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package org.openjdk.bench.vm.compiler;

import org.openjdk.jmh.annotations.*;

import java.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Fork(value = 3)
@Warmup(iterations = 5, time = 2)
@Measurement(iterations = 5, time = 3)
@State(Scope.Thread)
public class LoopSafepoint {
    static int someInts0 = 1;
    static int someInts1 = 2;

    @CompilerControl(CompilerControl.Mode.DONT_INLINE)
    private void empty() {}

    // All benchmarks below are in sync with the IR test
    // `compiler.loopopts.TestRedundantSafepointElimination.java`.
    // Check the comments in the IR test for more details.

    @Benchmark
    public int topLevelCountedLoop() {
        int sum = 0;
        for (int i = 0; i < 100000; i++) {
            sum += someInts0;
        }
        return sum;
    }

    @Benchmark
    public int topLevelCountedLoopWithDomCall() {
        int sum = 0;
        for (int i = 0; i < 100000; i++) {
            empty();
            sum += someInts0;
        }
        return sum;
    }

    @Benchmark
    public int topLevelUncountedLoop() {
        int sum = 0;
        for (int i = 0; i < 100000; i += someInts0) {
            sum += someInts1;
        }
        return sum;
    }

    @Benchmark
    public int topLevelUncountedLoopWithDomCall() {
        int sum = 0;
        for (int i = 0; i < 100000; i += someInts0) {
            empty();
            sum += someInts1;
        }
        return sum;
    }

    @Benchmark
    public int outerLoopWithDomCall() {
        int sum = 0;
        for (int i = 0; i < 100; i += someInts0) {
            empty();
            for (int j = 0; j < 1000; j++) {
                sum += someInts1;
            }
        }
        return sum;
    }

    @Benchmark
    public int outerAndInnerLoopWithDomCall() {
        int sum = 0;
        for (int i = 0; i < 100; i += someInts0) {
            empty();
            for (int j = 0; j < 1000; j++) {
                empty();
                sum += someInts1;
            }
        }
        return sum;
    }

    @Benchmark
    public int outerLoopWithLocalNonCallSafepoint() {
        int sum = 0;
        for (int i = 0; i < 100; i += someInts0) {
            for (int j = 0; j < 1000; j++) {
                sum += someInts1;
            }
        }
        return sum;
    }

    @Benchmark
    public void loopNeedsToPreserveSafepoint() {
        int i = 0, stop;
        while (i < 1000) {
            stop = i + 10;
            while (i < stop) {
                i += 1;
            }
        }
    }
}