[r15-6361 Regression] FAIL: gcc.dg/field-merge-16.c scan-tree-dump-times ifcombine "optimizing" 6 on Linux/x86_64

[haochen.jiang]

On Linux/x86_64,

87f97ffba93a2de17eca3927af901e3b3a103df7 is the first bad commit
commit 87f97ffba93a2de17eca3927af901e3b3a103df7
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Wed Dec 18 22:17:31 2024 -0300

    ifcombine field merge: handle masks with sign extensions

caused

FAIL: gcc.dg/field-merge-16.c scan-tree-dump-times ifcombine "optimizing" 6

with GCC configured with

../../gcc/configure --prefix=/export/users/haochenj/src/gcc-bisect/master/master/r15-6361/usr --enable-clocale=gnu --with-system-zlib --with-demangler-in-ld --with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl --enable-libmpx x86_64-linux --disable-bootstrap

To reproduce:

$ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gcc.dg/field-merge-16.c --target_board='unix{-m32}'"
$ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gcc.dg/field-merge-16.c --target_board='unix{-m32\ -march=cascadelake}'"

(Please do not reply to this email, for question about this report, contact me at haochen dot jiang at intel.com.)
(If you met problems with cascadelake related, disabling AVX512F in command line might save that.)
(However, please make sure that there is no potential problems with AVX512.)