Re: [PATCH] Canonicalize vec_perm index to make the first index come from the first vector.

[Hongtao Liu <crazylht@gmail.com>]

On Wed, Oct 19, 2022 at 7:49 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Tue, Oct 18, 2022 at 4:25 PM liuhongt <hongtao.liu@intel.com> wrote:
> >
> > Fix unexpected non-canon form from gimple vector selector.
> >
> > Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> > Ok for trunk?
> >
> > gcc/ChangeLog:
> >
> >         PR target/107271
> >         * config/i386/i386-expand.cc (ix86_vec_perm_index_canon): New.
> >         (expand_vec_perm_shufps_shufps): Call
> >         ix86_vec_perm_index_canon
> >
> > gcc/testsuite/ChangeLog:
> >
> >         * gcc.target/i386/pr107271.c: New test.
> > ---
> >  gcc/config/i386/i386-expand.cc           | 17 +++++++++++++++++
> >  gcc/testsuite/gcc.target/i386/pr107271.c | 16 ++++++++++++++++
> >  2 files changed, 33 insertions(+)
> >  create mode 100644 gcc/testsuite/gcc.target/i386/pr107271.c
> >
> > diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
> > index 6baff6d0e61..4f121516091 100644
> > --- a/gcc/config/i386/i386-expand.cc
> > +++ b/gcc/config/i386/i386-expand.cc
> > @@ -19604,6 +19604,22 @@ expand_vec_perm_1 (struct expand_vec_perm_d *d)
> >    return false;
> >  }
> >
> > +/* Canonicalize vec_perm index to make the first index
> > +   always comes from the first index.  */
>                                                     vector?
Yes.
> > +static void
> > +ix86_vec_perm_index_canon (struct expand_vec_perm_d *d)
> > +{
> > +  unsigned nelt = d->nelt;
> > +  if (d->perm[0] < nelt)
> > +    return;
> > +
> > +  for (unsigned i = 0; i != nelt; i++)
> > +    d->perm[i] = (d->perm[i] + nelt) % (2 * nelt);
> > +
> > +  std::swap (d->op0, d->op1);
> > +  return;
> > +}
> > +
> >  /* A subroutine of ix86_expand_vec_perm_const_1. Try to implement D
> >     in terms of a pair of shufps+ shufps/pshufd instructions.  */
> >  static bool
> > @@ -19621,6 +19637,7 @@ expand_vec_perm_shufps_shufps (struct expand_vec_perm_d *d)
> >    if (d->testing_p)
> >      return true;
> >
> > +  ix86_vec_perm_index_canon (d);
> >    for (i = 0; i < 4; ++i)
> >      count += d->perm[i] > 3 ? 1 : 0;
> >
> > diff --git a/gcc/testsuite/gcc.target/i386/pr107271.c b/gcc/testsuite/gcc.target/i386/pr107271.c
> > new file mode 100644
> > index 00000000000..fe89c9a5bef
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr107271.c
> > @@ -0,0 +1,16 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O0" } */
> > +
> > +typedef int __attribute__((__vector_size__ (16))) V;
> > +
> > +static inline __attribute__((__always_inline__)) V
> > +bar (V v128u32_0)
> > +{
> > +  return __builtin_shuffle ((V){}, v128u32_0, v128u32_0);
> > +}
> > +
> > +V
> > +foo (void)
> > +{
> > +  return bar ((V){7, 4, 4});
> > +}
> > --
> > 2.27.0
> >
>
>
> --
> H.J.



-- 
BR,
Hongtao