[LLVMdev] A question about instruction operands.

[Richard Osborne]

sanjiv gupta wrote:
> I have a question:
> In the pattern below from X86
>
> def INC8r  : I<0xFE, MRM0r, (outs GR8 :$dst), (ins GR8 :$src),
> 			"inc{b}\tdst",
> 		  [(set GR8:$dst, (add GR8:$src, 1))]>;
>
> Since we are emitting only "inc $dst",
> What makes sure that the $src and $dst are same register?
>
> - Sanjiv
It's enclosed inside :

let isTwoAddress = 1 in {
...
}

(you'll need to scroll up a fair amount to find this).

Richard