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From: "liuhongt at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/115069] [14/15 regression] 8 bit integer vector performance regression, x86, between gcc-14 and gcc-13 using avx2 target clones on skylake platform
Date: Mon, 20 May 2024 06:35:01 +0000 [thread overview]
Message-ID: <bug-115069-4-P8fuZeDpeW@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-115069-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115069
--- Comment #14 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
(In reply to Uroš Bizjak from comment #13)
> (In reply to Haochen Jiang from comment #12)
> > (In reply to Hongtao Liu from comment #11)
> > > (In reply to Haochen Jiang from comment #10)
> > > > A patch like Comment 8 could definitely solve the problem. But I need to
> > > > test more benchmarks to see if there is surprise.
> > > >
> > > > But, yes, as Uros said in Comment 9, maybe there is a chance we could do it
> > > > better.
> > >
> > > Could you add "arch=skylake-avx512" to target_clones and try disable whole
> > > ix86_expand_vecop_qihi2 to see if there's any performance improvement?
> > > For x86, cross-lane permutation(truncation) is not very efficient(3-4 cycles
> > > for both vpermq and vpmovwb).
> >
> > When I disable/enable ix86_expand_vecop_qihi2 with arch=skylake-avx512 on
> > trunk, there is no performance regression comparing to GCC13 + avx2.
> >
> > It seems that the regression only happens when GCC14 + avx2.
>
> This is what the patch in Comment #8 prevents. skylake-avx512 enables
> TARGET_AVX512BW, so VPMOVB is emitted instead of problematic VPERMQ.
Yes, the patch looks good to me.
next prev parent reply other threads:[~2024-05-20 6:35 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-13 13:05 [Bug target/115069] New: " colin.king at intel dot com
2024-05-13 13:07 ` [Bug target/115069] " colin.king at intel dot com
2024-05-13 13:07 ` colin.king at intel dot com
2024-05-15 8:51 ` haochen.jiang at intel dot com
2024-05-16 1:49 ` [Bug target/115069] [14/15 regression] " sjames at gcc dot gnu.org
2024-05-17 6:59 ` kkanas at fastmail dot com
2024-05-17 7:06 ` liuhongt at gcc dot gnu.org
2024-05-17 7:08 ` haochen.jiang at intel dot com
2024-05-17 8:26 ` ubizjak at gmail dot com
2024-05-17 8:41 ` ubizjak at gmail dot com
2024-05-17 8:48 ` ubizjak at gmail dot com
2024-05-17 9:13 ` haochen.jiang at intel dot com
2024-05-20 1:23 ` liuhongt at gcc dot gnu.org
2024-05-20 5:50 ` haochen.jiang at intel dot com
2024-05-20 6:27 ` ubizjak at gmail dot com
2024-05-20 6:35 ` liuhongt at gcc dot gnu.org [this message]
2024-05-20 6:38 ` haochen.jiang at intel dot com
2024-05-20 6:40 ` liuhongt at gcc dot gnu.org
2024-05-20 6:47 ` ubizjak at gmail dot com
2024-05-21 5:56 ` haochen.jiang at intel dot com
2024-05-21 5:58 ` haochen.jiang at intel dot com
2024-05-22 2:25 ` cvs-commit at gcc dot gnu.org
2024-05-22 2:27 ` cvs-commit at gcc dot gnu.org
2024-05-22 2:27 ` haochen.jiang at intel dot com
2024-05-22 5:13 ` liuhongt at gcc dot gnu.org
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