[Bug target/100869] New: z13: Inefficient code for vec_reve(vector double)

[Bug target/100869] New: z13: Inefficient code for vec_reve(vector double)

[jens.seifert at de dot ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100869

            Bug ID: 100869
           Summary: z13: Inefficient code for vec_reve(vector double)
           Product: gcc
           Version: 10.2.1
            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
        larl    %r5,.L12
        vl      %v0,.L13-.L12(%r5),3
        vperm   %v24,%v24,%v24,%v0
        br      %r14


Optimal code sequence:

vector double reve_z13(vector double a)
{
   return vec_permi(a,a,2);
}

creates:

_Z6reve_2Dv2_d:
.LFB6:
        .cfi_startproc
        vpdi    %v24,%v24,%v24,4
        br      %r14
        .cfi_endproc

[Bug target/100869] z13: Inefficient code for vec_reve(vector double)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100869

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

https://gcc.gnu.org/g:8cdebe087619329facf19ba849d4d489a9a933e2

commit r13-2248-g8cdebe087619329facf19ba849d4d489a9a933e2
Author: Robin Dapp <rdapp@linux.ibm.com>
Date:   Fri Jun 24 15:15:14 2022 +0200

    s390: Use vpdi and verllg in vec_reve.

    Swapping the two elements of a V2DImode or V2DFmode vector can be done
    with vpdi instead of using the generic way of loading a permutation mask
    from the literal pool and vperm.

    Analogous to the V2DI/V2DF case reversing the elements of a four-element
    vector can be done by first swapping the elements of the first
    doubleword as well the ones of the second one and subsequently rotate
    the doublewords by 32 bits.

    gcc/ChangeLog:

            PR target/100869
            * config/s390/vector.md (@vpdi4_2<mode>): New pattern.
            (rotl<mode>3_di): New pattern.
            * config/s390/vx-builtins.md: Use vpdi and verll for reversing
            elements.

    gcc/testsuite/ChangeLog:

            * gcc.target/s390/zvector/vec-reve-int-long.c: New test.