+/**
+ * Walks only over Block nodes in the graph. Has it's own visited
+ * flag, so that it can be interleaved with the other walker.
+ *
+ * @param block the start block
+ * @param pre the pre visit function
+ * @param post the post visit function
+ * @param env the environment for the walker
+ */
+void irg_block_edges_walk(ir_node *block, irg_walk_func *pre, irg_walk_func *post, void *env);
+