https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84416
--- Comment #2 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- Ignoring weird targets (m32c...), there's no valid use for array indices larger than size_t / ptrdiff_t (beyond I suppose any optimization effects from knowing that the conversion of the array index, or offset added to a pointer, to a pointer-sized integer of the same signedness does not change the value).