[Ffmpeg-cvslog] r6573 - trunk/libavcodec/cabac.h

Uoti Urpala uoti.urpala
Sun Oct 8 01:45:31 CEST 2006

On Sun, 2006-10-08 at 00:42 +0200, Michael Niedermayer wrote:
> On Sat, Oct 07, 2006 at 06:53:35PM +0300, Uoti Urpala wrote:
> > I did overall performance benchmarks for them and they're all slower
> > than the C  version. My first benchmark (under MPlayer) was with a
> > --enable-debug compile, the differences were somewhat bigger with a
> > default compile. The first and second alternatives (P3:683 and P3:680)
> > were around 1% slower, the other 3 over 2% slower.
> ive run my own tests on athlon and i cannot confirm your results, actually
> gcc here turns the c code into the lea,shr,shl,shl sequence from the first
> asm, the result is also running at the same speed as the c code (not 
> surprising)
> ive not done any overall speed tests as the code is the same and the function
> itself runs at the same speed  ...

I can still reproduce it. Even if gcc compiles the function to
essentially the same code in isolation it can have a different effect
when inlined, and the resulting code does indeed look different.

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