[FFmpeg-devel] Fw: [foms] Paper submissions to LCA
Fri Jul 17 11:08:26 CEST 2009
Carl Eugen Hoyos <cehoyos at ag.or.at> writes:
> M?ns Rullg?rd <mans <at> mansr.com> writes:
>> On that topic, does anyone know why so many FATE tests are failing
>> with icc?
> (It exclusively fails for 11.x 64bit and I wrote a wiki page about it.)
> Some files are mis-compiled at optimisations > 0:
That much is more or less clear from the test results. ;-)
> Earlier this year, I looked into wmv2dec.c (it is the shortest of
> these files), and found that the problem is wmv2_pred_motion().
> (Adding printf's after the initialisation of *C shows that mot_val,
> A, B and C often differ from compilation with -O0 while xy and
> wrap are unchanged.)
> Perhaps you could have a look what is so special about this (short)
> function? I could upload the assembly of O0 and O1 if you want.
> I reported the problem to Intel, but it took them some time to reproduce the
> problem. It is reproduced (escalated) now (issue 540759):
> "I've narrowed down the problem to one of our internal modules"
Good to know they're working on it.
> I have no idea if the other files have the same problem (there is
> some indication that vc1.c has a different problem), but they are
> rather big making it difficult to find the failing function.
I just wanted to make sure it wasn't some silly aliasing violation in
our code causing it. There are quite a few warnings of that kind from
mans at mansr.com
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