What is faster (x < 0) or (x == -1)?

Question

Variable x is int with possible values: -1, 0, 1, 2, 3. Which expression will be faster (in CPU ticks):

1. (x < 0)
2. (x == -1)
         


        

Answer 1

x < 0 will be faster. If nothing else, it prevents fetching the constant -1 as an operand. Most architectures have special instructions for comparing against zero, so that will help too.