/*

 * Copyright (c) 2011, 2019, Oracle and/or its affiliates. All rights reserved.

 * 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.core.test;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.debug.DebugDumpScope;

import org.graalvm.compiler.loop.DefaultLoopPolicies;

import org.graalvm.compiler.loop.phases.LoopUnswitchingPhase;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions;

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

import org.junit.Test;

public class LoopUnswitchTest extends GraalCompilerTest {

    public static int referenceSnippet1(int a) {

        int sum = 0;

        if (a > 2) {

            for (int i = 0; i < 1000; i++) {

                sum += 2;

            }

        } else {

            for (int i = 0; i < 1000; i++) {

                sum += a;

            }

        }

        return sum;

    }

    public static int test1Snippet(int a) {

        int sum = 0;

        for (int i = 0; i < 1000; i++) {

            if (a > 2) {

                sum += 2;

            } else {

                sum += a;

            }

        }

        return sum;

    }

    public static int referenceSnippet2(int a) {

        int sum = 0;

        switch (a) {

            case 0:

                for (int i = 0; i < 1000; i++) {

                    sum += System.currentTimeMillis();

                }

                break;

            case 1:

                for (int i = 0; i < 1000; i++) {

                    sum += 1;

                    sum += 5;

                }

                break;

            case 55:

                for (int i = 0; i < 1000; i++) {

                    sum += 5;

                }

                break;

            default:

                for (int i = 0; i < 1000; i++) {

                    // nothing

                }

                break;

        }

        return sum;

    }

    @SuppressWarnings("fallthrough")

    public static int test2Snippet(int a) {

        int sum = 0;

        for (int i = 0; i < 1000; i++) {

            switch (a) {

                case 0:

                    sum += System.currentTimeMillis();

                    break;

                case 1:

                    sum += 1;

                    // fall through

                case 55:

                    sum += 5;

                    break;

                default:

                    // nothing

                    break;

            }

        }

        return sum;

    }

    @Test

    public void test1() {

        test("test1Snippet", "referenceSnippet1");

    }

    @Test

    public void test2() {

        test("test2Snippet", "referenceSnippet2");

    }

    @SuppressWarnings("try")

    private void test(String snippet, String referenceSnippet) {

        DebugContext debug = getDebugContext();

        final StructuredGraph graph = parseEager(snippet, AllowAssumptions.NO);

        final StructuredGraph referenceGraph = parseEager(referenceSnippet, AllowAssumptions.NO);

        new LoopUnswitchingPhase(new DefaultLoopPolicies()).apply(graph);

        // Framestates create comparison problems

        graph.clearAllStateAfter();

        referenceGraph.clearAllStateAfter();

        new CanonicalizerPhase().apply(graph, getProviders());

        new CanonicalizerPhase().apply(referenceGraph, getProviders());

        try (DebugContext.Scope s = debug.scope("Test", new DebugDumpScope("Test:" + snippet))) {

            assertEquals(referenceGraph, graph);

        } catch (Throwable e) {

            throw debug.handle(e);

        }

    }

}