> let Defs = [ECX], Uses = [EAX, EDX] in > def RDMSR : I<0x32, RawFrm, (outs), (ins), "rdmsr", [], IIC_RDMSR>, TB; Sorry, that's backwards. I think it should be: let Defs = [EAX, EDX], Uses = [ECX] in def RDMSR : I<0x32, RawFrm, (outs), (ins), "rdmsr", [], IIC_RDMSR>, TB; Cheers. Tim.