Re: "Subtract C, add Ada"

[rs9320@pegasus.cc.ucf.edu (Robert C. Soong)]

RonaldS60 (ronalds60@aol.com) wrote:

: Gary Frankel (gfrankel@rational.com) wrote
: >As of late 1989, I was involved in a commerical Ada optimizing 
: >compiler... We published results on a wide variety of benchmarks
: >(Hennessey,etc) that showed that the Ada compiler was producing
: >better code than any commercially available C compiler at that time
: >and far better than most C compilers.  This was true for workstations
: >and cross compilers.
: >
: >I cant vouch to the same degree for the current state of the art
: >since I havent done the same studies recently, but I believe
: >that you will find tha the optimizing Ada compilers can produce
: >comparable or better code than C compilers.  I have also noticed
: >that a number of C++ compilers produce poorer code - probably due
: >to the current level of maturity.

: About two years ago a IEEE article (in one of the s/w engineering
: journals) compared the percentages of dead code (I assume using some
: reachability algorithm) between Fortran, C, and C++.  The numbers
: were suprising (to say the least) and indicated that while Fortran
: had the least dead code (followed by C) C++ could have upto 60%-75%
: dead code.  The exact quantity being undecidable in a static analysis
: due to virtual function calls.  This research hasn't had any obvious
: effect on the C++ crowd (or any of the OO people) that I have seen.

: >Generally, an optimizing Ada compiler is actually at an advantage over
: >C compilers due to Ada sources providing more useful type information
: >and the aliasing problems of C.  Ada compilers will tend to 
: >compile more slowly since they do considerably more checking than
: >C compilers.

: One of the problems with aliasing is covered in an article titled 
: 'The Undecidability of Aliasing' by G. Ramalingam in ACM Transactions
: on Programming Languages and Systems, vol. 16 no. 5, September 1994.

: >So, I think that anyone who does a careful study will simply not
: >find that C has any advantages in code efficiency over Ada at all
: >(at least on any program more than a few short lines).

: Actually there was an article around 1989 to 1991 covering the 
: difference between two programs (that did the same thing) written in
: C and Ada.  They were both compiled on the best compilers that could
: be found.  C won for overall speed, by less than 2% when runtime 
: checking was disabled (as it could be when the program was validated.)
: A 1% to 2% difference in speed isn't much price to pay when the
: overall development cycle is shortened (especially in testing) as
: much as Ada allows (when compared to C.)  Just think how nice it
: would have been if that company in Redmond had used Ada instead of
: C (oooh, software that actually works! and on time! ;{))).

: >-- Gary Frankel
: >
: >
: >Mitch Gart (mg@asp.camb.inmet.com) wrote:
: >: Jay Martin (jmartin@oahu.cs.ucla.edu) wrote:
: >
: >: : I read the abstracts to these papers before I posted, there is not
: >: : one peep about the relative efficiency between C and Ada which
: >: : should be the central topic of discussion in my opinion.
: >
: >: I wrote a paper on this, which is now pretty dated, but still might
: >: possibly be of interest:
: >
: >: "Benchmarking Ada, C, and Pascal", SigAda conference, July 1986,
: >: Pittsburgh.
: >
: >:  Mitch Gart


: Ron
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