From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24662 invoked by alias); 29 Oct 2014 20:11:04 -0000 Mailing-List: contact libffi-discuss-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libffi-discuss-owner@sourceware.org Received: (qmail 24649 invoked by uid 89); 29 Oct 2014 20:11:04 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.1 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=3.3.2 X-HELO: shards.monkeyblade.net Received: from shards.monkeyblade.net (HELO shards.monkeyblade.net) (149.20.54.216) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 29 Oct 2014 20:11:02 +0000 Received: from localhost (nat-pool-rdu-t.redhat.com [66.187.233.202]) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 314D1581CDA; Wed, 29 Oct 2014 13:11:00 -0700 (PDT) Date: Wed, 29 Oct 2014 20:11:00 -0000 Message-Id: <20141029.161058.1101864756322678040.davem@davemloft.net> To: rth@twiddle.net Cc: libffi-discuss@sourceware.org Subject: Re: [PATCH 3/8] sparc: Rewrite everything From: David Miller In-Reply-To: <545147A9.9090401@twiddle.net> References: <1414525555-21256-4-git-send-email-rth@twiddle.net> <20141029.141027.901195445453157818.davem@davemloft.net> <545147A9.9090401@twiddle.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-SW-Source: 2014/txt/msg00171.txt.bz2 From: Richard Henderson Date: Wed, 29 Oct 2014 13:01:45 -0700 > On 10/29/2014 11:10 AM, David Miller wrote: >> Maybe I'm missing something? > > The two limits are in fact different. In gcc, see sparc_return_in_memory and > sparc_pass_by_reference. My bad, thanks for clarifying. That's the only thing that caught my eye. I think for most v9 chips a 'return' is slightly more expensive than a 'ret/restore'. 'return' is good for saving an instruction when you can put something in that delay slot, but if you can't then you might as well do 'ret/restore'. Series otherwise looks great, nice work!