001/* 002 * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved. 003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 004 * 005 * This code is free software; you can redistribute it and/or modify it 006 * under the terms of the GNU General Public License version 2 only, as 007 * published by the Free Software Foundation. 008 * 009 * This code is distributed in the hope that it will be useful, but WITHOUT 010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 011 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 012 * version 2 for more details (a copy is included in the LICENSE file that 013 * accompanied this code). 014 * 015 * You should have received a copy of the GNU General Public License version 016 * 2 along with this work; if not, write to the Free Software Foundation, 017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 018 * 019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 020 * or visit www.oracle.com if you need additional information or have any 021 * questions. 022 */ 023package com.oracle.graal.nodes.calc; 024 025import jdk.internal.jvmci.meta.*; 026 027import com.oracle.graal.compiler.common.calc.*; 028import com.oracle.graal.compiler.common.type.*; 029import com.oracle.graal.graph.*; 030import com.oracle.graal.graph.spi.Canonicalizable.BinaryCommutative; 031import com.oracle.graal.graph.spi.*; 032import com.oracle.graal.nodeinfo.*; 033import com.oracle.graal.nodes.*; 034import com.oracle.graal.nodes.util.*; 035 036@NodeInfo(shortName = "==") 037public class PointerEqualsNode extends CompareNode implements BinaryCommutative<ValueNode> { 038 039 public static final NodeClass<PointerEqualsNode> TYPE = NodeClass.create(PointerEqualsNode.class); 040 041 public PointerEqualsNode(ValueNode x, ValueNode y) { 042 this(TYPE, x, y); 043 } 044 045 public static LogicNode create(ValueNode x, ValueNode y) { 046 LogicNode result = findSynonym(x, y); 047 if (result != null) { 048 return result; 049 } 050 return new PointerEqualsNode(x, y); 051 } 052 053 protected PointerEqualsNode(NodeClass<? extends PointerEqualsNode> c, ValueNode x, ValueNode y) { 054 super(c, Condition.EQ, false, x, y); 055 assert x.stamp() instanceof AbstractPointerStamp; 056 assert y.stamp() instanceof AbstractPointerStamp; 057 } 058 059 @Override 060 public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) { 061 LogicNode result = findSynonym(forX, forY); 062 if (result != null) { 063 return result; 064 } 065 return super.canonical(tool, forX, forY); 066 } 067 068 public static LogicNode findSynonym(ValueNode forX, ValueNode forY) { 069 if (GraphUtil.unproxify(forX) == GraphUtil.unproxify(forY)) { 070 return LogicConstantNode.tautology(); 071 } else if (forX.stamp().alwaysDistinct(forY.stamp())) { 072 return LogicConstantNode.contradiction(); 073 } else if (((AbstractPointerStamp) forX.stamp()).alwaysNull()) { 074 return new IsNullNode(forY); 075 } else if (((AbstractPointerStamp) forY.stamp()).alwaysNull()) { 076 return new IsNullNode(forX); 077 } else { 078 return null; 079 } 080 } 081 082 @Override 083 protected CompareNode duplicateModified(ValueNode newX, ValueNode newY) { 084 return new PointerEqualsNode(newX, newY); 085 } 086 087 @Override 088 public Stamp getSucceedingStampForX(boolean negated) { 089 if (!negated) { 090 Stamp xStamp = getX().stamp(); 091 Stamp newStamp = xStamp.join(getY().stamp()); 092 if (!newStamp.equals(xStamp)) { 093 return newStamp; 094 } 095 } 096 return null; 097 } 098 099 @Override 100 public Stamp getSucceedingStampForY(boolean negated) { 101 if (!negated) { 102 Stamp yStamp = getY().stamp(); 103 Stamp newStamp = yStamp.join(getX().stamp()); 104 if (!newStamp.equals(yStamp)) { 105 return newStamp; 106 } 107 } 108 return null; 109 } 110 111 @Override 112 public TriState tryFold(Stamp xStampGeneric, Stamp yStampGeneric) { 113 if (xStampGeneric instanceof ObjectStamp && yStampGeneric instanceof ObjectStamp) { 114 ObjectStamp xStamp = (ObjectStamp) xStampGeneric; 115 ObjectStamp yStamp = (ObjectStamp) yStampGeneric; 116 if (xStamp.alwaysDistinct(yStamp)) { 117 return TriState.FALSE; 118 } else if (xStamp.neverDistinct(yStamp)) { 119 return TriState.TRUE; 120 } 121 } 122 return TriState.UNKNOWN; 123 } 124}