/*

 * Copyright (c) 2014, 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 static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1;

import org.graalvm.compiler.core.common.type.ArithmeticOpTable;

import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp;

import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp.Narrow;

import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp.SignExtend;

import org.graalvm.compiler.core.common.type.IntegerStamp;

import org.graalvm.compiler.core.common.type.PrimitiveStamp;

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.NodeView;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;

/**

 * The {@code SignExtendNode} converts an integer to a wider integer using sign extension.

 */

@NodeInfo(cycles = CYCLES_1)

public final class SignExtendNode extends IntegerConvertNode<SignExtend, Narrow> {

    public static final NodeClass<SignExtendNode> TYPE = NodeClass.create(SignExtendNode.class);

    public SignExtendNode(ValueNode input, int resultBits) {

        this(input, PrimitiveStamp.getBits(input.stamp(NodeView.DEFAULT)), resultBits);

        assert 0 < PrimitiveStamp.getBits(input.stamp(NodeView.DEFAULT)) && PrimitiveStamp.getBits(input.stamp(NodeView.DEFAULT)) <= resultBits;

    }

    public SignExtendNode(ValueNode input, int inputBits, int resultBits) {

        super(TYPE, ArithmeticOpTable::getSignExtend, ArithmeticOpTable::getNarrow, inputBits, resultBits, input);

    }

    public static ValueNode create(ValueNode input, int resultBits, NodeView view) {

        return create(input, PrimitiveStamp.getBits(input.stamp(view)), resultBits, view);

    }

    public static ValueNode create(ValueNode input, int inputBits, int resultBits, NodeView view) {

        IntegerConvertOp<SignExtend> signExtend = ArithmeticOpTable.forStamp(input.stamp(view)).getSignExtend();

        ValueNode synonym = findSynonym(signExtend, input, inputBits, resultBits, signExtend.foldStamp(inputBits, resultBits, input.stamp(view)));

        if (synonym != null) {

            return synonym;

        }

        return canonical(null, input, inputBits, resultBits, view);

    }

    @Override

    public boolean isLossless() {

        return true;

    }

    @Override

    public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) {

        NodeView view = NodeView.from(tool);

        ValueNode ret = super.canonical(tool, forValue);

        if (ret != this) {

            return ret;

        }

        return canonical(this, forValue, getInputBits(), getResultBits(), view);

    }

    private static ValueNode canonical(SignExtendNode self, ValueNode forValue, int inputBits, int resultBits, NodeView view) {

        if (forValue instanceof SignExtendNode) {

            // sxxx -(sign-extend)-> ssss sxxx -(sign-extend)-> ssssssss sssssxxx

            // ==> sxxx -(sign-extend)-> ssssssss sssssxxx

            SignExtendNode other = (SignExtendNode) forValue;

            return SignExtendNode.create(other.getValue(), other.getInputBits(), resultBits, view);

        } else if (forValue instanceof ZeroExtendNode) {

            ZeroExtendNode other = (ZeroExtendNode) forValue;

            if (other.getResultBits() > other.getInputBits()) {

                // sxxx -(zero-extend)-> 0000 sxxx -(sign-extend)-> 00000000 0000sxxx

                // ==> sxxx -(zero-extend)-> 00000000 0000sxxx

            }

        }

        if (forValue.stamp(view) instanceof IntegerStamp) {

            IntegerStamp inputStamp = (IntegerStamp) forValue.stamp(view);

            if ((inputStamp.upMask() & (1L << (inputBits - 1))) == 0L) {

                // 0xxx -(sign-extend)-> 0000 0xxx

                // ==> 0xxx -(zero-extend)-> 0000 0xxx

            }

        }

        return self != null ? self : new SignExtendNode(forValue, inputBits, resultBits);

    }

    @Override

    public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {

        nodeValueMap.setResult(this, gen.emitSignExtend(nodeValueMap.operand(getValue()), getInputBits(), getResultBits()));

    }

    @Override

    public boolean mayNullCheckSkipConversion() {

        return true;

    }

}