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Predicated Instructions for Code Compaction

  • Warren Cheung
  • William Evans
  • Jeremy Moses
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2826)

Abstract

Procedural abstraction, the replacement of several identical code sequences with calls to a single representative function, is a powerful tool in producing compact executables. We explore how predicated instructions can be used to allow procedural abstraction of non-identical basic blocks. A predicated instruction is one that the processor executes if a condition (specified in the opcode) is true, otherwise the instruction has no effect. Architectures such as the ARM provide predicated versions of most of their instructions. By using predicated instructions within a representative function and setting the appropriate flags prior to the call, a single function can serve to represent several different code sequences.

To find representative functions, we group sequences that have a short common supersequence and use this supersequence as a representative. We report results on the use of predication for procedural abstraction on the ARM and also indicate the potential compaction benefit of allowing more predication conditions.

Keywords

Basic Block Code Size Code Fragment Longe Common Subsequence Register Allocation 
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 2003

Authors and Affiliations

  • Warren Cheung
    • 1
  • William Evans
    • 1
  • Jeremy Moses
    • 1
  1. 1.Department of Computer ScienceUniversity of British ColumbiaVancouver

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