Peter Willy Markstein

A methodology for the real world

Register allocation may be viewed as a graph coloring problem. Each node in the graph stands for a computed quantity that resides in a machine register, and two nodes are connected by an edge if the quantities interfere with each other, that is, if they are simultaneously live at some point in the object program. This approach, though mentioned in the literature, was never implemented before. Preliminary results of an experimental implementation in a PL/I optimizing compiler suggest that global register allocation approaching that of hand-coded assembly language may be attainable.

Computation of elementary functions on the IBM RISC System/6000 processor

The additional speed and precision of the IBM RISC System/6000 floating-point unit have motivated reexamination of algorithms to perform division, square root, and the elementary functions. New results are obtained which avoid the necessity of doing special testing to get the last bit rounded correctly in accordance with all of the IEEE rounding modes in the case of division and square root. For the elementary function library, a technique is described for always getting the last bit rounded correctly in the selected rounding mode.

Optimization of range checking

An analysis is given for optimizing run-time range checks in regions of high execution frequency. These optimizations are accomplished using strength reduction, code motion and common subexpression elimination. Test programs, using the above optimizations, are used to illustrate run-time improvements.

Strength reduction for division and modulo with application to accessing a multilevel store

A method for replacing certain division and modulo operations by additions and subtractions is presented. This optimization allows efficient and easy use of partitioned arrays to access a multilevel store.

Wide format floating-point math libraries

No abstract available