Re: [r16-5526 Regression] FAIL: gcc.dg/vect/bb-slp-41.c scan-tree-dump-not slp1 "vectorizing stmts using SLP" on Linux/x86_64

[Kugan Vivekanandarajah]

Hi,

I can reproduce this on x86_64. The issue is that bb-slp-41.c expects BB 
vevtorization to not happen. Look like the original test case had other checks 
too that has since gone.
I have added -fno-tree-loop-im and tested to keep the behaviour the same. Is 
this OK?

Thanks,
Kugan



> On 23 Nov 2025, at 7:20 pm, Haochen Jiang <haochen.ji...@intel.com> wrote:
>
> External email: Use caution opening links or attachments
>
>
> On Linux/x86_64,
>
> ed1911b9f1f1ab0c1b631f0b6427b798c7056200 is the first bad commit
> commit ed1911b9f1f1ab0c1b631f0b6427b798c7056200
> Author: Kugan Vivekanandarajah <kvivekana...@nvidia.com>
> Date:   Sun Nov 23 15:27:10 2025 +1100
>
>    [tree-optimization] Allow LICM to hoist loads in "self write" patterns
>
> caused
>
> FAIL: gcc.dg/vect/bb-slp-41.c -flto -ffat-lto-objects  scan-tree-dump-not 
> slp1 "vectorizing stmts using SLP"
> FAIL: gcc.dg/vect/bb-slp-41.c scan-tree-dump-not slp1 "vectorizing stmts 
> using SLP"
>
> with GCC configured with
>
> ../../gcc/configure 
> --prefix=/export/users3/haochenj/src/gcc-bisect/master/master/r16-5526/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-41.c --target_board='unix{-m32}'"
> $ cd {build_dir}/gcc && make check 
> RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-41.c --target_board='unix{-m32\ 
> -march=cascadelake}'"
> $ cd {build_dir}/gcc && make check 
> RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-41.c --target_board='unix{-m64\ 
> -march=cascadelake}'"
>
> (Please directly reply to this email for question about this report.)
> (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.)

0001-TESTSUITE-bb-slp-41.c-Adjust-to-prevent-LICM-to-keep.patch
Description: 0001-TESTSUITE-bb-slp-41.c-Adjust-to-prevent-LICM-to-keep.patch