[Ffmpeg-devel] -fwhole-program -combine
Mon Feb 26 16:47:32 CET 2007
On Mon, 2007-02-26 at 09:14 +0000, M?ns Rullg?rd wrote:
> Ramiro Polla <angustia at arrozcru.no-ip.org> writes:
> > Basically, ffmpeg_g got 9% larger, ffmpeg got 8.2% larger, and the
> > benchmarks showed a slowdown of 1.3%. Way to go gcc =)
> > Pretty frustrating... I was hoping it would be faster or smaller. Am I
> > missing something to get the "agressive" optimizations to work
> > properly?
> My guess is that those options are mostly intended to get around
> inefficiencies in C++.
>From the documentation it looks like it isn't even supported for C++,
only C. My guess is that gcc did more inlining when the used functions
were in the same compilation unit but increased inlining was a net loss
for FFmpeg. Compiling at -O2 instead of -O3 might be worth trying. I'd
expect that to remove/lessen the code size increase.
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