Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!sdd.hp.com!hplabs!hpcc05!hp-ptp!marcb
From: marcb@hp-ptp.HP.COM (Marc Brandis)
Newsgroups: comp.arch
Subject: Re: numeric comparison (was Re: a style question)
Message-ID: <1300003@hp-ptp.HP.COM>
Date: 4 Oct 90 20:24:19 GMT
References: <4147@bingvaxu.cc.binghamton.edu>
Organization: HP Pacific Technology Park - Sunnyvale, Ca.
Lines: 31

>In article <41898@mips.mips.COM> mash@mips.COM (John Mashey) writes:
>:At the code level, this is probably true, although it certainly is the
>:case that there are fundamental computer system design reasons why
>:== might be faster than <.  Whether these reasons show up in any
......
>:It probably doesn't matter most places, except in some technical code
>:with short loops with many iterations.
>
>My point was only that I felt that any performance advantage (one or
>two clocks was bandied about) is grossly outweighed by the rest of the
>loop, and given that, I tend to prefer the < syntax (since it is pretty
>much required for floating-point variables.)

Probably you should not care too much about it. A smart optimizer may
be able detect most of these cases, where < may be replaced by ==,
and do the replacement. This is certainly true for loops like

	for (i = 0; i < n; i++) stat;

where stat is known not to change i.


(* I speak only for myself.
	Marc-Michael Brandis
	Institut fuer Computersysteme
	ETH Zentrum
	CH-8092 Zuerich, Switzerland
	e-mail: brandis@inf.ethz.ch
		brandis@iis.ethz.ch
   Temporarily at HP, marcb@hp-ptp.ptp.hp.com
*)