Improving memory utilization in transforming recursive programs

Abstract

In this paper we present some ideas for improving memory utilization in recursive programs. We give a method for transforming programs into "destructive" ones, in which variable values are discarded (by means of special operations) as soon as they are no longer necessary for computing other values. The corresponding memory cells may then be reused for storing results which will be obtained later on. We first extend the language of first order recursion equations, so that destructive operations may be represented in it, and we introduce its denotational semantics. We then study, under given hypotheses, the correctness problem of destructive programs and consider algorithms and heuristics for making their memory efficiency as high as possible.