--- /dev/null	2016-05-31 09:42:47.975716356 -0700
+++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/LocationIdentity.java	2016-12-07 13:47:52.818197320 -0800
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2011, 2016, 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.
+ */
+package org.graalvm.compiler.core.common;
+
+import java.util.IdentityHashMap;
+
+// JaCoCo Exclude
+
+/**
+ * Marker interface for location identities. A different location identity of two memory accesses
+ * guarantees that the two accesses do not interfere.
+ *
+ * Clients of {@link LocationIdentity} must use {@link #equals(Object)}, not {@code ==}, when
+ * comparing two {@link LocationIdentity} values for equality. Likewise, they must not use
+ * {@link IdentityHashMap}s with {@link LocationIdentity} values as keys.
+ */
+public abstract class LocationIdentity {
+
+    private static final class AnyLocationIdentity extends LocationIdentity {
+        @Override
+        public boolean isImmutable() {
+            return false;
+        }
+
+        @Override
+        public String toString() {
+            return "ANY_LOCATION";
+        }
+    }
+
+    public static final LocationIdentity ANY_LOCATION = new AnyLocationIdentity();
+
+    public static LocationIdentity any() {
+        return ANY_LOCATION;
+    }
+
+    /**
+     * Denotes a location is unchanging in all cases. Not that this is different than the Java
+     * notion of final which only requires definite assignment.
+     */
+    public abstract boolean isImmutable();
+
+    public final boolean isMutable() {
+        return !isImmutable();
+    }
+
+    public final boolean isAny() {
+        return this == ANY_LOCATION;
+    }
+
+    public final boolean isSingle() {
+        return this != ANY_LOCATION;
+    }
+
+    public final boolean overlaps(LocationIdentity other) {
+        return isAny() || other.isAny() || this.equals(other);
+    }
+}