[LLVMdev] Re: Spilling register and frame indices

Chris Lattner sabre at nondot.org
Wed May 24 10:22:41 PDT 2006

On Wed, 24 May 2006, Vladimir Prus wrote:
> Chris Lattner wrote:
>> This is one approach.  Another approach is to have to spiller scavange
>> registers, which is the subject of this enhancement request:
>> http://llvm.org/PR768
> Can you given some references for this "scavange" thing? Google and
> ResearchIndex are silent on the topic.

It's not a very deep concept. :)  The basic idea is that, when you find 
that you need to insert a reload for spill code, you look to see if there 
are any unused registers.  If so, use one.

Otherwise, you need to find one to spill to memory, and do so in a way 
that you can spill and reload without also needing a register for THAT 
reload.  :)



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