[Bug target/103753] New: Unoptimal avx2 V16HF vector insert to element 0

[Bug target/103753] New: Unoptimal avx2 V16HF vector insert to element 0

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103753

            Bug ID: 103753
           Summary: Unoptimal avx2 V16HF vector insert to element 0
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ubizjak at gmail dot com
  Target Milestone: ---

(Cloned from PR103571#18)

Following testcase:

--cut here--
typedef _Float16 __v16hf __attribute__ ((__vector_size__ (32)));

__v16hf foo (_Float16 x)
{
  return (__v16hf) { x, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
}
--cut here--

compiles with -O2 -mavx2 to:

        vpxor   %xmm1, %xmm1, %xmm1
        vpbroadcastw    %xmm0, %ymm0
        vpblendw        $1, %ymm0, %ymm1, %ymm0
        vpblendd        $15, %ymm0, %ymm1, %ymm1
        vmovdqa %ymm1, %ymm0
        ret

while similar version with 16bit integer:

--cut here--
typedef short __v16hi __attribute__ ((__vector_size__ (32)));

__v16hi bar (short x)
{
  return (__v16hi) { x, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
}
--cut here--

compiles to much shorter:

        vpxor   %xmm1, %xmm1, %xmm1
        vpinsrw $0, %edi, %xmm1, %xmm0
        vinserti128     $0x1, %xmm1, %ymm0, %ymm0
        ret

Please also note that with -O2 -mavx, the _Float16 version compiles to optimal:

        vpxor   %xmm1, %xmm1, %xmm1
        vpblendw        $1, %xmm0, %xmm1, %xmm0
        vinsertf128     $0x1, %xmm1, %ymm0, %ymm0
        ret

[Bug target/103753] Unoptimal avx2 V16HF vector insert to element 0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103753

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

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

[Bug target/103753] Unoptimal avx2 V16HF vector insert to element 0

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103753

--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by hongtao Liu <liuhongt@gcc.gnu.org>:

https://gcc.gnu.org/g:1f759dbdcddd5eae795da48f46edae274a431cbc

commit r12-6337-g1f759dbdcddd5eae795da48f46edae274a431cbc
Author: liuhongt <hongtao.liu@intel.com>
Date:   Wed Jan 5 15:26:18 2022 +0800

    Optimize V16HF vector insert to element 0 for AVX2.

    gcc/ChangeLog:

            PR target/103753
            * config/i386/i386-expand.c (ix86_expand_vector_set): Not use
            gen_avx2_pblendph_1 when elt == 0.
            * config/i386/sse.md (avx2_pblendph): Rename to ..
            (avx2_pblend<ssemodesuffix>_1).. this, and extend to V16HI.
            (*avx2_pblendw): Rename to ..
            (*avx2_pblend<ssemodesuffix>): .. this, and extend to V16HF.
            (avx2_pblendw): Rename to ..
            (*avx2_pblend<ssemodesuffix>): .. this, and extend to V16HF.
            (blendsuf): Removed.
            (sse4_1_pblend<blendsuf>): Renamed to ..
            (sse4_1_pblend<ssemodesuffix>): .. this.

    gcc/testsuite/ChangeLog:

            * gcc.target/i386/pr103753.c: New test.

[Bug target/103753] Unoptimal avx2 V16HF vector insert to element 0

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103753

--- Comment #2 from Hongtao.liu <crazylht at gmail dot com> ---
Fixed in GCC12.

[Bug target/103753] Unoptimal avx2 V16HF vector insert to element 0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103753

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

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

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed.