The dead code should get removed by the compiler if the condition depends on a compile time constant, so technically it wouldn't hurt to keep it in. However I prefer to rather comment it since this improves the readability of the code.
If you want to be able to quickly switch between two code alternatives you can use the following convenient comment construct:
alternative 1 is active
alternative 2 is commented out
if you remove only the first
/ in the first comment line it becomes:
alternative 1 is commented out
alternative 2 is active
With this you can switch between the alternatives by just adding or removing a single
/ in the code.
This may look a bit strange at first but once you got accustomed to it you'll easily recognize it as some kind of pattern.
You can even chain this and thus switch multiple blocks at once with a single char:
first block of code for alternative 1
first block of code for alternative 2
second block of code for alternative 1
second block of code for alternative 2
I wouldn't use it this way but it works.