An efficient algorithm for pointer-to-array access conversion for compiling and optimizing DSP applications

Abstract

The complexity of Digital Signal Processing (DSP) applications has been steadily increasing due to advances in hardware design for embedded processors. To meet critical power consumption and timing constraints, many DSP applications are hand-coded in assembly. Because the cost of hand-coding is becoming prohibitive for developing an embedded system, there is a trend toward the use of high-level programming languages, particularly C, and the use of optimizing compilers for software development. Consequently, more than ever there is a need for compilers to optimize DSP application to make effective use of the available hardware resources. Existing DSP codes are often riddled with pointer-based data accesses, because DSP programmers have the mistaken belief that a compiler will always generate better target code. The use of extensive pointer arithmetic makes analysis and optimization difficult for compilers for modern DSPs with regular architectures and large homogeneous registers sets. In this paper, we present a novel algorithm for converting pointer-based code to code with explicit array accesses. The conversion enables a compiler to perform data flow analysis and loop optimizations on DSP codes.