| The combination of intersection and union types with flow types gives the compiler writer unprecedented flexibility in choosing data representations in the context of a typed intermediate language. We present the design of such a language and the design of a framework for exploiting the type system to support multiple representations of the same data type in a single program. The framework can transform the input term, in a type-safe way, so that different data representations can be used in the transformed term—even if they share a use site in the pre-transformed term. We have implemented a compiler using the typed intermediate language and instantiated the framework to allow specialized function representations. We test the compiler on a set of benchmarks and show that the compile-time performance is reasonable. We further show that the compiled code does indeed benefit from specialized function representations. |
