This patch enables expansion or custom lowering for some integer
condition codes so that any xori that is needed is created before
the last DAG combine to enable optimization.
I've seen cases where we end up with
(or (xori (setcc), 1), (xori (setcc), 1)) which we would ideally
convert to (xori (and (setcc), (setcc)), 1). This patch doesn't
accomplish that yet, but it should allow us to add DAG
combines as follow ups. Example https://godbolt.org/z/Y4qnvsq1b
I'm not following something here. You're increment the rhs of a GT or UGT in the manner I'd expect to apply to a GE or UGE, but also not changing the condition code?
This looks like a dag combine btw, why does this need to be done during lowering at all?