Updated the fix in attachment. Is it OK for trunk?
Tested on aarch64-unknown-linux-gnu and x86_64-pc-linux-gnu.
Thanks,
Di Zhao
> -----Original Message-----
> From: Di Zhao OS <diz...@os.amperecomputing.com>
> Sent: Sunday, December 17, 2023 8:31 PM
> To: Thomas Schwinge <tho...@codesourcery.com>; gcc-patches@gcc.gnu.org
> Cc: Richard Biener <richard.guent...@gmail.com>
> Subject: RE: [PATCH v4] [tree-optimization/110279] Consider FMA in
> get_reassociation_width
>
> Hello Thomas,
>
> > -----Original Message-----
> > From: Thomas Schwinge <tho...@codesourcery.com>
> > Sent: Friday, December 15, 2023 5:46 PM
> > To: Di Zhao OS <diz...@os.amperecomputing.com>; gcc-patches@gcc.gnu.org
> > Cc: Richard Biener <richard.guent...@gmail.com>
> > Subject: RE: [PATCH v4] [tree-optimization/110279] Consider FMA in
> > get_reassociation_width
> >
> > Hi!
> >
> > On 2023-12-13T08:14:28+0000, Di Zhao OS <diz...@os.amperecomputing.com>
> wrote:
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.dg/pr110279-2.c
> > > @@ -0,0 +1,41 @@
> > > +/* PR tree-optimization/110279 */
> > > +/* { dg-do compile } */
> > > +/* { dg-options "-Ofast --param tree-reassoc-width=4 --param fully-
> > pipelined-fma=1 -fdump-tree-reassoc2-details -fdump-tree-optimized" } */
> > > +/* { dg-additional-options "-march=armv8.2-a" { target aarch64-*-* } } */
> > > +
> > > +#define LOOP_COUNT 800000000
> > > +typedef double data_e;
> > > +
> > > +#include <stdio.h>
> > > +
> > > +__attribute_noinline__ data_e
> > > +foo (data_e in)
> >
> > Pushed to master branch commit 91e9e8faea4086b3b8aef2355fc12c1559d425f6
> > "Fix 'gcc.dg/pr110279-2.c' syntax error due to '__attribute_noinline__'",
> > see attached.
> >
> > However:
> >
> > > +{
> > > + data_e a1, a2, a3, a4;
> > > + data_e tmp, result = 0;
> > > + a1 = in + 0.1;
> > > + a2 = in * 0.1;
> > > + a3 = in + 0.01;
> > > + a4 = in * 0.59;
> > > +
> > > + data_e result2 = 0;
> > > +
> > > + for (int ic = 0; ic < LOOP_COUNT; ic++)
> > > + {
> > > + /* Test that a complete FMA chain with length=4 is not broken. */
> > > + tmp = a1 + a2 * a2 + a3 * a3 + a4 * a4 ;
> > > + result += tmp - ic;
> > > + result2 = result2 / 2 - tmp;
> > > +
> > > + a1 += 0.91;
> > > + a2 += 0.1;
> > > + a3 -= 0.01;
> > > + a4 -= 0.89;
> > > +
> > > + }
> > > +
> > > + return result + result2;
> > > +}
> > > +
> > > +/* { dg-final { scan-tree-dump-not "was chosen for reassociation"
> > "reassoc2"} } */
> > > +/* { dg-final { scan-tree-dump-times {\.FMA } 3 "optimized"} } */
>
> Thank you for the fix.
>
> > ..., I still see these latter two tree dump scans FAIL, for GCN:
> >
> > $ grep -C2 'was chosen for reassociation' pr110279-2.c.197t.reassoc2
> > 2 *: a3_40
> > 2 *: a2_39
> > Width = 4 was chosen for reassociation
> > Transforming _15 = powmult_1 + powmult_3;
> > into _63 = powmult_1 + a1_38;
> > $ grep -F .FMA pr110279-2.c.265t.optimized
> > _63 = .FMA (a2_39, a2_39, a1_38);
> > _64 = .FMA (a3_40, a3_40, powmult_5);
> >
> > ..., nvptx:
> >
> > $ grep -C2 'was chosen for reassociation' pr110279-2.c.197t.reassoc2
> > 2 *: a3_40
> > 2 *: a2_39
> > Width = 4 was chosen for reassociation
> > Transforming _15 = powmult_1 + powmult_3;
> > into _63 = powmult_1 + a1_38;
> > $ grep -F .FMA pr110279-2.c.265t.optimized
> > _63 = .FMA (a2_39, a2_39, a1_38);
> > _64 = .FMA (a3_40, a3_40, powmult_5);
>
> For these 2 targets, the reassoc_width for FMUL is 1 (default value),
> While the testcase assumes that to be 4. The bug was introduced when I
> updated the patch but forgot to update the testcase.
