--- a/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/Graph.java	Thu Oct 02 13:13:00 2014 +0200
+++ b/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/Graph.java	Thu Oct 02 14:22:16 2014 +0200
@@ -78,7 +78,12 @@
     int compressions;
 
     NodeEventListener nodeEventListener;
-    private final HashMap<CacheEntry, Node> cachedNodes = new HashMap<>();
+
+    /**
+     * Used to global value number {@link ValueNumberable} {@linkplain NodeClass#isLeafNode() leaf}
+     * nodes.
+     */
+    private final HashMap<CacheEntry, Node> cachedLeafNodes = new HashMap<>();
 
     /*
      * Indicates that the graph should no longer be modified. Frozen graphs can be used my multiple
@@ -86,19 +91,22 @@
      */
     private boolean isFrozen = false;
 
+    /**
+     * Entry in {@link Graph#cachedLeafNodes}.
+     */
     private static final class CacheEntry {
 
         private final Node node;
 
         public CacheEntry(Node node) {
-            assert node instanceof ValueNumberable;
-            assert node.isLeafNode();
+            assert node.getNodeClass().valueNumberable();
+            assert node.getNodeClass().isLeafNode();
             this.node = node;
         }
 
         @Override
         public int hashCode() {
-            return Node.USE_GENERATED_NODES ? node.getValueNumber() : node.getNodeClass().valueNumber(node);
+            return Node.USE_GENERATED_NODES ? node.valueNumberLeaf() : node.getNodeClass().valueNumber(node);
         }
 
         @Override
@@ -446,7 +454,7 @@
             return (T) other;
         } else {
             Node result = addIfMissing ? addHelper(node) : node;
-            if (node.isLeafNode()) {
+            if (node.getNodeClass().isLeafNode()) {
                 putNodeIntoCache(result);
             }
             return (T) result;
@@ -456,15 +464,15 @@
     void putNodeIntoCache(Node node) {
         assert node.graph() == this || node.graph() == null;
         assert node.getNodeClass().valueNumberable();
-        assert node.isLeafNode() : node.getClass();
-        cachedNodes.put(new CacheEntry(node), node);
+        assert node.getNodeClass().isLeafNode() : node.getClass();
+        cachedLeafNodes.put(new CacheEntry(node), node);
     }
 
     Node findNodeInCache(Node node) {
         CacheEntry key = new CacheEntry(node);
-        Node result = cachedNodes.get(key);
+        Node result = cachedLeafNodes.get(key);
         if (result != null && result.isDeleted()) {
-            cachedNodes.remove(key);
+            cachedLeafNodes.remove(key);
             return null;
         }
         return result;
@@ -473,7 +481,8 @@
     public Node findDuplicate(Node node) {
         NodeClass nodeClass = node.getNodeClass();
         assert nodeClass.valueNumberable();
-        if (node.isLeafNode()) {
+        if (nodeClass.isLeafNode()) {
+            // Leaf node: look up in cache
             Node cachedNode = findNodeInCache(node);
             if (cachedNode != null) {
                 return cachedNode;
@@ -481,6 +490,10 @@
                 return null;
             }
         } else {
+            // Non-leaf node: look for another usage of the node's inputs that
+            // has the same data, inputs and successors as the node. To reduce
+            // the cost of this computation, only the input with estimated highest
+            // usage count is considered.
 
             int minCount = Integer.MAX_VALUE;
             Node minCountNode = null;

--- a/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/Node.java	Thu Oct 02 13:13:00 2014 +0200
+++ b/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/Node.java	Thu Oct 02 14:22:16 2014 +0200
@@ -143,6 +143,14 @@
         boolean setStampFromReturnType() default false;
     }
 
