Fuzzlyn-Bad-Program-Reduced.cs

// Generated by Fuzzlyn v1.1 on 2018-08-22 15:19:26
// Seed: 14928117313359926641
// Reduced from 256.3 KiB to 0.4 KiB in 00:01:58
// Debug: Prints 0 line(s)
// Release: Prints 1 line(s)
public class Program
{
    static short s_18;
    static byte s_33 = 1;
    static int[] s_40 = new int[]{0};
    static short s_74 = 1;
    public static void Main()
    {
        s_18 = -1;
        // This comparision is the bug, in Debug it's False, in Release it's True
        // '(ushort)(s_18 | 2L)' is 65,535 in Debug *and* Release
        if (((ushort)(s_18 | 2L) <= s_40[0])) 
        {
            s_74 = 0;
        }

        bool vr10 = s_74 < s_33;
        if (vr10)
        {
            System.Console.WriteLine(0);
        }
    }
}

I think that it's a dupe of https://github.com/dotnet/coreclr/issues/18238. It does not seem to repro with the latest bits, so definitely seems fixed.