The benchmarks would probably be somewhat misleading in a lot of cases here. I'm fairly certain that most compilers will replace a /2 with >>1 for example, so that isn't really going to end up being reflected when you compile it.
That depends on the CPU used. Modern CPU have more arithmetic units than logical units and can perform more divisions than bit shifts. There was a good video presentation of that, but
I can't find the link now.
