[FFmpeg-devel] [PATCH] h264_i386: Optimize decode_significance_8x8_x86 for 64 bit.

Michael Niedermayer michaelni at gmx.at
Wed Dec 3 01:40:50 CET 2014


On Sat, Nov 22, 2014 at 02:09:01PM +0100, Reimar Döffinger wrote:
> On Mon, Nov 17, 2014 at 01:41:13PM +0100, Michael Niedermayer wrote:
> > On Mon, Nov 17, 2014 at 08:19:32AM +0100, Reimar Döffinger wrote:
> > > On 17.11.2014, at 02:37, Michael Niedermayer <michaelni at gmx.at> wrote:
> > > > On Sat, Nov 15, 2014 at 06:16:03PM +0100, Reimar Döffinger wrote:
> > > >> 11674 -> 10877 decicycles on my Phenom II.
> > > >> Overall speedup was unfortunately within measurement error.
> > > > 
> > > > here its  10153 ->10135
> > > 
> > > I suspect it also depends a bit on the compiler and how it changes the surrounding code.
> > > Note that I also tested with PIC actually.
> > > 
> > > > but ive a slightly odd feeling about the chnages to the asm code,
> > > > iam not sure if all assemblers will be happy about the changed
> > > > code
> > > 
> > > Do you mean particularly the movzbl change?
> > 
> > yes and the k stuff
> > 
> > 
> > > I am also unsure about that, I think there was a reason for that %k6 mess...
> > > But this as well as movzx seemed to work for me...
> > 
> > it works here too i just have the feeling it might fail on some odd
> > assembler or platform. Thats not meant to keep you from pushing this
> > just that it might require to be reverted or fixed if such
> > problems actually occor
> 
> I pushed it.
> If anyone sees issues please tell me and I'll look into it!

i think these fate failures are caused by it but thats based just
on other commits in the range looking unlikely:

http://fate.ffmpeg.org/report.cgi?time=20141122231657&slot=x86_64-darwin-clang-3.5-O3
http://fate.ffmpeg.org/report.cgi?time=20141122223720&slot=x86_64-darwin-clang-3.5

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct answer.
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