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
Organization: T-Online
Lines: 38
Message-ID: <adigc2$n1d$03$1@news.t-online.com>
References: <3CFCB642 DOT 252CFFF7 AT bigfoot DOT com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-Trace: news.t-online.com 1023198403 03 23597 2m36btwVSvAYrH 020604 13:46:43
X-Complaints-To: abuse AT t-online DOT com
X-Sender: 320053623259-0001 AT t-dialin DOT net
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

"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