[LLVMdev] caller-saved register saving

Jonas Paulsson jnspaulsson at hotmail.com
Sat Aug 27 07:36:41 PDT 2011


Hi,

I am working on a new target, and would like to save the caller-saved regs at the call-site.

I have used the ADJCALLSTACKDOWN / UP pseudo-instructions, and my idea was to eliminate these, and in doing this using the RegScavenger to find the caller-saved live regs, and the push / pop these.

I find that there are no such regs actually live there. It seems that these registers are somehow COPY:d and not coalesced, and thus not live across the call. 

Is this correct? How does this work? It looked like there was a method in PrologueEpilogueInserter for these regs before, but it has been removed. Please explain.

Thanks,

Jonas

 		 	   		  
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