[FFmpeg-devel] [PATCH] update doc/optimization.txt

[Michael Niedermayer]

On Mon, Sep 20, 2010 at 08:03:29PM -0400, Ronald S. Bultje wrote:
> Hi Reimar,
> 
> On Mon, Sep 20, 2010 at 7:34 PM, Reimar D?ffinger
> <Reimar.Doeffinger at gmx.de> wrote:
> > While the "obvious" failures may be gone, proper clobber lists
> > for inline asm are still necessary and some parts like
> > merging asm block would have been quite independent of how
> > you write it.
> 
> I agree partly with this. I did try the clobberlist-approach first, by
> the way, but this broke fate on various BSDs and possibly other
> systems. We could argue that we don't need to mark clobbers on
> Unix-like systems but I believe that this is just asking for disaster
> to hit us later on. We need something that works on all systems.

id say a compiler that doesnt know about SSE registers in asm() clobbers
also doesnt know how to use SSE for anything else and thus doesnt need
the clobbers.

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

Awnsering whenever a program halts or runs forever is
On a turing machine, in general impossible (turings halting problem).
On any real computer, always possible as a real computer has a finite number
of states N, and will either halt in less than N cycles or never halt.
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