Null check benchmarks

main.cs

using System;
using System.Runtime.CompilerServices;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;
using BenchmarkDotNet.Running;
// ReSharper disable RedundantToStringCall
// ReSharper disable NotAccessedField.Local
#pragma warning disable 169

BenchmarkRunner.Run<NullChecksBenchmark>();

[SimpleJob(RuntimeMoniker.Net48)]
[SimpleJob(RuntimeMoniker.NetCoreApp31)]
[SimpleJob(RuntimeMoniker.Net50)]
[SimpleJob(RuntimeMoniker.Net60)]
public class NullChecksBenchmark
{
  private readonly string[] myBox = { "abc" };
  private string myField;
  private int myField2;
  private const int Count = 100;

  [Benchmark]
  public void IfThenThrow() => IfThenThrow(myBox[0]);

  private void IfThenThrow(string s)
  {
    if (s == null)
      throw new ArgumentNullException(nameof(s));

    // do some work
    // for (var index = 0; index < Count; index++)
    // {
    //   myField = s.ToString();
    //   myField2 = index;
    // }
    myField = s.ToString();
  }

  [Benchmark]
  public void HelperMethod() => HelperMethod(myBox[0]);

  private void HelperMethod(string s)
  {
    if (s == null)
      ThrowHelper(nameof(s));

    // do some work
    // for (var index = 0; index < Count; index++)
    // {
    //   myField = s.ToString();
    //   myField2 = index;
    // }
    myField = s.ToString();
  }

  private static void ThrowHelper( string parameterName)
  {
    throw new ArgumentNullException(parameterName);
  }

  [Benchmark]
  public void HelperMethodNoInline() => HelperMethodNoInline(myBox[0]);

  private void HelperMethodNoInline(string s)
  {
    if (s == null)
      ThrowHelperNoInline(nameof(s));

    // do some work
    // for (var index = 0; index < Count; index++)
    // {
    //   myField = s.ToString();
    //   myField2 = index;
    // }
    myField = s.ToString();
  }

  [MethodImpl(MethodImplOptions.NoInlining)]
  private static void ThrowHelperNoInline(string parameterName)
  {
    throw new ArgumentNullException(parameterName);
  }

  [Benchmark]
  public void HelperMethodNoArgs() => HelperMethodNoArgs(myBox[0]);

  private void HelperMethodNoArgs(string s)
  {
    if (s == null)
      ThrowHelperNoArgs();

    // do some work
    // for (var index = 0; index < Count; index++)
    // {
    //   myField = s.ToString();
    //   myField2 = index;
    // }
    myField = s.ToString();
  }

  [MethodImpl(MethodImplOptions.NoInlining)]
  private static void ThrowHelperNoArgs()
  {
    throw new ArgumentNullException("s");
  }
}

proj.csproj

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFrameworks>net48;netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
    <LangVersion>latest</LangVersion>
  </PropertyGroup>

  <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="BenchmarkDotNet" Version="0.13.0" />
  </ItemGroup>
</Project>