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package compiler.c2.irTests;

import jdk.test.lib.Asserts;
import jdk.test.lib.Utils;

import java.util.Random;

import compiler.lib.ir_framework.*;

/*
 * @test
 * @bug 8332268
 * @summary Test that Ideal transformations of ModINode* are being performed as expected.
 * @library /test/lib /
 * @run driver compiler.c2.irTests.ModINodeIdealizationTests
 */
public class ModINodeIdealizationTests {
    public static final int RANDOM_POWER_OF_2 = 1 << (1 + Utils.getRandomInstance().nextInt(30));

    public static void main(String[] args) {
        TestFramework.run();
    }

    @Run(test = {"constant", "constantAgain", "powerOf2", "powerOf2Random", "powerOf2Minus1",
                 "positivePowerOf2", "positivePowerOf2Random"})
    public void runMethod() {
        int a = RunInfo.getRandom().nextInt();
        a = (a == 0) ? 2 : a;
        int b = RunInfo.getRandom().nextInt();
        b = (b == 0) ? 2 : b;

        int min = Integer.MIN_VALUE;
        int max = Integer.MAX_VALUE;

        assertResult(0, 0, true);
        assertResult(a, b, false);
        assertResult(min, min, false);
        assertResult(max, max, false);
    }

    @DontCompile
    public void assertResult(int a, int b, boolean shouldThrow) {
        try {
            Asserts.assertEQ(a % a, constant(a));
            Asserts.assertFalse(shouldThrow, "Expected an exception to be thrown.");
        } catch (ArithmeticException e) {
            Asserts.assertTrue(shouldThrow, "Did not expect an exception to be thrown.");
        }

        Asserts.assertEQ(a % 32, powerOf2(a));
        Asserts.assertEQ(a % RANDOM_POWER_OF_2, powerOf2Random(a));
        Asserts.assertEQ(Math.max(0, a) % 32, positivePowerOf2(a));
        Asserts.assertEQ(Math.max(0, a) % RANDOM_POWER_OF_2, positivePowerOf2Random(a));
        Asserts.assertEQ(a % 127, powerOf2Minus1(a));
        Asserts.assertEQ(a % 1, constantAgain(a));
    }

    @Test
    @IR(failOn = {IRNode.MOD_I, IRNode.MUL})
    @IR(counts = {IRNode.DIV_BY_ZERO_TRAP, "1"})
    // Checks x % x => 0
    public int constant(int x) {
        return x % x;
    }

    @Test
    @IR(failOn = {IRNode.MOD_I})
    // Checks x % 1 => 0
    public int constantAgain(int x) {
        return x % 1;
    }

    @Test
    @IR(failOn = {IRNode.MOD_I, IRNode.RSHIFT, IRNode.ADD, IRNode.SUB})
    @IR(counts = {IRNode.AND_I, "1"})
    public int positivePowerOf2(int x) {
        return Math.max(0, x) % 32;
    }

    @Test
    @IR(failOn = {IRNode.MOD_I, IRNode.RSHIFT, IRNode.ADD, IRNode.SUB})
    @IR(counts = {IRNode.AND_I, "1"})
    public int positivePowerOf2Random(int x) {
        return Math.max(0, x) % RANDOM_POWER_OF_2;
    }

    @Test
    @IR(failOn = {IRNode.MOD_I, IRNode.DIV})
    @IR(counts = {IRNode.AND_I, "1"})
    public int powerOf2(int x) {
        return x % 32;
    }

    @Test
    @IR(failOn = {IRNode.MOD_I, IRNode.DIV})
    @IR(counts = {IRNode.AND_I, "1"})
    public int powerOf2Random(int x) {
        return x % RANDOM_POWER_OF_2;
    }

    @Test
    @IR(failOn = {IRNode.MOD_I})
    @IR(counts = {IRNode.AND_I, ">=1", IRNode.RSHIFT, ">=1", IRNode.CMP_I, "2"})
    // Special optimization for the case 2^k-1 for bigger k
    public int powerOf2Minus1(int x) {
        return x % 127;
    }
}