[r15-4787 Regression] FAIL: gcc.dg/vect/bb-slp-77.c scan-tree-dump-times slp1 "optimized: basic block" 1 on Linux/x86_64

[haochen.jiang]

On Linux/x86_64,

acba8b3d8dec0124c8b3a7e112b3a784a5091214 is the first bad commit
commit acba8b3d8dec0124c8b3a7e112b3a784a5091214
Author: Kugan Vivekanandarajah <kvivekananda@nvidia.com>
Date:   Thu Oct 31 07:23:10 2024 +1100

    [PATCH] Fix SLP when ifcvt versioned loop is not vectorized

caused

FAIL: gcc.dg/vect/bb-slp-77.c -flto -ffat-lto-objects  scan-tree-dump-times slp1 "optimized: basic block" 1
FAIL: gcc.dg/vect/bb-slp-77.c scan-tree-dump-times slp1 "optimized: basic block" 1

with GCC configured with

../../gcc/configure --prefix=/export/users/haochenj/src/gcc-bisect/master/master/r15-4787/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="vect.exp=gcc.dg/vect/bb-slp-77.c --target_board='unix{-m32}'"
$ cd {build_dir}/gcc && make check RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-77.c --target_board='unix{-m32\ -march=cascadelake}'"
$ cd {build_dir}/gcc && make check RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-77.c --target_board='unix{-m64}'"
$ cd {build_dir}/gcc && make check RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-77.c --target_board='unix{-m64\ -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.)