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Author Englund, Donald E. ♦ Busam, Vincent A.
Source ACM Digital Library
Content type Text
Publisher Association for Computing Machinery (ACM)
File Format PDF
Language English
Subject Keyword Compilation ♦ Subscripts ♦ Common subexpressions ♦ Expressions ♦ Do loops ♦ Optimization ♦ Register allocation ♦ Fortran ♦ Compilers ♦ Invariant calculations
Abstract A method of optimizing the computation of arithmetic and indexing expressions of a Fortran program is presented. The method is based on a linear analysis of the definition points of the variables and the branching and DO loop structure of the program.The objectives of the processing are (1) to eliminate redundant calculations when references are made to common sub-expression values, (2) to remove invariant calculations from DO loops, (3) to efficiently compute subscripts containing DO iteration variables, and (4) to provide efficient index register usage.The method presented requires at least a three-pass compiler, the second of which is scanned backward. It has been used in the development of several FORTRAN compilers that have proved to produce excellent object code without significantly reducing the compilation speed.
Description Affiliation: Computer Sciences Corp., El Segundo, CA (Busam, Vincent A.; Englund, Donald E.)
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2005-08-01
Publisher Place New York
Journal Communications of the ACM (CACM)
Volume Number 12
Issue Number 12
Page Count 9
Starting Page 666
Ending Page 674

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Source: ACM Digital Library