jdk-24/test/jdk/java/lang/Math/RoundTests.java

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/*
 * @test
 * @bug 6430675 8010430
 * @summary Check for correct implementation of {Math, StrictMath}.round
 * @run main/othervm -XX:Tier3CompileThreshold=50 -XX:CompileThresholdScaling=0.01 -XX:+TieredCompilation RoundTests
 */
public class RoundTests {
    public static void main(String... args) {
        int failures = 0;
        for (int i = 0; i < 500; i++) {
            failures += testNearFloatHalfCases();
            failures += testNearDoubleHalfCases();
            failures += testUnityULPCases();
            failures += testSpecialCases();

            if (failures > 0) {
                System.err.println("Testing {Math, StrictMath}.round incurred "
                                   + failures + " failures.");
                throw new RuntimeException();
            }
        }
    }

    private static int testNearDoubleHalfCases() {
        int failures = 0;
        double [][] testCases = {
            {+0x1.fffffffffffffp-2,  0.0},
            {+0x1.0p-1,              1.0}, // +0.5
            {+0x1.0000000000001p-1,  1.0},

            {-0x1.fffffffffffffp-2,  0.0},
            {-0x1.0p-1,              0.0}, // -0.5
            {-0x1.0000000000001p-1, -1.0},
        };

        for(double[] testCase : testCases) {
            failures += testNearHalfCases(testCase[0], (long)testCase[1]);
        }

        return failures;
    }

    private static int testNearHalfCases(double input, double expected) {
        int failures = 0;

        failures += Tests.test("Math.round",        input, Math::round,       expected);
        failures += Tests.test("StrictMath.round",  input, StrictMath::round, expected);

        return failures;
    }

    private static int testNearFloatHalfCases() {
        int failures = 0;
        float [][] testCases = {
            {+0x1.fffffep-2f,  0.0f},
            {+0x1.0p-1f,       1.0f}, // +0.5
            {+0x1.000002p-1f,  1.0f},

            {-0x1.fffffep-2f,  0.0f},
            {-0x1.0p-1f,       0.0f}, // -0.5
            {-0x1.000002p-1f, -1.0f},
        };

        for(float[] testCase : testCases) {
            failures += testNearHalfCases(testCase[0], (int)testCase[1]);
        }

        return failures;
    }

    private static int testNearHalfCases(float input, float expected) {
        int failures = 0;

        failures += Tests.test("Math.round",        input, Math.round(input),       expected);
        failures += Tests.test("StrictMath.round",  input, StrictMath.round(input), expected);

        return failures;
    }

    private static int testUnityULPCases() {
        int failures = 0;
        for (float sign : new float[]{-1, 1}) {
            for (float v1 : new float[]{1 << 23, 1 << 24}) {
                for (int k = -5; k <= 5; k++) {
                    float value = (v1 + k) * sign;
                    float actual = Math.round(value);
                    failures += Tests.test("Math.round", value, actual, value);
                }
            }
        }

        if (failures != 0) {
            System.out.println();
        }

        for (double sign : new double[]{-1, 1}) {
            for (double v1 : new double[]{1L << 52, 1L << 53}) {
                for (int k = -5; k <= 5; k++) {
                    double value = (v1 + k) * sign;
                    double actual = Math.round(value);
                    failures += Tests.test("Math.round", value, actual, value);
                }
            }
        }

        return failures;
    }

    private static int testSpecialCases() {
        int failures = 0;

        failures += Tests.test("Math.round", Float.NaN, Math.round(Float.NaN), 0.0F);
        failures += Tests.test("Math.round", Float.POSITIVE_INFINITY,
                Math.round(Float.POSITIVE_INFINITY), Integer.MAX_VALUE);
        failures += Tests.test("Math.round", Float.NEGATIVE_INFINITY,
                Math.round(Float.NEGATIVE_INFINITY), Integer.MIN_VALUE);
        failures += Tests.test("Math.round", -(float)Integer.MIN_VALUE,
                Math.round(-(float)Integer.MIN_VALUE), Integer.MAX_VALUE);
        failures += Tests.test("Math.round", (float) Integer.MIN_VALUE,
                Math.round((float) Integer.MIN_VALUE), Integer.MIN_VALUE);
        failures += Tests.test("Math.round", 0F, Math.round(0F), 0.0F);
        failures += Tests.test("Math.round", Float.MIN_VALUE,
                Math.round(Float.MIN_VALUE), 0.0F);
        failures += Tests.test("Math.round", -Float.MIN_VALUE,
                Math.round(-Float.MIN_VALUE), 0.0F);

        failures += Tests.test("Math.round", Double.NaN,               Math::round, 0.0);
        failures += Tests.test("Math.round", Double.POSITIVE_INFINITY, Math::round, Long.MAX_VALUE);
        failures += Tests.test("Math.round", Double.NEGATIVE_INFINITY, Math::round, Long.MIN_VALUE);
        failures += Tests.test("Math.round", -(double)Long.MIN_VALUE,  Math::round, Long.MAX_VALUE);
        failures += Tests.test("Math.round", (double) Long.MIN_VALUE,  Math::round, Long.MIN_VALUE);
        failures += Tests.test("Math.round", 0,                        Math::round, 0.0);
        failures += Tests.test("Math.round", Double.MIN_VALUE,         Math::round, 0.0);
        failures += Tests.test("Math.round", -Double.MIN_VALUE,        Math::round, 0.0);

        return failures;
    }
}