I've done something similar for DBus deserialization. It turns out that I stumbled upon something called fixed-point optimization for loops (in DBus: arrays), similar to what the JVM does according to Cliff Click's very interesting talks. It was pretty fun to write basically a toy optimizer that is even useful. As a friend said, it's probably overdesigned, but it was fun and it does yield code with not much left to improve. Well, except for embarrassingly optimizable types such as arrays of fixed-length elements.

We will probably see more such things as the consequences of the end of the free performance lunch play out. Hardware and software will specialize more, plenty of interesting work to do.