--- a/graal/com.oracle.graal.api.code/src/com/oracle/graal/api/code/TypeCheckHints.java	Wed Nov 28 18:45:54 2012 +0100
+++ b/graal/com.oracle.graal.api.code/src/com/oracle/graal/api/code/TypeCheckHints.java	Wed Nov 28 18:48:17 2012 +0100
@@ -22,11 +22,13 @@
  */
 package com.oracle.graal.api.code;
 
-import java.lang.reflect.*;
+import static com.oracle.graal.api.meta.MetaUtil.*;
+import static java.lang.reflect.Modifier.*;
+
 import java.util.*;
 
 import com.oracle.graal.api.meta.*;
-import com.oracle.graal.api.meta.JavaTypeProfile.*;
+import com.oracle.graal.api.meta.JavaTypeProfile.ProfiledType;
 
 /**
  * Utility for deriving hint types for a type check instruction (e.g. checkcast or instanceof)
@@ -58,7 +60,7 @@
      * @param maxHints the maximum length of {@link #types}
      */
     public TypeCheckHints(ResolvedJavaType type, JavaTypeProfile profile, Assumptions assumptions, double minHintHitProbability, int maxHints) {
-        if (type != null && isFinalClass(type)) {
+        if (type != null && canHaveSubtype(type)) {
             types = new ResolvedJavaType[] {type};
             exact = true;
         } else {
@@ -105,15 +107,12 @@
     }
 
     /**
-     * Determines if a given type can have subtypes. This analysis is purely static; no
+     * Determines if a given type can have subtypes other than itself. This analysis is purely static; no
      * assumptions are made.
      *
      * @return true if {@code type} has no subtype(s)
      */
-    public static boolean isFinalClass(ResolvedJavaType type) {
-        if (type.isArray()) {
-            return isFinalClass(type.getComponentType());
-        }
-        return Modifier.isFinal(type.getModifiers());
+    public static boolean canHaveSubtype(ResolvedJavaType type) {
+        return isFinal(getElementalType(type).getModifiers());
     }
 }

--- a/graal/com.oracle.graal.api.meta/src/com/oracle/graal/api/meta/ResolvedJavaType.java	Wed Nov 28 18:45:54 2012 +0100
+++ b/graal/com.oracle.graal.api.meta/src/com/oracle/graal/api/meta/ResolvedJavaType.java	Wed Nov 28 18:48:17 2012 +0100
@@ -181,12 +181,14 @@
      * Attempts to get a unique concrete subclass of this type.
      * <p>
      * For an {@linkplain #isArray() array} type A, the unique concrete subclass is A if
-     * the element type of A is primitive or has no subtype. Otherwise there is no unique concrete subclass.
+     * the {@linkplain MetaUtil#getElementalType(ResolvedJavaType) elemental} type of A
+     * is final (which includes primitive types). Otherwise {@code null} is returned for A.
      * <p>
-     * For a non-array type T, the result is the unique concrete type in the complete hierarchy of T.
+     * For a non-array type T, the result is the unique concrete type in the current hierarchy of T.
      * <p>
      * A runtime may decide not to manage or walk a large hierarchy and so the result is conservative.
      * That is, a non-null result is guaranteed to be the unique concrete class in T's hierarchy
+     * <b>at the current point in time</b>
      * but a null result does not necessarily imply that there is no unique concrete class in T's hierarchy.
      * <p>
      * If the compiler uses the result of this method for its compilation, it must register an assumption because

--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotResolvedObjectType.java	Wed Nov 28 18:45:54 2012 +0100
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotResolvedObjectType.java	Wed Nov 28 18:48:17 2012 +0100
@@ -160,26 +160,11 @@
         return javaComponentType == null ? null : fromClass(javaComponentType);
     }
 
-    private static boolean hasSubtype(ResolvedJavaType type) {
-        assert !type.isArray() : type;
-        if (type.isPrimitive()) {
-            return false;
-        }
-        HotSpotVMConfig config = HotSpotGraalRuntime.getInstance().getConfig();
-        if (unsafeReadWord(((HotSpotResolvedObjectType) type).metaspaceKlass + config.subklassOffset) != 0) {
-            return true;
-        }
-        return false;
-    }
-
     @Override
     public ResolvedJavaType findUniqueConcreteSubtype() {
         HotSpotVMConfig config = HotSpotGraalRuntime.getInstance().getConfig();
         if (isArray()) {
-            if (hasSubtype(getElementalType(this))) {
-                return null;
-            }
-            return this;
+            return isFinal(getElementalType(this).getModifiers()) ? this : null;
         } else {
             HotSpotResolvedObjectType type = this;
             while (isAbstract(type.getModifiers())) {
@@ -254,7 +239,7 @@
         if (isArray()) {
             return getComponentType().asExactType() != null ? this : null;
         }
-        return Modifier.isFinal(getModifiers()) ? this : null;
+        return isFinal(getModifiers()) ? this : null;
     }
 
     @Override
@@ -402,7 +387,7 @@
             fieldCache.put(id, result);
         } else {
             assert result.getName().equals(fieldName);
-            assert result.getModifiers() == (Modifier.fieldModifiers() & flags);
+            assert result.getModifiers() == (fieldModifiers() & flags);
         }
 
         return result;

--- a/graal/com.oracle.graal.java/src/com/oracle/graal/java/GraphBuilderPhase.java	Wed Nov 28 18:45:54 2012 +0100
+++ b/graal/com.oracle.graal.java/src/com/oracle/graal/java/GraphBuilderPhase.java	Wed Nov 28 18:48:17 2012 +0100
@@ -623,7 +623,7 @@
     }
 
     private JavaTypeProfile getProfileForTypeCheck(ResolvedJavaType type) {
-        if (!optimisticOpts.useTypeCheckHints() || TypeCheckHints.isFinalClass(type)) {
+        if (!optimisticOpts.useTypeCheckHints() || TypeCheckHints.canHaveSubtype(type)) {
             return null;
         } else {
             ResolvedJavaType uniqueSubtype = type.findUniqueConcreteSubtype();