Got all size+speed optimization challenges in Human Resource Machine!
Some of them are HARD.
I have new appreciation for being able to std::swap (in one expression), or use, like, any literals
And the ending. The reward is a creepy cutscene...

A task in Human Resource Machine.

The idea is to write a program that computes Fibbonacci numbers; the program is comprised of simple assembly-like instructions. The game gives you special bonuses for optimizing for speed or size.

This approach uses loop unrolling. The resulting program is really unwieldy and cumbersome to follow, but outperforms the speed goal by a lot.