Program that demonstrates issues with branch ofsets

Branches.cs

using System;
using System.IO;
using System.Linq;
using Mono.Cecil;
using Mono.Cecil.Cil;
using Mono.Cecil.Rocks;

namespace CecilSandbox
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length == 0)
            {
                var programName = Path.GetFileName(Environment.GetCommandLineArgs()[0]);
                Console.WriteLine($"run: '{programName} modify <num>' to save a modified version of the assembly where <num> is the number of NOP instructions to inject and then\n");
                Console.WriteLine($"run: '{programName} run' to execute the method with the modified body.");
                return;
            }
            var nopCount = 0;
            if (args.Length == 2 && args[0] == "modify" && !int.TryParse(args[1], out nopCount))
            {
                Console.WriteLine($"'{args[1]}' is not a valid # of nops to inject.");
                return;
            }
            else if(args.Length == 1 && args[0] == "run")
            {
                Console.WriteLine("Trying to run the modified method...");
                Foo(1);
                return;
            }
            else if (nopCount == 0)
            {
                Console.WriteLine("Invalid command line args");
                return;
            }

            using (var a = AssemblyDefinition.ReadAssembly(typeof(Program).Assembly.Location))
            {
                var t = a.MainModule.Types.Single(tc => tc.Name == "Program");
                var m = t.Methods.Single(mc => mc.Name == "Foo");
                foreach (var i in m.Body.Instructions)
                {
                    Console.WriteLine(i);
                }

                if (nopCount == -1)
                    return;

                m.Body.SimplifyMacros();
                
                var branch = m.Body.Instructions.First(i => i.OpCode.OperandType == OperandType.ShortInlineBrTarget || i.OpCode.OperandType == OperandType.InlineBrTarget);
                var il = m.Body.GetILProcessor();
                for(int i = 0; i < nopCount; i++)
                    il.InsertAfter(branch, Instruction.Create(OpCodes.Nop));

                m.Body.OptimizeMacros();

                var targetAssemblyPath = Path.Combine(Path.GetTempPath(), "Output.exe");
                a.Write(targetAssemblyPath);
                Console.WriteLine($"Modified assembly saved to '{targetAssemblyPath}'. Run it with '{targetAssemblyPath} run'");
            }
        }

        static void Foo(int i)
        {
            if (i > 0)
            {
                Console.WriteLine("" + i);
                Console.WriteLine("" + i++);
                Console.WriteLine("" + i++);
                Console.WriteLine("" + i++);
            }

            Console.WriteLine("The End");
        }
    }
}