I check whether the caller’s assembly code has a call instruction to the callee. Or, in this case where I know what I want the answer to be, I use the always_inline GCC attribute.

Agreed, thanks for these additions Daniel.

Right. Hadn’t planned it, but that could be an interesting measure. However, as you’re pointing out, inlining would play a big role. Actually, I’m not sure how to check whether a function has been inline in a simple way (nor in a complicated one), do you have an idea how we do this?

* If you care about performance that much, you really should be using at least -O1. Then it doesn’t matter, at least for this simple test case.
* If all else fails and you need to make the code less readable, you can always use comments if the less readable code is particularly bad.

Personally, I wouldn’t care about perf of such
simple expressions for the most code. As you mentioned it’s important in
hot spots and critical code in the system.

Do you plan to
measure if (statements…) vs if (functionCall()) ? But if the
functionCall is simple that should be inlined by the compiler and the
perf should be the same… just loud thinking 🙂