[FFmpeg-devel] [FFmpeg-cvslog] r12171 - trunk/doc/optimization.txt

Mike Melanson mike
Thu Feb 21 21:19:51 CET 2008

?smail D?nmez wrote:
> Hi,
> On Thu, Feb 21, 2008 at 9:57 PM, Uoti Urpala <uoti.urpala at pp1.inet.fi> wrote:
>> On Thu, 2008-02-21 at 20:11 +0100, Michael Niedermayer wrote:
>>  > As you can see gcc injects 2 unneeded lea instructions in the innermost loop.
>>  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 supports my theory that gcc 4.3 is a big improvement optimization wise.

According to the data FATE has been collecting, FFmpeg binaries built
using gcc out of SVN are not performing as well as gcc <= 4.2.x. Much
worse in fact. This only seems to be an issue on x86_32.

	-Mike Melanson

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