Automatic Generation of Vectorizing Compilers for Customizable Digital Signal Processors

Embedded applications extract the best power-performance trade-off from digital signal processors (DSPs) by making extensive use of vectorized execution. Rather than handwriting the many customized kernels these applications use, DSP engineers rely on auto-vectorizing compilers to quickly produce effective code. Building these compilers is a large and error-prone investment, and each new DSP architecture or application-specific ISA customization must repeat this effort to derive a new high-performance compiler.

We present Isaria, a framework for automatically generating vectorizing compilers for DSP architectures. Isaria uses equality saturation to search for vectorized DSP code using a system of rewrite rules. Rather than hand-crafting these rules, Isaria automatically synthesizes sound rewrite rules from an ISA specification, discovers phase structure within these rules that improve compilation performance, and schedules their application at compile time while pruning intermediate states of the search. We use Isaria to generate a compiler for an industrial DSP architecture, and show that the resulting kernels outperform existing DSP libraries by up to 6.9× and are competitive with those generated by expert-built compilers. We also demonstrate how Isaria can speed up exploration of new ISA customizations by automatically generating a high-quality vectorizing compiler.