[gcc r12-7647] Fix libitm.c/memset-1.c test fails with new peephole2s.

[gcc r12-7647] Fix libitm.c/memset-1.c test fails with new peephole2s.

[Roger Sayle]

https://gcc.gnu.org/g:6abc4e46f8c240aaab286414cdfb6d1e5eb9128a

commit r12-7647-g6abc4e46f8c240aaab286414cdfb6d1e5eb9128a
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Mon Mar 14 18:12:55 2022 +0000

    Fix libitm.c/memset-1.c test fails with new peephole2s.
    
    My sincere apologies for the breakage, but alas handling SImode in the
    recently added "xorl;movb -> movzbl" peephole2 turns out to be slightly
    more complicated that just using SWI48 as a mode iterator.  I'd failed
    to check the machine description carefully, but the *zero_extend<mode>si2
    define_insn is conditionally defined, based on x86 target tuning using
    TARGET_ZERO_EXTEND_WITH_AND, and therefore unavailable on 486 and pentium
    unless optimizing the code for size.  It turns out that the libitm testsuite
    specifies -m486 with make check RUNTESTFLAGS="--target_board='unix{-m32}'"
    and therefore encounters/catches oversight.
    
    Fixed by adding the appropriate conditions to the new peephole2 patterns.
    
    2022-03-14  Roger Sayle  <roger@nextmovesoftware.com>
                Uroš Bizjak  <ubizjak@gmail.com>
    
    gcc/ChangeLog
            * config/i386/i386.md (peephole2 xorl;movb -> movzbl): Disable
            transformation when *zero_extend<mode>si2 is not available.
    
    gcc/testsuite/ChangeLog
            * gcc.target/i386/pr98335.c: Skip this test if tuning for i486
            or pentium, and not optimizing for size.

Diff:
---
 gcc/config/i386/i386.md                 | 10 ++++++++--
 gcc/testsuite/gcc.target/i386/pr98335.c |  5 +++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index c8fbf605e41..46a266322d3 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -4316,7 +4316,10 @@
 	      (clobber (reg:CC FLAGS_REG))])
    (set (strict_low_part (match_operand:SWI12 1 "general_reg_operand"))
 	(match_operand:SWI12 2 "nonimmediate_operand"))]
-  "REGNO (operands[0]) == REGNO (operands[1])"
+  "REGNO (operands[0]) == REGNO (operands[1])
+   && (<SWI48:MODE>mode != SImode
+       || !TARGET_ZERO_EXTEND_WITH_AND
+       || !optimize_function_for_speed_p (cfun))"
   [(set (match_dup 0) (zero_extend:SWI48 (match_dup 2)))])
 
 ;; Likewise, but preserving FLAGS_REG.
@@ -4324,7 +4327,10 @@
   [(set (match_operand:SWI48 0 "general_reg_operand") (const_int 0))
    (set (strict_low_part (match_operand:SWI12 1 "general_reg_operand"))
 	(match_operand:SWI12 2 "nonimmediate_operand"))]
-  "REGNO (operands[0]) == REGNO (operands[1])"
+  "REGNO (operands[0]) == REGNO (operands[1])
+   && (<SWI48:MODE>mode != SImode
+       || !TARGET_ZERO_EXTEND_WITH_AND
+       || !optimize_function_for_speed_p (cfun))"
   [(set (match_dup 0) (zero_extend:SWI48 (match_dup 2)))])
 \f
 ;; Sign extension instructions
diff --git a/gcc/testsuite/gcc.target/i386/pr98335.c b/gcc/testsuite/gcc.target/i386/pr98335.c
index 7fa7ad70dce..bf731b4e387 100644
--- a/gcc/testsuite/gcc.target/i386/pr98335.c
+++ b/gcc/testsuite/gcc.target/i386/pr98335.c
@@ -1,5 +1,10 @@
 /* { dg-do compile } */
 /* { dg-options "-O2" } */
+/* { dg-skip-if "" { *-*-* } { "-march=i[45]86" } { "-O[sz]" } } */
+/* { dg-skip-if "" { *-*-* } { "-march=pentium" } { "-O[sz]" } } */
+/* { dg-skip-if "" { *-*-* } { "-mtune=i[45]86" } { "-O[sz]" } } */
+/* { dg-skip-if "" { *-*-* } { "-mtune=pentium" } { "-O[sz]" } } */
+
 union Data { char a; short b; };
 
 char c;