[LLVMdev] [RFC] Remat Enhancements

David A. Greene dag at cray.com
Mon Feb 27 09:51:09 PST 2012

dag at cray.com (David A. Greene) writes:

>>> The change requires that live interval analysis be able to determine
>>> whether and instruction is a load and whether an instruction writes to
>>> memory.
>> Just use MI->mayLoad(), MI->mayStore().
> Does this also account for arithmetic instructions with memops?  These
> interfaces didn't exist in 2.9.

This is important because if mayLoad includes arithmetic instructions
with source memops (which I assume it will), it is unsuitable for remat
analysis.  I don't think we want to remat general arithmetic quite yet.
At least that's not the intent of my change.  I'll need some way to
identify "real" loads and I don't know of any other way other than
listing opcodes.  Ideas?


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