Compiler optimization is an extremely hard problem. Unsolvable by our current standards and usually the compiler has less knowledge than the author of the code

Compiler optimization is an extremely hard problem. Unsolvable by our current standards and usually the compiler has less knowledge than the author of the code and has to make assumptions about the hardware it is going to run on. Language design feeds heavily into the types of optimizations that are even possible to reason about. So yes there has been an enormous amount of research into both the programming language design side of this equation, the compiler design, and the area in the middle. Probably hundreds of thousands of research papers since the 50s or 60s. Compilers and automated systems, in the general case at least, still can't out compete a domain expert that is familiar with the specific hardware being targeted, a good profiler, and the time to fiddle with the raw assembly.