[PATCH] x86: Check TARGET_AVX512VL when enabling FMA

[H.J. Lu]

On Thu, Jul 9, 2020 at 6:35 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Thu, Jul 9, 2020 at 5:04 AM Kirill Yukhin <kirill.yukhin@gmail.com> wrote:
> >
> > On 07 июл 09:06, H.J. Lu wrote:
> > > On Tue, Jul 7, 2020 at 8:56 AM Kirill Yukhin <kirill.yukhin@gmail.com> wrote:
> > > >
> > > > Hello HJ,
> > > >
> > > > On 28 июн 07:19, H.J. Lu via Gcc-patches wrote:
> > > > > Enable FMA in rsqrt<mode>2 expander and fold rsqrtv16sf2 expander into
> > > > > rsqrt<mode>2 expander which expands to UNSPEC_RSQRT28 for TARGET_AVX512ER.
> > > > > Although it doesn't show performance change in our workloads, FMA can
> > > > > improve other workloads.
> > > > >
> > > > > gcc/
> > > > >
> > > > >       PR target/88713
> > > > >       * config/i386/i386-expand.c (ix86_emit_swsqrtsf): Enable FMA.
> > > > >       * config/i386/sse.md (VF_AVX512VL_VF1_128_256): New.
> > > > >       (rsqrt<mode>2): Replace VF1_128_256 with VF_AVX512VL_VF1_128_256.
> > > > >       (rsqrtv16sf2): Removed.
> > > > >
> > > > > gcc/testsuite/
> > > > >
> > > > >       PR target/88713
> > > > >       * gcc.target/i386/pr88713-1.c: New test.
> > > > >       * gcc.target/i386/pr88713-2.c: Likewise.
> > > >
> > > > So, you've introduced new rsqrt expanders for DF vectors and relaxed
> > > > condition for V16SF. What I didn't get is why did you change unspec
> > > > type from RSQRT to RSQRT28 for V16SF expander?
> > > >
> > >
> > > UNSPEC in define_expand is meaningless when the pattern is fully
> > > expanded by ix86_emit_swsqrtsf.  I believe that UNSPEC in rsqrt<mode>2
> > > expander can be removed.
> >
> > Agree.
>
> I will leave UNSPEC alone here.
>
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr88713-1.c
> > @@ -0,0 +1,13 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -Ofast -mno-avx512f -mfma" } */
> >
> > I gues -O2 is useless here (and in -2.c test).
>
> Fixed.
>
> > Othwerwise LGTM.
> >
>
> This is the patch I am checking in.
>

This patch is needed for

FAIL: gcc.target/i386/avx512er-vrsqrt28ps-3.c (internal compiler error)
FAIL: gcc.target/i386/avx512er-vrsqrt28ps-3.c (test for excess errors)
FAIL: gcc.target/i386/avx512er-vrsqrt28ps-4.c (internal compiler error)
FAIL: gcc.target/i386/avx512er-vrsqrt28ps-4.c (test for excess errors)
FAIL: gcc.target/i386/avx512er-vrsqrt28ps-5.c (internal compiler error)
FAIL: gcc.target/i386/avx512er-vrsqrt28ps-5.c (test for excess errors)
FAIL: gcc.target/i386/avx512er-vrsqrt28ps-6.c (internal compiler error)
FAIL: gcc.target/i386/avx512er-vrsqrt28ps-6.c (test for excess errors)

-- 
H.J.
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