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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 *
 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package org.graalvm.compiler.core.test;

import org.graalvm.compiler.debug.DebugContext;
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.tiers.MidTierContext;
import org.graalvm.compiler.phases.tiers.PhaseContext;
import org.junit.Test;

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.
/**
 * 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", 4);
        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;
    }

    @Test
    public void test10() {
        // Exercise NormalizeCompareNode with long values
        test("test10Snippet", 0, 1);
    }

    public static long test10Snippet(int x, int y) {
        return (x < y) ? -1L : ((x == y) ? 0L : 1L);
    }

    @Test
    public void test11() {
        test("test11Snippet", 0, 1);
    }

    public static long test11Snippet(int x, int y) {
        long normalizeCompare = normalizeCompareLong(x, y);
        if (normalizeCompare == 0) {
            return 5;
        }
        return 1;
    }

    private static Long normalizeCompareLong(int x, int y) {
        return (x < y) ? -1L : ((x == y) ? 0L : 1L);
    }

    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 CanonicalizerPhase().apply(graph, context);
        assertDeepEquals(count, graph.getNodes().filter(IfNode.class).count());
    }

    private void test(String snippet) {
        StructuredGraph graph = parseEager(snippet, AllowAssumptions.YES);
        DebugContext debug = graph.getDebug();
        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(DebugContext.BASIC_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);
    }
}