From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,c4cb2c432feebd9d
X-Google-Thread: 1094ba,c4cb2c432feebd9d
X-Google-Thread: 101deb,15c6ed4b761968e6
X-Google-Attributes: gid103376,gid1094ba,gid101deb,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news2.google.com!news3.google.com!news.glorb.com!peer1.news.newnet.co.uk!194.159.246.34.MISMATCH!peer-uk.news.demon.net!kibo.news.demon.net!mutlu.news.demon.net!news.demon.co.uk!demon!not-for-mail
From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada,comp.lang.fortran,comp.lang.pl1
Subject: Re: Bounds Check Overhead
Date: Thu, 25 May 2006 23:08:50 +0100
Organization: Pushface
Message-ID: <m2mzd569l9.fsf@grendel.local>
References: <mubcg.13522$fb2.853@newssvr27.news.prodigy.net>
 <epcs4e.qb8.ln@hunter.axlog.fr> <tHkcg.6937$kR6.484@trnddc05>
 <0ugu4e.4i7.ln@hunter.axlog.fr>
 <PkHcg.90575$Fs1.7198@bgtnsc05-news.ops.worldnet.att.net>
 <To_cg.10095$S7.4017@news-server.bigpond.net.au>
 <%P_cg.155733$eR6.26337@bgtnsc04-news.ops.worldnet.att.net>
 <6H9dg.10258$S7.9150@news-server.bigpond.net.au>
 <XVadg.76594$_S7.45873@newssvr14.news.prodigy.com>
 <1hfv5wb.1x4ab1tbdzk7eN%nospam@see.signature>
 <pan.2006.05.25.12.11.52.919554@linuxchip.demon.co.uk.uk.uk>
 <4475DA61.3080001@comcast.net>
NNTP-Posting-Host: pogner.demon.co.uk
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: news.demon.co.uk 1148594936 27524 62.49.19.209 (25 May 2006 22:08:56
 GMT)
X-Complaints-To: abuse@demon.net
NNTP-Posting-Date: Thu, 25 May 2006 22:08:56 +0000 (UTC)
Cancel-Lock: sha1:ziT34FG5Ual69ZdFzBg7iehL68E=
User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (darwin)
Xref: g2news2.google.com comp.lang.ada:4475 comp.lang.fortran:10259
 comp.lang.pl1:1722
Date: 2006-05-25T23:08:50+01:00
List-Id: <comp.lang.ada>

Bob Lidral <l1dralspamba1t@comcast.net> writes:

> However, the performance hit of including explicit bounds checking
> can be significant -- especially for code with extremely short loops
> that are executed a lot of times.

In Ada one should where possible use the 'Range attribute:

   for I in Some_Array'Range loop
      Process (Some_Array (I));
   end loop;

where I _can't_ exceeed the bounds, so it would be surprising if a
compiler inserted bounds checks. Is there a Fortran equivalent? I seem
to remember something like that in VAX F77, but it's been a while...