>
> > ..., but also x86_64-pc-linux-gnu:
> >
> > $ grep -C2 'was chosen for reassociation' pr110279-2.c.197t.reassoc2
> > 2 *: a3_40
> > 2 *: a2_39
> > Width = 2 was chosen for reassociation
> > Transforming _15 = powmult_1 + powmult_3;
> > into _63 = powmult_1 + powmult_3;
> > $ grep -cF .FMA pr110279-2.c.265t.optimized
> > 0
>
> For x86_64 this needs "-mfma". Sorry the compile options missed that.
> Can the change below fix these issues? I moved them into
> testsuite/gcc.target/aarch64, since they rely on tunings.
>
> Tested on aarch64-unknown-linux-gnu.
>
> >
> > Grüße
> > Thomas
> >
> >
> > -----------------
> > Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201,
> 80634
> > München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas
> > Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht
> > München, HRB 106955
>
> Thanks,
> Di Zhao
>
> ---
> gcc/testsuite/{gcc.dg => gcc.target/aarch64}/pr110279-1.c | 3 +--
> gcc/testsuite/{gcc.dg => gcc.target/aarch64}/pr110279-2.c | 3 +--
> 2 files changed, 2 insertions(+), 4 deletions(-)
> rename gcc/testsuite/{gcc.dg => gcc.target/aarch64}/pr110279-1.c (83%)
> rename gcc/testsuite/{gcc.dg => gcc.target/aarch64}/pr110279-2.c (78%)
>
> diff --git a/gcc/testsuite/gcc.dg/pr110279-1.c
> b/gcc/testsuite/gcc.target/aarch64/pr110279-1.c
> similarity index 83%
> rename from gcc/testsuite/gcc.dg/pr110279-1.c
> rename to gcc/testsuite/gcc.target/aarch64/pr110279-1.c
> index f25b6aec967..97d693f56a5 100644
> --- a/gcc/testsuite/gcc.dg/pr110279-1.c
> +++ b/gcc/testsuite/gcc.target/aarch64/pr110279-1.c
> @@ -1,6 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-Ofast --param avoid-fma-max-bits=512 --param tree-reassoc-
> width=4 -fdump-tree-widening_mul-details" } */
> -/* { dg-additional-options "-march=armv8.2-a" { target aarch64-*-* } } */
> +/* { dg-options "-Ofast -mcpu=generic --param avoid-fma-max-bits=512 --param
> tree-reassoc-width=4 -fdump-tree-widening_mul-details" } */
>
> #define LOOP_COUNT 800000000
> typedef double data_e;
> diff --git a/gcc/testsuite/gcc.dg/pr110279-2.c
> b/gcc/testsuite/gcc.target/aarch64/pr110279-2.c
> similarity index 78%
> rename from gcc/testsuite/gcc.dg/pr110279-2.c
> rename to gcc/testsuite/gcc.target/aarch64/pr110279-2.c
> index b6b69969c6b..a88cb361fdc 100644
> --- a/gcc/testsuite/gcc.dg/pr110279-2.c
> +++ b/gcc/testsuite/gcc.target/aarch64/pr110279-2.c
> @@ -1,7 +1,6 @@
> /* PR tree-optimization/110279 */
> /* { dg-do compile } */
> -/* { dg-options "-Ofast --param tree-reassoc-width=4 --param fully-pipelined-
> fma=1 -fdump-tree-reassoc2-details -fdump-tree-optimized" } */
> -/* { dg-additional-options "-march=armv8.2-a" { target aarch64-*-* } } */
> +/* { dg-options "-Ofast -mcpu=generic --param tree-reassoc-width=4 --param
> fully-pipelined-fma=1 -fdump-tree-reassoc2-details -fdump-tree-optimized" } */
>
> #define LOOP_COUNT 800000000
> typedef double data_e;
> --
> 2.25.1
0001-Fix-compile-options-of-pr110279-1.c-and-pr110279-2.c.patch
Description: 0001-Fix-compile-options-of-pr110279-1.c-and-pr110279-2.c.patch
