Unisoft C Compiler for A/UX -- dhrystone and -O

jim@jagmac2.gsfc.nasa.gov (Jim Jagielski)
Fri, 06 Jul 90 14:06:00 GMT

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Unisoft C Compiler for A/UX -- dhrystone and -O jim@jagmac2.gsfc.nasa.gov (1990-07-06)
Re: Unisoft C Compiler for A/UX -- dhrystone and -O mike@hpfcso.HP.COM (1990-07-20)
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Newsgroups: comp.compilers
From: jim@jagmac2.gsfc.nasa.gov (Jim Jagielski)
Keywords: code, C, analysis, benchmarks
Organization: NASA Goddard Space Flight Center
Distribution: na
Date: Fri, 06 Jul 90 14:06:00 GMT

I have Unisoft's Optimizing C Compiler for A/UX (gcc -- NOT gnu cc) and
have noticed something strange.


When compiling the dhrystone benchmark, I get faster performance from the
non-optimized binary as compared to the optimized version. The difference
is small (~12000 vs ~11700, with maximum of ~12444 without opt. and a
min of ~11500 with opt.) but there. Doing other benchmarks, esp. with
floats and doubles, performance is expected (i.e., -O results in quicker
code, but a little bigger) but this discrepency in dhrystones is
interesting...


Anyone else have any experience with Unisoft or a similar occurance?
--
                      Jim Jagielski NASA/GSFC, Code 711.1
          jim@jagmac2.gsfc.nasa.gov Greenbelt, MD 20771
[Given that the instructions for Dhrystone tell you not to use a global
optimizer, I wouldn't rule out the possibility that this is yet another
compiler tweaked to make Dhrystone run fast. -John]
--

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