1 /*
2 * Copyright (c) 2013, 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.replacements.nodes.arithmetic;
24
25 import static org.graalvm.compiler.core.common.type.IntegerStamp.addOverflowsNegatively;
26 import static org.graalvm.compiler.core.common.type.IntegerStamp.addOverflowsPositively;
27 import static org.graalvm.compiler.core.common.type.IntegerStamp.carryBits;
28 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_2;
29 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_2;
30
31 import org.graalvm.compiler.core.common.type.IntegerStamp;
32 import org.graalvm.compiler.core.common.type.Stamp;
33 import org.graalvm.compiler.core.common.type.StampFactory;
34 import org.graalvm.compiler.graph.NodeClass;
35 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
36 import org.graalvm.compiler.nodeinfo.NodeInfo;
37 import org.graalvm.compiler.nodes.AbstractBeginNode;
38 import org.graalvm.compiler.nodes.ConstantNode;
39 import org.graalvm.compiler.nodes.ValueNode;
40 import org.graalvm.compiler.nodes.calc.AddNode;
41 import org.graalvm.compiler.nodes.spi.LoweringTool;
42
43 import jdk.vm.ci.code.CodeUtil;
44 import jdk.vm.ci.meta.JavaConstant;
45 import jdk.vm.ci.meta.JavaKind;
46
47 /**
48 * Node representing an exact integer addition that will throw an {@link ArithmeticException} in
49 * case the addition would overflow the 32 bit range.
50 */
51 @NodeInfo(cycles = CYCLES_2, size = SIZE_2)
52 public final class IntegerAddExactNode extends AddNode implements IntegerExactArithmeticNode {
53 public static final NodeClass<IntegerAddExactNode> TYPE = NodeClass.create(IntegerAddExactNode.class);
54
55 public IntegerAddExactNode(ValueNode x, ValueNode y) {
56 super(TYPE, x, y);
57 setStamp(x.stamp().unrestricted());
58 assert x.stamp().isCompatible(y.stamp()) && x.stamp() instanceof IntegerStamp;
59 }
60
61 @Override
62 public boolean inferStamp() {
63 /*
64 * Note: it is not allowed to use the foldStamp method of the regular add node as we do not
65 * know the result stamp of this node if we do not know whether we may deopt. If we know we
66 * can never overflow we will replace this node with its non overflow checking counterpart
67 * anyway.
68 */
69 return false;
70 }
71
72 @Override
73 public Stamp foldStamp(Stamp stampX, Stamp stampY) {
74 IntegerStamp a = (IntegerStamp) stampX;
75 IntegerStamp b = (IntegerStamp) stampY;
76
77 int bits = a.getBits();
78 assert bits == b.getBits();
79
80 long defaultMask = CodeUtil.mask(bits);
81 long variableBits = (a.downMask() ^ a.upMask()) | (b.downMask() ^ b.upMask());
82 long variableBitsWithCarry = variableBits | (carryBits(a.downMask(), b.downMask()) ^ carryBits(a.upMask(), b.upMask()));
83 long newDownMask = (a.downMask() + b.downMask()) & ~variableBitsWithCarry;
84 long newUpMask = (a.downMask() + b.downMask()) | variableBitsWithCarry;
85
86 newDownMask &= defaultMask;
87 newUpMask &= defaultMask;
88
89 long newLowerBound;
90 long newUpperBound;
91 boolean lowerOverflowsPositively = addOverflowsPositively(a.lowerBound(), b.lowerBound(), bits);
92 boolean upperOverflowsPositively = addOverflowsPositively(a.upperBound(), b.upperBound(), bits);
93 boolean lowerOverflowsNegatively = addOverflowsNegatively(a.lowerBound(), b.lowerBound(), bits);
94 boolean upperOverflowsNegatively = addOverflowsNegatively(a.upperBound(), b.upperBound(), bits);
95 if (lowerOverflowsPositively) {
96 newLowerBound = CodeUtil.maxValue(bits);
97 } else if (lowerOverflowsNegatively) {
98 newLowerBound = CodeUtil.minValue(bits);
99 } else {
100 newLowerBound = CodeUtil.signExtend((a.lowerBound() + b.lowerBound()) & defaultMask, bits);
101 }
102
103 if (upperOverflowsPositively) {
104 newUpperBound = CodeUtil.maxValue(bits);
105 } else if (upperOverflowsNegatively) {
106 newUpperBound = CodeUtil.minValue(bits);
107 } else {
108 newUpperBound = CodeUtil.signExtend((a.upperBound() + b.upperBound()) & defaultMask, bits);
109 }
110
111 IntegerStamp limit = StampFactory.forInteger(bits, newLowerBound, newUpperBound);
112 newUpMask &= limit.upMask();
113 newUpperBound = CodeUtil.signExtend(newUpperBound & newUpMask, bits);
114 newDownMask |= limit.downMask();
115 newLowerBound |= newDownMask;
116 return new IntegerStamp(bits, newLowerBound, newUpperBound, newDownMask, newUpMask);
117 }
118
119 @Override
120 public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
121 ValueNode result = findSynonym(forX, forY);
122 if (result == null) {
123 return this;
124 } else {
125 return result;
126 }
127 }
128
129 private static ValueNode findSynonym(ValueNode forX, ValueNode forY) {
130 if (forX.isConstant() && !forY.isConstant()) {
131 return new IntegerAddExactNode(forY, forX);
132 }
133 if (forX.isConstant()) {
134 ConstantNode constantNode = canonicalXconstant(forX, forY);
135 if (constantNode != null) {
136 return constantNode;
137 }
138 } else if (forY.isConstant()) {
139 long c = forY.asJavaConstant().asLong();
140 if (c == 0) {
141 return forX;
142 }
143 }
144 return null;
145 }
146
147 private static ConstantNode canonicalXconstant(ValueNode forX, ValueNode forY) {
148 JavaConstant xConst = forX.asJavaConstant();
149 JavaConstant yConst = forY.asJavaConstant();
150 if (xConst != null && yConst != null) {
151 assert xConst.getJavaKind() == yConst.getJavaKind();
152 try {
153 if (xConst.getJavaKind() == JavaKind.Int) {
154 return ConstantNode.forInt(Math.addExact(xConst.asInt(), yConst.asInt()));
155 } else {
156 assert xConst.getJavaKind() == JavaKind.Long;
157 return ConstantNode.forLong(Math.addExact(xConst.asLong(), yConst.asLong()));
158 }
159 } catch (ArithmeticException ex) {
160 // The operation will result in an overflow exception, so do not canonicalize.
161 }
162 }
163 return null;
164 }
165
166 @Override
167 public IntegerExactArithmeticSplitNode createSplit(AbstractBeginNode next, AbstractBeginNode deopt) {
168 return graph().add(new IntegerAddExactSplitNode(stamp(), getX(), getY(), next, deopt));
169 }
170
171 @Override
172 public void lower(LoweringTool tool) {
173 IntegerExactArithmeticSplitNode.lower(tool, this);
174 }
175 }