review (S) for 6984979: OptimizeFill misses some cases with an odd memory graph
vladimir.kozlov at oracle.com
Wed Sep 15 14:41:07 PDT 2010
Should we also check that n->is_Phi() && n->in(LoopNode::LoopBackControl) == store?
Tom Rodriguez wrote:
> 6984979: OptimizeFill misses some cases with an odd memory graph
> The logic for the new OptimizeFill code misses a case where the Phi
> usage is different than expected. Sometimes during transformation of
> the loop there are uses of the memory phi outside the loop. This
> appears to be a valid though slightly surprising structure but it
> interferes with the fill matching logic that assumes the store in the
> loop should be the only outgoing state. The fix is to allow the phi
> to be used outside the loop and replace it with the outgoing memory of
> the call to the fill. Tested with jbb, runthere and ctw.
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