# HG changeset patch
# User Roland Schatz <roland.schatz@oracle.com>
# Date 1373898243 -7200
# Node ID e82c28e94f08110bdd42f8063c310a460facd88d
# Parent  f4f46b734a4c73f0bb95bcc06344cabe96b50929
Don't add G1 prebarrier if the written location is uninitialized.

diff -r f4f46b734a4c -r e82c28e94f08 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/WriteBarrierAdditionPhase.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/WriteBarrierAdditionPhase.java	Mon Jul 15 15:29:01 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/WriteBarrierAdditionPhase.java	Mon Jul 15 16:24:03 2013 +0200
@@ -69,10 +69,12 @@
         WriteBarrierType barrierType = node.getWriteBarrierType();
         if (barrierType == WriteBarrierType.PRECISE) {
             if (useG1GC()) {
-                G1PreWriteBarrier preBarrier = graph.add(new G1PreWriteBarrier(node.object(), null, node.location(), true, node.getNullCheck()));
-                preBarrier.setDeoptimizationState(node.getDeoptimizationState());
-                node.setNullCheck(false);
-                graph.addBeforeFixed(node, preBarrier);
+                if (node.isInitialized()) {
+                    G1PreWriteBarrier preBarrier = graph.add(new G1PreWriteBarrier(node.object(), null, node.location(), true, node.getNullCheck()));
+                    preBarrier.setDeoptimizationState(node.getDeoptimizationState());
+                    node.setNullCheck(false);
+                    graph.addBeforeFixed(node, preBarrier);
+                }
                 graph.addAfterFixed(node, graph.add(new G1PostWriteBarrier(node.object(), node.value(), node.location(), true)));
             } else {
                 graph.addAfterFixed(node, graph.add(new SerialWriteBarrier(node.object(), node.location(), true)));
@@ -116,9 +118,11 @@
 
     private static void addArrayRangeBarriers(ArrayRangeWriteNode node, StructuredGraph graph) {
         if (useG1GC()) {
-            G1ArrayRangePreWriteBarrier g1ArrayRangePreWriteBarrier = graph.add(new G1ArrayRangePreWriteBarrier(node.getArray(), node.getIndex(), node.getLength()));
+            if (node.isInitialized()) {
+                G1ArrayRangePreWriteBarrier g1ArrayRangePreWriteBarrier = graph.add(new G1ArrayRangePreWriteBarrier(node.getArray(), node.getIndex(), node.getLength()));
+                graph.addBeforeFixed(node, g1ArrayRangePreWriteBarrier);
+            }
             G1ArrayRangePostWriteBarrier g1ArrayRangePostWriteBarrier = graph.add(new G1ArrayRangePostWriteBarrier(node.getArray(), node.getIndex(), node.getLength()));
-            graph.addBeforeFixed(node, g1ArrayRangePreWriteBarrier);
             graph.addAfterFixed(node, g1ArrayRangePostWriteBarrier);
         } else {
             SerialArrayRangeWriteBarrier serialArrayRangeWriteBarrier = graph.add(new SerialArrayRangeWriteBarrier(node.getArray(), node.getIndex(), node.getLength()));
diff -r f4f46b734a4c -r e82c28e94f08 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/UnsafeArrayCopyNode.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/UnsafeArrayCopyNode.java	Mon Jul 15 15:29:01 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/UnsafeArrayCopyNode.java	Mon Jul 15 16:24:03 2013 +0200
@@ -82,6 +82,11 @@
         return elementKind == Kind.Object;
     }
 
+    @Override
+    public boolean isInitialized() {
+        return true;
+    }
+
     public Kind getElementKind() {
         return elementKind;
     }
diff -r f4f46b734a4c -r e82c28e94f08 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ArrayRangeWriteNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ArrayRangeWriteNode.java	Mon Jul 15 15:29:01 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ArrayRangeWriteNode.java	Mon Jul 15 16:24:03 2013 +0200
@@ -54,4 +54,10 @@
      * Return true if the written array is an object array, false if it is a primitive array.
      */
     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.
+     */
+    public abstract boolean isInitialized();
 }
diff -r f4f46b734a4c -r e82c28e94f08 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteNode.java	Mon Jul 15 15:29:01 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteNode.java	Mon Jul 15 16:24:03 2013 +0200
@@ -37,6 +37,7 @@
 
     @Input private ValueNode value;
     @Input(notDataflow = true) private FrameState stateAfter;
+    private final boolean initialized;
 
     public FrameState stateAfter() {
         return stateAfter;
@@ -56,9 +57,22 @@
         return value;
     }
 
+    /**
+     * If {@link #isInitialized()} is true, the memory location contains a valid value. If
+     * {@link #isInitialized()} is false, the memory location is uninitialized or zero.
+     */
+    public boolean isInitialized() {
+        return initialized;
+    }
+
     public WriteNode(ValueNode object, ValueNode value, ValueNode location, WriteBarrierType barrierType, boolean compress) {
+        this(object, value, location, barrierType, compress, true);
+    }
+
+    public WriteNode(ValueNode object, ValueNode value, ValueNode location, WriteBarrierType barrierType, boolean compress, boolean initialized) {
         super(object, location, StampFactory.forVoid(), barrierType, compress);
         this.value = value;
+        this.initialized = initialized;
     }
 
     @Override