I agree. I don't have much sympathy for people who were doing things like writing multithreaded programs in the days before C documented its memory model and t

I agree. I don't have much sympathy for people who were doing things like writing multithreaded programs in the days before C documented its memory model and then becoming unhappy because new optimisations that legitimately help single-threaded code broke their programs. In my experience C compiler maintainers have generally been open to the idea of offering guarantees beyond a narrow reading of the standard, but they want to be able to clearly state what it is that they're guaranteeing. "Keep old programs running" isn't enough. I think the "Prevailing interpretation" that Yodaiken complains about is coming from the same place as suspicion of the "be lenient in what you accept" IETF principle: that sort of thing doesn't lead to robustness in the long run. The way forward at this point is surely to define more things that are currently undefined (whether in the standard or by widely-implemented extensions).