[LLVMdev] Selection DAG and register classes

Vladimir Prus ghost at cs.msu.su
Mon May 15 06:46:11 PDT 2006

say I have two register classes GR and AR, and a move instruction that can
move one register to another, no matter what the class is. What's the best
way to describe the operands DAG?

If I just write

   (ops GR:$src, GR:$dst)

this will cover 1/4 of all possible combinations, and writing 4 instructions
variants is troublesome. Is there any syntax that write something:

  pseudo-class R32 = GR | AR;
  (opts R32:$src, R32:$dst);

- Volodya

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