How large can you make this function without adding any lines of code that do nothing

Question

    public int UndocumentedCode(int a, int b)
    {
        while (true)
        {
            a -= b;
            b += a;
            a = b - a;
            if (b < a)
            {
                return b;
            }
            else
            {
                b += 1;
            }
        }
    }

First figure out what it does (or look at the spoiler) the challenge is to make it as long as possible without adding lines that do absolutely nothing e.g. if (true) or do anything completely meaningless e.g. a declaration that isn't used/needed.

any lines of code that can be removed, with the result still being the same, do not count

the more confusing looking, the better.

it is a function for getting the lesser of two numbers. the if (b < a) return b is self explanatory. The a and b calculations at the top are to swap b and a around, so when it loops it will check a < b. the b+=1 is to prevent infinite loops if they are the same

Answer 1

Not sure this is quite in the spirit of things, and I'm not going to write all the code, but technically all of the lines in the following would be necessary for the function to work. Note, for the sake of brevity I've changed the types to char, which I will assume is an 8-bit signed type (I didn't spot any mention of a specific language):

public char UndocumentedCode(char a, char b)
{
    if (a == -128 && b == -128)
        return -128;
    if (a == -127 && b == -128)
        return -128;
    if (a == -126 && b == -128)
        return -128;
    ...
    // can you see where I'm going with this?
    ...
    if (a == -128 && b == -127)
        return -128;
    if (a == -127 && b == -127)
        return -127;
    if (a == -126 && b == -127)
        return -127;
    ...
    // yawn...
    ...
    if (a == 125 && b == 127)
        return 125;
    if (a == 126 && b == 127)
        return 126;
    if (a == 127 && b == 127)
        return 127;

    // i think you get the idea by now
}

The code would of course be platform dependant, and cases would need to be written for all combinations of negative and positive numbers. Perhaps some kind of script to write the file, to save aching fingers, and to automatically generate the code based on platform-specific options.

If we just went with 8-bit ints, then the final code would be roughly 131075 lines long, with all lines being necessary to cover all possibilities.

Answer 2

 public int UndocumentedCode(int a, int b)
 {
   while (true)
   {
       a -= b;
       b += a;
       a = b - a;
       bool isGT? = b < a;
       if isGT?
       {
          return b;
       }
       else
       {
         b += 1;
       }
    }
}

Add another statement with boolean condition.

Answer 3

public int UndocumentedCode(int a, int b)
{
    int a1 = a;
    int a2 = a1;
    int a3 = a2;
    int a4 = a3;
    int a5 = a4;
    int a6 = a5;
    int a7 = a6;
    int a8 = a7;
    int a9 = a8;

    // etc

    int a9999 = a9998
    int c = a9999;
    while (true)
    {
        c -= b;
        b += c;
        c = b - c;
        if (b < c)
        {
            return b;
        }
        else
        {
            b += 1;
        }
    }
}