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.nodeinfo.NodeCycles.CYCLES_2; 26 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_2; 27 28 import org.graalvm.compiler.core.common.type.IntegerStamp; 29 import org.graalvm.compiler.graph.NodeClass; 30 import org.graalvm.compiler.graph.spi.CanonicalizerTool; 31 import org.graalvm.compiler.nodeinfo.NodeInfo; 32 import org.graalvm.compiler.nodes.AbstractBeginNode; 33 import org.graalvm.compiler.nodes.ConstantNode; 34 import org.graalvm.compiler.nodes.ValueNode; 35 import org.graalvm.compiler.nodes.calc.SubNode; 36 import org.graalvm.compiler.nodes.spi.LoweringTool; 37 import org.graalvm.compiler.nodes.util.GraphUtil; 38 39 import jdk.vm.ci.meta.JavaConstant; 40 import jdk.vm.ci.meta.JavaKind; 41 42 /** 43 * Node representing an exact integer substraction that will throw an {@link ArithmeticException} in 44 * case the addition would overflow the 32 bit range. 45 */ 46 @NodeInfo(cycles = CYCLES_2, size = SIZE_2) 47 public final class IntegerSubExactNode extends SubNode implements IntegerExactArithmeticNode { 48 public static final NodeClass<IntegerSubExactNode> TYPE = NodeClass.create(IntegerSubExactNode.class); 49 50 public IntegerSubExactNode(ValueNode x, ValueNode y) { 51 super(TYPE, x, y); 52 setStamp(x.stamp().unrestricted()); 53 assert x.stamp().isCompatible(y.stamp()) && x.stamp() instanceof IntegerStamp; 54 } 55 56 @Override 57 public boolean inferStamp() { 58 /* 59 * Note: it is not allowed to use the foldStamp method of the regular sub node as we do not 60 * know the result stamp of this node if we do not know whether we may deopt. If we know we 61 * can never overflow we will replace this node with its non overflow checking counterpart 62 * anyway. 63 */ 64 return false; 65 } 66 67 @Override 68 public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) { 69 if (GraphUtil.unproxify(forX) == GraphUtil.unproxify(forY)) { 70 return ConstantNode.forIntegerStamp(stamp(), 0); 71 } 72 if (forX.isConstant() && forY.isConstant()) { 73 return canonicalXYconstant(forX, forY); 74 } else if (forY.isConstant()) { 75 long c = forY.asJavaConstant().asLong(); 76 if (c == 0) { 77 return forX; 78 } 79 } 80 if (!IntegerStamp.subtractionCanOverflow((IntegerStamp) x.stamp(), (IntegerStamp) y.stamp())) { 81 return new SubNode(x, y).canonical(tool); 82 } 83 return this; 84 } 85 86 private ValueNode canonicalXYconstant(ValueNode forX, ValueNode forY) { 87 JavaConstant xConst = forX.asJavaConstant(); 88 JavaConstant yConst = forY.asJavaConstant(); 89 assert xConst.getJavaKind() == yConst.getJavaKind(); 90 try { 91 if (xConst.getJavaKind() == JavaKind.Int) { 92 return ConstantNode.forInt(Math.subtractExact(xConst.asInt(), yConst.asInt())); 93 } else { 94 assert xConst.getJavaKind() == JavaKind.Long; 95 return ConstantNode.forLong(Math.subtractExact(xConst.asLong(), yConst.asLong())); 96 } 97 } catch (ArithmeticException ex) { 98 // The operation will result in an overflow exception, so do not canonicalize. 99 } 100 return this; 101 } 102 103 @Override 104 public IntegerExactArithmeticSplitNode createSplit(AbstractBeginNode next, AbstractBeginNode deopt) { 105 return graph().add(new IntegerSubExactSplitNode(stamp(), getX(), getY(), next, deopt)); 106 } 107 108 @Override 109 public void lower(LoweringTool tool) { 110 IntegerExactArithmeticSplitNode.lower(tool, this); 111 } 112 }