[FFmpeg-devel] [PATCH V2] Fixes compiler bug - replace vec_lvsl/vec_perm with vec_xl

Carl Eugen Hoyos ceffmpeg at gmail.com
Tue Aug 13 03:26:31 EEST 2019


Am Fr., 2. Aug. 2019 um 17:24 Uhr schrieb ckerchne
<ckerchne at linux.vnet.ibm.com>:
>
> A bug exist with the gcc compilers for Power in versions 6.x and 7.x
> (verified with 6.3 and 7.4). It was fixed in version 8.x (verified with
> 8.3). I was using a Power 9 ppc64le machine for building and testing.
> This is to address ticket #7124.
>
> It appears the compiler is generating the wrong code for little endian
> machines for the vec_lvsl/vec_perm instruction combos in some cases. If
> these instructions are replaced with vec_xl, the problem goes away for
> all versions of the compilers

I tested with gcc 7 (gcc 6 fails compilation for ppc64le) and was unable
to see a speed difference on be, so pushed.

For future patches: Please provide patches as made by git format-patch,
not diff files.

Thank you for the fix, Carl Eugen


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