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Re: [tree-ssa] [PATCH]: Loop invariant code motion for trees

On Mon, 2003-08-25 at 15:10, Daniel Berlin wrote:
> 
> On Monday, August 25, 2003, at 2:50 PM, Andrew MacLeod wrote:
> 
>
> >
> > As a guess, Did you hoist it across an abnormal edge?
> > or at least make it now live across an abnormal edge?  That'll do it 
> > :-)
> 
> Possibly
> :)
> How can i tell given only the bb it's in, and the bb's it's going to be 
> moved to?
> >
> 

Interesting question :-)

If there is an abnormal edge on the path from 'going to' to 'in', its a
hazardous thing to do.  I don't suppose we're lucky and your variable
has the SSA_NAME_OCCURS_IN_ABNORMAL_PHI flag set?   If it does, I'd
suggest not hoisting those. We can't copy propagate them either yet...

Andrew
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