[Bug target/100868] New: PPC: Inefficient code for vec_reve(vector double)

[Bug target/100868] New: PPC: Inefficient code for vec_reve(vector double)

[jens.seifert at de dot ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100868

            Bug ID: 100868
           Summary: PPC: Inefficient code for vec_reve(vector double)
           Product: gcc
           Version: 8.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jens.seifert at de dot ibm.com
  Target Milestone: ---

Input:

vector double reve(vector double a)
{
   return vec_reve(a);
}

creates:

_Z4reveDv2_d:
.LFB3:
        .cfi_startproc
.LCF3:
0:      addis 2,12,.TOC.-.LCF3@ha
        addi 2,2,.TOC.-.LCF3@l
        .localentry     _Z4reveDv2_d,.-_Z4reveDv2_d
        addis 9,2,.LC2@toc@ha
        addi 9,9,.LC2@toc@l
        lvx 0,0,9
        xxlnor 32,32,32
        vperm 2,2,2,0
        blr

Optimal sequence would be:

vector double reve_pwr7(vector double a)
{
   return vec_xxpermdi(a,a,2);
}

which creates:

_Z9reve_pwr7Dv2_d:
.LFB4:
        .cfi_startproc
        xxpermdi 34,34,34,2
        blr

[Bug target/100868] PPC: Inefficient code for vec_reve(vector double)

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100868

Segher Boessenkool <segher at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-06-02
           Severity|normal                      |enhancement
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Confirmed.

[Bug target/100868] PPC: Inefficient code for vec_reve(vector double)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100868

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by HaoChen Gui <guihaoc@gcc.gnu.org>:

https://gcc.gnu.org/g:f4eae6450e46224454ce067ac43bd7e9f66fc18b

commit r12-5463-gf4eae6450e46224454ce067ac43bd7e9f66fc18b
Author: Haochen Gui <guihaoc@gcc.gnu.org>
Date:   Wed Nov 17 16:16:02 2021 +0800

    rs6000: Optimize code generation of vec_reve [PR100868]

    gcc/
            PR target/100868
            * config/rs6000/altivec.md (altivec_vreve<mode>2 for VEC_K): Use
            xxbrq for v16qi, xxbrq + xxbrh for v8hi and xxbrq + xxbrw for v4si
            or v4sf when p9_vector is set.
            (altivec_vreve<mode>2 for VEC_64): Defined. Implemented by xxswapd.

    gcc/testsuite/
            PR target/100868
            * gcc.target/powerpc/vec_reve_1.c: New test.
            * gcc.target/powerpc/vec_reve_2.c: Likewise.

[Bug target/100868] PPC: Inefficient code for vec_reve(vector double)

[guihaoc at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100868

HaoChen Gui <guihaoc at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
                 CC|                            |guihaoc at gcc dot gnu.org
             Status|NEW                         |RESOLVED

--- Comment #3 from HaoChen Gui <guihaoc at gcc dot gnu.org> ---
Fixed on trunk.