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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.CoreProviders;
import org.graalvm.compiler.nodes.spi.LoweringTool;
import org.graalvm.compiler.phases.OptimisticOptimizations;
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.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.
 */
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);
        CoreProviders context = getProviders();
        new LoweringPhase(createCanonicalizerPhase(), 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(createCanonicalizerPhase(), LoweringTool.StandardLoweringStage.MID_TIER).apply(graph, midContext);
        createCanonicalizerPhase().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");
        createCanonicalizerPhase().apply(graph, 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);
    }
}
