/*

 * Copyright (c) 2011, 2015, 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.junit.Test;

import org.graalvm.compiler.debug.Debug;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.nodes.ConstantNode;

import org.graalvm.compiler.nodes.FrameState;

import org.graalvm.compiler.nodes.IfNode;

import org.graalvm.compiler.nodes.ParameterNode;

import org.graalvm.compiler.nodes.StructuredGraph;

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

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

import org.graalvm.compiler.phases.OptimisticOptimizations;

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

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

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

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

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

import org.graalvm.compiler.phases.tiers.MidTierContext;

import org.graalvm.compiler.phases.tiers.PhaseContext;

/**

 * In the following tests, the usages of local variable "a" are replaced with the integer constant

 * 0. Then canonicalization is applied and it is verified that the resulting graph is equal to the

 * graph of the method that just has a "return 1" statement in it.

 */

public class IfCanonicalizerTest extends GraalCompilerTest {

    private static final String REFERENCE_SNIPPET = "referenceSnippet";

    @SuppressWarnings("all")

    public static int referenceSnippet(int a) {

        return 1;

    }

    @Test

    public void test1() {

        test("test1Snippet");

    }

    @SuppressWarnings("all")

    public static int test1Snippet(int a) {

        if (a == 0) {

            return 1;

        } else {

            return 2;

        }

    }

    @Test

    public void test2() {

        test("test2Snippet");

    }

    @SuppressWarnings("all")

    public static int test2Snippet(int a) {

        if (a == 0) {

            if (a == 0) {

                if (a == 0) {

                    return 1;

                }

            }

        } else {

            return 2;

        }

        return 3;

    }

    @Test

    public void test3() {

        test("test3Snippet");

    }

    @SuppressWarnings("all")

    public static int test3Snippet(int a) {

        if (a == 0) {

            if (a != 1) {

                if (a == 1) {

                    return 3;

                } else {

                    if (a >= 0) {

                        if (a <= 0) {

                            if (a > -1) {

                                if (a < 1) {

                                    return 1;

                                }

                            }

                        }

                    }

                }

            }

        } else {

            return 2;

        }

        return 3;

    }

    @Test

    public void test4() {

        test("test4Snippet");

    }

    public static int test4Snippet(int a) {

        if (a == 0) {

            return 1;

        }

        return 1;

    }

    @Test

    public void test5() {

        test("test5Snippet");

    }

    public static int test5Snippet(int a) {

        int val = 2;

        if (a == 0) {

            val = 1;

        }

        if (a * (3 + val) == 0) {

            return 1;

        }

        return 1;

    }

    @Test

    public void test6() {

        testCombinedIf("test6Snippet", 3);

        test("test6Snippet", new int[]{0});

    }

    public static int test6Snippet(int[] a) {

        int i = a[0];

        if (i >= 0 && i < a.length) {

            return a[i];

        }

        return 1;

    }

    @Test

    public void test7() {

        testCombinedIf("test7Snippet", 1);

        test("test7Snippet", -1);

    }

    public static int test7Snippet(int v) {

        if (v >= 0 && v < 1024) {

            return v + 1;

        }

        return v - 1;

    }

    @Test

    public void test8() {

        testCombinedIf("test8Snippet", 1);

        test("test8Snippet", -1);

    }

    public static int test8Snippet(int v) {

        if (v >= 0 && v <= 1024) {

            return v + 1;

        }

        return v - 1;

    }

    @Test

    public void test9() {

        testCombinedIf("test9Snippet", 2);

        test("test9Snippet", -1);

        test("test9Snippet", 1025);

    }

    public static int test9Snippet(int n) {

        return (n < 0) ? 1 : (n >= 1024) ? 1024 : n + 1;

    }

    private void testCombinedIf(String snippet, int count) {

        StructuredGraph graph = parseEager(snippet, AllowAssumptions.YES);

        PhaseContext context = new PhaseContext(getProviders());

        new LoweringPhase(new CanonicalizerPhase(), LoweringTool.StandardLoweringStage.HIGH_TIER).apply(graph, context);

        new FloatingReadPhase().apply(graph);

        MidTierContext midContext = new MidTierContext(getProviders(), getTargetProvider(), OptimisticOptimizations.ALL, graph.getProfilingInfo());

        new GuardLoweringPhase().apply(graph, midContext);

        new LoweringPhase(new CanonicalizerPhase(), LoweringTool.StandardLoweringStage.MID_TIER).apply(graph, midContext);

        new ValueAnchorCleanupPhase().apply(graph);

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

        assertDeepEquals(count, graph.getNodes().filter(IfNode.class).count());

    }

    private void test(String snippet) {

        StructuredGraph graph = parseEager(snippet, AllowAssumptions.YES);

        ParameterNode param = graph.getNodes(ParameterNode.TYPE).iterator().next();

        ConstantNode constant = ConstantNode.forInt(0, graph);

        for (Node n : param.usages().snapshot()) {

            if (!(n instanceof FrameState)) {

                n.replaceFirstInput(param, constant);

            }

        }

        Debug.dump(Debug.BASIC_LOG_LEVEL, graph, "Graph");

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

        for (FrameState fs : param.usages().filter(FrameState.class).snapshot()) {

            fs.replaceFirstInput(param, null);

            param.safeDelete();

        }

        StructuredGraph referenceGraph = parseEager(REFERENCE_SNIPPET, AllowAssumptions.YES);

        assertEquals(referenceGraph, graph);

    }

}