Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752726AbcDUVLG (ORCPT ); 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 ); Thu, 21 Apr 2016 17:11:04 -0400 Date: Thu, 21 Apr 2016 22:10:51 +0100 From: "Maciej W. Rozycki" To: Ralf Baechle CC: Fengguang Wu , , Paul Burton , , Philip Li 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: References: <201604201320.YHjfc2dZ%fengguang.wu@intel.com> <20160420133021.GG24051@linux-mips.org> <20160421045129.GB4038@wfg-t540p.sh.intel.com> <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: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1022 Lines: 21 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