Mercurial > hg > truffle
view graal/com.oracle.graal.replacements/src/com/oracle/graal/replacements/nodes/BitScanReverseNode.java @ 17450:45b45f902bed
removed Node generation (GRAAL-857)
author | Doug Simon <doug.simon@oracle.com> |
---|---|
date | Wed, 15 Oct 2014 15:35:33 +0200 |
parents | 189479d72dc8 |
children | 9619ba4daf4c |
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/* * Copyright (c) 2012, 2014, 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 com.oracle.graal.replacements.nodes; import com.oracle.graal.api.code.*; import com.oracle.graal.api.meta.*; import com.oracle.graal.compiler.common.type.*; import com.oracle.graal.graph.spi.*; import com.oracle.graal.nodeinfo.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.calc.*; import com.oracle.graal.nodes.spi.*; /** * Determines the index of the most significant "1" bit. Note that the result is undefined if the * input is zero. */ @NodeInfo public class BitScanReverseNode extends UnaryNode implements LIRLowerable { public static BitScanReverseNode create(ValueNode value) { return new BitScanReverseNode(value); } protected BitScanReverseNode(ValueNode value) { super(StampFactory.forInteger(Kind.Int, 0, ((PrimitiveStamp) value.stamp()).getBits()), value); assert value.getKind() == Kind.Int || value.getKind() == Kind.Long; } @Override public boolean inferStamp() { IntegerStamp valueStamp = (IntegerStamp) getValue().stamp(); int min; int max; long mask = CodeUtil.mask(valueStamp.getBits()); int lastAlwaysSetBit = scan(valueStamp.downMask() & mask); if (lastAlwaysSetBit == -1) { min = -1; } else { min = lastAlwaysSetBit; } int lastMaybeSetBit = scan(valueStamp.upMask() & mask); max = lastMaybeSetBit; return updateStamp(StampFactory.forInteger(Kind.Int, min, max)); } @Override public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) { if (forValue.isConstant()) { Constant c = forValue.asConstant(); if (c.asLong() != 0) { return ConstantNode.forInt(forValue.getKind() == Kind.Int ? scan(c.asInt()) : scan(c.asLong())); } } return this; } /** * Utility method with defined return value for 0. * * @param v * @return index of first set bit or -1 if {@code v} == 0. */ public static int scan(long v) { return 63 - Long.numberOfLeadingZeros(v); } /** * Utility method with defined return value for 0. * * @param v * @return index of first set bit or -1 if {@code v} == 0. */ public static int scan(int v) { return 31 - Integer.numberOfLeadingZeros(v); } /** * Raw intrinsic for bsr instruction. * * @param v * @return index of first set bit or an undefined value if {@code v} == 0. */ @NodeIntrinsic public static native int unsafeScan(int v); /** * Raw intrinsic for bsr instruction. * * @param v * @return index of first set bit or an undefined value if {@code v} == 0. */ @NodeIntrinsic public static native int unsafeScan(long v); @Override public void generate(NodeLIRBuilderTool gen) { Value result = gen.getLIRGeneratorTool().emitBitScanReverse(gen.operand(getValue())); gen.setResult(this, result); } }