[Bug tree-optimization/49869] New: Excessive loop versioning done by vectorization + predictive commoning

[Bug tree-optimization/49869] New: Excessive loop versioning done by vectorization + predictive commoning

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49869

           Summary: Excessive loop versioning done by vectorization +
                    predictive commoning
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: rguenth@gcc.gnu.org


SUBROUTINE ANYAVG(NLVLS,HTS,PARRAY,ZBOT,NDXABV,ZTOP,NDXBLW,VALAVG)
      IMPLICIT NONE
      INTEGER I , NLVLS , NDXABV , NDXBLW
      REAL HTS(NLVLS) , PARRAY(NLVLS) , ZBOT , ZTOP , SUM , VALAVG
      REAL VALBOT , VALTOP
      IF ( ZBOT.LT.0.5 ) THEN
         ZBOT = 0.5
         NDXABV = 2
      ENDIF
      IF ( ZTOP.LT.0.51 ) THEN
         ZTOP = 0.51
         NDXBLW = 2
      ENDIF
      IF ( NDXBLW.LE.NDXABV ) GOTO 200
      DO I = NDXABV + 1 , NDXBLW
         SUM = SUM + (HTS(I)-HTS(I-1))*0.5*(PARRAY(I)+PARRAY(I-1))
      ENDDO
 200  CONTINUE
      VALAVG = SUM/(ZTOP-ZBOT)
      END

ends up with 5 loop copies.

[Bug tree-optimization/49869] Excessive loop versioning done by vectorization + predictive commoning

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49869

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
On the trunk I only see one copy of the loop:
.L11:
        movups  (%rbx,%rax), %xmm7
        movups  0(%rbp,%rax), %xmm0
        movups  (%r9,%rax), %xmm1
        subps   %xmm7, %xmm0
        movups  (%r11,%rax), %xmm7
        addq    $16, %rax
        addps   %xmm7, %xmm1
        mulps   %xmm6, %xmm0
        mulps   %xmm1, %xmm0
        movaps  %xmm0, %xmm1
        addss   %xmm2, %xmm1
        movaps  %xmm0, %xmm2
        shufps  $85, %xmm0, %xmm2
        addss   %xmm2, %xmm1
        movaps  %xmm0, %xmm2
        unpckhps        %xmm0, %xmm2
        shufps  $255, %xmm0, %xmm0
        addss   %xmm2, %xmm1
        movaps  %xmm1, %xmm2
        addss   %xmm0, %xmm2
        cmpq    %rax, %r10
        jne     .L11

[Bug tree-optimization/49869] Excessive loop versioning done by vectorization + predictive commoning

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49869

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |WORKSFORME
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
pcom and vect have been exchanged, now we no longer perform predictive
commoning.  We're also better in identifying single-iteration loops.  Let's
close the issue.