https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108447
--- Comment #11 from Aldy Hernandez <aldyh at gcc dot gnu.org> --- Hmmm, I wonder if we could do this all in validate_relation like Andrew had planned. If NAN is a possibility in either x or y, then we could disallow any relation recording right off the bat, and avoid any special casing in union/intersect. Perhaps allow the != relation even if NAN?
