https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89119
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> --- There are only a couple of spots that build this: constexpr.c: e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); constexpr.c: tree range = build2 (RANGE_EXPR, size_type_node, init.c: ce.index = build2 (RANGE_EXPR, sizetype, size_zero_node, init.c: ce.index = build2 (RANGE_EXPR, sizetype, size_zero_node, max_index); init.c: field = build2 (RANGE_EXPR, sizetype, field, typeck2.c: tree range = build2 (RANGE_EXPR, size_type_node, As you can see, all of them are sizetype or size_type_node and the operands should be really the same type. Several of them assert that what they are building the RANGE_EXPR with is INTEGER_CST, other spots use size_int () or similar to construct those INTEGER_CSTs. In any case, RANGE_EXPRs make only sense with constant ranges, for anything else there should be runtime loop initializing it, and they are about array indexes, which is something expressed in sizetype.
