[Bug tree-optimization/29789] Missed optimization in libquantum

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2006-11-09 22:07 -------
If the fold transformation is disabled we can force lim to move the shifts out
of the loop by specifying --param lim-expensive=1 (it considers the shifts
being of cost one).  The default of the param is 20 though.

PRE thinks the shifts are loop induction variables, so it doesn't move them out
of the loop.

With the above "fixes" we get

.L4:
        movl    (%edi,%ecx,4), %edx
        testl   %edx, %ebx
        je      .L5
        testl   %edx, %esi
        je      .L5
        xorl    %eax, %edx
        movl    %edx, (%edi,%ecx,4)
        .p2align 4,,7
.L5:
        addl    $1, %ecx
        cmpl    24(%ebp), %ecx
        jne     .L4


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29789