IsInRange bench

IsInRange.cs

public class Bench
{
	private const int Rep = 10_000_000;
	private int[] _a = new int[Rep];

	[GlobalSetup]
	public void Setup()
	{
		Random.Shared.GetItems([..Enumerable.Range(0, Rep)], _a);
	}

	[Benchmark(Baseline = true)]
	public int IsInRangeV1()
	{
		var sum = 0;
		for (var i = 0; i < Rep; i++)
		{
			var c = _a[i];
			sum += c >= i - 100 && c <= i + 100 ? 1 : 0;
		}

		return sum;
	}

	[Benchmark]
	public int IsInRangeV2()
	{
		const long mask = (1L << 63) | (1L << 31);

		var sum = 0;
		for (var i = 0; i < Rep; i++)
		{
			var c = (long)_a[i];
			var r = (((long)i + 100) << 32) | ((long)i - 100);
			var isFit = BitOperations.PopCount((ulong)((((c << 32) | c) - r) & mask)) & 1;
			sum += isFit;
		}

		return sum;
	}

	[Benchmark]
	public int IsInRangeV3()
	{
		var sum = 0;
		for (var i = 0; i < Rep; i++)
		{
			var c = _a[i];
			sum += ((c - (i - 100)) | (i + 100 - c)) > 0 ? 1 : 0;
		}

		return sum;
	}
}

public static void RunBenchmark()
{
	var enough = Job.Default
		.WithWarmupCount(1)
		.WithIterationTime(TimeInterval.FromSeconds(0.25))
		.WithMaxIterationCount(20);

	IConfig config = DefaultConfig.Instance
		.HideColumns(Column.EnvironmentVariables, Column.RatioSD, Column.Error)
		.AddDiagnoser(new MemoryDiagnoser(new MemoryDiagnoserConfig(false)))
		.AddDiagnoser(new DisassemblyDiagnoser(new DisassemblyDiagnoserConfig(exportGithubMarkdown: true, printInstructionAddresses: false)));

	config.AddJob(enough);

	BenchmarkRunner.Run<Bench>(config);
}