If you don't find anything else, maybe some of our old code from PADL 2010 can help as a starting point [1]. Probably it'll be easier to put something together from scratch, assuming you don't care about performance or need variables.
Is there a library somewhere where I can represent and simplify simple bit operation expressions? Add, subtract, exclusive or, or, and, divide, multiply, modulus, composed recursively, and operations on the expression type, such as simplify?