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 * This code is distributed in the hope that it will be useful, but WITHOUT

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 * 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_1;

import org.graalvm.compiler.core.common.calc.CanonicalCondition;

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.ZeroExtend;

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

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

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

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;

import jdk.vm.ci.code.CodeUtil;

/**

 * The {@code ZeroExtendNode} converts an integer to a wider integer using zero extension.

 */

@NodeInfo(cycles = CYCLES_1)

public final class ZeroExtendNode extends IntegerConvertNode<ZeroExtend, Narrow> {

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

    private final boolean inputAlwaysPositive;

    public ZeroExtendNode(ValueNode input, int resultBits) {

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

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

    }

    public ZeroExtendNode(ValueNode input, int inputBits, int resultBits, boolean inputAlwaysPositive) {

        this.inputAlwaysPositive = inputAlwaysPositive;

    }

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

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

    }

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

        return create(input, inputBits, resultBits, view, false);

    }

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

        IntegerConvertOp<ZeroExtend> signExtend = ArithmeticOpTable.forStamp(input.stamp(view)).getZeroExtend();

        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, alwaysPositive);

    }

    @Override

    public boolean isLossless() {

        return true;

    }

    public boolean isInputAlwaysPositive() {

        return inputAlwaysPositive;

    }

    @Override

    public boolean preservesOrder(CanonicalCondition cond) {

        switch (cond) {

            case LT:

                return false;

            default:

                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, inputAlwaysPositive);

    }

    private static ValueNode canonical(ZeroExtendNode zeroExtendNode, ValueNode forValue, int inputBits, int resultBits, NodeView view, boolean alwaysPositive) {

        ZeroExtendNode self = zeroExtendNode;

        if (forValue instanceof ZeroExtendNode) {

            // xxxx -(zero-extend)-> 0000 xxxx -(zero-extend)-> 00000000 0000xxxx

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

            ZeroExtendNode other = (ZeroExtendNode) forValue;

            return new ZeroExtendNode(other.getValue(), other.getInputBits(), resultBits, other.isInputAlwaysPositive());

        }

        if (forValue instanceof NarrowNode) {

            NarrowNode narrow = (NarrowNode) forValue;

            Stamp inputStamp = narrow.getValue().stamp(view);

            if (inputStamp instanceof IntegerStamp) {

                IntegerStamp istamp = (IntegerStamp) inputStamp;

                long mask = CodeUtil.mask(PrimitiveStamp.getBits(narrow.stamp(view)));

                if ((istamp.upMask() & ~mask) == 0) {

                    // The original value cannot change because of the narrow and zero extend.

                    if (istamp.getBits() < resultBits) {

                        // Need to keep the zero extend, skip the narrow.

                        return create(narrow.getValue(), resultBits, view);

                    } else if (istamp.getBits() > resultBits) {

                        // Need to keep the narrow, skip the zero extend.

                        return NarrowNode.create(narrow.getValue(), resultBits, view);

                    } else {

                        assert istamp.getBits() == resultBits;

                        // Just return the original value.

                        return narrow.getValue();

                    }

                }

            }

        }

        if (self == null) {

            self = new ZeroExtendNode(forValue, inputBits, resultBits, alwaysPositive);

        }

        return self;

    }

    @Override

    public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {

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

    }

    @Override

    public boolean mayNullCheckSkipConversion() {

        return true;

    }

}