Richard Kenner wrote:
Yes, one possibility is to use a RTX hook for this too. By default you
would return NULL (and this would propagate up); in combine you could
override it to return the CLOBBER.
I really don't see why. Look at when combine calls the simplify routines now.
If they return zero, it uses the original value.
Some of the combine simplifications (you obviously know that) work by
"hoping" that the CLOBBER is simplified away. I don't think you can
preserve all their power if you propagate NULL. In most cases you can
replace CLOBBER with NULL, but I don't think that's possible everywhere.
Paolo
