[cris-decc0,14/14] cris: Enable "neg" to set condition codes.

Message ID 202002120705.01C757jv027193@ignucius.se.axis.com
State New
Headers show
Series
  • Untitled series #22648
Related show

Commit Message

Hans-Peter Nilsson Feb. 12, 2020, 7:05 a.m.
* config/cris/cris.c (cris_select_cc_mode): Return CC_NZmode for
NEG too.  Correct comment.
* config/cris/cris.md ("<anz>neg<mode>2<setnz>"): Rename from
"neg<mode>2".

While gcc seems to prefer transforming tests on the result of
reversible operations, into tests on the original, it also can
work with the destination, if allocated to the same register as
it commonly-enough is.  The re-use is easily covered in a
test-case.  (N.B.: the value 0x80000000 appears to be considered
invalid and unimportant.)  Spotted as a "microregression" in
libgcc when comparing to the cc0 version.
---
 gcc/config/cris/cris.c  | 8 ++++----
 gcc/config/cris/cris.md | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

-- 
2.11.0

brgds, H-P

Patch

diff --git a/gcc/config/cris/cris.c b/gcc/config/cris/cris.c
index d0807adc8..2bad9393c 100644
--- a/gcc/config/cris/cris.c
+++ b/gcc/config/cris/cris.c
@@ -1531,9 +1531,9 @@  cris_select_cc_mode (enum rtx_code op, rtx x, rtx y)
     return CCmode;
 
   /* If we have a comparison that doesn't have to look at V or C, check
-     operand x; if it looks like a binary operator, return CC_NZmode,
-     else CCmode, so we only use CC_NZmode for the cases where we don't
-     actually have both V and C valid.  */
+     operand x; if it's a valid operator, return CC_NZmode, else CCmode,
+     so we only use CC_NZmode for the cases where we don't actually have
+     both V and C valid.  */
   if (op == EQ || op ==  NE || op ==  GTU || op ==  LEU
       || op ==  LT || op ==  GE)
     {
@@ -1542,7 +1542,7 @@  cris_select_cc_mode (enum rtx_code op, rtx x, rtx y)
     /* Mentioning the rtx_code here is required but not sufficient: the
        insn also needs to be decorated with <setnz> (and the
        anonymization prefix <anz> for a named pattern).  */
-      return e == PLUS || e == MINUS || e == MULT || e == NOT
+      return e == PLUS || e == MINUS || e == MULT || e == NOT || e == NEG
 	? CC_NZmode : CCmode;
     }
 
diff --git a/gcc/config/cris/cris.md b/gcc/config/cris/cris.md
index 1e895a375..081041fa2 100644
--- a/gcc/config/cris/cris.md
+++ b/gcc/config/cris/cris.md
@@ -1734,7 +1734,7 @@  (define_insn "*expanded_negsf2"
 ;; No "negdi2" although we could make one up that may be faster than
 ;; the one in libgcc.
 
-(define_insn "neg<mode>2"
+(define_insn "<anz>neg<mode>2<setnz>"
   [(set (match_operand:BWD 0 "register_operand" "=r")
 	(neg:BWD (match_operand:BWD 1 "register_operand" "r")))
    (clobber (reg:CC CRIS_CC0_REGNUM))]