+/**
+ * Debug helpers: You can indicate wether you are currently using visited or
+ * block_visited flags. If NDEBUG is not defined, then the compiler will abort
+ * if 2 parties try to use the flags.
+ */
+#ifndef NDEBUG
+void set_using_block_visited(ir_graph *irg);
+void clear_using_block_visited(ir_graph *irg);
+int using_block_visited(const ir_graph *irg);
+void set_using_visited(ir_graph *irg);
+void clear_using_visited(ir_graph *irg);
+int using_visited(const ir_graph *irg);
+void set_using_irn_link(ir_graph *irg);
+void clear_using_irn_link(ir_graph *irg);
+int using_irn_link(const ir_graph *irg);
+#else
+static INLINE void set_using_block_visited(ir_graph *irg) { (void) irg; }
+static INLINE void clear_using_block_visited(ir_graph *irg) { (void) irg; }
+static INLINE int using_block_visited(const ir_graph *irg) { (void) irg; return 0; }
+static INLINE void set_using_visited(ir_graph *irg) { (void) irg; }
+static INLINE void clear_using_visited(ir_graph *irg) { (void) irg; }
+static INLINE int using_visited(const ir_graph *irg) { (void) irg; return 0; }
+static INLINE void set_using_irn_link(ir_graph *irg) { (void) irg; }
+static INLINE void clear_using_irn_link(ir_graph *irg) { (void) irg; }
+static INLINE int using_irn_link(const ir_graph *irg) { (void) irg; return 0; }
+#endif
+