int?のベンチマーク

NullableBench-report-github.md

BenchmarkDotNet=v0.10.14, OS=Windows 10.0.17134
Intel Core i7-6700 CPU 3.40GHz (Skylake), 1 CPU, 8 logical and 4 physical cores
Frequency=3328124 Hz, Resolution=300.4696 ns, Timer=TSC
.NET Core SDK=2.1.403
  [Host] : .NET Core 2.1.5 (CoreCLR 4.6.26919.02, CoreFX 4.6.26919.02), 64bit RyuJIT
  Core   : .NET Core 2.1.5 (CoreCLR 4.6.26919.02, CoreFX 4.6.26919.02), 64bit RyuJIT

Job=Core  Runtime=Core  

Method	x	Mean	Error	StdDev	Min	Max	Gen 0	Allocated
HasValue	1	1.065 ns	0.0716 ns	0.0670 ns	0.9574 ns	1.150 ns	-	0 B
IsInt	1	52.917 ns	0.3573 ns	0.2984 ns	52.5679 ns	53.499 ns	0.0057	24 B
IsIntY	1	1.184 ns	0.0492 ns	0.0460 ns	1.1125 ns	1.273 ns	-	0 B

NullableBench.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Attributes.Columns;
using BenchmarkDotNet.Attributes.Jobs;
using System.Collections.Generic;

namespace Bench
{
    [CoreJob]
    [MeanColumn, MinColumn, MaxColumn]
    [MemoryDiagnoser]
    public class NullableBench
    {
        public IEnumerable<object> Source()
        {
            yield return (int?)1;
        }

        [Benchmark]
        [ArgumentsSource(nameof(Source))]
        public bool HasValue(int? x)
        {
            if (x.HasValue)
            {
                return true;
            }
            return false;
        }

        [Benchmark]
        [ArgumentsSource(nameof(Source))]
        public bool IsInt(int? x)
        {
            if (x is int)
            {
                return true;
            }
            return false;
        }

        [Benchmark]
        [ArgumentsSource(nameof(Source))]
        public bool IsIntY(int? x)
        {
            if (x is int y)
            {
                return true;
            }
            return false;
        }
    }
}