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Title:

``So Optimization Breaks Your Code ...''

Abstract:

Many compiler options can have an adverse affect on a code. Most notably, various levels of optimization can ``break'' a code, such that the program gives erroneous results. One option is to compile for the lowest common denominator. The other option is to identify which routines are adversely affected. The local utility, bchop performs a binary chop between object files in two directories (./good and ./bad), compares the output and isolates which object files are causing the differences in output. This helps isolate problems due to changing compiler or preprocessor options. The number of runs performed is approximately 2*E*log₂(N) where N is the number of object files and E is the number of object modules causing errors. This utility, bchop, is similar to CRI's atchop for isolating multitasking problems.

Author: R.K.Owen,Ph.D. National Energy Research Scientific Computing Center

Address:

NERSC / MS 50C
One Cyclotron Road
Berkeley,CA 94720

Email:

rk@owen.sj.ca.us rkowen@nersc.gov

• Article for CUG proceedings
• Slides for CUG talk presented Thursday, October 17, 1996.
• All the Slides collected together

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Last Modified: 1999/05/05 14:42:21

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Brought to you by: R.K. Owen,Ph.D.
This page is http://owen.sj.ca.us/rkowen/howto/bchop/index.html