How Generic is a Generic Back End? Using MLRISC as a Back End for the TIL Compiler (Preliminary Report)

We describe the integration of MLRISC, a \generic" compiler back end, with TIL, a type-directed compiler for Standard ML. The TIL run-time system uses a form of type information to enable partially tag-free garbage collection. We show how we propagate this information through the nal phases of the compiler, even though the back end is unaware of the existence of this information. Additionally, we identify the characteristics of MLRISC that enable us to use it with TIL and suggest ways in which it might better support our compiler. Preliminary performance measurements show that we pay a signi cant cost for using MLRISC, relative to a custom back end.