2016-07-03 23:39 GMT+02:00 Hendrik Leppkes <h.lepp...@gmail.com>: > On Tue, Jun 28, 2016 at 12:01 PM, Hendrik Leppkes <h.lepp...@gmail.com> wrote: >> On Tue, Jun 28, 2016 at 11:48 AM, Hendrik Leppkes <h.lepp...@gmail.com> >> wrote: >>> Visual Studio 2015 Update 3 introduced a new SSA optimizer, however >>> it unfortunately causes miscompilations. Until it is fixed, the new >>> optimizations are disabled and should be re-checked on subsequent >>> compiler releases. >>> >>> Fixes recent FATE failure of fate-lavf-pam on VS2015. >> >> On that note, i'm not exactly sure which code actually miscompiles. >> I though its pamenc, but the generated files are identical, then I >> though its the crc computing code (crcenc/adler32), but those seem >> fine as well and would likely screw up in more then one case if they >> would miscompile. >> >> So that leaves pnmdec, I suppose, but I didn't make much headway to >> poke around in that. If anyone has any handy hints how to find the >> code in question that might be helpful. >> Maybe the code is actually not-quite-right and might enjoy some straigtening. >> > > Applied the patch to disable the new optimizations in MSVC as I did > not spot anything obviously "bad" in pamdec - which does not mean > there isn't anything there, of course. >
This is pretty bad miscompilation in new SSA optimizer. It assumes that variable declared in loop doesn't change the value even if there is assignment. I minimized testcese and reported the bug https://connect.microsoft.com/VisualStudio/feedback/details/2890170 - Kacper _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
