From:	"Heinz Ozwirk" <wansor42 AT gmx DOT de>
Newsgroups:	comp.os.msdos.djgpp,comp.lang.c++
Subject:	Re: Optimization and operator&&
Date:	Tue, 4 Jun 2002 15:44:07 +0200
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"Alex Vinokur" <alexvn AT bigfoot DOT com> wrote in message
news:3CFCB642 DOT 252CFFF7 AT bigfoot DOT com...
>
> ###############
> Windows98
> gcc/gpp 2.95.3
> ###############
>
>
> A program below measures performance (time) :
>   * of operator&& and operator+
>   * with automatic and static unsigned int
>   * with optimizations : No optimization, O1, O2, O3
>
> We can see that Optimization causes
>   an increase in elapsed time for operator&& .
> Any explanation?
...
> automatic, PLUS [1] Total time : 24
> automatic, PLUS [2] Total time : 24
> automatic, PLUS [3] Total time : 17
> automatic, PLUS [4] Total time : 18
> automatic, PLUS [5] Total time : 18
> automatic, PLUS [6] Total time : 17
> automatic, PLUS [7] Total time : 17
> automatic, PLUS [8] Total time : 18
> automatic, PLUS [9] Total time : 17
> automatic, PLUS [10] Total time : 18
...

Your results are useless. They differ by about 25%. Probably the resolution
of your timer is too large (or your processor is too fast). Run your tests
again, but this time measure at least 10,000,000 iterations.

Regards
    Heinz

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