I've only ever known about these through compilers, very cool.

On one project, through a variety of circumstances, dead code elimination was straight up not working, but we wanted to show the theoretical improvement of some approach - but we couldn't figure out why at the moment (we did spend a whole week chasing down the root cause after - maybe worth in hindsight...).

We were doing it by hand at one point, but someone suggested using CReduce for shrinking the code. Definitely was an interesting test-iterate loop...