--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotGraphBuilderPluginsProvider.java	Tue Feb 10 20:44:08 2015 +0100
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotGraphBuilderPluginsProvider.java	Thu Feb 12 20:28:45 2015 +0100
@@ -75,6 +75,19 @@
                 return false;
             }
         });
+        r.register2("isInstance", Receiver.class, Object.class, new InvocationPlugin() {
+            public boolean apply(GraphBuilderContext builder, ValueNode rcvr, ValueNode object) {
+                if (rcvr.isConstant() && !rcvr.isNullConstant() && object.isConstant()) {
+                    ResolvedJavaType type = builder.getConstantReflection().asJavaType(rcvr.asConstant());
+                    if (type != null && !type.isPrimitive()) {
+                        builder.push(Kind.Boolean.getStackKind(), builder.append(ConstantNode.forBoolean(type.isInstance(object.asJavaConstant()))));
+                        return true;
+                    }
+                }
+                return false;
+            }
+        });
+
         // StableOptionValue.class
         r = new Registration(plugins, metaAccess, StableOptionValue.class);
         r.register1("getValue", Receiver.class, new InvocationPlugin() {