Code Compaction Using Post-Increment/Decrement Addressing Modes

During computation, locality of reference is often observed, and can be exploited to achieve performance increases in several ways. This locality is an artifact of the computational abstractions and architectures that we use, such as iterating over an arrays or encapsulating tasks into distinct functions with local state. With this in mind, some architectures have been created with features designed specifically to exploit locality. In this paper, we extend the work of [1] to benefit as much as possible from one such particular feature: post-increment and post-decrement addressing modes. With careful placement of stack variables in memory, we can minimize the amount of necessary address arithmetic. This problem is NP-complete, and we present a 2-approximation algorithm for the case of a single address register, along with experimental results.