On 07 июл 09:06, H.J. Lu wrote:
> On Tue, Jul 7, 2020 at 8:56 AM Kirill Yukhin <kirill.yuk...@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.
--- /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).
Othwerwise LGTM.
--
K
>
> --
> H.J.
