HARDWARE AND SOFTWARE SOLUTIONS TO DIVERGENT BRANCHES IN A PARALLEL PIPELINE

摘要

A system and method for efficiently processing instructions in hardware parallel execution lanes within a processor. In response to a given divergent point within an identified loop, a compiler arranges instructions within the identified loop into very large instruction words (VLIW's). At least one VLIW includes instructions intermingled from different basic blocks between the given divergence point and a corresponding convergence point. The compiler generates code wherein when executed assigns at runtime instructions within a given VLIW to multiple parallel execution lanes within a target processor. The target processor includes a single instruction multiple data (SIMD) micro-architecture. The assignment for a given lane is based on branch direction found at runtime for the given lane at the given divergent point. The target processor includes a vector register for storing indications indicating which given instruction within a fetched VLIW for an associated lane to execute.