That is the exact goal of the post. I arrived to the algorithm through evolution with random initialization. I enforced absolutely no heuristic to make it converge to this equation.

I know, but can we prove there's no heuristic on that algorithm? Because if the answer is "yes", this should be general enough to find other optimizations. It's fun to think about.

The best answer I can provide is: The code is there. There are no heuristics in it. Everytime you run it, you get different results (because of random initialization seeds and the stochastic nature of EA). It may find the (a - (x >> 1)) equation on a specific execution, or not. Over the runs I made, this equation (or similar) was the most popular and nothing come close to it. In fact, it finds a lot of other optimizations; either less accurate or way more complex. I remember getting tens and tens of operations in equations with "bof" accuracies.

Why is that a relevant question now? How would doing this be more helpful without the results of the algorithm you're attempting to cut corners to approximate?