From: David Miller <davem@davemloft.net>
To: cl@linux-foundation.org
Cc: andi@firstfloor.org, rusty@rustcorp.com.au, sfr@canb.auug.org.au,
linux-next@vger.kernel.org, travis@sgi.com, mingo@elte.hu,
rth@twiddle.net, akpm@linux-foundation.org
Subject: Re: linux-next: manual merge of the rr tree
Date: Thu, 08 Jan 2009 14:25:10 -0800 (PST) [thread overview]
Message-ID: <20090108.142510.263686170.davem@davemloft.net> (raw)
In-Reply-To: <Pine.LNX.4.64.0901081539360.14124@quilx.com>
From: Christoph Lameter <cl@linux-foundation.org>
Date: Thu, 8 Jan 2009 16:21:32 -0600 (CST)
> On Thu, 8 Jan 2009, Andi Kleen wrote:
>
> > On Thu, Jan 08, 2009 at 03:15:48PM -0600, Christoph Lameter wrote:
> > > This also then means that RELOC_HIDE can simply be pointer arithmetic on
> > > non PPC, right?
> >
> > No, the C standard and the gcc optimizer are the same on all architectures.
>
> The wrapping is okay on platforms that use straight 2 complement without
> additional tricks in high bits. Some platforms do not wrap.
It's not okay for loop termination conditions and that's where GCC
takes advantage of this invariant.
Otherwise, if overflow is possible, tranforming an array index
comparison into a pointer comparison is no longer legal.
next prev parent reply other threads:[~2009-01-08 22:25 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-05 3:32 linux-next: manual merge of the rr tree Stephen Rothwell
2009-01-05 6:57 ` Rusty Russell
2009-01-05 12:47 ` Ingo Molnar
2009-01-06 8:51 ` Rusty Russell
2009-01-06 9:20 ` Ingo Molnar
2009-01-06 13:13 ` Mike Travis
2009-01-06 13:19 ` Ingo Molnar
2009-01-06 14:21 ` Mike Travis
2009-01-06 14:59 ` Ingo Molnar
2009-01-07 2:46 ` Rusty Russell
2009-01-05 15:29 ` Christoph Lameter
2009-01-06 1:04 ` Rusty Russell
2009-01-06 15:05 ` Christoph Lameter
2009-01-07 2:47 ` Rusty Russell
2009-01-07 16:11 ` Christoph Lameter
2009-01-07 17:20 ` Andi Kleen
2009-01-07 19:01 ` Christoph Lameter
2009-01-08 20:48 ` Andi Kleen
2009-01-08 20:50 ` Andrew Morton
2009-01-08 21:15 ` Christoph Lameter
2009-01-08 21:49 ` Andi Kleen
2009-01-08 22:21 ` Christoph Lameter
2009-01-08 22:25 ` David Miller [this message]
2009-01-09 14:42 ` Christoph Lameter
2009-01-09 22:54 ` David Miller
2009-01-05 19:46 ` Mike Travis
2009-01-05 8:41 ` Rusty Russell
2009-01-06 3:46 ` Stephen Rothwell
2009-01-06 13:26 ` Ingo Molnar
-- strict thread matches above, loose matches on Subject: below --
2009-01-09 1:53 Stephen Rothwell
2009-01-09 1:53 ` Stephen Rothwell
2009-01-06 3:11 Stephen Rothwell
2008-12-29 7:51 Stephen Rothwell
2008-12-29 7:47 Stephen Rothwell
2008-12-29 8:02 ` Stephen Rothwell
2008-12-22 6:32 Stephen Rothwell
2008-12-22 7:58 ` Rusty Russell
2008-12-22 8:45 ` Mark McLoughlin
2009-01-04 23:30 ` Stephen Rothwell
2009-01-05 4:36 ` Greg KH
2009-01-05 5:56 ` Stephen Rothwell
2008-12-16 5:29 Stephen Rothwell
2008-12-15 6:15 Stephen Rothwell
2008-11-24 3:20 Stephen Rothwell
2008-11-20 3:24 Stephen Rothwell
2008-11-20 4:28 ` Rusty Russell
2008-11-14 4:13 Stephen Rothwell
2008-11-14 4:20 ` Stephen Rothwell
2008-11-14 4:30 ` David Miller
2008-11-14 4:36 ` Stephen Rothwell
2008-11-14 4:41 ` David Miller
2008-11-14 5:06 ` Stephen Rothwell
2008-11-14 6:42 ` David Miller
2008-11-15 22:32 ` Rusty Russell
2008-11-17 2:57 ` David Miller
2008-11-07 5:01 Stephen Rothwell
2008-10-29 4:28 Stephen Rothwell
2008-10-29 4:33 ` Stephen Rothwell
2008-10-29 22:42 ` Rusty Russell
2008-10-28 2:55 Stephen Rothwell
2008-10-28 7:19 ` Heiko Carstens
2008-10-28 7:24 ` Stephen Rothwell
2008-10-27 3:32 Stephen Rothwell
2008-10-24 2:21 Stephen Rothwell
2008-10-23 4:12 Stephen Rothwell
2008-10-23 5:16 ` Rusty Russell
2008-10-23 12:26 ` Rusty Russell
2008-10-23 12:50 ` Mike Travis
2008-10-23 4:01 Stephen Rothwell
2008-10-23 7:17 ` Peter Zijlstra
2008-10-23 13:32 ` Rusty Russell
2008-10-23 3:56 Stephen Rothwell
2008-10-23 12:25 ` Rusty Russell
2008-09-12 21:53 Stephen Rothwell
2008-07-28 3:16 Stephen Rothwell
2008-07-28 3:13 Stephen Rothwell
2008-07-28 3:09 Stephen Rothwell
2008-07-22 4:58 Stephen Rothwell
2008-07-22 14:21 ` Mike Travis
2008-07-16 8:15 Stephen Rothwell
2008-07-17 5:46 ` Max Krasnyansky
2008-07-18 4:31 ` Rusty Russell
2008-07-14 6:52 Stephen Rothwell
2008-07-03 5:03 Stephen Rothwell
2008-07-03 5:56 ` Ingo Molnar
2008-07-03 8:07 ` Stephen Rothwell
2008-07-03 8:19 ` Ingo Molnar
2008-07-04 0:45 ` Rusty Russell
2008-07-04 0:29 ` Rusty Russell
2008-06-25 6:27 Stephen Rothwell
2008-06-25 6:38 ` Christian Borntraeger
2008-06-25 15:23 ` Stephen Rothwell
2008-06-25 6:27 Stephen Rothwell
2008-06-25 7:47 ` Ingo Molnar
2008-06-25 8:33 ` Rusty Russell
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