From: Uros Bizjak <ubizjak@gmail.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Kirill Yukhin <kirill.yukhin@gmail.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Tweak gcc.target/i386/avx2-vp{add,sub}q-3.c (PR target/82851)
Date: Thu, 22 Feb 2018 18:56:00 -0000 [thread overview]
Message-ID: <CAFULd4Y1UttzdqM2=N2ZmcouDmT=h-vdyNgvFvDw2P02F3856Q@mail.gmail.com> (raw)
In-Reply-To: <20180222181658.GW5867@tucnak>
On Thu, Feb 22, 2018 at 7:16 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> These tests FAIL the vp.*q.*ymm insn scan with some tunings, e.g.
> -mtune=silvermont or -mtune=atom, because vectorizing it using AVX2
> is based on costs considered too expensive.
> E.g. for -mtune=silvermont I see for VF 4:
>
> avx2-vpop-check.h:16:3: note: Cost model analysis:
> Vector inside of loop cost: 330
> Vector prologue cost: 0
> Vector epilogue cost: 0
> Scalar iteration cost: 48
> Scalar outside cost: 0
> Vector outside cost: 0
> prologue iterations: 0
> epilogue iterations: 0
> avx2-vpop-check.h:16:3: note: cost model: the vector iteration cost = 330 divided by the scalar iteration cost = 48 is greater or equal to the vect
> orization factor = 4.
> avx2-vpop-check.h:16:3: note: not vectorized: vectorization not profitable.
> avx2-vpop-check.h:16:3: note: not vectorized: vector version will never be profitable.
> avx2-vpop-check.h:16:3: note: ***** Re-trying analysis with vector size 16
>
> while with -mtune=generic I see:
>
> avx2-vpop-check.h:16:3: note: Cost model analysis:
> Vector inside of loop cost: 64
> Vector prologue cost: 0
> Vector epilogue cost: 0
> Scalar iteration cost: 40
> Scalar outside cost: 0
> Vector outside cost: 0
> prologue iterations: 0
> epilogue iterations: 0
> Calculated minimum iters for profitability: 0
>
> I think we can either use -mtune=generic as in the patch below,
> or add -fno-vect-cost-model.
>
> Tested on x86_64-linux with:
> make check-gcc RUNTESTFLAGS='--target_board=unix\{-m32,-m32/-mtune=silvermont,-m32/-mtune=atom,-m64,-m64/-mtune=silvermont,-m64/-mtune=atom\} i386.exp=avx2-vp*q-3.c'
> Ok for trunk?
>
> 2018-02-22 Jakub Jelinek <jakub@redhat.com>
>
> PR target/82851
> * gcc.target/i386/avx2-vpaddq-3.c: Add -mtune=generic to dg-options.
> * gcc.target/i386/avx2-vpsubq-3.c: Likewise.
OK.
Thanks,
Uros.
> --- gcc/testsuite/gcc.target/i386/avx2-vpaddq-3.c.jj 2015-05-29 15:02:59.475249515 +0200
> +++ gcc/testsuite/gcc.target/i386/avx2-vpaddq-3.c 2018-02-22 18:44:45.353178253 +0100
> @@ -1,5 +1,5 @@
> /* { dg-do run } */
> -/* { dg-options "-mavx2 -mno-prefer-avx128 -O2 -ftree-vectorize -save-temps" } */
> +/* { dg-options "-mavx2 -mno-prefer-avx128 -O2 -ftree-vectorize -mtune=generic -save-temps" } */
> /* { dg-require-effective-target avx2 } */
>
>
> --- gcc/testsuite/gcc.target/i386/avx2-vpsubq-3.c.jj 2015-05-29 15:03:00.572232560 +0200
> +++ gcc/testsuite/gcc.target/i386/avx2-vpsubq-3.c 2018-02-22 18:45:02.131168864 +0100
> @@ -1,5 +1,5 @@
> /* { dg-do run } */
> -/* { dg-options "-mavx2 -mno-prefer-avx128 -O2 -ftree-vectorize -save-temps" } */
> +/* { dg-options "-mavx2 -mno-prefer-avx128 -O2 -ftree-vectorize -mtune=generic -save-temps" } */
> /* { dg-require-effective-target avx2 } */
>
>
>
> Jakub
prev parent reply other threads:[~2018-02-22 18:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-22 18:49 Jakub Jelinek
2018-02-22 18:56 ` Uros Bizjak [this message]
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