- case iro_Cmp: {
- ir_node *left = get_Cmp_left(node);
- ir_node *right = get_Cmp_right(node);
- ir_mode *cmp_mode = get_irn_mode(left);
- ir_relation relation = get_Cmp_relation(node);
-
- if ((mode_is_int(cmp_mode) || mode_is_reference(cmp_mode)) &&
- (get_mode_size_bits(cmp_mode) < get_mode_size_bits(mode) ||
- (mode_is_signed(cmp_mode) && is_Const(right) && is_Const_null(right) && relation != ir_relation_greater))) {
- int need_not = 0;
- ir_node *a = NULL;
- ir_node *b = NULL;
- int bits;
- ir_tarval *tv;
- ir_node *shift_cnt;
-
- if (relation == ir_relation_less) {
- /* a < b -> (a - b) >> 31 */
- a = left;
- b = right;
- } else if (relation == ir_relation_less_equal) {
- /* a <= b -> ~(a - b) >> 31 */
- a = right;
- b = left;
- need_not = 1;
- } else if (relation == ir_relation_greater) {
- /* a > b -> (b - a) >> 31 */
- a = right;
- b = left;
- } else if (relation == ir_relation_greater_equal) {
- /* a >= b -> ~(a - b) >> 31 */
- a = left;
- b = right;
- need_not = 1;
- } else {
- goto synth_zero_one;
- }
-
- bits = get_mode_size_bits(mode);
- tv = new_tarval_from_long(bits-1, mode_Iu);
- shift_cnt = new_rd_Const(dbgi, irg, tv);
-
- if (cmp_mode != mode) {
- a = new_rd_Conv(dbgi, block, a, mode);
- b = new_rd_Conv(dbgi, block, b, mode);
- }
-
- res = new_rd_Sub(dbgi, block, a, b, mode);
- if (need_not) {
- res = new_rd_Not(dbgi, block, res, mode);
- }
- res = new_rd_Shr(dbgi, block, res, shift_cnt, mode);
- } else {
- /* synthesize the 0/1 value */
-synth_zero_one:
- res = config->create_set(node);
- }