Linux is an excellent example. There has been a fork that made it compile with the Intel compiler and if I remember correctly it was moderately faster. Of cours

Linux is an excellent example. There has been a fork that made it compile with the Intel compiler and if I remember correctly it was moderately faster. Of course it went nowhere. Writing standard conformant code is hard and you do it if you have a good reason to do it. A lot of software has. The Linux kernal hasn't and that is fine. If your project also doesn't have that constraint, good for you. 30 years ago you would still choose C and a particular compiler and you could get things done. Nowadays, why bother? You could choose a language that has no UB, compiles on any hardware that is reasonably common and is still performant.