Don't try to evaluate pointer comparisons using FP predicates; don't rerun DSE/DIE if you skipped it first time around.
Don't copy intoptr or ptrtoint operands without adornment if they're scalars (e.g. inttoptr(-1))
Treat null pointers as constants when we get to using the constant solver.
Prevent BAA from walking around the latch edge of a loop, which malfunctions without the proper logic to navigate contexts.

Also prevent pointless requerying with BAA when we know we've got a partial alias.