http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60905
Bug ID: 60905
Summary: ffmpeg built with gcc 4.9 RC produces incorrect loco
playback code
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: cehoyos at ag dot or.at
gcc 4.9.0 RC miscompiles FFmpeg's loco decoder (an old video format), this is
reproducible with current FFmpeg git head (e70b9b32) and the last release,
2.2.1:
The problem can be reproduced with the fate tests (FFmpeg's self test, the
samples are large):
$ ./configure && make ffmpeg
$ make SAMPLES=fate-samples fate-rsync
$ make SAMPLES=fate-samples fate-loco-rgb
$ make SAMPLES=fate-samples fate-loco-yuy2
Both tests take a very long time instead of fractions of a second and output
incorrect data.
Also reproducible without running the tests:
$ rsync -t rsync://fate-suite.ffmpeg.org/fate-suite/loco/pig* .
$ ffmpeg -i pig-loco-0.avi out1.avi
$ ffmpeg -i pig-loco-rgb.avi out2.avi
The output files look completely broken.
Works fine with many previous versions of gcc, including 4.8.2 and 4.7.2.
This may or may not be related to Bug 60902 and Bug 60904
I originally found the problem when testing FFmpeg ticket #3559:
https://trac.ffmpeg.org/ticket/3559
