+ if (flags_proj == NULL) {
+ res = new_rd_ia32_Neg(dbg, irg, block, in2);
+ arch_set_irn_register(cg->arch_env, res, in2_reg);
+
+ /* add to schedule */
+ sched_add_before(irn, res);
+
+ /* generate the add */
+ res = new_rd_ia32_Add(dbg, irg, block, noreg, noreg, nomem, res, in1);
+ arch_set_irn_register(cg->arch_env, res, out_reg);
+ set_ia32_commutative(res);
+
+ /* exchange the add and the sub */
+ edges_reroute(irn, res, irg);
+
+ /* add to schedule */
+ sched_add_before(irn, res);
+ } else {
+ ir_node *stc, *cmc, *not, *adc;
+ ir_node *adc_flags;
+
+ /*
+ * ARG, the above technique does NOT set the flags right.
+ * So, we must produce the following code:
+ * t1 = ~b
+ * t2 = a + ~b + Carry
+ * Complement Carry
+ *
+ * a + -b = a + (~b + 1) would set the carry flag IF a == b ...
+ */
+ not = new_rd_ia32_Not(dbg, irg, block, in2);
+ arch_set_irn_register(cg->arch_env, not, in2_reg);
+ sched_add_before(irn, not);
+
+ stc = new_rd_ia32_Stc(dbg, irg, block);
+ arch_set_irn_register(cg->arch_env, stc,
+ &ia32_flags_regs[REG_EFLAGS]);
+ sched_add_before(irn, stc);
+
+ adc = new_rd_ia32_Adc(dbg, irg, block, noreg, noreg, nomem, not,
+ in1, stc);
+ arch_set_irn_register(cg->arch_env, adc, out_reg);
+ sched_add_before(irn, adc);
+
+ set_irn_mode(adc, mode_T);
+ adc_flags = new_r_Proj(irg, block, adc, mode_Iu, pn_ia32_Adc_flags);
+ arch_set_irn_register(cg->arch_env, adc_flags,
+ &ia32_flags_regs[REG_EFLAGS]);
+
+ cmc = new_rd_ia32_Cmc(dbg, irg, block, adc_flags);
+ arch_set_irn_register(cg->arch_env, cmc,
+ &ia32_flags_regs[REG_EFLAGS]);
+ sched_add_before(irn, cmc);
+
+ exchange(flags_proj, cmc);
+ if (res_proj != NULL) {
+ set_Proj_pred(res_proj, adc);
+ set_Proj_proj(res_proj, pn_ia32_Adc_res);
+ }