gt:                 nextNode = nodes.next();
context: /*
   * Copyright (c) 2011, 2011, 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 com.oracle.graal.graph;
  
  import java.util.Arrays;
  import java.util.Iterator;
  
  import com.oracle.graal.graph.iterators.NodeIterable;
  
  public final class NodeBitMap implements NodeIterable<Node> {
      private static final int SHIFT = 6;
  
      private long[] bits;
      private int nodeCount;
      private int counter;
      private final Graph graph;
  
      public NodeBitMap(Graph graph) {
          this.nodeCount = graph.nodeIdCount();
          this.bits = new long[sizeForNodeCount(nodeCount)];
          this.graph = graph;
      }
  
      private static int sizeForNodeCount(int nodeCount) {
          return (nodeCount + Long.SIZE - 1) >> SHIFT;
      }
  
      public int getCounter() {
          return counter;
      }
  
      private NodeBitMap(NodeBitMap other) {
          this.bits = other.bits.clone();
          this.nodeCount = other.nodeCount;
          this.graph = other.graph;
      }
  
      public Graph graph() {
          return graph;
      }
  
      public boolean isNew(Node node) {
          return node.id() >= nodeCount;
      }
  
      public boolean isMarked(Node node) {
          assert check(node, false);
          return isMarked(node.id());
      }
  
      public boolean checkAndMarkInc(Node node) {
          if (!isMarked(node)) {
              this.counter++;
              this.mark(node);
              return true;
          } else {
              return false;
          }
      }
  
      public boolean isMarked(int id) {
          return (bits[id >> SHIFT] & (1L << id)) != 0;
      }
  
      public boolean isMarkedAndGrow(Node node) {
          assert check(node, true);
          int id = node.id();
          checkGrow(id);
          return isMarked(id);
      }
  
      public void mark(Node node) {
          assert check(node, false);
          int id = node.id();
          bits[id >> SHIFT] |= (1L << id);
      }
  
      public void markAndGrow(Node node) {
          assert check(node, true);
          int id = node.id();
          checkGrow(id);
          bits[id >> SHIFT] |= (1L << id);
      }
  
      public void clear(Node node) {
          assert check(node, false);
          int id = node.id();
          bits[id >> SHIFT] &= ~(1L << id);
      }
  
      public void clearAndGrow(Node node) {
          assert check(node, true);
          int id = node.id();
          checkGrow(id);
          bits[id >> SHIFT] &= ~(1L << id);
      }
  
      private void checkGrow(int id) {
          if (id >= nodeCount) {
              if ((id >> SHIFT) >= bits.length) {
                  grow();
              } else {
                  nodeCount = id + 1;
              }
          }
      }
  
      public void clearAll() {
          Arrays.fill(bits, 0);
      }
  
      public void intersect(NodeBitMap other) {
          assert graph() == other.graph();
          int commonLength = Math.min(bits.length, other.bits.length);
          for (int i = commonLength; i < bits.length; i++) {
              bits[i] = 0;
          }
          for (int i = 0; i < commonLength; i++) {
              bits[i] &= other.bits[i];
          }
      }
  
      public void subtract(NodeBitMap other) {
          assert graph() == other.graph();
          int commonLength = Math.min(bits.length, other.bits.length);
          for (int i = 0; i < commonLength; i++) {
              bits[i] &= ~other.bits[i];
          }
      }
  
      public void union(NodeBitMap other) {
          assert graph() == other.graph();
          grow();
          if (bits.length < other.bits.length) {
              bits = Arrays.copyOf(bits, other.bits.length);
          }
          for (int i = 0; i < bits.length; i++) {
              bits[i] |= other.bits[i];
          }
      }
  
      public void grow() {
          nodeCount = Math.max(nodeCount, graph().nodeIdCount());
          int newLength = sizeForNodeCount(nodeCount);
          if (newLength > bits.length) {
              newLength = Math.max(newLength, (bits.length * 3 / 2) + 1);
              bits = Arrays.copyOf(bits, newLength);
          }
      }
  
      private boolean check(Node node, boolean grow) {
          assert node.graph() == graph() : "this node is not part of the graph";
          assert grow || !isNew(node) : "node was added to the graph after creating the node bitmap: " + node;
          assert node.isAlive() : "node is deleted!" + node;
          return true;
      }
  
      public <T extends Node> void markAll(Iterable<T> nodes) {
          for (Node node : nodes) {
              mark(node);
          }
      }
  
      private static class MarkedNodeIterator implements Iterator<Node> {
  
          private final NodeBitMap visited;
          private Iterator<Node> nodes;
          private Node nextNode;
  
          MarkedNodeIterator(NodeBitMap visited, Iterator<Node> nodes) {
              this.visited = visited;
              this.nodes = nodes;
              forward();
          }
  
          private void forward() {
              do {
                  if (!nodes.hasNext()) {
                      nextNode = null;
                      return;
                  }
  