+ /**
+ * Insert the instructions necessary to lower a return statement,
+ * before the given return instruction.
+ */
+ void insert_lowered_return(ir_return *ir)
+ {
+ ir_variable* return_flag = this->function.get_return_flag();
+ if(!this->function.signature->return_type->is_void()) {
+ ir_variable* return_value = this->function.get_return_value();
+ ir->insert_before(
+ new(ir) ir_assignment(
+ new (ir) ir_dereference_variable(return_value),
+ ir->value));
+ }
+ ir->insert_before(
+ new(ir) ir_assignment(
+ new (ir) ir_dereference_variable(return_flag),
+ new (ir) ir_constant(true)));
+ this->loop.may_set_return_flag = true;
+ }
+
+ /**
+ * If the given instruction is a return, lower it to instructions
+ * that store the return value (if there is one), set the return
+ * flag, and then break.
+ *
+ * It is safe to pass NULL to this function.
+ */
+ void lower_return_unconditionally(ir_instruction *ir)
+ {
+ if (get_jump_strength(ir) != strength_return) {
+ return;
+ }
+ insert_lowered_return((ir_return*)ir);
+ ir->replace_with(new(ir) ir_loop_jump(ir_loop_jump::jump_break));
+ }
+
+ /**
+ * Create the necessary instruction to replace a break instruction.
+ */
+ ir_instruction *create_lowered_break()
+ {
+ void *ctx = this->function.signature;
+ return new(ctx) ir_assignment(
+ new(ctx) ir_dereference_variable(this->loop.get_break_flag()),
+ new(ctx) ir_constant(true),
+ 0);
+ }
+
+ /**
+ * If the given instruction is a break, lower it to an instruction
+ * that sets the break flag, without consulting
+ * should_lower_jump().
+ *
+ * It is safe to pass NULL to this function.
+ */
+ void lower_break_unconditionally(ir_instruction *ir)
+ {
+ if (get_jump_strength(ir) != strength_break) {
+ return;
+ }
+ ir->replace_with(create_lowered_break());
+ }
+
+ /**
+ * If the block ends in a conditional or unconditional break, lower
+ * it, even though should_lower_jump() says it needn't be lowered.
+ */
+ void lower_final_breaks(exec_list *block)
+ {
+ ir_instruction *ir = (ir_instruction *) block->get_tail();
+ lower_break_unconditionally(ir);
+ ir_if *ir_if = ir->as_if();
+ if (ir_if) {
+ lower_break_unconditionally(
+ (ir_instruction *) ir_if->then_instructions.get_tail());
+ lower_break_unconditionally(
+ (ir_instruction *) ir_if->else_instructions.get_tail());
+ }
+ }
+