Fortran v1.2 optimization with SunOS 4.0.3?

[Greg Henley]

I recently obtained a 2000-3000 line CFD (Computational Fluid Dynamics)
program which was written in Fortran and which requires a considerable
amount of storage space and cpu time (approx. 65 meg and 2 hours to run
one cycle on a Sun 4/280). From previous experience on other C and Fortran
programs, full optimization could give a 2 to 3 times speedup.  However,
when I try optimization level -O2 or -O3, the program crashes with a huge
core dump. Level -O1 works but doesn't give any noticeable improvement in
execution time. We are running SunOS 4.0.3 and have Fortran version 1.2.
Has anyone else experienced this? If so, is there a bug fix? 

I was able to compile it on another Sun which was running SunOS 4.0 and
Fortran version 1.1. Level -O3 worked with no apparent problems and gave
about a 2 times speedup. Any help appreciated.

Greg Henley, Research Engineer
Mississippi State University
Dept. of Electrical Engineering
INET: henley at ee.msstate.edu