SGI compiler options

[trevor #*at*# grserv.wustl.edu (Trevor Creamer)]

 Bruce Luxon wrote :
 >
 >Dan Severance recently wrote regarding SGI machines -
 >
 >>If you have an R4000 or R4400 machine, you need to add the
 "-mips2"
 >>option, since "-mips1" is the default (compatibility mode,
 will run on
 >>both R3000 and R4000 machines).  (The fast square-root is incorporated
 >>when you specify -mips2) ...
 >>
 >>   Another compiler option (fairly new) to try is the -sopt, and is
 >>documented in the f77 man page, and under the "fopt" manpage
 (-sopt
 >>runs the program fopt).  One user got a 40% speedup, we don't; it
 >>depends on your code.
 >
 >I and several other users attempted this and were not able to get either
 >of these options to work. I have an Indigo XS24 R4000 with the F77 compiler
 >3.4.1, Development option 4.0.1, and Irix 4.0.5 so I believe I have most
 >(but apparently not all) the goodies.
 >
 >When trying to make using the -mips2 option I received the following note -
 >
 >	f77: Error: malformed or unknown option -mips2
 >	*** Error code 2
 This worked fine for me with the same set-up. Are you using IRIX 4.0.5F ?
 Or just plain old 4.0.5 ?
 >
 >I checked my cdroms to see if I had all the options installed and it
 'appears'
 >I do.  What am I doing wrong or what isn't installed?
 >
 >Regarding -sopt, when this option was included in the makefile the compiler
 >seemed to go into hibernation after it encountered the first routine to
 >compile.  After awhile (ca. 10 minutes) I lost patience and aborted the
 make.
 >Again, any suggestions what went wrong or I didn't do correctly?
 The -sopt option seems to require LOTS of memory - when I did this my
 machine seemed to spend a lot of time swapping stuff in and out of the
 swap space. Try watching gr_osview while compiling - it can be educational.
 >
 >Thanks in advance to Dan and any others with responses,
 >
 >Bruce
 I tried these options on my Monte Carlo program. Normally I use the -O4
 optimization flag with f77. When I added -mips2 I got a 1.15x speed-up.
 With -sopt as well I got no appreciable difference (other than a much
 longer compilation time; ~15min.s with -sopt vs. ~1.5 min.s without).
 Cheers,
        Trevor
 Trevor P. Creamer                          Dept. of Biochemistry
 Email  - trevor #*at*# grserv.wustl.edu   ,-_|\   & Molecular Biophysics
 Phone  - (314) 362 4123           /     \  Washington University
 Fax    - (314) 362 4115           *_,-._/  St. Louis, Missouri 63110
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