[FFmpeg-devel] [PATCH] avcodec/h264_mb: Fix undefined shifts

Christophe Gisquet christophe.gisquet at gmail.com
Thu Mar 12 17:04:50 CET 2015


Hi,

2015-03-12 16:29 GMT+01:00 Michael Niedermayer <michaelni at gmx.at>:
> from "(mx >> 2) << pixel_shift)" a compiler could imply that
> (mx >> 2) is >= 0 as the alterantive is undefined

Well, (mvx >> 2) is implementation-defined, according to 6.5.7. But
gcc produces the same instruction, so...

-- 
Christophe


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