On Aug 25, 2005, at 2:09 PM, Fariborz Jahanian wrote:

Compiled with -O1 -mdynamic-no-pic -march=pentium4 produces:

        pxor    %xmm0, %xmm0
        movsd   %xmm0, 16(%eax)
        movsd   %xmm0, 8(%eax)
        movsd   %xmm0, (%eax)

But following code results in 7% performance gain in eon as reported by one of Apple's performance people:

        movl    $0, 16(%eax)
        movl    $0, 20(%eax)
        movl    $0, 8(%eax)
        movl    $0, 12(%eax)
        movl    $0, (%eax)
        movl    $0, 4(%eax)

Actually that does not make sense for a real processor but then again this is x86 we are talking about. Because we have less complex instructions and less instructions
at that matter.

-- Pinski

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