/*

 * 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

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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.IntegerStamp;

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

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.graph.spi.Canonicalizable.BinaryCommutative;

import org.graalvm.compiler.graph.spi.CanonicalizerTool;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.BinaryOpLogicNode;

import org.graalvm.compiler.nodes.LogicConstantNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.ValueNode;

import jdk.vm.ci.meta.TriState;

/**

 * This node will perform a "test" operation on its arguments. Its result is equivalent to the

 * expression "(x & y) == 0", meaning that it will return true if (and only if) no bit is set in

 * both x and y.

 */

@NodeInfo(cycles = CYCLES_2, size = SIZE_2)

public final class IntegerTestNode extends BinaryOpLogicNode implements BinaryCommutative<ValueNode> {

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

    public IntegerTestNode(ValueNode x, ValueNode y) {

        super(TYPE, x, y);

    }

    @Override

    public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {

        NodeView view = NodeView.from(tool);

        if (forX.isConstant() && forY.isConstant()) {

            return LogicConstantNode.forBoolean((forX.asJavaConstant().asLong() & forY.asJavaConstant().asLong()) == 0);

        }

        if (forX.stamp(view) instanceof IntegerStamp && forY.stamp(view) instanceof IntegerStamp) {

            IntegerStamp xStamp = (IntegerStamp) forX.stamp(view);

            IntegerStamp yStamp = (IntegerStamp) forY.stamp(view);

            if ((xStamp.upMask() & yStamp.upMask()) == 0) {

                return LogicConstantNode.tautology();

            } else if ((xStamp.downMask() & yStamp.downMask()) != 0) {

                return LogicConstantNode.contradiction();

            }

        }

        return this;

    }

    @Override

    public Stamp getSucceedingStampForX(boolean negated, Stamp xStamp, Stamp yStamp) {

        return getSucceedingStamp(negated, xStamp, yStamp);

    }

    private static Stamp getSucceedingStamp(boolean negated, Stamp xStampGeneric, Stamp otherStampGeneric) {

        if (xStampGeneric instanceof IntegerStamp && otherStampGeneric instanceof IntegerStamp) {

            IntegerStamp xStamp = (IntegerStamp) xStampGeneric;

            IntegerStamp otherStamp = (IntegerStamp) otherStampGeneric;

            if (negated) {

                if (Long.bitCount(otherStamp.upMask()) == 1) {

                    long newDownMask = xStamp.downMask() | otherStamp.upMask();

                    if (xStamp.downMask() != newDownMask) {

                        return IntegerStamp.stampForMask(xStamp.getBits(), newDownMask, xStamp.upMask()).join(xStamp);

                    }

                }

            } else {

                long restrictedUpMask = ((~otherStamp.downMask()) & xStamp.upMask());

                if (xStamp.upMask() != restrictedUpMask) {

                    return IntegerStamp.stampForMask(xStamp.getBits(), xStamp.downMask(), restrictedUpMask).join(xStamp);

                }

            }

        }

        return null;

    }

    @Override

    public Stamp getSucceedingStampForY(boolean negated, Stamp xStamp, Stamp yStamp) {

        return getSucceedingStamp(negated, yStamp, xStamp);

    }

    @Override

    public TriState tryFold(Stamp xStampGeneric, Stamp yStampGeneric) {

        if (xStampGeneric instanceof IntegerStamp && yStampGeneric instanceof IntegerStamp) {

            IntegerStamp xStamp = (IntegerStamp) xStampGeneric;

            IntegerStamp yStamp = (IntegerStamp) yStampGeneric;

            if ((xStamp.upMask() & yStamp.upMask()) == 0) {

                return TriState.TRUE;

            } else if ((xStamp.downMask() & yStamp.downMask()) != 0) {

                return TriState.FALSE;

            }

        }

        return TriState.UNKNOWN;

    }

}