[llvm-commits] CVS: llvm/lib/Transforms/Scalar/InstructionCombining.cpp

[Reid Spencer]

On Mon, 2006-12-04 at 10:22 -0800, Chris Lattner wrote:
> >    // If this is another cast that can be eliminated, it isn't  
> > codegen either.
> >    if (const CastInst *CI = dyn_cast<CastInst>(V))
> > -    if (isEliminableCastPair(CI, CastInst::getCastOpcode(V, Ty),  
> > Ty, TD))
> > +    if (isEliminableCastPair(CI, CastInst::getCastOpcode(
> > +            V, V->getType()->isSigned(), Ty, Ty->isSigned()), Ty,  
> > TD))
> >        return false;
> >    return true;
> >  }
> 
> Won't this miscompile stuff like:
> 
> %B = zext sbyte %A to ushort
> %C = zext ushort %B to uint
> 
> into a sext?

No. This patch doesn't change anything. The only reason for this change
is the change in signature for getCastOpcode. See the corresponding
change in getCastOpcode.  This passed everything on Linux last night
before I committed it.

Reid.

> 
> -Chris
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