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 * Copyright (c) 2014, 2019, 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.
 *
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package org.graalvm.compiler.nodes.calc;

import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_2;
import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_2;

import org.graalvm.compiler.core.common.type.ArithmeticOpTable;
import org.graalvm.compiler.core.common.type.ArithmeticOpTable.BinaryOp.MulHigh;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.graph.spi.Canonicalizable;
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.NodeView;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;

import jdk.vm.ci.meta.Constant;
import jdk.vm.ci.meta.PrimitiveConstant;
import jdk.vm.ci.meta.Value;

@NodeInfo(shortName = "*H", cycles = CYCLES_2, size = SIZE_2)
public final class IntegerMulHighNode extends BinaryArithmeticNode<MulHigh> implements Canonicalizable.BinaryCommutative<ValueNode> {
    public static final NodeClass<IntegerMulHighNode> TYPE = NodeClass.create(IntegerMulHighNode.class);

    public IntegerMulHighNode(ValueNode x, ValueNode y) {
        super(TYPE, ArithmeticOpTable::getMulHigh, x, y);
    }

    @Override
    public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {
        Value a = nodeValueMap.operand(getX());
        Value b = nodeValueMap.operand(getY());
        nodeValueMap.setResult(this, gen.emitMulHigh(a, b));
    }

    @Override
    public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
        ValueNode ret = super.canonical(tool, forX, forY);
        if (ret != this) {
            return ret;
        }

        if (forX.isConstant() && !forY.isConstant()) {
            // we try to swap and canonicalize
            ValueNode improvement = canonical(tool, forY, forX);
            if (improvement != this) {
                return improvement;
            }
            // if this fails we only swap
            return new IntegerMulHighNode(forY, forX);
        }
        return canonical(this, forY);
    }

    private static ValueNode canonical(IntegerMulHighNode self, ValueNode forY) {
        if (forY.isConstant()) {
            Constant c = forY.asConstant();
            if (c instanceof PrimitiveConstant && ((PrimitiveConstant) c).getJavaKind().isNumericInteger()) {
                long i = ((PrimitiveConstant) c).asLong();
                if (i == 0 || i == 1) {
                    return ConstantNode.forIntegerStamp(self.stamp(NodeView.DEFAULT), 0);
                }
            }
        }
        return self;
    }
}