+/**
+ * Pre-Walker: Copies blocks and nodes from the original method graph
+ * to the copied graph.
+ *
+ * @param n A node from the original method graph.
+ * @param env The copied graph.
+ */
+static void copy_all_nodes(ir_node *node, void *env)
+{
+ ir_graph *irg = env;
+ ir_node *new_node = irn_copy_into_irg(node, irg);
+
+ set_irn_link(node, new_node);
+
+ /* fix access to entities on the stack frame */
+ if (is_Sel(new_node)) {
+ ir_entity *ent = get_Sel_entity(new_node);
+ ir_type *tp = get_entity_owner(ent);
+
+ if (is_frame_type(tp)) {
+ /* replace by the copied entity */
+ ent = get_entity_link(ent);
+
+ assert(is_entity(ent));
+ assert(get_entity_owner(ent) == get_irg_frame_type(irg));
+ set_Sel_entity(new_node, ent);
+ }
+ }
+}
+
+/**
+ * Post-walker: Set the predecessors of the copied nodes.
+ * The copied nodes are set as link of their original nodes. The links of
+ * "irn" predecessors are the predecessors of copied node.
+ */
+static void rewire(ir_node *irn, void *env)
+{
+ (void) env;
+ irn_rewire_inputs(irn);
+}
+
+static ir_node *get_new_node(const ir_node *old_node)
+{
+ return (ir_node*) get_irn_link(old_node);
+}
+
+/*
+ * Create a new graph that is a copy of a given one.
+ */
+ir_graph *create_irg_copy(ir_graph *irg)
+{
+ ir_graph *res;
+
+ res = alloc_graph();
+
+ res->n_loc = 0;
+ res->visited = 0; /* visited flag, for the ir walker */
+ res->block_visited = 0; /* visited flag, for the 'block'-walker */
+ res->obst = XMALLOC(struct obstack);
+ obstack_init(res->obst);
+ res->extbb_obst = NULL;
+
+ res->last_node_idx = 0;
+
+ res->phase_state = irg->phase_state;
+ res->irg_pinned_state = irg->irg_pinned_state;
+ res->extblk_state = ir_extblk_info_none;
+ res->fp_model = irg->fp_model;
+
+ new_identities(res);
+
+ /* clone the frame type here for safety */
+ irp_reserve_resources(irp, IR_RESOURCE_ENTITY_LINK);
+ res->frame_type = clone_frame_type(irg->frame_type);
+
+ res->phase_state = irg->phase_state;
+
+ ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
+
+ /* copy all nodes from the graph irg to the new graph res */
+ irg_walk_anchors(irg, copy_all_nodes, rewire, res);
+
+ /* copy the Anchor node */
+ res->anchor = get_new_node(irg->anchor);
+
+ /* -- The end block -- */
+ set_irg_end_block (res, get_new_node(get_irg_end_block(irg)));
+ set_irg_end (res, get_new_node(get_irg_end(irg)));
+
+ /* -- The start block -- */
+ set_irg_start_block(res, get_new_node(get_irg_start_block(irg)));
+ set_irg_bad (res, get_new_node(get_irg_bad(irg)));
+ set_irg_no_mem (res, get_new_node(get_irg_no_mem(irg)));
+ set_irg_start (res, get_new_node(get_irg_start(irg)));
+
+ /* Proj results of start node */
+ set_irg_initial_mem(res, get_new_node(get_irg_initial_mem(irg)));
+
+ /* Copy the node count estimation. Would be strange if this
+ is different from the original one. */
+ res->estimated_node_count = irg->estimated_node_count;
+
+ ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
+ irp_free_resources(irp, IR_RESOURCE_ENTITY_LINK);
+
+ return res;
+}