Re: [PATCH]i386: Optimize pmovskb on zero_extend of subreg HI of the result [PR98461]

[Hongtao Liu <crazylht@gmail.com>]

On Mon, Jan 4, 2021 at 3:40 PM Uros Bizjak <ubizjak@gmail.com> wrote:
>
> On Mon, Jan 4, 2021 at 6:54 AM Hongtao Liu <crazylht@gmail.com> wrote:
> >
> > Hi:
> >   The following patch adds define_insn_and_split to optimize
> >
> >        vpmovmskb       %xmm0, %eax
> > -       movzwl  %ax, %eax
> >         notl    %eax
> >
> >   Bootstrapped/regtested on x86_64-linux-gnu {,-m32}.
> >   Ok for trunk?
> >
> > gcc/ChangeLog
> >         PR target/98461
> >         * config/i386/sse.md (*sse2_pmovskb_zexthisi): New
> >         define_insn_and_split for zero_extend of subreg HI of pmovskb
> >         result.
> >
> > gcc/testsuite/ChangeLog
> >         * gcc.target/i386/sse-pr98461-2.c: New test.
> > ---
> >  gcc/config/i386/sse.md                         | 11 +++++++++++
> >  gcc/testsuite/gcc.target/i386/sse2-pr98461-2.c | 13 +++++++++++++
> >  2 files changed, 24 insertions(+)
> >  create mode 100644 gcc/testsuite/gcc.target/i386/sse2-pr98461-2.c
> >
> > diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
> > index d84103807ff..4ed6b9ae476 100644
> > --- a/gcc/config/i386/sse.md
> > +++ b/gcc/config/i386/sse.md
> > @@ -16099,6 +16099,17 @@ (define_insn "*sse2_pmovmskb_ext"
> >     (set_attr "prefix" "maybe_vex")
> >     (set_attr "mode" "SI")])
> >
> > +(define_insn_and_split "*sse2_pmovskb_zexthisi"
> > +  [(set (match_operand:SI 0 "register_operand")
> > +       (zero_extend:SI (subreg:HI (unspec:SI
> > +         [(match_operand:V16QI 1 "register_operand")]
> > +          UNSPEC_MOVMSK) 0)))]
> > +  "TARGET_SSE2"
>
> This needs ix86_pre_reload_split () in insn predicate.
>

Yes, there's subreg in the pattern.
Assume patch is pre-approved with that change and
regtested/bootstrapped on x86_64-linux-gnu{-m32,}.

> Uros.
>
> > +  "#"
> > +  "&& 1"
> > +  [(set (match_dup 0)
> > +       (unspec:SI [(match_dup 1)] UNSPEC_MOVMSK))])
> > +
> >  (define_split
> >    [(set (match_operand:SI 0 "register_operand")
> >         (unspec:SI
> > diff --git a/gcc/testsuite/gcc.target/i386/sse2-pr98461-2.c
> > b/gcc/testsuite/gcc.target/i386/sse2-pr98461-2.c
> > new file mode 100644
> > index 00000000000..60fc1f3e9c1
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/sse2-pr98461-2.c
> > @@ -0,0 +1,13 @@
> > +/* PR target/98461 */
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -msse2 -mno-sse3 -masm=att" } */
> > +/* { dg-final { scan-assembler-times "\tpmovmskb\t" 1 } } */
> > +/* { dg-final { scan-assembler-not "\tmovzwl" } } */
> > +/* { dg-final { scan-assembler-times "\tnotl" 1 } } */
> > +
> > +#include <immintrin.h>
> > +
> > +unsigned int movemask_not1(__m128i logical) {
> > +  unsigned short res = (unsigned short)(_mm_movemask_epi8(logical));
> > +  return ~res;
> > +}
> > --
> > 2.18.1
> >
> >
> > --
> > BR,
> > Hongtao



-- 
BR,
Hongtao