On Tue, 15 Oct 2024, Jakub Jelinek wrote:
> On Mon, Oct 14, 2024 at 08:53:29AM +0200, Jakub Jelinek wrote:
> > > PR middle-end/116891
> > > * match.pd ((negate (IFN_FNMS@3 @0 @1 @2)) -> (IFN_FMA @0 @1 @2)):
> > > Only enable for !HONOR_SIGN_DEPENDENT_ROUNDING.
> >
> > Guess it would be nice to have a testcase which FAILs without the patch and
> > PASSes with it, but it can be added later.
>
> I've added such a testcase now, and additionally found the fix only fixed
> one of the 4 problematic similar cases.
>
> Here is a patch which fixes the others too and adds the testcases.
> fma-pr116891.c FAILed without your patch, FAILs with your patch too (but
> only due to the bar/baz/qux checks) and PASSes with the patch.
Whoops - I did search but for some reasons I was blind ...
> Ok for trunk if it passes full bootstrap/regtest?
OK.
Thanks a lot,
Richard.
> 2024-10-15 Jakub Jelinek <ja...@redhat.com>
>
> PR middle-end/116891
> * match.pd ((negate (fmas@3 @0 @1 @2)) -> (IFN_FNMS @0 @1 @2)):
> Only enable for !HONOR_SIGN_DEPENDENT_ROUNDING.
> ((negate (IFN_FMS@3 @0 @1 @2)) -> (IFN_FNMA @0 @1 @2)): Likewise.
> ((negate (IFN_FNMA@3 @0 @1 @2)) -> (IFN_FMS @0 @1 @2)): Likewise.
>
> * gcc.dg/pr116891.c: New test.
> * gcc.target/i386/fma-pr116891.c: New test.
>
> --- gcc/match.pd.jj 2024-10-15 12:50:47.699905473 +0200
> +++ gcc/match.pd 2024-10-15 12:57:19.547400416 +0200
> @@ -9452,7 +9452,7 @@ (define_operator_list SYNC_FETCH_AND_AND
> (IFN_FNMS @0 @1 @2))
> (simplify
> (negate (fmas@3 @0 @1 @2))
> - (if (single_use (@3))
> + (if (!HONOR_SIGN_DEPENDENT_ROUNDING (type) && single_use (@3))
> (IFN_FNMS @0 @1 @2))))
>
> (simplify
> @@ -9466,7 +9466,7 @@ (define_operator_list SYNC_FETCH_AND_AND
> (IFN_FNMA @0 @1 @2))
> (simplify
> (negate (IFN_FMS@3 @0 @1 @2))
> - (if (single_use (@3))
> + (if (!HONOR_SIGN_DEPENDENT_ROUNDING (type) && single_use (@3))
> (IFN_FNMA @0 @1 @2)))
>
> (simplify
> @@ -9480,7 +9480,7 @@ (define_operator_list SYNC_FETCH_AND_AND
> (IFN_FMS @0 @1 @2))
> (simplify
> (negate (IFN_FNMA@3 @0 @1 @2))
> - (if (single_use (@3))
> + (if (!HONOR_SIGN_DEPENDENT_ROUNDING (type) && single_use (@3))
> (IFN_FMS @0 @1 @2)))
>
> (simplify
> --- gcc/testsuite/gcc.dg/pr116891.c.jj 2024-10-15 12:31:57.619723244
> +0200
> +++ gcc/testsuite/gcc.dg/pr116891.c 2024-10-15 12:56:37.809987933 +0200
> @@ -0,0 +1,47 @@
> +/* PR middle-end/116891 */
> +/* { dg-do run } */
> +/* { dg-require-effective-target fenv } */
> +/* { dg-require-effective-target hard_float } */
> +/* { dg-require-effective-target c99_runtime } */
> +/* { dg-options "-O2 -frounding-math" } */
> +
> +#include <fenv.h>
> +
> +__attribute__((noipa)) double
> +foo (double x, double y, double z)
> +{
> + return -__builtin_fma (-x, y, -z);
> +}
> +
> +__attribute__((noipa)) double
> +bar (double x, double y, double z)
> +{
> + return -__builtin_fma (-x, y, z);
> +}
> +
> +__attribute__((noipa)) double
> +baz (double x, double y, double z)
> +{
> + return -__builtin_fma (x, y, -z);
> +}
> +
> +__attribute__((noipa)) double
> +qux (double x, double y, double z)
> +{
> + return -__builtin_fma (x, y, z);
> +}
> +
> +int
> +main ()
> +{
> +#if defined (FE_DOWNWARD) && __DBL_MANT_DIG__ == 53 && __DBL_MAX_EXP__ ==
> 1024
> + fesetround (FE_DOWNWARD);
> + double a = foo (-0x1.p256, 0x1.p256, 0x1.p-256);
> + if (a != -__builtin_nextafter (0x1p256 * 0x1p256, 0.))
> + __builtin_abort ();
> + if (a != bar (-0x1.p256, 0x1.p256, -0x1.p-256)
> + || a != baz (0x1.p256, 0x1.p256, 0x1.p-256)
> + || a != qux (0x1.p256, 0x1.p256, -0x1.p-256))
> + __builtin_abort ();
> +#endif
> +}
> --- gcc/testsuite/gcc.target/i386/fma-pr116891.c.jj 2024-10-15
> 12:42:39.711719596 +0200
> +++ gcc/testsuite/gcc.target/i386/fma-pr116891.c 2024-10-15
> 12:44:56.692806834 +0200
> @@ -0,0 +1,19 @@
> +/* PR middle-end/116891 */
> +/* { dg-do run } */
> +/* { dg-require-effective-target fenv } */
> +/* { dg-require-effective-target hard_float } */
> +/* { dg-require-effective-target c99_runtime } */
> +/* { dg-require-effective-target fma } */
> +/* { dg-options "-O2 -mfma -frounding-math" } */
> +
> +#include <fenv.h>
> +#include "fma-check.h"
> +
> +#define main() do_main ()
> +#include "../../gcc.dg/pr116891.c"
> +
> +static void
> +fma_test (void)
> +{
> + do_main ();
> +}
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
