[FFmpeg-devel] [FFmpeg-cvslog] r12171 - trunk/doc/optimization.txt
Thu Feb 21 21:08:19 CET 2008
On Thu, 2008-02-21 at 21:57 +0200, Uoti Urpala wrote:
> It'd need at least one other instruction instead though. Anyway I do not
> see that behavior with Debian's gcc-4.3, gcc always uses 3 instructions
> for the adds (same as the handwritten asm).
That was gcc-4.2 actually, gcc-4.3 seems to use either
addq %rcx, %rsi
addq %rcx, %rdx
addq $16, %rax
leaq (%rsi,%r8), %rdx
leaq (%r10,%r8), %rax
addq %rcx, %r8
addq $16, %r9
depending on whether the loop is unrolled.
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