On 6/29/06, Yuval Ronen <ronen_yuval@yahoo.com> wrote:
This warning is not so bad, IMO. It tells you that you are trying evaluate a compile-time constant in run-time, and that's wasting CPU cycles. The runtime 'if' can be substituted by a compile-time specialization.
[...]
This will prevent the compiler from generating the runtime comparison. Sure this is a small piece of code we are trying to optimize, and a good optimizing compiler would remove it anyway, but if we can write more efficient code without relying on a compiler optimization that might or might not be there, isn't it better?
Surely if a compiler is smart enough to know that a conditional is constant then it should be able to get rid of the test-and-branch anyways. I know that g++ can resolve an if ( boost::is_signed<T>::value ) at compile-time and only emit code for the branch that is taken. And, of course, it doesn't have this warning. ~ Scott McMurray