[FFmpeg-devel] [PATCH] Fix warnings in bidir_refine (in libavcodec/motion_est.c)

[Reimar Döffinger]

On Sat, Jul 03, 2010 at 01:17:56AM -0700, Eli Friedman wrote:
> On Sat, Jul 3, 2010 at 12:45 AM, Reimar D?ffinger
> <Reimar.Doeffinger at gmx.de> wrote:
> >
> > On Sat, Jul 03, 2010 at 12:19:12AM -0700, Eli Friedman wrote:
> > > Patch attached. ?Fixes a bunch of warnings of the form "large integer
> > > implicitly truncated to unsigned type" coming from the static table
> > > "hash". ?No significant change in the generated code.
> >
> > I don't believe that, it generated quite a few useless extra instructions
> > for me (gcc 4.4.4 on x86_64).
> 
> I'm using gcc 4.4.3, so I'll assume I got the same output; the output
> patched was only 1 instruction longer.  Is my threshold for "no
> significant change" not sensitive enough?

Well, for me it definitely is also 32 bytes longer, due to replacing a
lot of mov by movzbl.
Through this mess I haven't been able to figure out what exactly goes on,
but one instruction more in the innermost loop sure would be relevant.
Also check for the patch for this I sent some time ago, I think there were
some comments on how to solve it "properly".