--- /dev/null 2016-05-31 09:42:47.975716356 -0700 +++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/calc/UnsignedRightShiftNode.java 2016-12-09 00:55:23.710934791 -0800 @@ -0,0 +1,107 @@ +/* + * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package org.graalvm.compiler.nodes.calc; + +import org.graalvm.compiler.core.common.type.ArithmeticOpTable; +import org.graalvm.compiler.core.common.type.ArithmeticOpTable.ShiftOp.UShr; +import org.graalvm.compiler.core.common.type.IntegerStamp; +import org.graalvm.compiler.graph.NodeClass; +import org.graalvm.compiler.graph.spi.CanonicalizerTool; +import org.graalvm.compiler.lir.gen.ArithmeticLIRGeneratorTool; +import org.graalvm.compiler.nodeinfo.NodeInfo; +import org.graalvm.compiler.nodes.ConstantNode; +import org.graalvm.compiler.nodes.ValueNode; +import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool; + +import jdk.vm.ci.meta.JavaKind; + +@NodeInfo(shortName = ">>>") +public final class UnsignedRightShiftNode extends ShiftNode { + + public static final NodeClass TYPE = NodeClass.create(UnsignedRightShiftNode.class); + + public UnsignedRightShiftNode(ValueNode x, ValueNode y) { + super(TYPE, ArithmeticOpTable::getUShr, x, y); + } + + @Override + public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) { + ValueNode ret = super.canonical(tool, forX, forY); + if (ret != this) { + return ret; + } + + if (forY.isConstant()) { + int amount = forY.asJavaConstant().asInt(); + int originalAmout = amount; + int mask = getShiftAmountMask(); + amount &= mask; + if (amount == 0) { + return forX; + } + if (forX instanceof ShiftNode) { + ShiftNode other = (ShiftNode) forX; + if (other.getY().isConstant()) { + int otherAmount = other.getY().asJavaConstant().asInt() & mask; + if (other instanceof UnsignedRightShiftNode) { + int total = amount + otherAmount; + if (total != (total & mask)) { + return ConstantNode.forIntegerKind(getStackKind(), 0); + } + return new UnsignedRightShiftNode(other.getX(), ConstantNode.forInt(total)); + } else if (other instanceof LeftShiftNode && otherAmount == amount) { + if (getStackKind() == JavaKind.Long) { + return new AndNode(other.getX(), ConstantNode.forLong(-1L >>> amount)); + } else { + assert getStackKind() == JavaKind.Int; + return new AndNode(other.getX(), ConstantNode.forInt(-1 >>> amount)); + } + } + } + } + if (originalAmout != amount) { + return new UnsignedRightShiftNode(forX, ConstantNode.forInt(amount)); + } + } + return this; + } + + @Override + public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) { + nodeValueMap.setResult(this, gen.emitUShr(nodeValueMap.operand(getX()), nodeValueMap.operand(getY()))); + } + + @Override + public boolean isNarrowable(int resultBits) { + if (super.isNarrowable(resultBits)) { + /* + * For unsigned right shifts, the narrow can be done before the shift if the cut off + * bits are all zero. + */ + IntegerStamp inputStamp = (IntegerStamp) getX().stamp(); + return (inputStamp.upMask() & ~(resultBits - 1)) == 0; + } else { + return false; + } + } +}