| /* |
| * 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.Shr; |
| 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.code.CodeUtil; |
| |
| @NodeInfo(shortName = ">>") |
| public final class RightShiftNode extends ShiftNode<Shr> { |
| |
| public static final NodeClass<RightShiftNode> TYPE = NodeClass.create(RightShiftNode.class); |
| |
| public RightShiftNode(ValueNode x, ValueNode y) { |
| super(TYPE, ArithmeticOpTable::getShr, 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 (forX.stamp() instanceof IntegerStamp && ((IntegerStamp) forX.stamp()).isPositive()) { |
| return new UnsignedRightShiftNode(forX, forY); |
| } |
| |
| 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 RightShiftNode) { |
| int total = amount + otherAmount; |
| if (total != (total & mask)) { |
| assert other.getX().stamp() instanceof IntegerStamp; |
| IntegerStamp istamp = (IntegerStamp) other.getX().stamp(); |
| |
| if (istamp.isPositive()) { |
| return ConstantNode.forIntegerKind(getStackKind(), 0); |
| } |
| if (istamp.isStrictlyNegative()) { |
| return ConstantNode.forIntegerKind(getStackKind(), -1L); |
| } |
| |
| /* |
| * if we cannot replace both shifts with a constant, replace them by a |
| * full shift for this kind |
| */ |
| assert total >= mask; |
| return new RightShiftNode(other.getX(), ConstantNode.forInt(mask)); |
| } |
| return new RightShiftNode(other.getX(), ConstantNode.forInt(total)); |
| } |
| } |
| } |
| if (originalAmout != amount) { |
| return new RightShiftNode(forX, ConstantNode.forInt(amount)); |
| } |
| } |
| return this; |
| } |
| |
| @Override |
| public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) { |
| nodeValueMap.setResult(this, gen.emitShr(nodeValueMap.operand(getX()), nodeValueMap.operand(getY()))); |
| } |
| |
| @Override |
| public boolean isNarrowable(int resultBits) { |
| if (super.isNarrowable(resultBits)) { |
| /* |
| * For signed right shifts, the narrow can be done before the shift if the cut off bits |
| * are all equal to the sign bit of the input. That's equivalent to the condition that |
| * the input is in the signed range of the narrow type. |
| */ |
| IntegerStamp inputStamp = (IntegerStamp) getX().stamp(); |
| return CodeUtil.minValue(resultBits) <= inputStamp.lowerBound() && inputStamp.upperBound() <= CodeUtil.maxValue(resultBits); |
| } else { |
| return false; |
| } |
| } |
| } |