Why does n++ execute faster than n=n+1?

Question

In C language, Why does n++ execute faster than n=n+1?

(int n=...;  n++;)
(int n=...;  n=n+1;)

Our instructor asked

Answer 1

It doesn't really. The compiler will make changes specific to the target architecture. Micro-optimizations like this often have dubious benefits, but importantly, are certainly not worth the programmer's time.