test/hotspot/jtreg/compiler/conversions/TestMoveConvI2LOrCastIIThruAddIs.java

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package compiler.conversions;

import java.util.Objects;
import java.util.Random;
import jdk.test.lib.Asserts;

/*
 * @test
 * @bug 8254317 8256730
 * @requires vm.compiler2.enabled
 * @summary Exercises the optimization that moves integer-to-long conversions
 *          upwards through different shapes of integer addition
 *          subgraphs. Contains three small functional tests and two stress
 *          tests that resulted in a compilation time and memory explosion
 *          before fixing bug 8254317. The stress tests run with -Xbatch to wait
 *          for C2, so that a timeout or an out-of-memory error is triggered if
 *          there was an explosion. These tests use a timeout of 30s to catch
 *          the explosion earlier.
 * @library /test/lib /
 * @run main/othervm
 *      compiler.conversions.TestMoveConvI2LOrCastIIThruAddIs functional
 * @run main/othervm/timeout=30 -Xbatch
 *      compiler.conversions.TestMoveConvI2LOrCastIIThruAddIs stress1
 * @run main/othervm/timeout=30 -Xbatch
 *      compiler.conversions.TestMoveConvI2LOrCastIIThruAddIs stress2
 * @run main/othervm/timeout=30 -Xbatch
 *      compiler.conversions.TestMoveConvI2LOrCastIIThruAddIs stress3
 * @run main/othervm/timeout=30 -Xbatch
 *      compiler.conversions.TestMoveConvI2LOrCastIIThruAddIs stress4
 */

public class TestMoveConvI2LOrCastIIThruAddIs {

    // Number of repetitions of each test. Should be sufficiently large for the
    // method under test to be compiled with C2.
    static final int N = 100_000;

    // Chain-shaped functional test.
    static long testChain(boolean cnd) {
        int a = cnd ? 1 : 2;
        int b = a + a;
        int c = b + b;
        int d = c + c;
        return d;
    }

    // Tree-shaped functional test.
    static long testTree(boolean cnd) {
        int a0 = cnd ? 1 : 2;
        int a1 = cnd ? 1 : 2;
        int a2 = cnd ? 1 : 2;
        int a3 = cnd ? 1 : 2;
        int a4 = cnd ? 1 : 2;
        int a5 = cnd ? 1 : 2;
        int a6 = cnd ? 1 : 2;
        int a7 = cnd ? 1 : 2;
        int b0 = a0 + a1;
        int b1 = a2 + a3;
        int b2 = a4 + a5;
        int b3 = a6 + a7;
        int c0 = b0 + b1;
        int c1 = b2 + b3;
        int d = c0 + c1;
        return d;
    }

    // DAG-shaped functional test.
    static long testDAG(boolean cnd) {
        int a0 = cnd ? 1 : 2;
        int a1 = cnd ? 1 : 2;
        int a2 = cnd ? 1 : 2;
        int a3 = cnd ? 1 : 2;
        int b0 = a0 + a1;
        int b1 = a1 + a2;
        int b2 = a2 + a3;
        int c0 = b0 + b1;
        int c1 = b1 + b2;
        int d = c0 + c1;
        return d;
    }

    // Chain-shaped stress test. Before fixing bug 8254317, this test would
    // result in an out-of-memory error after minutes running.
    static long testStress1(boolean cnd) {
        // C2 infers a finite, small value range for a. Note that there are
        // different ways to achieve this, for example a might take the value of
        // the induction variable in an outer counted loop.
        int a = cnd ? 1 : 2;
        // C2 fully unrolls this loop, creating a long chain of AddIs.
        for (int i = 0; i < 28; i++) {
            a = a + a;
        }
        // C2 places a ConvI2L at the end of the AddI chain.
        return a;
    }

    // DAG-shaped stress test. Before fixing bug 8254317, this test would result
    // in an out-of-memory error after minutes running.
    static long testStress2(boolean cnd) {
        int a = cnd ? 1 : 2;
        int b = a;
        int c = a + a;
        for (int i = 0; i < 20; i++) {
            b = b + c;
            c = b + c;
        }
        int d = b + c;
        return d;
    }

    // Same as testStress1 for CastII
    static long testStress3(int a) {
        Objects.checkIndex(a, 2);
        for (int i = 0; i < 28; i++) {
            a = a + a;
        }
        return Objects.checkIndex(a, 2);
    }

    // Same as testStress2 for CastII
    static long testStress4(int a) {
        a = Objects.checkIndex(a, 2);
        int b = a;
        int c = a + a;
        for (int i = 0; i < 20; i++) {
            b = b + c;
            c = b + c;
        }
        int d = b + c;
        return Objects.checkIndex(d, 2);
    }

    public static void main(String[] args) {
        // We use a random number generator to avoid constant propagation in C2
        // and produce a variable ("a" in the different tests) with a finite,
        // small value range.
        Random rnd = new Random();
        switch(args[0]) {
        case "functional":
            // Small, functional tests.
            for (int i = 0; i < N; i++) {
                boolean cnd = rnd.nextBoolean();
                Asserts.assertEQ(testChain(cnd), cnd ? 8L : 16L);
                Asserts.assertEQ(testTree(cnd), cnd ? 8L : 16L);
                Asserts.assertEQ(testDAG(cnd), cnd ? 8L : 16L);
            }
            break;
        case "stress1":
            // Chain-shaped stress test.
            for (int i = 0; i < N; i++) {
                boolean cnd = rnd.nextBoolean();
                Asserts.assertEQ(testStress1(cnd),
                                 cnd ? 268435456L : 536870912L);
            }
            break;
        case "stress2":
            // DAG-shaped stress test.
            for (int i = 0; i < N; i++) {
                boolean cnd = rnd.nextBoolean();
                Asserts.assertEQ(testStress2(cnd),
                                 cnd ? 701408733L : 1402817466L);
            }
            break;
        case "stress3":
            for (int i = 0; i < N; i++) {
                testStress3(0);
            }
            break;
        case "stress4":
            // DAG-shaped stress test.
            for (int i = 0; i < N; i++) {
                testStress4(0);
            }
            break;
        default:
            System.out.println("invalid mode");
        }
    }
}