* Does not work for Calls that use the exception stuff.
*
* @param irg the graph to be optimized
+ *
+ * @return non-zero if the optimization could be applied, 0 else
*/
-void opt_tail_rec_irg(ir_graph *irg);
+int opt_tail_rec_irg(ir_graph *irg);
/*
* Optimize tail-recursion calls for all IR-Graphs.