From: Jakub Jelinek <jakub@redhat.com>
To: Kirill Yukhin <kirill.yukhin@gmail.com>, Uros Bizjak <ubizjak@gmail.com>
Cc: gcc-patches@gcc.gnu.org
Subject: [PATCH] Tweak gcc.target/i386/avx2-vp{add,sub}q-3.c (PR target/82851)
Date: Thu, 22 Feb 2018 18:49:00 -0000 [thread overview]
Message-ID: <20180222181658.GW5867@tucnak> (raw)
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.
--- 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
next reply other threads:[~2018-02-22 18:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-22 18:49 Jakub Jelinek [this message]
2018-02-22 18:56 ` Uros Bizjak
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