https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94779
--- Comment #21 from Martin Liška <marxin at gcc dot gnu.org> --- > See my comment above. It isn't any integration of VRP, just asking the > ranger about the range, and it isn't useless because to be able to optimize > properly, > you need to figure out for each value one of the 3 possibilities (handled > explicitly by switch and well defined, handled by default and never > reachable or UB). I've got the point that we have these 3 possibilities for each case. However, we also have it for "holes" which are removed and we can't distinguish them in between __builtin_unreachable and falling to the default case. I believe a better place for Ranger is to improve: simplify_using_ranges::simplify_switch_using_ranges (gswitch *stmt) Note that even if CSWITCH does not do a transformation other passes can still benefit from a more canonical gswitch form. That said, I don't like the idea of using Ranger in cswitch because similar should do each pass that somehow works with switches.
