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Re: Semi-Latent Bug in tree vectorizer


On Fri, 2005-04-08 at 13:27, Andrew MacLeod wrote:
> On Fri, 2005-04-08 at 12:52, Jeffrey A Law wrote:

> > When we rescan the operands, we get a different set of V_MAY_DEFS,
> > specifically we lose the V_MAY_DEF for SFT.3_20.  Which results in
> > uses of SFT.3_20 later, but SFT.3_20 is never defined
> 
> 
> What are these uses?  If they are references to things that aliased
> *D.1470_8, we should eliminate the VUSE/MAYDEF, shouldnt we? I presume
> they arent relevant any more if vec_px.17 isnt in the same alias set.
> 
> And if they are relevant, then we need to find out what the new variable
> is, and change all the uses to the new one
> 

Hopefully it is the first (eliminate uses) and not the second.

virtual operands are different in that the LHS and RHS must be the same
root variable... so going out and changing USEs in the RHS of a
V_MAY_DEF could cause very bad things to happen.

Andrew


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