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From: Bill Davidsen <davidsen@tmr.com>
To: Lee Revell <rlrevell@joe-job.com>
Cc: Bernd Petrovitsch <bernd@firmix.at>,
	Andrew Morton <akpm@osdl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Grant Coady <lkml@dodo.com.au>,
	Jan Engelhardt <jengelh@linux01.gwdg.de>,
	Puneet Vyas <vyas.puneet@gmail.com>
Subject: Re: xor as a lazy comparison
Date: Mon, 25 Jul 2005 16:24:04 -0400	[thread overview]
Message-ID: <42E54A64.7010107@tmr.com> (raw)
In-Reply-To: <1122318659.1472.14.camel@mindpipe>

Lee Revell wrote:
> On Mon, 2005-07-25 at 13:55 -0400, Steven Rostedt wrote: 
> 
>>Doesn't matter. The cycles saved for old compilers is not rational to
>>have obfuscated code.
> 
> 
> Where do we draw the line with this?  Is x *= 2 preferable to x <<= 2 as
> well?

In addition to the obvious error, let's not use x += x as well. If you 
want to multiple by two, do it.

Wasn't there a CPU where multiple was faster than add? Doesn't matter, 
let the compiler make the optimizations so you don't have to.

-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me

  parent reply	other threads:[~2005-07-25 20:22 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-07-24 16:40 xor as a lazy comparison Jan Engelhardt
2005-07-24 20:07 ` Grant Coady
2005-07-24 21:43   ` Jan Engelhardt
2005-07-24 22:15     ` Puneet Vyas
2005-07-25  8:57       ` Bernd Petrovitsch
2005-07-25 17:55         ` Steven Rostedt
2005-07-25 19:10           ` Lee Revell
2005-07-25 19:16             ` Philippe Troin
2005-07-25 19:18               ` Lee Revell
2005-07-26  6:07                 ` Jan Engelhardt
2005-07-26  8:30                   ` Bernd Petrovitsch
2005-07-25 19:24               ` Steven Rostedt
2005-07-25 19:27               ` Lee Revell
2005-07-25 19:23             ` Paulo Marques
2005-07-25 19:25               ` Lee Revell
2005-07-25 20:24             ` Bill Davidsen [this message]
2005-07-25 18:00         ` [PATCH] make signal.c more readable (was: Re: xor as a lazy comparison) Steven Rostedt
  -- strict thread matches above, loose matches on Subject: below --
2005-07-27 18:24 xor as a lazy comparison Clayton Weaver
2005-07-27 19:58 ` linux-os (Dick Johnson)
2005-07-28  0:04   ` Grant Coady

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