调试和发布之间的C＃区别

Question

Following code produces same output on 95% of machines, but on several there is difference. In Debug mode there is output:

Changing from New to Fin
OK

but in Release mode:

Changing from New to Fin

The OK line is missing. The project is targeted to .Net 4.0, build with VS 2015. You can download full sample here .

Source code

using System;
namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            Status current = Values.Status;
            if (current != Next())
                Console.WriteLine("OK");
        }

        static VO Values = new VO();
        private static Status Next()
        {
            Status res = Status.Fin;
            if (Values.Status == Status.New && Values.Cond)
                res = Status.Fin;
            else if (Values.Status == Status.Fin)
                res = Status.Fin;

            Log("Changing from {0} to {1}", Values.Status, res);
            Values.Status = res;
            return res;
        }
        public static void Log(string format, params object[] args)
        {
            Console.WriteLine(format, args);
        }
    }

    public class VO
    {
        public Status Status;
        public bool Cond;
    }

    public enum Status { New, Fin }
}

This is in my opinion the minimal version to reproduce the error. After removing some of the conditions in Next(), inlining Log method, replacing Values.Cond with false causes the application behaves correctly.

Edit : It's not hardware related - operating system was extracted to Hyper-V and the problem persists.

Answer 1

Based on Hans Passant's comment the problem was still reproducible with clrjit.dll version 4.6. After upgrading to 4.7 it disappears.