[Ffmpeg-devel] [PATCH] fix x86 asm compilation

Rich Felker dalias
Mon May 30 17:28:41 CEST 2005


On Mon, May 30, 2005 at 09:57:48AM +0200, Michel Bardiaux wrote:
> Rich Felker wrote:
> >On Mon, May 30, 2005 at 12:39:23AM +0200, Aurelien Jacobs wrote:
> >
> >>Hi,
> >>
> >>Currently i386/dsputil_mmx.c fails to compiles on x86 when configured
> >>with --disable-opts. (At least for me with gcc 3.3.4)
> >
> >
> >Why does this option to configure exist? It's known that disabling
> >optimizations is not supported for asm...
> >
> >
> >>I've written a small patch which fixes this. I don't like it very much,
> >>but I've no better idea right now.
> >
> >
> >If you insist on disabling optimizations (there is no good reason for
> >this), then disable asm while you're at it too...
> 
> There *is* one good reason to disable optimisations: when you need 
> debugging (which of course never happens with ffmpeg :-) ), gdb is often 
> very confused by optimisations. Being unable to have asm and no-opt 
> simultaneously makes debugging of code containing asm a real PITA.

I've never had any trouble debugging with optimizations on... Just
read the lines around the line number it reports, then read the asm
and it should be obvious what asm goes with what C...

Rich





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