Abstract

In this paper we describe a series of program transformations that are currently being implemented in the Glasgow Haskell Compiler. They are semantics preserving program transformations and therefore are perfectly suitable for incorporation in a compiler. We describe some of the transformations, how they interact and their impact on the time/space behaviour of some programs. 1 Introduction Program transformations can considerably improve the performance of certain programs, by transforming inefficient code into more efficient versions. In other cases it can change the space behaviour of a program, making it use less memory. The Glasgow Haskell Compiler was designed with program transformations in mind, allowing for transformation passes to be easily incorporated into the compiler. Here we will show some of the transformations that have been actually implemented and how they affect the time/space behaviour of some programs. We initially describe the basic idea behind some transformati...