[FFmpeg-devel] [PATCH/RFC] mathops/x86: work around inline asm?miscompilation with GCC 4.8.1

[Michael Niedermayer]

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[0], B[0], C[0]);
> 
> 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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