I think that the register and volatile keywords in C and C++ and the inline keyword in C++ basically constitute real world research into exactly that process. I

I think that the register and volatile keywords in C and C++ and the inline keyword in C++ basically constitute real world research into exactly that process. In pretty much all cases it seems to have been eventually determined that the combination of the compiler needing to override the programmer's wishes when the programmer was wrong (as well as the fact that it will sometimes implement the optimization without being asked) and the programmer's inability to recognize cases where the optimization will actually make things worse has led to them becoming less and less relevant to the compiler's decisions over time. Usually this results in a "YES I REALLY MEAN IT" compiler directive, which just looks like an arms race. I suppose it's possible this has been the wrong direction, but I suspect it was effectively correct.