c++coptimization

++i versus i++ : is there any difference on any modern compiler?

Possible Duplicate:
Is there a performance difference between i++ and ++i in C++?

I understand that:

i++;

Is supposed to take more instructions than

++i;

Because it's generating an intermediate result that you don't need to use, so people put "++i" on lines of code that have no use for the intermediate result.

However, compilers are really smart, and they can tell if a result is being used or not. They can tell all kinds of things. But they aren't magic

So I am curious - on modern compilers does picking one way over the other actually matter or will it simply compile to the same machine code regardless?

Solution

  • It does not matter when using it on an int. However, when using iterators or other objects that overload operator++, it might still make a difference.