A substantial amount of work has been devoted to the proof of correctness of various program analyses but much less attention has been paid to the correctness of compiler optimisations based on these analyses. In this paper we tackle the problem in the context of strictness analysis for lazy functional languages. We show that compiler optimisations based on strictness analysis can be expressed formally in the functional framework using continuations. This formal presentation has two benefits: it allows us to give a rigorous correctness proof of the optimised compiler; and it exposes the various optimisations made possible by a strictness analysis. 1 Introduction Realistic compilers for imperative or functional languages include a number of optimisations based on non-trivial global analyses. Proving the correctness of such optimising compilers can be done in three steps: 1. proving the correctness of the original (unoptimised) compiler; Correspondence regarding this paper should be ...

. We show that compiler optimisations based on strictness analysis can be expressed formally in the functional framework using continuations. This formal presentation has two benefits: it allows us to give a rigorous correctness proof of the optimised compiler; and it exposes the various optimisations made possible by a strictness analysis. 1 Introduction Realistic compilers for imperative or functional languages include a number of optimisations based on non-trivial global analyses. Proving the correctness of such optimising compilers can be done in three steps: 1. proving the correctness of the original (unoptimised) compiler; 2. proving the correctness of the analysis; and 3. proving the correctness of the modifications of the simple-minded compiler to exploit the results of the analysis. A substantial amount of work has been devoted to steps (1) and (2) but there have been surprisingly few attempts at tackling step (3). In this paper we show how to carry out this third step in the...

. In this paper we show that the critical part of a correctness proof for implementations of higher--order functional languages is amenable to machine--assisted proof. An extended version of the lambdacalculus is considered, and the congruence between its direct and continuation semantics is proved. The proof has been constructed with the help of a generic theorem prover --- Isabelle. The major part of the problem lies in establishing the existence of predicates which describe the congruence. This has been solved using Milne's inclusive predicate strategy [5]. The most important intermediate results and the main theorem as derived by Isabelle are quoted in the paper. Keywords: Compiler Correctness, Theorem Prover, Congruence Proof, Denotational Semantics, Lambda Calculus 1 Introduction Much of the work done previously in compiler correctness concerns restricted subsets of imperative languages. Some studies involve machine--checked correctness---e.g. Cohn [1], [2]. A lot of research h...

A new compilation technique for left-linear term rewriting systems is presented, where rewrite rules are transformed into so-called minimal rewrite rules. These minimal rules have such a simple form that they can be viewed as instructions for an abstract rewriting machine (ARM).

A new paradigm for Genetic Programming (GP) is proposed. In the new paradigm the genetic representation is separated from the tree structure of the program with a layer of abstraction, and it is argued that this will allow more efficient evolution of large programs. A GP system which can evolve Turing-complete programs has been developed and is presented. Emphasis is placed on the evolution of real-time functional programs which handle input and output using lazy streams. The design of the language in which the evolving programs are expressed is influenced by some properties of the natural genetic mechanism including order-independence of genes, inversion, a dominant--recessive mechanism and the presence of introns. Contents Preface 3 1 Evolutionary Algorithms --- What Are They? 5 1.1 Genetic Algorithms : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 5 1.2 Genetic Programming : : : : : : : : : : : : : : : : : : : : : : : : : : : : 7 2 A Survey of Evolution 8 2.1 The Pr...

We show that compiler optimisations based on strictness analysis can be expressed formally in the functional framework using continuations. This formal presentation has two benefits: it allows us to give a rigorous correctness proof of the optimised compiler; and it exposes the various optimisations made possible by a strictness analysis. These benefits are especially significant in the presence of partially evaluated data structures. 1 Introduction Realistic compilers for imperative or functional languages include a number of optimisations based on non-trivial global analyses. Proving the correctness of such optimising compilers should involve three steps: 1. proving the correctness of the original (unoptimised) compiler; 2. proving the correctness of the analysis; and 3. proving the correctness of the modifications of the simple-minded compiler to exploit the results of the analysis. A substantial amount of work has been devoted to steps (1) and (2) but there has been surprisingly ...