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[Bug middle-end/16660] attribute((aligned)) doesn't work for variables on the stack for greater than required alignement
- From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 3 Oct 2007 22:07:52 -0000
- Subject: [Bug middle-end/16660] attribute((aligned)) doesn't work for variables on the stack for greater than required alignement
- References: <bug-16660-1824@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #8 from pinskia at gcc dot gnu dot org 2007-10-03 22:07 -------
Subject: Re: attribute((aligned)) doesn't work for variables on the stack for
greater than required alignement
On 3 Oct 2007 22:04:28 -0000, hjl at lucon dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #7 from hjl at lucon dot org 2007-10-03 22:04 -------
> What is the performance impact of
>
> http://gcc.gnu.org/ml/gcc-patches/2007-05/msg01167.html
The performance impact is non if the variables don't need aligned.
Otherwise you get a small penality at the very begining for the
alignment of the variable itself. Really this is only to be used with
big alignments like 128byte alignment (for using with a DMA system
like in the Cell).
-- Pinski
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16660