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Re: [PATCH]: Implement must-def kill operand



On Oct 20, 2004, at 5:03 PM, Diego Novillo wrote:


On Wed, 2004-10-20 at 16:55, Daniel Berlin wrote:

That will, in turn, mark the *feeders* of the phi as necessary, because
they will be added to the worklist, and propagate_necessity doesn't
know that it doesn't need to mark the feeders unless they are phi
nodes, thus you will miss dead code being eliminated.


Ah, good point.  Sigh.  I think I'm about to ask you to just let the
regular renamer run and insert needed PHIs, but I agree that PHI node
churn should be avoided.

How much additional code are we talking about?
All told, including all necessary changes to DCE and comments, it's 89 lines of code added.

A good chunk of the
algorithm you described already exists in DCE.  Can it be factored?
I factored what i could. :)



Diego.



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