Automatic Generation of SIMD DSP Code

Short vector SIMD instructions on recent microprocessors, such as SSE on Pentium III and 4, speed up code but are a major challenge to software developers. This report introduces a compiler that automatically generates C code enhanced with short vector instructions for digital signal processing (DSP) transforms, such as the fast Fourier transform (FFT). The input to the compiler is a concise mathematical description of a DSP algorithm in the language SPL. SPL is used in the Spiral system (http://www.ece.cmu.edu/∼spiral) to generate highly optimized architecture adapted implementations of DSP transforms. Interfacing the newly developed compiler with Spiral yields speed-ups of up to a factor of 2 in several important cases including the FFT and the discrete cosine transform (DCT) used, for instance, in the JPEG compression standard. For the FFT the automatically generated code is competitive with the hand-coded Intel Math Kernel Library (MKL).