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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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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,

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package org.graalvm.compiler.loop.phases;

import jdk.internal.vm.compiler.collections.EconomicMap;

import jdk.internal.vm.compiler.collections.Equivalence;

import org.graalvm.compiler.graph.Graph;

import org.graalvm.compiler.loop.LoopEx;

import org.graalvm.compiler.loop.LoopPolicies;

import org.graalvm.compiler.loop.LoopsData;

import org.graalvm.compiler.nodes.LoopBeginNode;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.extended.OpaqueNode;

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

import org.graalvm.compiler.phases.common.CanonicalizerPhase;

import org.graalvm.compiler.phases.common.util.EconomicSetNodeEventListener;

public class LoopPartialUnrollPhase extends LoopPhase<LoopPolicies> {

    private final CanonicalizerPhase canonicalizer;

    public LoopPartialUnrollPhase(LoopPolicies policies, CanonicalizerPhase canonicalizer) {

        super(policies);

        this.canonicalizer = canonicalizer;

    }

    @Override

    @SuppressWarnings("try")

    protected void run(StructuredGraph graph, CoreProviders context) {

        if (graph.hasLoops()) {

            EconomicSetNodeEventListener listener = new EconomicSetNodeEventListener();

            boolean changed = true;

            EconomicMap<LoopBeginNode, OpaqueNode> opaqueUnrolledStrides = null;

            while (changed) {

                changed = false;

                try (Graph.NodeEventScope nes = graph.trackNodeEvents(listener)) {

                    LoopsData dataCounted = new LoopsData(graph);

                    dataCounted.detectedCountedLoops();

                    Graph.Mark mark = graph.getMark();

                    boolean prePostInserted = false;

                    for (LoopEx loop : dataCounted.countedLoops()) {

                        if (!LoopTransformations.isUnrollableLoop(loop)) {

                            continue;

                        }

                        if (getPolicies().shouldPartiallyUnroll(loop)) {

                            if (loop.loopBegin().isSimpleLoop()) {

                                // First perform the pre/post transformation and do the partial

                                // unroll when we come around again.

                                LoopTransformations.insertPrePostLoops(loop);

                                prePostInserted = true;

                            } else {

                                if (opaqueUnrolledStrides == null) {

                                    opaqueUnrolledStrides = EconomicMap.create(Equivalence.IDENTITY);

                                }

                                LoopTransformations.partialUnroll(loop, opaqueUnrolledStrides);

                            }

                            changed = true;

                        }

                    }

                    dataCounted.deleteUnusedNodes();

                    if (!listener.getNodes().isEmpty()) {

                        canonicalizer.applyIncremental(graph, context, listener.getNodes());

                        listener.getNodes().clear();

                    }

                    assert !prePostInserted || checkCounted(graph, mark);

                }

            }

            if (opaqueUnrolledStrides != null) {

                try (Graph.NodeEventScope nes = graph.trackNodeEvents(listener)) {

                    for (OpaqueNode opaque : opaqueUnrolledStrides.getValues()) {

                        opaque.remove();

                    }

                    if (!listener.getNodes().isEmpty()) {

                        canonicalizer.applyIncremental(graph, context, listener.getNodes());

                    }

                }

            }

        }

    }

    private static boolean checkCounted(StructuredGraph graph, Graph.Mark mark) {

        LoopsData dataCounted;

        dataCounted = new LoopsData(graph);

        dataCounted.detectedCountedLoops();

        for (LoopEx anyLoop : dataCounted.loops()) {

            if (graph.isNew(mark, anyLoop.loopBegin())) {

                assert anyLoop.isCounted() : "pre/post transformation loses counted loop " + anyLoop.loopBegin();

            }

        }

        return true;

    }

    @Override

    public boolean checkContract() {

        return false;

    }

}