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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.

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package org.graalvm.compiler.phases.common;

import org.graalvm.compiler.core.common.GraalOptions;

import org.graalvm.compiler.core.common.PermanentBailoutException;

import org.graalvm.compiler.debug.TTY;

import org.graalvm.compiler.graph.Graph.NodeEventScope;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.nodes.StructuredGraph;

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

import org.graalvm.compiler.phases.BasePhase;

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

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

public class IterativeConditionalEliminationPhase extends BasePhase<CoreProviders> {

    private static final boolean DEBUG_PHASE = false;

    private static final int DEBUG_MAX_ITERATIONS = 256;

    private final CanonicalizerPhase canonicalizer;

    private final boolean fullSchedule;

    public IterativeConditionalEliminationPhase(CanonicalizerPhase canonicalizer, boolean fullSchedule) {

        this.canonicalizer = canonicalizer;

        this.fullSchedule = fullSchedule;

    }

    @Override

    @SuppressWarnings("try")

    protected void run(StructuredGraph graph, CoreProviders context) {

        final int maxIterations = GraalOptions.ConditionalEliminationMaxIterations.getValue(graph.getOptions());

        EconomicSetNodeEventListener listener = new EconomicSetNodeEventListener();

        int count = 0;

        while (true) {

            count++;

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

                new ConditionalEliminationPhase(fullSchedule).apply(graph, context);

            }

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

                break;

            }

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

            listener.getNodes().clear();

            if (count >= maxIterations) {

                if (DEBUG_PHASE) {

                    if (count >= DEBUG_MAX_ITERATIONS - 5) {

                        TTY.println();

                        TTY.println("------------------------------------");

                        TTY.println("Iteration " + count);

                        TTY.println("Conditional elimination changed nodes: ");

                        for (Node n : listener.getNodes()) {

                            TTY.println(n.toString());

                            for (Node input : n.inputs()) {

                                TTY.println("    input: " + input);

                            }

                        }

                        TTY.println("Canonicalization with node listener: ");

                        try (NodeEventScope debugNes = graph.trackNodeEvents(new TracingNodeEventListener())) {

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

                        }

                    }

                    if (count >= DEBUG_MAX_ITERATIONS) {

                        throw new PermanentBailoutException("Number of iterations in ConditionalEliminationPhase phase exceeds %d", DEBUG_MAX_ITERATIONS);

                    }

                }

                break;

            }

        }

    }

    @Override

    public float codeSizeIncrease() {

        return 2.0f;

    }

}