[PATCH 2/2] CmmOpt cannot assume single assignment for hand-written or new codegen Cmm.
Edward Z. Yang
ezyang at MIT.EDU
Tue Apr 5 11:43:15 CEST 2011
Excerpts from Simon Marlow's message of Tue Apr 05 04:31:56 -0400 2011:
> > + -- XXX The above is not actually true: hand-written Cmm and Cmm from
> > + -- the new code generator are not single-assignment. So we do an
> > + -- extra check to make sure that the register being changed is not
> > + -- one we were relying on. I don't know how much of a performance
> > + -- hit this is; if it's a big problem we may want to make a set of
> > + -- used registers and match against that. -- EZY
> It looks from the patch like you already made a register set to optimise
> this. Is the comment out of date?
Oh yes, that's out of date. I'll fix that.
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