
index 000000000000..01b1b291aecd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr85027.C
@@ -0,0 +1,8 @@ 
+// { dg-do compile }
+
+// Avoid -pedantic-error default
+// { dg-options "" }
+
+struct A { static int a; };
+
+int t = A::A ? : 0; // { dg-error "cannot resolve" }