[Ffmpeg-devel] [PATCH] dead code elimination

[Aurelien Jacobs]

On Mon, 26 Feb 2007 00:46:38 +0000
M?ns Rullg?rd <mans at mansr.com> wrote:

> Aurelien Jacobs <aurel at gnuage.org> writes:
> 
> > On Sat, 24 Feb 2007 18:35:48 +0100
> > Michael Niedermayer <michaelni at gmx.at> wrote:
> >
> >> Hi
> >> 
> >> On Sat, Feb 24, 2007 at 02:05:24PM -0300, ramiro at lisha.ufsc.br wrote:
> >> > Dead since r1029
> >> 
> >> rejected, resurrect and benchmark it rather
> >
> > I've just benchmarked it on amd64. For this, I've just disabled SIMD and
> > used START/STOP_TIMER around idctRowCondDC().
> > Results without FAST_64BIT:
> >   567 dezicycles in fast64bits, 1048564 runs, 12 skips
> > with #define FAST_64BIT:
> >   516 dezicycles in fast64bits, 1048570 runs, 6 skips
> > I've repeated the test with several videos and got similar results.
> >
> > So defining FAST_64BIT on amd64 (and probably other 64bits arch) is
> > definitely a win.
> > I guess I should commit attached patch ?
> >
> > Aurel
> >
> > @@ -957,6 +958,7 @@
> >      if [ x"$canon_arch" = x"x86_64" -o x"$canon_arch" = x"amd64" ]; then
> >        if [ -z "`echo $CFLAGS | grep -- -m32`"  ]; then
> >          arch="x86_64"
> > +        enable fast_64bit
> >        fi
> >      fi
> >    ;;
> 
> Not OK.  This should be set for all 64-bit CPUs we currently have
> special settings for.

OK. I first wanted to be on a safe side, but indeed, if it's not changed right
now for all 64 bits arch, I may never be changed.

> These include Alpha, PPC64, and Sparc64.

I guess this also includes ia64 and parisc64 ;-)

Updated patch attached.

Aurel
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