From: Geert Bosch <bosch@gnat.com>
To: Jason Merrill <jason@redhat.com>
Cc: Alexandre Oliva <aoliva@redhat.com>,
kenner@vlsi1.ultra.nyu.edu (Richard Kenner),
gcc-patches@gcc.gnu.org, gcc@gcc.gnu.org,
Jakub Jelinek <jakub@redhat.com>
Subject: Re: DATA_ALIGNMENT vs. DECL_USER_ALIGNMENT
Date: Thu, 24 Apr 2003 08:43:00 -0000 [thread overview]
Message-ID: <386D9560-7618-11D7-8766-00039344BF4A@gnat.com> (raw)
In-Reply-To: <wvlu1cod123.fsf@prospero.boston.redhat.com>
On Wednesday, Apr 23, 2003, at 23:30 America/New_York, Jason Merrill
wrote:
> It also sounds like in Ada, specifying an alignment for a type means
> "don't
> reduce", but specifying it for an object means both "don't reduce" and
> "don't increase". It seems to me that the way to handle this is to set
> DECL_PACKED on such objects.
No, this is not the case. Specifying an alignment for an object means
"don't reduce". Of course the compiler should have a good reason to
increase, but that's a quality of implementation issue. For example,
a compiler might well align all 14-byte local objects of a 2-byte
aligned type to 16 bytes and then take advantage of that stricter
alignment in code generation.
Specifying an alignment for a type means "don't reduce" the alignment
for any allocations of objects of this type and "don't assume increased"
alignment for any objects accessed of this type.
-Geert
next prev parent reply other threads:[~2003-04-24 5:47 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-23 2:20 Richard Kenner
2003-04-23 5:31 ` Alexandre Oliva
2003-04-24 6:23 ` Jason Merrill
2003-04-24 8:43 ` Geert Bosch [this message]
2003-04-24 17:48 ` Jason Merrill
2003-04-24 18:04 ` Zack Weinberg
2003-04-24 19:31 ` Jason Merrill
2003-04-24 21:32 ` Geert Bosch
2003-04-24 23:24 ` Jason Merrill
2003-04-25 2:56 ` Richard Henderson
-- strict thread matches above, loose matches on Subject: below --
2003-04-23 3:29 Robert Dewar
2003-04-22 15:08 Richard Kenner
2003-04-23 1:07 ` Alexandre Oliva
2003-04-22 0:15 Robert Dewar
2003-04-22 1:58 ` Jamie Lokier
2003-04-22 0:11 Robert Dewar
2003-04-22 1:35 ` Jamie Lokier
2003-04-21 21:25 Richard Kenner
2003-04-21 20:59 Richard Kenner
2003-04-21 21:14 ` Jamie Lokier
2003-04-21 20:45 Richard Kenner
2003-04-21 20:58 ` Jamie Lokier
2003-04-21 18:14 Richard Kenner
2003-04-21 20:33 ` Jamie Lokier
2003-04-21 17:25 Richard Kenner
2003-04-21 18:14 ` Jamie Lokier
2003-04-22 9:00 ` Alexandre Oliva
2003-04-20 21:28 Robert Dewar
2003-04-21 17:05 ` Alexandre Oliva
2003-04-20 21:19 Robert Dewar
2003-04-18 11:41 Richard Kenner
2003-04-18 8:06 Richard Kenner
2003-04-18 8:59 ` Richard Henderson
2003-04-17 21:41 Richard Kenner
2003-04-17 23:20 ` Alexandre Oliva
2003-04-18 1:16 ` Richard Henderson
2003-04-17 21:40 Richard Kenner
2003-04-17 11:56 Richard Kenner
2003-04-17 20:35 ` Alexandre Oliva
2003-04-17 22:41 ` Geert Bosch
2003-04-17 23:19 ` Alexandre Oliva
2003-04-17 10:44 Robert Dewar
2003-04-17 20:30 ` Alexandre Oliva
2003-04-17 8:12 Richard Kenner
2003-04-17 8:38 ` Alexandre Oliva
2003-04-11 22:26 Robert Dewar
2003-04-11 16:59 Robert Dewar
2003-04-11 18:49 ` Laurent Guerby
2003-04-11 16:51 Robert Dewar
2003-04-11 14:52 Robert Dewar
2003-04-11 4:45 Richard Kenner
2003-04-17 5:39 ` Alexandre Oliva
2003-04-11 0:45 Ulrich Weigand
2003-04-10 22:43 Richard Kenner
2003-04-11 0:31 ` Richard Henderson
2003-04-11 2:19 ` David Edelsohn
2003-04-10 22:23 Richard Kenner
2003-04-10 22:16 Richard Kenner
2003-04-10 22:07 Richard Kenner
2003-04-10 22:23 ` David Edelsohn
2003-04-10 22:05 Robert Dewar
2003-04-10 22:02 Richard Kenner
2003-04-10 22:24 ` Richard Henderson
2003-04-11 11:20 ` Laurent Guerby
2003-04-11 11:57 ` Arnaud Charlet
2003-04-11 14:16 ` Laurent Guerby
2003-04-10 21:56 Richard Kenner
2003-04-10 22:02 ` David Edelsohn
2003-04-10 21:45 Richard Kenner
2003-04-10 21:52 ` David Edelsohn
2003-04-10 21:57 ` Richard Henderson
2003-04-10 21:44 Richard Kenner
2003-04-10 21:32 Robert Dewar
2003-04-10 21:32 ` David Edelsohn
2003-04-10 21:31 Richard Kenner
2003-04-10 21:29 Robert Dewar
2003-04-10 21:10 Robert Dewar
2003-04-10 21:17 ` David Edelsohn
2003-04-10 21:10 Richard Kenner
2003-04-10 21:04 Richard Kenner
2003-04-10 21:41 ` Geoff Keating
2003-04-10 20:57 Robert Dewar
2003-04-10 21:07 ` Ulrich Weigand
2003-04-10 20:52 Robert Dewar
2003-04-10 20:39 Richard Kenner
2003-04-10 21:00 ` Geoff Keating
2003-04-10 21:01 ` Ulrich Weigand
2003-04-10 21:44 ` Richard Henderson
2003-04-10 20:13 Richard Kenner
2003-04-10 20:28 ` Ulrich Weigand
2003-04-10 19:20 Richard Kenner
2003-04-10 5:33 Richard Kenner
2003-04-10 7:20 ` Ulrich Weigand
2003-04-09 23:31 Ulrich Weigand
2003-04-10 2:27 ` Richard Henderson
2003-04-10 3:10 ` Ulrich Weigand
2003-04-10 16:20 ` Ulrich Weigand
2003-04-10 16:39 ` Geoff Keating
2003-04-10 16:44 ` Ulrich Weigand
2003-04-10 18:06 ` Richard Henderson
2003-04-08 17:47 Ulrich Weigand
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