Intr*Mem flags meaning

I'd like to clarify the meaning of "Intr*Mem" flags used in intrinsics
definitions. If an intrinsic does not access memory but read and write
control registers, what flag should I apply in this case: IntrNoMem or
IntrReadWriteArgMem or nothing?

Thanks.

Nothing; control registers are still "memory" in the sense of Intr*Mem
because they hold state. It doesn't matter that they aren't
addressable.

-Eli