+    /**
+     * Marker for a node that can be replaced by another node via global value numbering. A
+     * {@linkplain NodeClass#isLeafNode() leaf} node can be replaced by another node of the same
+     * type that has exactly the same {@linkplain NodeClass#getData() data} values. A non-leaf node
+     * can be replaced by another node of the same type that has exactly the same data values as
+     * well as the same {@linkplain Node#inputs() inputs} and {@linkplain Node#successors()
+     * successors}.
+     */
     public interface ValueNumberable {
     }
 
@@ -739,7 +747,7 @@
 
     final Node clone(Graph into, boolean clearInputsAndSuccessors) {
         NodeClass nodeClass = getNodeClass();
-        if (into != null && nodeClass.valueNumberable() && isLeafNode()) {
+        if (into != null && nodeClass.valueNumberable() && nodeClass.isLeafNode()) {
             Node otherNode = into.findNodeInCache(this);
             if (otherNode != null) {
                 return otherNode;
@@ -767,20 +775,13 @@
         newNode.extraUsages = NO_NODES;
         newNode.predecessor = null;
 
-        if (into != null && nodeClass.valueNumberable() && isLeafNode()) {
+        if (into != null && nodeClass.valueNumberable() && nodeClass.isLeafNode()) {
             into.putNodeIntoCache(newNode);
         }
         newNode.afterClone(this);
         return newNode;
     }
 
-    /**
-     * @returns true if this node has no inputs and no successors
-     */
-    public boolean isLeafNode() {
-        return USE_GENERATED_NODES || getNodeClass().isLeafNode();
-    }
-
     protected void afterClone(@SuppressWarnings("unused") Node other) {
     }
 
@@ -996,14 +997,13 @@
     }
 
     /**
-     * If this node is {@link ValueNumberable}, gets a digest for this node based on the current
-     * value of it's {@link NodeClass#getData() data} fields. If this node is not
-     * {@link ValueNumberable}, 0 is returned.
+     * If this node is a {@linkplain NodeClass#isLeafNode() leaf} node, returns a hash for this node
+     * based on its {@linkplain NodeClass#getData() data} fields otherwise return 0.
      *
-     * Overridden by a method generated for {@link ValueNumberable} subclasses.
+     * Overridden by a method generated for leaf nodes.
      */
-    public int getValueNumber() {
-        assert !(this instanceof ValueNumberable);
+    protected int valueNumberLeaf() {
+        assert !getNodeClass().isLeafNode();
         return 0;
     }
 
@@ -1012,7 +1012,7 @@
      *
      * @param other
      */
-    protected boolean valueEqualsGen(Node other) {
+    protected boolean dataEquals(Node other) {
         return true;
     }
 
@@ -1021,13 +1021,12 @@
      * fields of another node of the same type. Primitive fields are compared by value and
      * non-primitive fields are compared by {@link Objects#equals(Object, Object)}.
      *
-     * The result of this method undefined if {@code other.getClass() != this.getClass()} or if this
-     * node is not {@link ValueNumberable}
+     * The result of this method undefined if {@code other.getClass() != this.getClass()}.
      *
      * @param other a node of exactly the same type as this node
      * @return true if the data fields of this object and {@code other} are equal
      */
     public boolean valueEquals(Node other) {
-        return USE_GENERATED_NODES ? valueEqualsGen(other) : getNodeClass().valueEqual(this, other);
+        return USE_GENERATED_NODES ? dataEquals(other) : getNodeClass().dataEquals(this, other);
     }
 }

--- a/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/NodeClass.java	Thu Oct 02 13:13:00 2014 +0200
+++ b/graal/com.oracle.graal.graph/src/com/oracle/graal/graph/NodeClass.java	Thu Oct 02 14:22:16 2014 +0200
@@ -553,7 +553,7 @@
         return eq;
     }
 
-    public boolean valueEqual(Node a, Node b) {
+    public boolean dataEquals(Node a, Node b) {
         assert a.getClass() == b.getClass();
         for (int i = 0; i < data.getCount(); ++i) {
             Class<?> type = data.getType(i);
@@ -827,6 +827,9 @@
         }
     }
 
