From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by sourceware.org (Postfix) with ESMTPS id 06D433858C3A for ; Thu, 4 Nov 2021 04:41:56 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 06D433858C3A Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 1A43lYUV022137; Thu, 4 Nov 2021 04:41:55 GMT Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 3c47x4rrfj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 04 Nov 2021 04:41:55 +0000 Received: from m0098404.ppops.net (m0098404.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 1A44cWlt030462; Thu, 4 Nov 2021 04:41:55 GMT Received: from ppma04wdc.us.ibm.com (1a.90.2fa9.ip4.static.sl-reverse.com [169.47.144.26]) by mx0a-001b2d01.pphosted.com with ESMTP id 3c47x4rrf5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 04 Nov 2021 04:41:55 +0000 Received: from pps.filterd (ppma04wdc.us.ibm.com [127.0.0.1]) by ppma04wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 1A44cmbB004588; Thu, 4 Nov 2021 04:41:53 GMT Received: from b03cxnp08025.gho.boulder.ibm.com (b03cxnp08025.gho.boulder.ibm.com [9.17.130.17]) by ppma04wdc.us.ibm.com with ESMTP id 3c0wpbyv1v-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 04 Nov 2021 04:41:53 +0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 1A44fqmV53412142 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 4 Nov 2021 04:41:52 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 96B77C605B; Thu, 4 Nov 2021 04:41:52 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F4225C6059; Thu, 4 Nov 2021 04:41:51 +0000 (GMT) Received: from toto.the-meissners.org (unknown [9.65.76.254]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTPS; Thu, 4 Nov 2021 04:41:51 +0000 (GMT) Date: Thu, 4 Nov 2021 00:41:50 -0400 From: Michael Meissner To: Thomas Koenig Cc: Jakub Jelinek , wschmidt@linux.ibm.com, "fortran@gcc.gnu.org" , Segher Boessenkool , Peter Bergner , David Edelsohn , Michael Meissner Subject: Re: [RFC] User-visible changes for powerpc64-le-linux ABI changes Message-ID: Mail-Followup-To: Michael Meissner , Thomas Koenig , Jakub Jelinek , wschmidt@linux.ibm.com, "fortran@gcc.gnu.org" , Segher Boessenkool , Peter Bergner , David Edelsohn References: <63b5434e-f8fa-97b3-d357-e25094579b16@netcologne.de> <7cee9ce9-7fea-4d2d-5c53-e5d708f93c6b@netcologne.de> <20211101174533.GV304296@tucnak> <0622fb27-0dd5-90c0-cfa7-03c8947da660@netcologne.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0622fb27-0dd5-90c0-cfa7-03c8947da660@netcologne.de> X-TM-AS-GCONF: 00 X-Proofpoint-GUID: DnceLJJuB03l8Wg4P8f_-tJodqnQKxhd X-Proofpoint-ORIG-GUID: LLv5l5Jvn6vCZwNn6U90iumu6thQSj5y X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.790,Hydra:6.0.425,FMLib:17.0.607.475 definitions=2021-11-04_01,2021-11-03_01,2020-04-07_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 mlxscore=0 phishscore=0 lowpriorityscore=0 spamscore=0 suspectscore=0 bulkscore=0 mlxlogscore=999 impostorscore=0 adultscore=0 priorityscore=1501 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2110150000 definitions=main-2111040025 X-Spam-Status: No, score=-3.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_EF, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: fortran@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Fortran mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Nov 2021 04:41:59 -0000 On Tue, Nov 02, 2021 at 07:19:10AM +0100, Thomas Koenig wrote: > > On 01.11.21 18:45, Jakub Jelinek wrote: > > Note, if we go the way of C/C++ with -mabi=ieeelongdouble vs. > > -mabi=ibmlongdouble choosing between the two ABIs and libgfortran being > > ABI compatible with both, then we don't need to bump soname. > > Sounds like one major pain solved. I think we should do if it possible. > > > But, if we don't bump it, we need to keep double double there backwards > > compatible (i.e. _r16 etc. being the double double, not IEEE). > > Correct. I would actually go for 17 for the IEEE because it is > the larger number, but that is a pure style issue and has no > impact on something that is user visible :-) > > > When in the future we bump the soname, we can swap those two and > > make _r16 newly stand for IEEE quad and _r15 or _r16d or whatever > > for double double. > > Yep. > > We do need to do something about the generated module files, though, to > make programs compiled with one option incompatible with the other ones > on that level. In general, I wouldn't expect mixing and matching long double options to work. But you do want the library to have both versions of the library functions with different names. And as I've found out, outside of the official libraries, you run into smaller libraries (like gmp, mpfr, and mpc used in the compiler) that also need to be compiled with the right options because they have random functions that have long double elements (even if the app doesn't use the long double arguments). For example, in the C world, we need to have 3 versions of each of the *printf functions, since printf can be passed long double. > Or are people expected to get that right? :-) In terms of testing, it isn't ideal, but if you make a branch that we (IBM) can access, we can run it on our various systems. -- Michael Meissner, IBM PO Box 98, Ayer, Massachusetts, USA, 01432 email: meissner@linux.ibm.com