A simple, verified validator for software pipelining

Software pipelining is a loop optimization that overlaps the execution of several iterations of a loop to expose more instruction-level parallelism. It can result in first-class performance characteristics, but at the cost of significant obfuscation of the code, making this optimization difficult to test and debug. In this paper, we present a translation validation algorithm that uses symbolic evaluation to detect semantics discrepancies between a loop and its pipelined version. Our algorithm can be implemented simply and efficiently, is provably sound, and appears to be complete with respect to most modulo scheduling algorithms. A conclusion of this case study is that it is possible and effective to use symbolic evaluation to reason about loop transformations. Categories and Subject Descriptors D.2.4 [Software Engineering]: Software/Program Verification - Correctness proofs; D.3.4 [Programming Languages]: Processors - Optimization General Terms Languages, Verification, Algorithms Key...

• Type: Conference
• Year: 2010
• Where: POPL
• Authors: Jean-Baptiste Tristan, Xavier Leroy
• Keywords: Loop Optimization, POPL 2010, Programming Languages, Symbolic Evaluation, Translation Validation Algorithm