[FFmpeg-devel] [PATCH] configure: disable the new optimizer in Visual Studio 2015 Update 3

[Michael Niedermayer]

On Tue, Jun 28, 2016 at 12:01:54PM +0200, Hendrik Leppkes wrote:
> On Tue, Jun 28, 2016 at 11:48 AM, Hendrik Leppkes <h.leppkes at 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.

it could be atempted to identify or confirm the file that causes the
issue by building each file with its own optimization flags and use
this to "bisect" over the (likely) files

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Into a blind darkness they enter who follow after the Ignorance,
they as if into a greater darkness enter who devote themselves
to the Knowledge alone. -- Isha Upanishad
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