[LLVMdev] Spilling multi-word virtual registers

Jakob Stoklund Olesen stoklund at 2pi.dk
Tue Jul 27 15:29:23 PDT 2010


On Jul 27, 2010, at 4:48 AM, Ken Dyck wrote:
>> 
>> To be safe, you should probably only return
>> true from isLoadFromStackSlot when the
>> instruction loads the whole stack slot. That
>> is, the offset is zero, and the stack slot
>> size matches the register size.
> 
> This seems to result in dead frame indices being passed to
> eliminateFrameIndex(). I'm currently handling these by removing the
> load/store instructions in which they appear. I haven't found any errors
> in the code that gets generated so far, but I also notice that none of
> the other back ends seem to have any special logic to handle dead slots
> in eliminateFrameIndex(). Should I be concerned? 

I am not sure. Why are there instructions referencing dead spill slots?

/jakob




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