https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107767
--- Comment #8 from Коренберг Марк <socketpair at gmail dot com> --- Okay, but why switch-case is not handled using fast implementation using masks (when difference between smallest and biggest integer <=64 ? See the first function in my first message where it works as expected. Seems, the problem is not in converting to switch-case, but missing optimisation for switch-case case.