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 * 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

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package org.graalvm.compiler.nodes.java;

import static org.graalvm.compiler.nodeinfo.InputType.Memory;

import static org.graalvm.compiler.nodeinfo.InputType.State;

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

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.nodeinfo.InputType;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.FrameState;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.StateSplit;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.memory.FixedAccessNode;

import org.graalvm.compiler.nodes.memory.LIRLowerableAccess;

import org.graalvm.compiler.nodes.memory.MemoryCheckpoint;

import org.graalvm.compiler.nodes.memory.address.AddressNode;

import jdk.internal.vm.compiler.word.LocationIdentity;

/**

 * Low-level atomic compare-and-swap operation.

 */

@NodeInfo(allowedUsageTypes = {InputType.Value, Memory})

public abstract class AbstractCompareAndSwapNode extends FixedAccessNode implements StateSplit, LIRLowerableAccess, MemoryCheckpoint.Single {

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

    @Input ValueNode expectedValue;

    @Input ValueNode newValue;

    @OptionalInput(State) FrameState stateAfter;

    @Override

    public FrameState stateAfter() {

        return stateAfter;

    }

    @Override

    public void setStateAfter(FrameState x) {

        assert x == null || x.isAlive() : "frame state must be in a graph";

        updateUsages(stateAfter, x);

        stateAfter = x;

    }

    @Override

    public boolean hasSideEffect() {

        return true;

    }

    public ValueNode getExpectedValue() {

        return expectedValue;

    }

    public ValueNode getNewValue() {

        return newValue;

    }

    public AbstractCompareAndSwapNode(NodeClass<? extends AbstractCompareAndSwapNode> c, AddressNode address, LocationIdentity location, ValueNode expectedValue, ValueNode newValue,

                    BarrierType barrierType, Stamp stamp) {

        super(c, address, location, stamp, barrierType);

        assert expectedValue.getStackKind() == newValue.getStackKind();

        this.expectedValue = expectedValue;

        this.newValue = newValue;

    }

    @Override

    public boolean canNullCheck() {

        return false;

    }

    @Override

    public Stamp getAccessStamp() {

        return expectedValue.stamp(NodeView.DEFAULT).meet(newValue.stamp(NodeView.DEFAULT)).unrestricted();

    }

}