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by Juli Rew
The XL Fortran compiler version 7.1.1.1 is now IBM's production compiler, and it will be the only compiler available on newer platforms such as the Power-4. The compiler was installed on blackforest the weekend of 2-3 March 2002. Please report any problems to SCD Consulting at 303-497-1278.
When moving to a new compiler, SCD always recommends that you recompile your code, after saving a backup.
Threaded code problems
Some users who previously compiled under xlf 7.1.0.2 have reported difficulties with OpenMP (threaded) codes under xlf 7.1.1.1 (for example, segmentation faults or wrong results). SCD is working with IBM to resolve this and other issues discussed below.
In the meantime, a workaround for many threaded codes is to initialize automatic variables using the following compiler option:
-qinitauto=7FF7FFFF
If your code exhibits problems with inadequate stack space, you might try compiling with 64-bit addressing. Pros and cons are discussed at:
http://www.scd.ucar.edu/docs/blackforest/env.html#mem
Options to avoid
Avoid the following options:
- -qarch and -qtune: These options do not have any noticeable effect.
- -qcache and -qhot: These may not have the desired optimizing effect, or may cause the compilation to fail. We recommend sticking with -O3 -qstrict.
- -C or -qextchk: Turning on run-time bounds checking causes an internal compiler error.
If you have questions about txlf 7.1.1.1, please send email the SCD Consulting Office (consult1@ucar.edu) or call the consultants at 303-497-1278 Monday through Friday, 0800-1700 Mountain Time.
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