[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88531

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Blocks|                            |53947
           Severity|normal                      |enhancement


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations

[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88531

--- Comment #9 from Hongtao.liu <crazylht at gmail dot com> ---
I notice this testcase can be vectorized w/ gcc version 12.0.0 20210805
(experimental) (GCC) 

Guess it's related to Richi's
https://gcc.gnu.org/pipermail/gcc-patches/2021-August/576527.html

[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88531

--- Comment #10 from H.J. Lu <hjl.tools at gmail dot com> ---
It is fixed by r12-2733.

[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88531

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, that probably was an unintended side-effect of now doing

          /* Include the conversion if it is widening and we're using
             the IFN path or the target can handle the converted from
             offset or the current size is not already the same as the
             data vector element size.  */
          if ((TYPE_PRECISION (TREE_TYPE (op0))
               < TYPE_PRECISION (TREE_TYPE (off)))
              && (use_ifn_p
                  || (DR_IS_READ (dr)
                      ? (targetm.vectorize.builtin_gather
                         && targetm.vectorize.builtin_gather (vectype,
                                                              TREE_TYPE (op0),
                                                              scale))
                      : (targetm.vectorize.builtin_scatter
                         && targetm.vectorize.builtin_scatter (vectype,
                                                               TREE_TYPE (op0),
                                                               scale)))
                  || !operand_equal_p (TYPE_SIZE (TREE_TYPE (off)),
                                       TYPE_SIZE (TREE_TYPE (vectype)), 0)))
            {
              off = op0;
              offtype = TREE_TYPE (off);
              STRIP_NOPS (off);
              continue;
            }

that is we no longer try to consume the conversion because with the conversion
source the gather is not supported and the offset is also already of the
size of the data.

We should probably add this testcase to make sure any other heuristic
improvements in the above code doesn't break it again.

[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88531

--- Comment #12 from H.J. Lu <hjl.tools at gmail dot com> ---
For some reason,

-march=x86-64 -mx32

and

-march=x86-64 -m32 -mfpmath=sse

won't vectorize the loop.

[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88531

--- Comment #13 from H.J. Lu <hjl.tools at gmail dot com> ---
Here is the equivalent C code:

---
#include <stdint.h>

#define loop_t uint32_t
#define idx_t uint32_t

void loop(double * const __restrict__ dst,
          double const * const __restrict__ src,
          idx_t const * const __restrict__ idx,
          loop_t const begin,
          loop_t const end)
{
  for (loop_t i = begin; i < end; ++i)
    dst[i] = 42.0 * src[idx[i]];
}
---

[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88531

--- Comment #14 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by H.J. Lu <hjl@gcc.gnu.org>:

https://gcc.gnu.org/g:6866f4819ad8e6e62fef2177520f9fb217dfa353

commit r12-2795-g6866f4819ad8e6e62fef2177520f9fb217dfa353
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sat Aug 7 07:29:04 2021 -0700

    Add tests for PR tree-optimization/88531

            PR tree-optimization/88531
            * gcc.target/i386/pr88531-1a.c: New test.
            * gcc.target/i386/pr88531-1b.c: Likewise.
            * gcc.target/i386/pr88531-1c.c: Likewise.
            * gcc.target/i386/pr88531-2a.c: Likewise.
            * gcc.target/i386/pr88531-2b.c: Likewise.
            * gcc.target/i386/pr88531-2c.c: Likewise.

[Bug tree-optimization/88531] Index data types when targeting AVX-512 vectorization with gather/scatter

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88531

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |12.0
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #15 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed for GCC 12.