--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/Compiler/src/com/sun/c1x/ir/MonitorExit.java	Wed Apr 27 11:43:22 2011 +0200
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2009, 2011, 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 com.sun.c1x.ir;
+
+import com.sun.c1x.debug.*;
+import com.sun.c1x.value.*;
+
+/**
+ * The {@code MonitorExit} instruction represents a monitor release.
+ *
+ * @author Ben L. Titzer
+ */
+public final class MonitorExit extends AccessMonitor {
+
+    /**
+     * Creates a new MonitorExit instruction.
+     *
+     * @param object the instruction produces the object value
+     * @param lockAddress the address of the on-stack lock object or {@code null} if the runtime does not place locks on the stack
+     * @param lockNumber the number of the lock
+     * @param stateBefore the state before executing this instruction
+     */
+    public MonitorExit(Value object, Value lockAddress, int lockNumber, FrameState stateBefore) {
+        super(object, lockAddress, stateBefore, lockNumber);
+        if (object.isNonNull()) {
+            eliminateNullCheck();
+        }
+    }
+
+    @Override
+    public boolean canTrap() {
+        // C1X assumes that locks are well balanced and so there no need to handle
+        // IllegalMonitorStateExceptions thrown by monitorexit instructions.
+        return needsNullCheck();
+    }
+
+    @Override
+    public void accept(ValueVisitor v) {
+        v.visitMonitorExit(this);
+    }
+
+    @Override
+    public void print(LogStream out) {
+        out.print("exit monitor[").print(lockNumber).print("](").print(object()).print(')');
+    }
+}