From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 39952 invoked by alias); 2 Aug 2017 16:43:03 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 38176 invoked by uid 89); 2 Aug 2017 16:43:02 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY autolearn=no version=3.3.2 spammy=H*x:6.0, H*x:version, H*Ad:U*davem, H*UA:version X-HELO: shards.monkeyblade.net Received: from shards.monkeyblade.net (HELO shards.monkeyblade.net) (184.105.139.130) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 02 Aug 2017 16:43:01 +0000 Received: from localhost (74-93-104-98-Washington.hfc.comcastbusiness.net [74.93.104.98]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 211E5120FBEB6; Wed, 2 Aug 2017 09:42:58 -0700 (PDT) Date: Wed, 02 Aug 2017 16:43:00 -0000 Message-Id: <20170802.094255.903257310121261526.davem@davemloft.net> To: qing.zhao@oracle.com Cc: gcc-patches@gcc.gnu.org Subject: Re: [PATCH 1/1] sparc: support for -mmisalign in the SPARC M8 From: David Miller In-Reply-To: <1501687671-143345-1-git-send-email-qing.zhao@oracle.com> References: <1501687671-143345-1-git-send-email-qing.zhao@oracle.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2017-08/txt/msg00206.txt.bz2 From: qinzhao Date: Wed, 2 Aug 2017 10:27:51 -0500 > This patch adds support to GCC for the misaligned load/store > instructions introduced in the Oracle SPARC Architecture 2017 and > implemented by the SPARC M8 processor. > > A new command line option -mmisaligned is added, that activates the > usage of the new instructions. > > The SPARC backend is modified to use the misaligned load/store > instructions when loading/storing data from/to addresses that are > known to be misaligned at compile time (such as in packed structs). > > New tests are added to check that the proper instructions are used > when loading and storing from/to packed structs. > > The GCC manual is expanded to cover the new command-line option. STRICT_ALIGNMENT has a lot of implications. I think just because we happen to have misaligned loads and stores available doesn't mean we want all of the side effects associated with STRICT_ALIGNMENT being true.