__merge_switches
void __merge_switches(struct expression *switch_expr, struct range_list *case_rl);
__merge_switches(top_expression(switch_expr_stack), rl);
__merge_switches(top_expression(switch_expr_stack), NULL);
__merge_switches(top_expression(switch_expr_stack), rl);
__merge_switches(top_expression(switch_expr_stack), NULL);