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| Related articles |
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| [15 earlier articles] |
| Re: Intermediate Representation preston@titan.rice.edu (1990-08-13) |
| Re: Intermediate Representation jouvelot@brokaw.lcs.mit.edu (1990-08-13) |
| Re: Intermediate Representation marti@antares.inf.ethz.ch (1990-08-13) |
| Re: Intermediate Representation muller@procope.pa.dec.com (Eric Muller) (1990-08-14) |
| Re: Intermediate Representation pd@complex.Eng.Sun.COM (1990-08-15) |
| Re: Intermediate Representation staff@cadlab.sublink.org (1990-08-18) |
| Re: Intermediate Representation ok@goanna.cs.rmit.OZ.AU (1990-08-20) |
| intermediate representation han@cs.rochester.edu (1991-02-20) |
| Re: intermediate representation lavinus@csgrad.cs.vt.edu (1991-02-22) |
| Re: intermediate representation mike@vlsivie.tuwien.ac.at (1991-02-23) |
| Re: intermediate representation rfg@ncd.com (1991-02-26) |
| Re: intermediate representation megatest!djones@decwrl.dec.com (1991-02-27) |
| Re: intermediate representation tarvydas@turing.toronto.edu (1991-03-04) |
| Newsgroups: | comp.compilers |
| From: | ok@goanna.cs.rmit.OZ.AU (Richard A. O'Keefe) |
| Keywords: | optimize, C, Fortran |
| Organization: | Comp Sci, RMIT, Melbourne, Australia |
| References: | <1990Aug07.153407.8877@esegue.segue.boston.ma.us> <250@cadlab.sublink.ORG> |
| Date: | Mon, 20 Aug 90 02:00:02 GMT |
In article <250@cadlab.sublink.ORG>, staff@cadlab.sublink.org (Alex Martelli) writes:
> marti@antares.inf.ethz.ch writes:
> ...and don't forget Fortran... (see my msg of today in comp.lang.fortran-
> f2c + Sun's cc produce code which runs almost twice as fast as Sun's
> f77, for a strictly numerical code -2d complex fft- on a Sparcstation 1!).
On reading this I immediately went and converted a small numerical code
from Fortran to C and ran it on an Encore MultiMax (NS 32532 processors)
running UMAX V 2.2M. The f77 and cc compilers on that machine do not appear
to be ATT or Berkeley derived; the f77 compiler in particular is described
as "an advanced, optimizing compiler". The code didn't exploit any of the
micro-tasking or parallel features of Encore Fortran or Encore C, and no
special declarations ('register' or the like) were used. Both used double
precision. Result: the C code ran twice as fast (4 seconds / 8 seconds).
The Fortran code used 2D arrays. The C code used 1D with strength reduction
(a standard optimising technique) done by hand, and indexing replaced by
pointer increments (also a standard technique, and the NS32532 doesn't use
auto-??crement addressing) by hand. f2c starts to sound interesting...
So it wasn't just Sun. (I say "wasn't" because as the original poster
pointed out, Sun have some new compilers.)
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