[Bug tree-optimization/71361] [7 Regression] Changes in ivopts caused perf regression on x86

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71361

--- Comment #3 from amker at gcc dot gnu.org ---
(In reply to Jakub Jelinek from comment #2)
> Any progress with this?

I had a patch which can resolve the reported regression, and generate even
better code than the original:

.L5:
        movl    (%esi,%ecx,4), %eax
        movl    -4128(%ebp), %edx
        movl    -4124(%ebp), %ebx
        imull   (%edi,%ecx,4), %ebx
        imull   %eax, %edx
        imull   -4124(%ebp), %eax
        addl    %ebx, %edx
        movl    -4128(%ebp), %ebx
        imull   (%edi,%ecx,4), %ebx
        addl    %ebx, %eax
        movl    -4132(%ebp), %ebx
        movl    %edx, (%ebx,%ecx,4)
        movl    -4136(%ebp), %ebx
        movl    %edx, (%edi,%ecx,4)
        movl    %eax, (%ebx,%ecx,4)
        movl    %eax, (%esi,%ecx,4)
        addl    -4140(%ebp), %ecx
        cmpl    $511, %ecx
        jle     .L5

But this patch is a complete rewrite of major part of IVOPT, which is a stage 1
work.