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From: Hongtao Liu <crazylht@gmail.com>
To: Richard Biener <rguenther@suse.de>
Cc: "sunil.k.pandey" <skpandey@sc.intel.com>,
	Richard Sandiford <richard.sandiford@arm.com>,
	 GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [r12-3893 Regression] FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4 on Linux/x86_64
Date: Tue, 28 Sep 2021 15:43:52 +0800	[thread overview]
Message-ID: <CAMZc-bzj_otU3SZnCBsVqdB_FdxN95wmCYQnUbh-eMtYr7EyKg@mail.gmail.com> (raw)
In-Reply-To: <543s464s-6282-so3o-rqr2-o9o78851o1@fhfr.qr>

On Tue, Sep 28, 2021 at 2:59 PM Richard Biener via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Mon, 27 Sep 2021, sunil.k.pandey wrote:
>
> > On Linux/x86_64,
> >
> > 6390c5047adb75960f86d56582e6322aaa4d9281 is the first bad commit
> > commit 6390c5047adb75960f86d56582e6322aaa4d9281
> > Author: Richard Biener <rguenther@suse.de>
> > Date:   Wed Nov 18 09:36:57 2020 +0100
> >
> >     Allow different vector types for stmt groups
> >
> > caused
> >
> > FAIL: gcc.dg/vect/bb-slp-17.c -flto -ffat-lto-objects  scan-tree-dump-times slp2 "optimized: basic block" 1
> > FAIL: gcc.dg/vect/bb-slp-17.c scan-tree-dump-times slp2 "optimized: basic block" 1
>
> This shows that it is maybe a bad idea to support V2SImode vectorization
> with -m32 when we refuse to implement even plus.
>
> OTOH it's just the mode that's available, autovectorize_vector_modes
> doesn't include the corresponding mode but we still pick it up via
> the related vector mode for group-size == 2.
>
> > FAIL: gcc.dg/vect/bb-slp-pr65935.c -flto -ffat-lto-objects  scan-tree-dump-times slp1 "optimized: basic block" 10
> > FAIL: gcc.dg/vect/bb-slp-pr65935.c scan-tree-dump-times slp1 "optimized: basic block" 10
>
> We are now vectorizing the SSE tail when vectorizing with AVX.  I'll
> adjust the testcase to prefer SSE.
>
> > FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4
>
> With -mach=cascadelake we get
>
>         vpermpd $68, c, %ymm0
>         vpermpd $238, c, %ymm0
>
> instead of
>
>         vmovapd c, %ymm1
>         vinsertf128     $1, %xmm1, %ymm1, %ymm0
>         vperm2f128      $49, %ymm1, %ymm1, %ymm0
>
> what's a way to disallow additional -march= from taking effect?  It's
I usually add -mno-{avx,avx512f} and -mtune=generic or sometimes
-mprefer-vector-width=* to the testcases.
or use (?:vinsertf128|vpermpd) for alternative instructions.
> really impossible to cater for all possible ISA variants in these kind
> of testcases.
Additional option -march=cascadelake sometimes can find real regression.
>
> Richard.



-- 
BR,
Hongtao

  reply	other threads:[~2021-09-28  7:37 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-27 18:28 sunil.k.pandey
2021-09-28  6:59 ` Richard Biener
2021-09-28  7:43   ` Hongtao Liu [this message]
2021-09-28  8:02     ` Richard Biener
2021-09-28  8:18       ` Richard Biener

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