Indeed, the mindset is the key issue. In JVM land, where I learned most of my compiler ideas, the assumption is "optimization is not observable". JVMs move heav

Indeed, the mindset is the key issue. In JVM land, where I learned most of my compiler ideas, the assumption is "optimization is not observable". JVMs move heaven and earth to make it appear as if they were simple interpreters just running the bytecodes one by one. The C/C++ world is the only one I can think of where this is manifestly not the case: optimizations are routinely observable and an endless source of confusion and frustration for developers. In the presence of even a single bug in the application, suddenly UB results in the veritable gates of hell opening and the entire lower world of the guts of abstractions comes spilling out. Woe to those who would try to debug at this level, for they fight demons of every form.