From: Eli Zaretskii <eliz@gnu.org>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: emacs-devel@gnu.org
Subject: Re: VIRT_ADDR_VARIES
Date: Thu, 10 Nov 2011 20:06:27 +0200 [thread overview]
Message-ID: <83bosjhmxo.fsf@gnu.org> (raw)
In-Reply-To: <4EBC00DF.3010906@cs.ucla.edu>
> Date: Thu, 10 Nov 2011 08:50:39 -0800
> From: Paul Eggert <eggert@cs.ucla.edu>
> CC: emacs-devel@gnu.org
>
> On 11/10/11 08:43, Eli Zaretskii wrote:
> > But why would someone do such a thing?
>
> Performance.
>
> Comparing against my_edata takes just one instruction.
> Comparing against both the start and the end of 'pure'
> takes two comparisons and some glue instructions and
> typically includes a conditional branch.
I'm surprised. Saving a few instructions in something that is never
called inside any time-critical code would be more than just premature
optimization in my book.
next prev parent reply other threads:[~2011-11-10 18:06 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-06 17:18 VIRT_ADDR_VARIES Andreas Schwab
2011-11-07 1:50 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-07 8:38 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-07 23:23 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-08 8:56 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-08 17:34 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-08 18:38 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-08 21:17 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-08 22:06 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-09 17:44 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-09 21:32 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-10 8:17 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 9:29 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-10 16:19 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 11:06 ` VIRT_ADDR_VARIES Eli Zaretskii
2011-11-10 11:20 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-10 16:29 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 16:43 ` VIRT_ADDR_VARIES Eli Zaretskii
2011-11-10 16:50 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 18:06 ` Eli Zaretskii [this message]
2011-11-14 4:57 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 4:05 ` VIRT_ADDR_VARIES Stephen J. Turnbull
2011-11-10 5:40 ` VIRT_ADDR_VARIES Paul Eggert
2011-11-10 17:05 ` VIRT_ADDR_VARIES Andreas Schwab
2011-11-10 17:15 ` VIRT_ADDR_VARIES Paul Eggert
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