--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.word/src/org/graalvm/compiler/word/AtomicWord.java	2017-02-15 17:09:40.756605628 -0800
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2015, 2015, 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.word;
+
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * A {@link WordBase word} value that may be updated atomically. See the
+ * {@link java.util.concurrent.atomic} package specification for description of the properties of
+ * atomic variables.
+ *
+ * Similar to {@link AtomicReference}, but for {@link WordBase word} types. A dedicated
+ * implementation is necessary because Object and word types cannot be mixed.
+ */
+public class AtomicWord<T extends WordBase> {
+
+    /**
+     * For simplicity, we convert the word value to a long and delegate to existing atomic
+     * operations.
+     */
+    protected final AtomicLong value;
+
+    /**
+     * Creates a new AtomicLong with initial value {@link Word#zero}.
+     */
+    public AtomicWord() {
+        value = new AtomicLong();
+    }
+
+    /**
+     * Gets the current value.
+     *
+     * @return the current value
+     */
+    @SuppressWarnings("unchecked")
+    public final T get() {
+        return (T) Word.unsigned(value.get());
+    }
+
+    /**
+     * Sets to the given value.
+     *
+     * @param newValue the new value
+     */
+    public final void set(T newValue) {
+        value.set(newValue.rawValue());
+    }
+
+    /**
+     * Atomically sets to the given value and returns the old value.
+     *
+     * @param newValue the new value
+     * @return the previous value
+     */
+    @SuppressWarnings("unchecked")
+    public final T getAndSet(T newValue) {
+        return (T) Word.unsigned(value.getAndSet(newValue.rawValue()));
+    }
+
+    /**
+     * Atomically sets the value to the given updated value if the current value {@code ==} the
+     * expected value.
+     *
+     * @param expect the expected value
+     * @param update the new value
+     * @return {@code true} if successful. False return indicates that the actual value was not
+     *         equal to the expected value.
+     */
+    public final boolean compareAndSet(T expect, T update) {
+        return value.compareAndSet(expect.rawValue(), update.rawValue());
+    }
+}