They could use the same front end and enable optimisation passes in the backend with compile flags / heuristics. GHC for example uses for certain flow optimisat

They could use the same front end and enable optimisation passes in the backend with compile flags / heuristics. GHC for example uses for certain flow optimisations "fuel" once it runs out it stops doing further optimisations. For long running applications, ideally the runtime would profile the application during its execution and JIT / optimise based on the live state of the application. The JVM demonstrates that this can have major benefits over AOT compilation.