--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/NodeList.java	Tue Sep 24 08:54:08 2019 -0700
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/NodeList.java	Tue Sep 24 12:47:15 2019 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -108,6 +108,20 @@
         }
     }
 
+    /**
+     * Removes null values from the list.
+     */
+    public void trim() {
+        int newSize = 0;
+        for (int i = 0; i < nodes.length; ++i) {
+            if (nodes[i] != null) {
+                nodes[newSize] = nodes[i];
+                newSize++;
+            }
+        }
+        size = newSize;
+    }
+
     public boolean isList() {
         return true;
     }
@@ -143,7 +157,7 @@
     @SuppressWarnings("unchecked")
     @Override
     public boolean add(Node node) {
-        assert node == null || !node.isDeleted();
+        assert node == null || !node.isDeleted() : node;
         self.incModCount();
         incModCount();
         int length = nodes.length;