backend always expects outedges, assure them after place_code, optimize_graph_df

ir/be/ia32/bearch_ia32.c

@@ -692,6 +692,8 @@ static void ia32_prepare_graph(ir_graph *irg)
 
 	/* do local optimizations (mainly CSE) */
 	optimize_graph_df(irg);
+	/* backend code expects that outedges are always enabled */
+	edges_assure(irg);
 
 	if (irg_data->dump)
 		dump_ir_graph(irg, "transformed");
@@ -701,6 +703,8 @@ static void ia32_prepare_graph(ir_graph *irg)
 
 	/* do code placement, to optimize the position of constants */
 	place_code(irg);
+	/* backend code expects that outedges are always enabled */
+	edges_assure(irg);
 
 	if (irg_data->dump)
 		dump_ir_graph(irg, "place");

ir/be/sparc/sparc_transform.c

@@ -2530,6 +2530,8 @@ void sparc_transform_graph(ir_graph *irg)
 
 	/* do code placement, to optimize the position of constants */
 	place_code(irg);
+	/* backend expects outedges to be always on */
+	edges_assure(irg);
 }
 
 void sparc_init_transform(void)