The main reason a language like SML or Haskell is difficult to optimize is because it is incredibly difficult to canonicalize for the purpose of making peephole optimizations and abstract interpretation effective.
https://sunfishcode.github.io/blog/2018/10/22/Canonicalizati...
https://benchmarksgame-team.pages.debian.net/benchmarksgame/...
The main reason a language like SML or Haskell is difficult to optimize is because it is incredibly difficult to canonicalize for the purpose of making peephole optimizations and abstract interpretation effective. https://sunfishcode.github.io/blog/2018/10/22/Canonicalizati...