Hind et al. ([5]) use a standard dataflow framework [15, 16] to formulate an intra-procedural may-alias computation. The intra-procedural aliasing information is computed by applying well-known iterative techniques to the Sparse Evaluation Graph (SEG) ([3]). The computation requires a transfer function for each node that causes a potential pointer assignment (relating the dataflow information owing into and out of the node), and a set of aliases holding at the entry node of the SEG. The intra-procedural analysis assumes that precomputed information in the form of summary functions is available for all function-call sites in the procedure being analyzed. The time complexity of the intra-procedural mayalias computation for the algorithm presented by Hind et al. ([5]) is O(N 6 ) in the worst case (where N is the size of the SEG). In this paper we present a worst case O(N 3 ) time algorithm to compute the same may-alias information.

This note is a description of my research over the last few years as a doctoral student at the Courant Institute. A part of this research was collaborative work with my advisor Bob Paige. This statement is divided into three sections. The rst section is introductory, the second describes the work that will go into my dissertation, and the third section describes some other work that I have done, and some possible future directions for my research. 1 Introduction It is generally agreed that high level programming languages can not-only substantially reduce the time it takes to produce code but also help increase reliability of software. Such languages allow programs to be specied more in terms of algorithmic concepts than implementation details. A more conceptual level of discourse not only makes programs easier to write but also easier to prove correct. Widely used low level languages such as Fortran, C, C++ were designed to allow a straightforward translation of programs into ...

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We show how to efficiently evaluate generic map-filter-product queries, generalizations of select-project-join (SPJ) queries in relational algebra, based on a combination of two novel techniques: generic discrimination-based joins and lazy (formal) products. Discrimination-based joins are based on the notion of (equivalence) discriminator. A discriminator partitions a list of values according to a user-specified equivalence relation on keys the values are associated with. Equivalence relations can be specified in an expressive embedded language for denoting equivalence relations. We show that discriminators can be constructed generically (by structural recursion on equivalence expressions), purely functionally, and efficiently (worst-case linear time). The array-based basic multiset discrimination algorithm of Cai and Paige (1995) provides a base discriminator that is both asymptotically and practically