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Efficient Symbolic Analysis for Optimizing Compilers

  • Robert A. van Engelen
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2027)

Abstract

Because most of the execution time of a program is typically spend in loops, loop optimization is the main target of optimizing and restructuring compilers. An accurate determination of induction variables and dependencies in loops is of paramount importance to many loop optimization and parallelization techniques, such as generalized loop strength reduction, loop parallelization by induction variable substitution, and loop-invariant expression elimination. In this paper we present a new method for induction variable recognition. Existing methods are either ad-hoc and not powerful enough to recognize some types of induction variables, or existing methods are powerful but not safe. The most powerful method known is the symbolic differencing method as demonstrated by the Parafrase-2 compiler on parallelizing the Perfect Benchmarks(R). However, symbolic differencing is inherently unsafe and a compiler that uses this method may produce incorrectly transformed programs without issuing a warning. In contrast, our method is safe, simpler to implement in a compiler, better adaptable for controlling loop transformations, and recognizes a larger class of induction variables.

Keywords

Loop Body Induction Variable Program Language Design Automatic Parallelization Loop Parallelization 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Robert A. van Engelen
    • 1
  1. 1.Dept. of Computer ScienceFlorida State UniversityTallahassee

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