--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/WriteBarrierAdditionPhase.java	Mon Jul 22 10:46:26 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/WriteBarrierAdditionPhase.java	Mon Jul 22 10:54:43 2013 +0200
@@ -67,7 +67,7 @@
         BarrierType barrierType = node.getBarrierType();
         if (barrierType == BarrierType.PRECISE) {
             if (useG1GC()) {
-                if (node.isInitialized()) {
+                if (!node.isInitialization()) {
                     G1PreWriteBarrier preBarrier = graph.add(new G1PreWriteBarrier(node.object(), null, node.location(), true, node.getNullCheck()));
                     preBarrier.setDeoptimizationState(node.getDeoptimizationState());
                     node.setNullCheck(false);
@@ -116,7 +116,7 @@
 
     private static void addArrayRangeBarriers(ArrayRangeWriteNode node, StructuredGraph graph) {
         if (useG1GC()) {
-            if (node.isInitialized()) {
+            if (!node.isInitialization()) {
                 G1ArrayRangePreWriteBarrier g1ArrayRangePreWriteBarrier = graph.add(new G1ArrayRangePreWriteBarrier(node.getArray(), node.getIndex(), node.getLength()));
                 graph.addBeforeFixed(node, g1ArrayRangePreWriteBarrier);
             }

--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/UnsafeArrayCopyNode.java	Mon Jul 22 10:46:26 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/UnsafeArrayCopyNode.java	Mon Jul 22 10:54:43 2013 +0200
@@ -83,8 +83,8 @@
     }
 
     @Override
-    public boolean isInitialized() {
-        return true;
+    public boolean isInitialization() {
+        return false;
     }
 
     public Kind getElementKind() {

--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ArrayRangeWriteNode.java	Mon Jul 22 10:46:26 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ArrayRangeWriteNode.java	Mon Jul 22 10:54:43 2013 +0200
@@ -56,8 +56,9 @@
     public abstract boolean isObjectArray();
 
     /**
-     * If {@link #isInitialized()} is true, the memory location contains a valid value. If
-     * {@link #isInitialized()} is false, the memory location is uninitialized or zero.
+     * Returns whether this write is the initialization of the written location. Fit it is true, the
+     * old value of the memory location is either uninitialized or zero. If it is false, the memory
+     * location is guaranteed to contain a valid value or zero.
      */
-    public abstract boolean isInitialized();
+    public abstract boolean isInitialization();
 }

--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteNode.java	Mon Jul 22 10:46:26 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteNode.java	Mon Jul 22 10:54:43 2013 +0200
@@ -37,7 +37,7 @@
 
     @Input private ValueNode value;
     @Input(notDataflow = true) private FrameState stateAfter;
-    private final boolean initialized;
+    private final boolean initialization;
 
     public FrameState stateAfter() {
         return stateAfter;
@@ -58,21 +58,22 @@
     }
 
     /**
-     * If {@link #isInitialized()} is true, the memory location contains a valid value. If
-     * {@link #isInitialized()} is false, the memory location is uninitialized or zero.
+     * Returns whether this write is the initialization of the written location. Fit it is true, the
+     * old value of the memory location is either uninitialized or zero. If it is false, the memory
+     * location is guaranteed to contain a valid value or zero.
      */
-    public boolean isInitialized() {
-        return initialized;
+    public boolean isInitialization() {
+        return initialization;
     }
 
     public WriteNode(ValueNode object, ValueNode value, ValueNode location, BarrierType barrierType, boolean compressible) {
-        this(object, value, location, barrierType, compressible, true);
+        this(object, value, location, barrierType, compressible, false);
     }
 
-    public WriteNode(ValueNode object, ValueNode value, ValueNode location, BarrierType barrierType, boolean compressible, boolean initialized) {
+    public WriteNode(ValueNode object, ValueNode value, ValueNode location, BarrierType barrierType, boolean compressible, boolean initialization) {
         super(object, location, StampFactory.forVoid(), barrierType, compressible);
         this.value = value;
-        this.initialized = initialized;
+        this.initialization = initialization;
     }
 
     @Override

--- a/graal/com.oracle.graal.word/src/com/oracle/graal/word/phases/WordTypeRewriterPhase.java	Mon Jul 22 10:46:26 2013 +0200
+++ b/graal/com.oracle.graal.word/src/com/oracle/graal/word/phases/WordTypeRewriterPhase.java	Mon Jul 22 10:54:43 2013 +0200
@@ -343,7 +343,7 @@
 
     private static ValueNode writeOp(StructuredGraph graph, ValueNode base, ValueNode value, Invoke invoke, LocationNode location, Opcode op) {
         assert op == Opcode.WRITE || op == Opcode.INITIALIZE;
-        WriteNode write = graph.add(new WriteNode(base, value, location, BarrierType.NONE, false, op == Opcode.WRITE));
+        WriteNode write = graph.add(new WriteNode(base, value, location, BarrierType.NONE, false, op == Opcode.INITIALIZE));
         write.setStateAfter(invoke.stateAfter());
         graph.addBeforeFixed(invoke.asNode(), write);
         return write;