From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11444 invoked by alias); 9 Oct 2014 11:20:38 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 11420 invoked by uid 89); 9 Oct 2014 11:20:37 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-Spam-User: qpsmtpd, 2 recipients X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Thu, 09 Oct 2014 11:20:36 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s99BKUh7001274 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 9 Oct 2014 07:20:31 -0400 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s99BKSR2004195; Thu, 9 Oct 2014 07:20:28 -0400 Message-ID: <54366F7B.4010209@redhat.com> Date: Thu, 09 Oct 2014 11:20:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: Walfred Tedeschi , michael.sturm@intel.com CC: Mark Kettenis , amodra@gmail.com, gbenson@redhat.com, binutils@sourceware.org, gdb-patches@sourceware.org Subject: Re: [PATCH] gdb/i387-tdep.c: Avoid warning for "-Werror=strict-overflow" References: <542EC11C.3020406@gmail.com> <201410031546.s93FknOM002165@glazunov.sibelius.xs4all.nl> <542EC9FC.8050107@gmail.com> <20141003164420.GK6927@adacore.com> <542EE1BF.7060203@redhat.com> <54365E01.6060800@intel.com> In-Reply-To: <54365E01.6060800@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-10/txt/msg00198.txt.bz2 On 10/09/2014 11:05 AM, Walfred Tedeschi wrote: > Am 10/3/2014 7:49 PM, schrieb Pedro Alves: >> On 10/03/2014 05:44 PM, Joel Brobecker wrote: >>>>> Sorry, but obfuscating code to make compilers happy is *not* the way to go. >>>>> >>>> OK, I can understand, but for me, these is no other better ways for it, >>>> except let gdb give up "-Werror" (if always need "--disable-werror" >>>> during "configure"). >>> I have to agree with Mark on this one, the proposed solution looks >>> awful. There has to be another way. Maybe declaring a local constant >>> whose value is I387_XMM0_REGNUM (tdep)? >> Likely, after transformations and intra-procedural analyses, gcc would >> end up with the same. >> >> This: >> >> for (i = I387_ST0_REGNUM (tdep); i < I387_XMM0_REGNUM (tdep); i++) >> >> always iterates exactly 16 times, because I387_XMM0_REGNUM >> is defined like: >> >> #define I387_XMM0_REGNUM(tdep) (I387_ST0_REGNUM (tdep) + 16) >> >> An alternative I think might work would be to give that magic >> 16 constant a name, say: >> >> #define I387_NUM_ST_REGS 16 >> >> and then do: >> >> for (i = 0; i < i < I387_NUM_ST_REGS; i++) >> { >> int r = I387_ST0_REGNUM (tdep) + i; >> >> ... use 'r' instead of 'i' ... >> } >> >> Thanks, >> Pedro Alves >> > Later on we have introduced the _END macros, as can be seen on i387-tdep.h. > Creating one or two of them migh be a good idea to homogeinize the way > we handle the registers. > > This will finally also join together all ideas presented before in only one. > > Using the end will then make > > for (i = I387_ST0_REGNUM (tdep); i < I387_XMM0_REGNUM (tdep); i++) > > to be > > for (i = I387_ST0_REGNUM (tdep); i < I387_STEND_REGNUM (tdep); i++) > > > We also define the number of regs for every technology in that file. I'm imagining I387_STEND_REGNUM to be just one of: #define I387_STEND_REGNUM(tdep) (I387_ST0_REGNUM (tdep) + 16) #define I387_STEND_REGNUM(tdep) (I387_ST0_REGNUM (tdep) + I387_NUM_ST_REGS) Thus exactly the same as I387_XMM0_REGNUM: #define I387_XMM0_REGNUM(tdep) (I387_ST0_REGNUM (tdep) + 16) And so it would trigger the same GCC warning. So we'd still need to do the local variable trick: end = I387_STEND_REGNUM (tdep); for (i = I387_ST0_REGNUM (tdep); i < end; i++) Thanks, Pedro Alves