1 /*
   2  * Copyright (c) 2009, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.graalvm.compiler.nodes;
  24 
  25 import org.graalvm.compiler.graph.NodeClass;
  26 import org.graalvm.compiler.nodeinfo.NodeInfo;
  27 
  28 /**
  29  * Denotes the merging of multiple control-flow paths.
  30  */
  31 @NodeInfo
  32 public final class MergeNode extends AbstractMergeNode {
  33 
  34     public static final NodeClass<MergeNode> TYPE = NodeClass.create(MergeNode.class);
  35 
  36     public MergeNode() {
  37         super(TYPE);
  38     }
  39 
  40     public static void removeMergeIfDegenerated(MergeNode node) {
  41         if (node.forwardEndCount() == 1 && node.hasNoUsages()) {
  42             FixedNode currentNext = node.next();
  43             node.setNext(null);
  44             EndNode forwardEnd = node.forwardEndAt(0);
  45             forwardEnd.replaceAtPredecessor(currentNext);
  46             node.markDeleted();
  47             forwardEnd.markDeleted();
  48         }
  49     }
  50 
  51     @Override
  52     public boolean verify() {
  53         assertTrue(this.forwardEndCount() > 1, "Must merge more than one end.");
  54         return true;
  55     }
  56 }