Abstract

Functional-language compilers often perform optimizations based on beta and delta reduction. To avoid speculative optimizations that can blow up the code size, we might wish to use only shrinking reduction rules guaranteed to make the program smaller: these include dead-variable elimination, constant folding, and a restricted beta rule that inlines only functions that are called just once. The restricted beta rule leads to a shrinking rewrite system that has not previously been studied. We show some e#cient normalization algorithms that are immediately useful in optimizing compilers; and we give a confluence proof for our system, showing that the choice of normalization algorithm does not a#ect final code quality. 1 Introduction The lambda calculus is a language of functions, so one of the most useful optimizations we can perform in a lambda-calculus-based language is function inlining. Inlining a function eliminates the expense of a procedure call, and instantiating the function argu...

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