Re: About g++ optimization

[address@hidden]

Peng,

The space between the ++ and i is fine. Some find ++i more readable,
that is all.

It is difficult to optimize away the repeated f(n) calls because f()
could have side effects and there is no guarantee it will always return
a constant. If f() always returns a constant, this could potentially be
optimized by interprocedural constant propagation(IPCP)

IPCP work is being done on the ipa branch but I don't think it is safe
to assume whether it will be optimized.

If your f() returns a constant, your best bet is to do:

 for (int i =0,  j = f(n); i < j; ++i) {
}

Regards,

Ryan Mansfield