001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm.compilers.opt.ssa;
014    
015    import org.jikesrvm.compilers.opt.util.SpaceEffGraphEdge;
016    
017    /**
018     * This class implements an edge in the value graph used in global value
019     * numbering
020     * ala Alpern, Wegman and Zadeck.  See Muchnick p.348 for a nice
021     * discussion.
022     */
023    final class ValueGraphEdge extends SpaceEffGraphEdge {
024    
025      ValueGraphEdge(ValueGraphVertex src, ValueGraphVertex target) {
026        super(src, target);
027      }
028    
029      public String toString() {
030        ValueGraphVertex src = (ValueGraphVertex) fromNode();
031        ValueGraphVertex dest = (ValueGraphVertex) toNode();
032        return src.getName() + " --> " + dest.getName();
033      }
034    }