[LLVMdev] [PATCH] Support asm comment output

David Greene dag at cray.com
Tue Jul 14 13:35:12 PDT 2009

On Monday 13 July 2009 15:58, David Greene wrote:

> Again, after answering the FI stack slot question, the IR-level instruction
> information is the only thing we can't do through asmprinter.  I'm open to
> other ways of capturing the information that don't require comments in
> MachineInstrs.  But the information has to be stored somewhere.

Ugh.  I just found another case I don't think we can synthesize in asmprinter.
We mark rematerialized instructions as well so our performance guys don't come
and ask us why we didn't hoist saomething out of a loop.  :)

We're also a bit more expressive in our spill/reload marking.  For example,
we're mark whether a spill or reload was merged with another instruction
and mark copy instructions that were inserted because the spiller could
reuse a previous reload.  These are all extra things the spiller inserts.  We
might be able to get folded spill/reload information synthesized by looking
at MachineOperands but I don't think we can get reuse copies or rematted 

Would it be acceptable to add a small flags field to MachineInstr that we
can use as a bitvector?


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