I don't think compilers are a good example. The economics of software development has won a long time ago. For example in Gamedev with well known soft real-time requirements people (mostly) stopped doing that machine code dance many hardware generations ago. Like it happened with memory optimizations: people measure memory in GB now not in KB =)

I am sure programmers cherish every case when they can do micro optimization but in the retrospect the high level cuts is what made the system fit the perf or memory budget.

Gamedev dev is a good example actually. True, handwritten assembly has gone out of style. But knowing how caches work, and how to lay out data to improve performance is important. And stuff like vector intrinsics also gets used.