https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108941
--- Comment #6 from jbeulich at suse dot com --- (In reply to Jakub Jelinek from comment #5) > GCC doesn't even have that information at all, at the RTL level it doesn't > know > if it was signed or unsigned. > All it has is the constraint and operand for it, like (reg:QI 126) or > (const_int -1). > As I said earlier, constants are always sign-extended from their mode. > One could e.g. have during expansion (set (reg:QI 126) (const_int -1)) > and later on asm_operands with "ic" and (reg:QI 126). Same assignment for > int8_t x = -1 or int8_t x = 255 or uint8_t x = -1 or uint8_t x = 255, at > GIMPLE one can differentiate that based on types, at RTL one has just mode. While for int8_t x = -1 or int8_t x = 255 I can see that the result is as described, for uint8_t x = -1 or uint8_t x = 255 (or, as in the example, a constant the was cast to an unsigned 8-bit type) why is it not (const int 255)?
