[PATCH] Make alias_sets_conflict_p less conservative

[Richard Kenner]

> The problem lies in the way how we represent load and store dependencies 
> as virtual operands.  Conflicts between a pair of mem accesses are not 
> evaluated by asking alias_set_conflicts_p() on both accesses, but instead 
> via a chain of virtual def and use operands.  

But I thought this whole discussion was about a change to
alias_sets_conflict_p.  So you've lost me.