only build switch fallthrough block when needed

[cparser] / ast2firm.c

diff --git a/ast2firm.c b/ast2firm.c
index 8830e7b..fe849fe 100644 (file)
--- a/ast2firm.c
+++ b/ast2firm.c
@@ -4267,13 +4267,22 @@ static void create_jump_statement(const statement_t *statement,
        set_cur_block(NULL);
 }
 
+static ir_node *get_break_label(void)
+{
+       if (break_label == NULL) {
+               ir_node *cur_block = get_cur_block();
+               break_label = new_immBlock();
+               set_cur_block(cur_block);
+       }
+       return break_label;
+}
+
 static void switch_statement_to_firm(const switch_statement_t *statement)
 {
        dbg_info *dbgi = get_dbg_info(&statement->base.source_position);
 
        ir_node *expression  = expression_to_firm(statement->expression);
        ir_node *cond        = new_d_Cond(dbgi, expression);
-       ir_node *break_block = new_immBlock();
 
        set_cur_block(NULL);
 
@@ -4282,32 +4291,33 @@ static void switch_statement_to_firm(const switch_statement_t *statement)
        const bool     old_saw_default_label = saw_default_label;
        saw_default_label                    = false;
        current_switch_cond                  = cond;
-       break_label                          = break_block;
+       break_label                          = NULL;
 
        if (statement->body != NULL) {
                statement_to_firm(statement->body);
        }
 
-       if(get_cur_block() != NULL) {
+       if (get_cur_block() != NULL) {
                ir_node *jmp = new_Jmp();
-               add_immBlock_pred(break_block, jmp);
+               add_immBlock_pred(get_break_label(), jmp);
        }
 
        if (!saw_default_label) {
                set_cur_block(get_nodes_block(cond));
                ir_node *const proj = new_d_defaultProj(dbgi, cond,
                                                        MAGIC_DEFAULT_PN_NUMBER);
-               add_immBlock_pred(break_block, proj);
+               add_immBlock_pred(get_break_label(), proj);
        }
 
+       if (break_label != NULL) {
+               mature_immBlock(break_label);
+       }
+       set_cur_block(break_label);
+
        assert(current_switch_cond == cond);
-       assert(break_label         == break_block);
        current_switch_cond = old_switch_cond;
        break_label         = old_break_label;
        saw_default_label   = old_saw_default_label;
-
-       mature_immBlock(break_block);
-       set_cur_block(break_block);
 }
 
 static void case_label_to_firm(const case_label_statement_t *statement)
@@ -4552,7 +4562,7 @@ static void statement_to_firm(statement_t *statement)
                declaration_statement_to_firm(&statement->declaration);
                return;
        case STATEMENT_BREAK:
-               create_jump_statement(statement, break_label);
+               create_jump_statement(statement, get_break_label());
                return;
        case STATEMENT_CONTINUE:
                create_jump_statement(statement, continue_label);