--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/NodeBitMap.java	Fri Feb 02 10:37:48 2018 -0500
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/NodeBitMap.java	Fri Feb 02 17:28:17 2018 -0800
@@ -160,6 +160,12 @@
         }
     }
 
+    public void invert() {
+        for (int i = 0; i < bits.length; i++) {
+            bits[i] = ~bits[i];
+        }
+    }
+
     public void grow() {
         nodeCount = Math.max(nodeCount, graph().nodeIdCount());
         int newLength = sizeForNodeCount(nodeCount);