There are lots of interesting little subproblems in compilation like instruction selection, register allocation and instruction scheduling. These can be expressed in declarative interlinked way to constraint solvers. I’ve been fiddling with probably 6 iterations of using constraint solvers for compiler backends over the last 3 years and never written a blog post on it. This is long over due, and still highly imperfect. I have found this post only gets harder to write and my standards rise. Write...