I have seen a similar optimization in GHC, where it's called "worker-wrapper", and used to reduce the cost of Haskell allocating everything on the heap. It spli

I have seen a similar optimization in GHC, where it's called "worker-wrapper", and used to reduce the cost of Haskell allocating everything on the heap. It splits each function into a "wrapper" which unboxes all arguments and boxes the return value, and a "worker" which actually does all the work on the unboxed values. The "wrapper" can then be inlined, which allows the compiler to remove unnecessary boxing (boxing a value only to immediately unbox it again).