You cannot do it before compiling the final executable, you have to do it while running. You can simulate the profiling but you will get the best results when y

You cannot do it before compiling the final executable, you have to do it while running. You can simulate the profiling but you will get the best results when you profile while executing. And I guess it is easier to do profiling in high level language than in low level. Another example is to unroll loops. Probably you know more than my about optimization, but I think the idea is clear here. It is easier to get better gains with high level code and profiling in real time, than with low level code and simulating the profiling.