respect dependency edges in dead code elimination

ir/common/irtools.c

@@ -180,6 +180,7 @@ void irn_rewire_inputs(ir_node *node)
 {
 	ir_node *new_node;
 	int      arity;
+	int      n_deps;
 	int      i;
 
 	new_node = get_new_node(node);
@@ -197,6 +198,13 @@ void irn_rewire_inputs(ir_node *node)
 		set_irn_n(new_node, i, new_in);
 	}
 
+	n_deps = get_irn_deps(new_node);
+	for (i = 0; i < n_deps; ++i) {
+		ir_node *dep     = get_irn_dep(node, i);
+		ir_node *new_dep = get_new_node(dep);
+		set_irn_dep(new_node, i, new_dep);
+	}
+
 	/* Now the new node is complete. We can add it to the hash table for CSE. */
 	add_identities(new_node);
 }

ir/opt/dead_code_elimination.c

@@ -75,13 +75,14 @@ static void copy_node_dce(ir_node *node, void *env)
  */
 static void copy_graph_env(ir_graph *irg)
 {
+	ir_node *anchor = irg->anchor;
 	ir_node *new_anchor;
 
 	/* copy nodes */
-	irg_walk_anchors(irg, copy_node_dce, rewire_inputs, NULL);
+	irg_walk_in_or_dep(anchor, copy_node_dce, rewire_inputs, NULL);
 
 	/* fix the anchor */
-	new_anchor = (ir_node*)get_irn_link(irg->anchor);
+	new_anchor = (ir_node*)get_irn_link(anchor);
 	assert(new_anchor != NULL);
 	irg->anchor = new_anchor;
 }