From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-return-72248-listarch-gcc=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 28504 invoked by alias); 21 Apr 2003 16:47:05 -0000
Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Archive: <http://gcc.gnu.org/ml/gcc/>
List-Post: <mailto:gcc@gcc.gnu.org>
List-Help: <http://gcc.gnu.org/ml/>
Sender: gcc-owner@gcc.gnu.org
Received: (qmail 28417 invoked from network); 21 Apr 2003 16:46:53 -0000
Received: from unknown (HELO vlsi1.ultra.nyu.edu) (128.122.140.213)
  by sources.redhat.com with SMTP; 21 Apr 2003 16:46:53 -0000
Received: by vlsi1.ultra.nyu.edu (4.1/1.34)
	id AA29704; Mon, 21 Apr 03 12:51:12 EDT
Date: Mon, 21 Apr 2003 17:25:00 -0000
From: kenner@vlsi1.ultra.nyu.edu (Richard Kenner)
Message-Id: <10304211651.AA29704@vlsi1.ultra.nyu.edu>
To: aoliva@redhat.com
Subject: Re: DATA_ALIGNMENT vs. DECL_USER_ALIGNMENT
Cc: gcc-patches@gcc.gnu.org, gcc@gcc.gnu.org
X-SW-Source: 2003-04/txt/msg00991.txt.bz2

    So if you turn:

    T i __attribute__((align(2)));
    T j __attribute__((align(2)));

    into

    typedef T T2 __attribute__((align(2)));
    T2 i, j;

    you say we could get different code?  

I say so, yes.

And the reason is as I said: you specify alignment for a type both for
interface and efficiency reasons, but for an object only for the latter.
So there is a difference in meaning between these two constructs.