That very much depends on the code. Program synthesis is an active area of research and the programs found would often be very difficult for a human to figure o

That very much depends on the code. Program synthesis is an active area of research and the programs found would often be very difficult for a human to figure out. Of course a sufficiently determined human can always do whatever these programs do, but I do think it is unfair to give an unlimited amount of time to human optimizers.