[FFmpeg-devel] llvm failure : don't do undefined shift

Michael Niedermayer michaelni
Sat Aug 22 16:14:02 CEST 2009

On Fri, Aug 21, 2009 at 04:31:39PM +0000, Matthieu CASTET wrote:
> M?ns Rullg?rd <mans <at> mansr.com> writes:
> > 
> > Michael Niedermayer <michaelni <at> gmx.at> writes:
> > 
> > > that clearly splits the put_bits()
> > 
> > Splitting it in the rare cases where exactly 32 is needed is probably
> > faster than checking every time.  Bear in mind that a lot of calls
> > have variable number of bits, so the compiler can't remove the check
> > even if we know it's always less than 32.

yes and theres also code cache pressure due to put_bits probably being
inlined alot, each single check added in it could be duplicated hundreadfold

> > 
> May be we could add a put_bits_long for this case.
> It will do the split without affecting code readability


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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