--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.phases.common/src/org/graalvm/compiler/phases/common/util/EconomicSetNodeEventListener.java	Thu Nov 15 09:04:07 2018 -0800
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2013, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+
+package org.graalvm.compiler.phases.common.util;
+
+import java.util.EnumSet;
+import java.util.Set;
+
+import jdk.internal.vm.compiler.collections.EconomicSet;
+import jdk.internal.vm.compiler.collections.Equivalence;
+import org.graalvm.compiler.graph.Graph.NodeEvent;
+import org.graalvm.compiler.graph.Graph.NodeEventListener;
+import org.graalvm.compiler.graph.Node;
+import org.graalvm.compiler.graph.Node.IndirectCanonicalization;
+
+/**
+ * A simple {@link NodeEventListener} implementation that accumulates event nodes in a
+ * {@link EconomicSet}.
+ */
+public class EconomicSetNodeEventListener extends NodeEventListener {
+
+    private final EconomicSet<Node> nodes;
+    private final Set<NodeEvent> filter;
+
+    /**
+     * Creates a {@link NodeEventListener} that collects nodes from all events.
+     */
+    public EconomicSetNodeEventListener() {
+        this.nodes = EconomicSet.create(Equivalence.IDENTITY);
+        this.filter = EnumSet.allOf(NodeEvent.class);
+    }
+
+    /**
+     * Creates a {@link NodeEventListener} that collects nodes from all events that match a given
+     * filter.
+     */
+    public EconomicSetNodeEventListener(Set<NodeEvent> filter) {
+        this.nodes = EconomicSet.create(Equivalence.IDENTITY);
+        this.filter = filter;
+    }
+
+    /**
+     * Excludes a given event from those for which nodes are collected.
+     */
+    public EconomicSetNodeEventListener exclude(NodeEvent e) {
+        filter.remove(e);
+        return this;
+    }
+
+    @Override
+    public void changed(NodeEvent e, Node node) {
+        if (filter.contains(e)) {
+            nodes.add(node);
+            if (node instanceof IndirectCanonicalization) {
+                for (Node usage : node.usages()) {
+                    nodes.add(usage);
+                }
+            }
+        }
+    }
+
+    /**
+     * Gets the set being used to accumulate the nodes communicated to this listener.
+     */
+    public EconomicSet<Node> getNodes() {
+        return nodes;
+    }
+}