[LLVMdev] Mips -> DLX Modifications as Target

Anton Korobeynikov anton at korobeynikov.info
Mon Jul 6 06:33:28 PDT 2009

Hello, Sean

> Mainly the problem is if the constant is specified as negative,  and
> when 0-constant can fit in 16-bits unsigned, wish it to use the SUBui
> instruction.
sub reg, imm is canonicalized in LLVM into add imm, -imm. You need to
"replay" this back via some "pipehole" pattern.

You might find ARM target useful as an example.

With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

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