From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31784 invoked by alias); 3 Oct 2007 22:08:02 -0000 Received: (qmail 31752 invoked by alias); 3 Oct 2007 22:07:52 -0000 Date: Wed, 03 Oct 2007 22:08:00 -0000 Message-ID: <20071003220752.31751.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug middle-end/16660] attribute((aligned)) doesn't work for variables on the stack for greater than required alignement In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "pinskia at gcc dot gnu dot org" Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2007-10/txt/msg00272.txt.bz2 ------- 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 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