Re: Speedy compilers

Rudi.Ziegaus@bingo.baynet.de (Rudi Ziegaus) wrote:
...
>I believe a clever algorithm can do much better than any optimation.
>Of course there are some cases (e. g. graphics programming, CAD, etc.)
>where performance counts.


          It would depend on the circumstances. It could go the other way,
too. I wouldn't throw out clever alorithm AND optimization.


>BUT : functionality before speed.


          Yes.


>I remember a book I read during my studies where the author cited a
>case, to which he was called. A program that had to be fast, did not
>work. He provided a program that was running correctly, but was way
>slower than the original one.
>
>The original program's author pointed to this speed difference. The
>author of the book replied, that he could write a program that would
>be done in less than a second, if the result was not importent ...


          Perhaps you are thinking of Steve McConnell's "Code Complete"?
The consultant's punchline there was that if his program didn't have
to be correct, he could make it take no time and no memory.


>I believe, many speed improvements can be gained by
>
>a) clever parameter passing (registers)
>b) optimized libraries


          c) a good optimizer.


[snip]


>[I can believe that MSC 5 had optimizer bugs, Microsoft's compilers are
>famous for optimizer bugs. But there really are optimizers that make
>your program run faster without breaking it, and there's no reason not
>to use them along with good algorithms. -John]


          Right!


Sincerely,


Gene Wirchenko
[That story sure gets around. Weinberg's version is the oldest print
one I've seen. -John]

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