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Re: [RFC] tree-ssa-ccp.c: Propagate even more ADDR_EXPRs.


On Tue, May 31, 2005 at 12:58:07PM -0400, Kazu Hirata wrote:
> Hi Jeff,
> 
> > I'd be surprised if we saw a difference as well.  About the only thing
> > that's done by forwprop.c that isn't done by CCP is some trivial
> > cost analysis -- ie, don't propagate an ADDR_EXPR into a loop nest,
> > don't propagate to multiple use sites (which undoes CSE).
> 
> Would propagating invariant ADDR_EXPRs (regardless of the number of
> their immediate uses) help alias analysis and/or dependence analysis?
> (I'm no expert in these areas.)
> 
Every ADDR_EXPR that we can fold inside an INDIRECT_REF
expression helps reduce the number of addressable variables.
That always helps aliasing.

You'd have to run checks on some code bases to see to what extent
does your transformation help.


Diego.


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