RE: [PATCH v3] i386: Disable ix86_expand_vecop_qihi2 when !TARGET_AVX512BW

["Jiang, Haochen" <haochen.jiang@intel.com>]

> -----Original Message-----
> From: Uros Bizjak <ubizjak@gmail.com>
> Sent: Tuesday, May 21, 2024 9:04 PM
> To: Jiang, Haochen <haochen.jiang@intel.com>
> Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao <hongtao.liu@intel.com>
> Subject: Re: [PATCH v3] i386: Disable ix86_expand_vecop_qihi2
> when !TARGET_AVX512BW
> 
> On Tue, May 21, 2024 at 11:01 AM Haochen Jiang
> <haochen.jiang@intel.com> wrote:
> >
> > Hi all,
> >
> > This is the v3 patch to fix PR115069. The new testcase has passed.
> >
> > Changes in v3:
> >   - Simplify the testcase.
> >
> > Changes in v2:
> >   - Add a testcase.
> >   - Change the comment for the early exit.
> >
> > Thx,
> > Haochen
> >
> > Since vpermq is really slow, we should avoid using it for permutation
> > when vpmovwb is not available (needs AVX512BW) for
> ix86_expand_vecop_qihi2
> > and fall back to ix86_expand_vecop_qihi.
> >
> > gcc/ChangeLog:
> >
> >         PR target/115069
> >         * config/i386/i386-expand.cc (ix86_expand_vecop_qihi2):
> >         Do not enable the optimization when AVX512BW is not enabled.
> >
> > gcc/testsuite/ChangeLog:
> >
> >         PR target/115069
> >         * gcc.target/i386/pr115069.c: New.
> 
> LGTM, with a nit below.

Ok and I will also backport the patch to GCC14.

Thx,
Haochen

> 
> Thanks,
> Uros.