+    /**
+     * @returns true if the node has no inputs and no successors
+     */
     public boolean isLeafNode() {
         return isLeafNode;
     }

--- a/graal/com.oracle.graal.nodeinfo.processor/src/com/oracle/graal/nodeinfo/processor/GraphNodeGenerator.java	Thu Oct 02 13:13:00 2014 +0200
+++ b/graal/com.oracle.graal.nodeinfo.processor/src/com/oracle/graal/nodeinfo/processor/GraphNodeGenerator.java	Thu Oct 02 14:22:16 2014 +0200
@@ -334,12 +334,12 @@
             boolean hasInputs = !inputFields.isEmpty() || !inputListFields.isEmpty();
             boolean hasSuccessors = !successorFields.isEmpty() || !successorListFields.isEmpty();
 
-            if (hasInputs || hasSuccessors) {
-                createIsLeafNodeMethod();
+            boolean isLeaf = !(hasInputs || hasSuccessors);
+
+            if (isLeaf && isAssignableWithErasure(node, ValueNumberable)) {
+                createValueNumberLeafMethod(node);
             }
-
-            createValueNumberMethod(node);
-            createValueEqualsMethod();
+            createDataEqualsMethod();
         }
         compilationUnit.add(genClass);
         return compilationUnit;
@@ -430,65 +430,56 @@
         }
     }
 
-    private void createIsLeafNodeMethod() {
-        CodeExecutableElement method = new CodeExecutableElement(modifiers(PUBLIC), getType(boolean.class), "isLeafNode");
-        method.createBuilder().startReturn().string("false").end();
+    private void createValueNumberLeafMethod(TypeElement node) {
+        CodeExecutableElement method = new CodeExecutableElement(modifiers(PUBLIC), getType(int.class), "valueNumberLeaf");
+        CodeTreeBuilder b = method.createBuilder();
+        b.startStatement().string("int number = " + node.hashCode()).end();
+        for (VariableElement f : dataFields) {
+            String fname = f.getSimpleName().toString();
+            switch (f.asType().getKind()) {
+                case BOOLEAN:
+                    b.startIf().string(fname).end().startBlock();
+                    b.startStatement().string("number += 7").end();
+                    b.end();
+                    break;
+                case BYTE:
+                case SHORT:
+                case CHAR:
+                case INT:
+                    b.startStatement().string("number += 13 * ", fname).end();
+                    break;
+                case FLOAT:
+                    b.startStatement().string("number += 17 * Float.floatToRawIntBits(", fname, ")").end();
+                    break;
+                case LONG:
+                    b.startStatement().string("number += 19 * ", fname + " ^ (", fname, " >>> 32)").end();
+                    break;
+                case DOUBLE:
+                    b.startStatement().string("long longValue = Double.doubleToRawLongBits(", fname, ")").end();
+                    b.startStatement().string("number += 23 * longValue ^ (longValue >>> 32)").end();
+                    break;
+                case ARRAY:
+                    if (((ArrayType) f.asType()).getComponentType().getKind().isPrimitive()) {
+                        b.startStatement().string("number += 31 * Arrays.hashCode(", fname, ")").end();
+                    } else {
+                        b.startStatement().string("number += 31 * Arrays.deepHashCode(", fname, ")").end();
+                    }
+                    break;
+                default:
+                    b.startIf().string(fname, " != null").end().startBlock();
+                    b.startStatement().string("number += 29 * ", fname + ".hashCode()").end();
+                    b.end();
+                    break;
+            }
+        }
+        b.end();
+        b.startReturn().string("number").end();
         genClass.add(method);
         checkOnlyInGenNode(method);
     }
 
