--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/GraalCompiler/src/com/sun/c1x/ir/CompareAndSwap.java	Wed Apr 27 11:50:44 2011 +0200
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2010, 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.*;
+import com.sun.cri.bytecode.*;
+
+/**
+ * Atomic update of a value in memory. Implements the {@link Bytecodes#PCMPSWP} family of instructions.
+ *
+ * Compares a suspected value with the actual value in a memory location.
+ * Iff they are same, a new value is placed into the location and the expected value is returned.
+ * Otherwise, the actual value is returned.
+ *
+ * @author Doug Simon
+ */
+public final class CompareAndSwap extends PointerOp {
+
+    /**
+     * The value to store.
+     */
+    Value expectedValue;
+
+    Value newValue;
+
+    /**
+     * Creates an instruction for a pointer store. If {@code displacement != null}, the effective of the address of the store is
+     * computed as the pointer plus a byte displacement plus a scaled index. Otherwise, the effective address is computed as the
+     * pointer plus a byte offset.
+     * @param pointer the value producing the pointer
+     * @param offset the value producing the byte offset
+     * @param expectedValue the value that must currently being in memory location for the swap to occur
+     * @param newValue the new value to store if the precondition is satisfied
+     * @param stateBefore the state before
+     * @param isVolatile {@code true} if the access is volatile
+     */
+    public CompareAndSwap(int opcode, Value pointer, Value offset, Value expectedValue, Value newValue, FrameState stateBefore, boolean isVolatile) {
+        super(expectedValue.kind, expectedValue.kind, opcode, pointer, null, offset, stateBefore, isVolatile);
+        assert offset != null;
+        this.expectedValue = expectedValue;
+        this.newValue = newValue;
+        setFlag(Flag.LiveStore);
+    }
+
+    @Override
+    public void accept(ValueVisitor v) {
+        v.visitCompareAndSwap(this);
+    }
+
+    public Value expectedValue() {
+        return expectedValue;
+    }
+
+    public Value newValue() {
+        return newValue;
+    }
+
+    @Override
+    public void inputValuesDo(ValueClosure closure) {
+        super.inputValuesDo(closure);
+        expectedValue = closure.apply(expectedValue);
+        newValue = closure.apply(newValue);
+    }
+
+    @Override
+    public void print(LogStream out) {
+        out.print(Bytecodes.nameOf(opcode)).print("(").print(pointer());
+        out.print(" + ").print(offset());
+        out.print(", ").print(expectedValue()).print(", ").print(newValue()).print(')');
+    }
+}