From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752726AbcDUVLG (ORCPT <rfc822;w@1wt.eu>);
	Thu, 21 Apr 2016 17:11:06 -0400
Received: from mailapp01.imgtec.com ([195.59.15.196]:64912 "EHLO
	mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751697AbcDUVLE (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 21 Apr 2016 17:11:04 -0400
Date: Thu, 21 Apr 2016 22:10:51 +0100
From: "Maciej W. Rozycki" <macro@imgtec.com>
To: Ralf Baechle <ralf@linux-mips.org>
CC: Fengguang Wu <fengguang.wu@intel.com>, <kbuild-all@01.org>,
        Paul Burton <paul.burton@imgtec.com>, <linux-kernel@vger.kernel.org>,
        Philip Li <philip.li@intel.com>
Subject: Re: [kbuild-all] mipsel-linux-gnu-gcc: error: unrecognized command
 line option '-mcompact-branches=optimal'
In-Reply-To: <20160421203415.GK24051@linux-mips.org>
Message-ID: <alpine.DEB.2.00.1604212159440.21846@tp.orcam.me.uk>
References: <201604201320.YHjfc2dZ%fengguang.wu@intel.com> <20160420133021.GG24051@linux-mips.org> <20160421045129.GB4038@wfg-t540p.sh.intel.com> <alpine.DEB.2.00.1604212043170.21846@tp.orcam.me.uk> <20160421203415.GK24051@linux-mips.org>
User-Agent: Alpine 2.00 (DEB 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
X-Originating-IP: [10.20.78.30]
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, 21 Apr 2016, Ralf Baechle wrote:

> >  I don't think it makes sense as the compiler won't support MIPSr6 code 
> > anyway, so first it'll bail out on `-march=mips32r6', and if we go even 
> > further and disable that too, then GAS will probably break somewhere on 
> > inline asm and GCC will produce code which does not make sense otherwise.
> 
> GCC 5.2.0 claims to support mips32r6 and mips64r6.  It's just the option
> -mcompact-branches which seem to have been added later only.

 Ah, I see -- I didn't track the timeline of support for this compiler's 
option and I took it from an earlier response that the compiler does not 
support R6 at all.

 In that case however it looks to me like these `-mcompact-branches=' 
options (all the three we support) need to be wrapped into `$(call 
cc-option,...)'.  They do not affect any functionality and they are an 
optimisation choice only anyway (and therefore I wonder why they've been 
placed in arch/mips/Kconfig.debug rather than arch/mips/Kconfig).

  Maciej