match.pd: Further fma negation fixes [PR116891]

match.pd: Further fma negation fixes [PR116891]

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.

2024-10-15  Jakub Jelinek  <jakub@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.