|Unisoft C Compiler for A/UX -- dhrystone and -O email@example.com (1990-07-06)|
|Re: Unisoft C Compiler for A/UX -- dhrystone and -O mike@hpfcso.HP.COM (1990-07-20)|
|From:||firstname.lastname@example.org (Jim Jagielski)|
|Keywords:||code, C, analysis, benchmarks|
|Organization:||NASA Goddard Space Flight Center|
|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
Anyone else have any experience with Unisoft or a similar occurance?
Jim Jagielski NASA/GSFC, Code 711.1
email@example.com 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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