[FFmpeg-devel] [PATCH/RFC] mathops/x86: work around inline asm?miscompilation with GCC 4.8.1
michaelni at gmx.at
Fri Jun 21 12:46:51 CEST 2013
On Fri, Jun 21, 2013 at 07:43:47AM +0000, Carl Eugen Hoyos wrote:
> Michael Niedermayer <michaelni <at> gmx.at> writes:
> > > I pin-pointed the specific uses of the function in
> > > question that cause it, but reading the generated
> > > asm didn't show anything obvious yet, but it could
> > > be the smallest thing.
> > > Its the 4 mid_pred calls in vc1_pred_b_mv, if
> > > anyone else wants to have a look.
> (Only the two first ones.)
> > can you post the generated asm? i mean the good one
> > without volatile and the bad with ?
> gcc 4.8.0, 32bit
> The relevant parts of the source where the change
> makes a difference for fate are lines 2156 and 2235
> of libavcodec/vc1dec.c:
> px = mid_pred(A, B, C);
> Following is the diff between the original
> ("notworking.txt") and the patched assembly
> ("working.txt"). I only changed the two
> relevant function calls, not any other part
> of the code:
someone should report this to the gcc devels
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
If you think the mosad wants you dead since a long time then you are either
wrong or dead since a long time.
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