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From: "Dave Korn" <dave.korn@artimi.com>
To: "'Shaun Jackman'" <sjackman@gmail.com>,
	"'Richard Henderson'" <rth@redhat.com>
Cc: "'Ian Lance Taylor'" <ian@airs.com>,
	"'Andrew Pinski'" <pinskia@physics.uc.edu>,
	"'Mike Stump'" <mrs@apple.com>,
	"'Paul Koning'" <pkoning@equallogic.com>,
	<gcc@sources.redhat.com>
Subject: RE: memcpy to an unaligned address
Date: Wed, 03 Aug 2005 18:19:00 -0000	[thread overview]
Message-ID: <SERRANOLc2Vtak2x1pk0000003a@SERRANO.CAM.ARTIMI.COM> (raw)
In-Reply-To: <7f45d93905080311152d530172@mail.gmail.com>

----Original Message----
>From: Shaun Jackman
>Sent: 03 August 2005 19:15

> On 8/3/05, Richard Henderson <rth@redhat.com> wrote:
>> It is nevertheless correct.  Examine all of the parts of the expression.
>> 
>> In particular, "&s->b".  What type does it have?  In an ideal world, it
>> would be "pointer to unaligned integer".  But we have no such type in
>> our type system, so it is "pointer to integer".  This expression is ONLY
>> THEN passed to memcpy.  At which point we query the argument for its
>> alignment, and get the non-intuitive result.
>> 
>> If you instead pass "s" to memcpy, you should get the correct unaligned
>> copy.  If that isn't happening, that's a bug.
> 
> I'm not sure I understood the last line. s is a structure,

  Not if "&s->b" makes any sense it isn't!


    cheers,
      DaveK
-- 
Can't think of a witty .sigline today....

  reply	other threads:[~2005-08-03 18:19 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-02 17:32 Shaun Jackman
2005-08-02 17:43 ` Dave Korn
2005-08-02 19:13   ` Shaun Jackman
2005-08-02 19:19     ` Paul Koning
2005-08-02 19:26       ` Shaun Jackman
2005-08-02 19:40         ` Dave Korn
2005-08-02 19:48           ` Paul Koning
2005-08-02 20:15           ` Shaun Jackman
2005-08-02 20:29             ` Mike Stump
2005-08-02 20:38               ` Andrew Pinski
2005-08-02 20:45                 ` Ian Lance Taylor
2005-08-02 21:30                   ` Mike Stump
2005-08-02 21:34                     ` Joe Buck
2005-08-03 18:00                   ` Richard Henderson
2005-08-03 18:15                     ` Shaun Jackman
2005-08-03 18:19                       ` Dave Korn [this message]
2005-08-03 21:26                       ` Richard Henderson
2005-08-04  4:42                     ` Ian Lance Taylor
2005-08-04 12:40                     ` Paul Koning
2005-08-02 20:46                 ` Paul Koning
2005-08-02 22:17                   ` Shaun Jackman
2005-08-03 17:16                     ` Paul Koning
2005-08-02 22:26                   ` Shaun Jackman
2005-08-02 22:29                     ` Shaun Jackman
2005-08-02 21:05                 ` Mike Stump
2005-08-02 21:11                   ` Joe Buck
2005-08-02 22:15                     ` Shaun Jackman
2005-08-02 22:12                       ` Joe Buck
2005-08-02 20:29             ` Paul Koning
2005-08-02 17:48 ` Falk Hueffner
2005-08-02 18:03 ` Mike Stump
     [not found] <345be691050804025955c0b4ab@mail.gmail.com>
2005-08-04 15:06 ` Shaun Jackman
2005-08-04 15:09   ` Christian Joensson
2005-08-05  8:41   ` Carl Whitwell
2005-08-05 16:09     ` Shaun Jackman

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