--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/WriteBarrierAdditionTest.java	Tue Apr 23 09:40:25 2013 +0200
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2013, 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.oracle.graal.compiler.test;
+
+import org.junit.*;
+
+import com.oracle.graal.api.code.*;
+import com.oracle.graal.debug.*;
+import com.oracle.graal.hotspot.phases.*;
+import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.WriteNode.WriteBarrierType;
+import com.oracle.graal.phases.common.*;
+
+public class WriteBarrierAdditionTest extends GraalCompilerTest {
+
+    public static class Container {
+
+        public Container a;
+        public Container b;
+    }
+
+    public static void test1Snippet() {
+        Container main = new Container();
+        Container temp1 = new Container();
+        Container temp2 = new Container();
+        main.a = temp1;
+        main.b = temp2;
+    }
+
+    public static void test2Snippet() {
+        boolean test = true;
+        Container main = new Container();
+        Container temp1 = new Container();
+        Container temp2 = new Container();
+        for (int i = 0; i < 10; i++) {
+            if (test) {
+                main.a = temp1;
+                main.b = temp2;
+                test = false;
+            } else {
+                main.a = temp2;
+                main.b = temp1;
+                test = true;
+            }
+        }
+    }
+
+    public static void test3Snippet() {
+        Container[] main = new Container[10];
+        Container temp1 = new Container();
+        Container temp2 = new Container();
+        for (int i = 0; i < 10; i++) {
+            main[i].a = main[i].b = temp1;
+        }
+
+        for (int i = 0; i < 10; i++) {
+            main[i].a = main[i].b = temp2;
+        }
+
+    }
+
+    @Test
+    public void test1() {
+        test("test1Snippet", 2);
+    }
+
+    @Test
+    public void test2() {
+        test("test2Snippet", 4);
+    }
+
+    @Test
+    public void test3() {
+        test("test3Snippet", 4);
+    }
+
+    private void test(final String snippet, final int expectedBarriers) {
+        Debug.scope("WriteBarrierAditionTest", new DebugDumpScope(snippet), new Runnable() {
+
+            public void run() {
+                StructuredGraph graph = parse(snippet);
+                new LoweringPhase(null, runtime(), replacements, new Assumptions(false)).apply(graph);
+                new WriteBarrierAdditionPhase().apply(graph);
+                Debug.dump(graph, "After Write Barrier Addition");
+                final int barriers = graph.getNodes(SerialWriteBarrier.class).count();
+                Assert.assertTrue(barriers == expectedBarriers);
+                for (WriteNode write : graph.getNodes(WriteNode.class)) {
+                    if (write.getWriteBarrierType() != WriteBarrierType.NONE) {
+                        Assert.assertTrue(write.successors().count() == 1);
+                        Assert.assertTrue(write.successors().first() instanceof SerialWriteBarrier);
+                    }
+                }
+            }
+        });
+    }
+}

--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/SerialWriteBarrier.java	Mon Apr 22 18:57:35 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/SerialWriteBarrier.java	Tue Apr 23 09:40:25 2013 +0200
@@ -22,11 +22,12 @@
  */
 package com.oracle.graal.nodes;
 
+import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.extended.*;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
 
-public final class SerialWriteBarrier extends FixedWithNextNode implements Lowerable {
+public final class SerialWriteBarrier extends FixedWithNextNode implements Lowerable, Node.IterableNodeType {
 
     @Input private ValueNode object;
     @Input private LocationNode location;