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From: "jamborm at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/58041] Unaligned access to arrays in packed structure
Date: Thu, 01 Aug 2013 23:06:00 -0000 [thread overview]
Message-ID: <bug-58041-4-84f3l35Stv@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-58041-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58041
--- Comment #19 from Martin Jambor <jamborm at gcc dot gnu.org> ---
(In reply to Bill Schmidt from comment #15)
> Bernd, Mikael, Martin: Could you please test this on your respective
> targets?
Well, "my target" is x86_64 but yes, it works.
(In reply to Bill Schmidt from comment #11)
> Hi Martin,
>
> Your assumptions are correct, but I'm not sure this is the best place to
> handle it. It looks like what you are doing is replacing one already
> correct memory reference with another, both of which will generate somewhat
> nasty code. Therefore there isn't much reason to do the transformation at
> all in the first place. I think I would rather analyze the reference when
> considering adding the reference to the candidate table, and leaving it out
> of consideration altogether. What do you think?
I don't know, at least in theory the optimization might help somewhat
anyway, especially on targets that can handle misalignment memory
accesses. But you are right that generally misaligned access will be
slow either way.
Anyway, I don't really care, I assume you contributed the code so you
are more qualified to make a judgment and if you prefer one way over
the other, go for it.
I'll leave it to you and won't submit any patch then. Please make
sure that the two testcases are added to the testsuite before you
close the bug. The x86_64-linux tetcase from comment #10 is generic
enough that it can go to gcc.dg/torture/, the original ARM one needs
to go to some arm-specific place.
next prev parent reply other threads:[~2013-08-01 23:06 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-01 7:26 [Bug middle-end/58041] New: " bernd.edlinger at hotmail dot de
2013-08-01 7:31 ` [Bug middle-end/58041] " bernd.edlinger at hotmail dot de
2013-08-01 9:09 ` mikpe at it dot uu.se
2013-08-01 11:36 ` mikpe at it dot uu.se
2013-08-01 11:51 ` mikpe at it dot uu.se
2013-08-01 13:26 ` wschmidt at gcc dot gnu.org
2013-08-01 16:18 ` wschmidt at gcc dot gnu.org
2013-08-01 16:23 ` jamborm at gcc dot gnu.org
2013-08-01 16:48 ` jamborm at gcc dot gnu.org
2013-08-01 17:27 ` jamborm at gcc dot gnu.org
2013-08-01 17:49 ` wschmidt at gcc dot gnu.org
2013-08-01 17:54 ` wschmidt at gcc dot gnu.org
2013-08-01 18:17 ` bernd.edlinger at hotmail dot de
2013-08-01 18:29 ` wschmidt at gcc dot gnu.org
2013-08-01 18:32 ` wschmidt at gcc dot gnu.org
2013-08-01 19:09 ` bernd.edlinger at hotmail dot de
2013-08-01 19:20 ` wschmidt at gcc dot gnu.org
2013-08-01 19:36 ` mikpe at it dot uu.se
2013-08-01 23:06 ` jamborm at gcc dot gnu.org [this message]
2013-08-02 15:22 ` wschmidt at gcc dot gnu.org
2013-08-02 15:28 ` wschmidt at gcc dot gnu.org
2013-08-02 15:54 ` ebotcazou at gcc dot gnu.org
2013-08-02 16:06 ` wschmidt at gcc dot gnu.org
2013-08-02 16:58 ` jamborm at gcc dot gnu.org
2013-08-02 17:12 ` wschmidt at gcc dot gnu.org
2013-08-02 18:07 ` wschmidt at gcc dot gnu.org
2013-08-03 8:31 ` bernd.edlinger at hotmail dot de
2013-08-05 17:43 ` jamborm at gcc dot gnu.org
2013-08-06 11:59 ` jamborm at gcc dot gnu.org
2013-08-06 14:24 ` bernd.edlinger at hotmail dot de
2013-08-06 15:18 ` jamborm at gcc dot gnu.org
2013-08-06 15:19 ` jamborm at gcc dot gnu.org
2013-08-06 15:33 ` bernd.edlinger at hotmail dot de
2013-08-06 15:56 ` bernd.edlinger at hotmail dot de
2013-08-06 16:06 ` jamborm at gcc dot gnu.org
2013-08-06 16:12 ` bernd.edlinger at hotmail dot de
2013-08-06 16:36 ` bernd.edlinger at hotmail dot de
2013-08-06 16:59 ` jamborm at gcc dot gnu.org
2013-08-06 17:07 ` bernd.edlinger at hotmail dot de
2013-08-06 17:37 ` jamborm at gcc dot gnu.org
2013-08-06 18:19 ` wschmidt at gcc dot gnu.org
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