-    private void createValueNumberMethod(TypeElement node) {
-        if (isAssignableWithErasure(node, ValueNumberable)) {
-            CodeExecutableElement method = new CodeExecutableElement(modifiers(PUBLIC), getType(int.class), "getValueNumber");
-            CodeTreeBuilder b = method.createBuilder();
-            b.startStatement().string("int number = " + node.hashCode()).end();
-            for (VariableElement f : dataFields) {
-                String fname = f.getSimpleName().toString();
-                switch (f.asType().getKind()) {
-                    case BOOLEAN:
-                        b.startIf().string(fname).end().startBlock();
-                        b.startStatement().string("number += 7").end();
-                        b.end();
-                        break;
-                    case BYTE:
-                    case SHORT:
-                    case CHAR:
-                    case INT:
-                        b.startStatement().string("number += 13 * ", fname).end();
-                        break;
-                    case FLOAT:
-                        b.startStatement().string("number += 17 * Float.floatToRawIntBits(", fname, ")").end();
-                        break;
-                    case LONG:
-                        b.startStatement().string("number += 19 * ", fname + " ^ (", fname, " >>> 32)").end();
-                        break;
-                    case DOUBLE:
-                        b.startStatement().string("long longValue = Double.doubleToRawLongBits(", fname, ")").end();
-                        b.startStatement().string("number += 23 * longValue ^ (longValue >>> 32)").end();
-                        break;
-                    case ARRAY:
-                        if (((ArrayType) f.asType()).getComponentType().getKind().isPrimitive()) {
-                            b.startStatement().string("number += 31 * Arrays.hashCode(", fname, ")").end();
-                        } else {
-                            b.startStatement().string("number += 31 * Arrays.deepHashCode(", fname, ")").end();
-                        }
-                        break;
-                    default:
-                        b.startIf().string(fname, " != null").end().startBlock();
-                        b.startStatement().string("number += 29 * ", fname + ".hashCode()").end();
-                        b.end();
-                        break;
-                }
-            }
-            b.end();
-            b.startReturn().string("number").end();
-            genClass.add(method);
-            checkOnlyInGenNode(method);
-        }
-    }
-
-    private void createValueEqualsMethod() {
-        CodeExecutableElement method = new CodeExecutableElement(modifiers(PUBLIC), getType(boolean.class), "valueEqualsGen");
+    private void createDataEqualsMethod() {
+        CodeExecutableElement method = new CodeExecutableElement(modifiers(PUBLIC), getType(boolean.class), "dataEquals");
         addParameter(method, Node.asType(), "other");
         CodeTreeBuilder b = method.createBuilder();
         if (!dataFields.isEmpty()) {

--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/IfNode.java	Thu Oct 02 13:13:00 2014 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/IfNode.java	Thu Oct 02 14:22:16 2014 +0200
@@ -235,7 +235,8 @@
                         graph().addBeforeFixed(this, trueNext);
                         for (Node usage : trueNext.usages().snapshot()) {
                             if (usage.isAlive()) {
-                                if (usage.getNodeClass().valueNumberable() && !usage.isLeafNode()) {
+                                NodeClass usageNodeClass = usage.getNodeClass();
+                                if (usageNodeClass.valueNumberable() && !usageNodeClass.isLeafNode()) {
                                     Node newNode = graph().findDuplicate(usage);
                                     if (newNode != null) {
                                         usage.replaceAtUsages(newNode);

--- a/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/CanonicalizerPhase.java	Thu Oct 02 13:13:00 2014 +0200
+++ b/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/CanonicalizerPhase.java	Thu Oct 02 14:22:16 2014 +0200
@@ -213,7 +213,7 @@
         }
 
         public static boolean tryGlobalValueNumbering(Node node, NodeClass nodeClass) {
-            if (nodeClass.valueNumberable() && !node.isLeafNode()) {
+            if (nodeClass.valueNumberable() && !nodeClass.isLeafNode()) {
                 Node newNode = node.graph().findDuplicate(node);
                 if (newNode != null) {
                     assert !(node instanceof FixedNode || newNode instanceof FixedNode);