From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762128AbYETXUV (ORCPT ); Tue, 20 May 2008 19:20:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753481AbYETXUH (ORCPT ); Tue, 20 May 2008 19:20:07 -0400 Received: from az33egw02.freescale.net ([192.88.158.103]:63573 "EHLO az33egw02.freescale.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753150AbYETXUG (ORCPT ); Tue, 20 May 2008 19:20:06 -0400 Date: Tue, 20 May 2008 16:14:49 -0700 (PDT) From: Trent Piepho X-X-Sender: xyzzy@t2.domain.actdsltmp To: Andreas Schwab cc: linuxppc-dev@ozlabs.org, Scott Wood , linux-kernel@vger.kernel.org Subject: Re: [PATCH] [POWERPC] Improve (in|out)_beXX() asm code In-Reply-To: Message-ID: References: <1211316025-29069-1-git-send-email-tpiepho@freescale.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 May 2008, Andreas Schwab wrote: > Trent Piepho writes: > >> It's the _le versions that have a problem, since we can't get gcc to just use >> the register indexed mode. It seems like an obvious thing to have a >> constraint for, but I guess there weren't enough instructions that only come >> in 'x' versions to bother with it. There is a 'Z' constraint, "Memory operand >> that is an indexed or indirect from a register", but I tried it and it can use >> both "rb,ri" and "disp(rb)" forms. Actually, I'm not sure how 'Z' is any >> different than "m"? > > 'Z' will never emit a non-zero constant displacement. It's too bad gas doesn't appear to be smart enough to turn: stwbrx 0, 0(3) -or- stwbr 0, 0(3) into the desired: stwbrx 0, 0, 3