Compiler optimization-space exploration

S. Triantafyllis, M. Vachharajani, N. Vachharajani, David I. August

Research output: Chapter in Book/Report/Conference proceedingConference contribution

149 Scopus citations


To meet the demands of modern architectures, optimizing compilers must incorporate an ever larger number of increasingly complex transformation algorithms. Since code transformations may often degrade performance or interfere with subsequent transformations, compilers employ predictive heuristics to guide optimizations by predicting their effects a priori. Unfortunately, the unpredictability of optimization interaction and the irregularity of today's wide-issue machines severely limit the accuracy of these heuristics. As a result, compiler writers may temper high variance optimizations with overly conservative heuristics or may exclude these optimizations entirely. While this process results in a compiler capable of generating good average code quality across the target benchmark set, it is at the cost of missed optimization opportunities in individual code segments. To replace predictive heuristics, researchers have proposed compilers which explore many optimization options, selecting the best one a posteriori. Unfortunately, these existing iterative compilation techniques are not practical for reasons of compile time and applicability. We present the Optimization-Space Exploration (OSE) compiler organization, the first practical iterative compilation strategy applicable to optimizations in general-purpose compilers. Instead of replacing predictive heuristics, OSE uses the compiler writer's knowledge encoded in the heuristics to select a small number of promising optimization alternatives for a given code segment. Compile time is limited by evaluating only these alternatives for hot code segments using a general compile-time performance estimator An OSE-enhanced version of Intel's highly-tuned, aggressively optimizing production compiler for IA-64 yields a significant performance improvement, more than 20% in some cases, on Itanium for SPEC codes.

Original languageEnglish (US)
Title of host publicationInternational Symposium on Code Generation and Optimization, CGO 2003
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages12
ISBN (Electronic)076951913X, 9780769519135
StatePublished - 2003
EventInternational Symposium on Code Generation and Optimization, CGO 2003 - San Francisco, United States
Duration: Mar 23 2003Mar 26 2003

Publication series

NameInternational Symposium on Code Generation and Optimization, CGO 2003


OtherInternational Symposium on Code Generation and Optimization, CGO 2003
Country/TerritoryUnited States
CitySan Francisco

All Science Journal Classification (ASJC) codes

  • Hardware and Architecture
  • Signal Processing


  • Computer architecture
  • Computer science
  • Cost function
  • Degradation
  • Microarchitecture
  • Optimizing compilers
  • Parallel processing
  • Performance gain
  • Production
  • Resource management

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