--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/opto/replacednodes.hpp	Tue Jun 10 13:37:16 2014 +0200
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_OPTO_REPLACEDNODES_HPP
+#define SHARE_VM_OPTO_REPLACEDNODES_HPP
+
+#include "opto/connode.hpp"
+
+// During parsing, when a node is "improved",
+// GraphKit::replace_in_map() is called to update the current map so
+// that the improved node is used from that point
+// on. GraphKit::replace_in_map() doesn't operate on the callers maps
+// and so some optimization opportunities may be lost. The
+// ReplacedNodes class addresses that problem.
+//
+// A ReplacedNodes object is a list of pair of nodes. Every
+// SafePointNode carries a ReplacedNodes object. Every time
+// GraphKit::replace_in_map() is called, a new pair of nodes is pushed
+// on the list of replaced nodes. When control flow paths merge, their
+// replaced nodes are also merged. When parsing exits a method to
+// return to a caller, the replaced nodes on the exit path are used to
+// update the caller's map.
+class ReplacedNodes VALUE_OBJ_CLASS_SPEC {
+ private:
+  class ReplacedNode VALUE_OBJ_CLASS_SPEC {
+  private:
+    Node* _initial;
+    Node* _improved;
+  public:
+    ReplacedNode() : _initial(NULL), _improved(NULL) {}
+    ReplacedNode(Node* initial, Node* improved) : _initial(initial), _improved(improved) {}
+    Node* initial() const  { return _initial; }
+    Node* improved() const { return _improved; }
+
+    bool operator==(const ReplacedNode& other) {
+      return _initial == other._initial && _improved == other._improved;
+    }
+  };
+  GrowableArray<ReplacedNode>* _replaced_nodes;
+
+  void allocate_if_necessary();
+  bool has_node(const ReplacedNode& r) const;
+  bool has_target_node(Node* n) const;
+
+ public:
+  ReplacedNodes()
+    : _replaced_nodes(NULL) {}
+
+  void clone();
+  void record(Node* initial, Node* improved);
+  void transfer_from(const ReplacedNodes& other, uint idx);
+  void reset();
+  void apply(Node* n);
+  void merge_with(const ReplacedNodes& other);
+  bool is_empty() const;
+  void dump(outputStream *st) const;
+  void apply(Compile* C, Node* ctl);
+};
+
+#endif // SHARE_VM_OPTO_REPLACEDNODES_HPP