It seems that in many compiler resources (even the modern ones), there is still a lot of focus on the front-end—things like lexing, parsing, DFAs, regex matchin

It seems that in many compiler resources (even the modern ones), there is still a lot of focus on the front-end—things like lexing, parsing, DFAs, regex matching, recursive descent. I would like to see greater focus on the back-end: optimisation strategies like dead code elimination, register allocation, parallelisation, vectorisation, detecting SIMD-able code, and even whole-program optimisation. Even on the front-end, it would be nice to see focus on the failure cases—printing nicely formatted error messages, for instance. IMO these are strictly larger contributors to the quality of a compiler suite than merely lexing and parsing, which are generally solved problems.