[LLVMdev] Question about coalescing

Fernando Magno Quintao Pereira fernando at CS.UCLA.EDU
Mon Dec 17 13:59:46 PST 2007

> How do you handle dataflow upsdates in your coalescer?  JoinCopy does
> all that stuff, so I assume you just let that handle it.  JoinCopy also
> updates some data structures internal to SimpleRegisterCoalescing, so
> again, it does more work than necessary.


Once I find that two variables can be coalesced, I simply call 
JoinCopy(...). Ideally, the method to join two intervals (which also would 
updates all the data structures internal to the LiveIntervals class) 
should be separate from the method that tells when it is legal to 
coalesce two variables. In this way, the same join method could be called 
by different register coalescers, without loss in performance.



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