Retargetable code optimization with SIMD instructions

Retargetable C compilers are nowadays widely used to quickly obtain compiler support for new embedded processors and to perform early processor architecture exploration. One frequent concern about retargetable compilers, though, is their lack of machine-specific code optimization techniques in order to achieve highest code quality. While this problem is partially inherent to the retargetable compilation approach, it can be circumvented by designing flexible, configurable code optimization techniques that apply to a certain range of target architectures. This paper focuses on target machines with SIMD instruction support which is widespread in embedded processors for multimedia applications. We present an efficient and quickly retargetable SIMD code optimization technique that is integrated into an industrial retargetable C compiler. Experimental results for the Philips Trimedia processor demonstrate that the proposed technique applies to real-life target machines and that it produces code quality improvements close to the theoretical limit.