[LLVMdev] Re: Spilling register and frame indices

Vladimir Prus
Wed, 24 May 2006 06:10:45 -0000

Chris Lattner wrote:


>> and then have 'virtual_register' allocated on next iteration of
register
>> allocator?
>
> 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.

>> Also, while RegAllocLocal and RegAllocSimple directly call
>> storeRegToStackSlot, I would not found any calls to that method in
>> RegAllocLinearScan. Am I missing something?
>
> RegAllocLinearScan just does register assignment, then the code in
> VirtRegMap.cpp (poorly named) actually takes the register assignment and
> inserts/optimizes the spill code.

Yea, now that you mention this I see the 'spiller_' member of linear
scan
register allocator.

- Volodya