From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) by sourceware.org (Postfix) with ESMTPS id 096C03858D38; Fri, 10 Mar 2023 19:47:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 096C03858D38 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=troutmask.apl.washington.edu Authentication-Results: sourceware.org; spf=none smtp.mailfrom=troutmask.apl.washington.edu Received: from troutmask.apl.washington.edu (localhost [127.0.0.1]) by troutmask.apl.washington.edu (8.17.1/8.17.1) with ESMTPS id 32AJlYLA071729 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Fri, 10 Mar 2023 11:47:34 -0800 (PST) (envelope-from sgk@troutmask.apl.washington.edu) Received: (from sgk@localhost) by troutmask.apl.washington.edu (8.17.1/8.17.1/Submit) id 32AJlY84071728; Fri, 10 Mar 2023 11:47:34 -0800 (PST) (envelope-from sgk) Date: Fri, 10 Mar 2023 11:47:34 -0800 From: Steve Kargl To: Richard Biener via Fortran Cc: Thomas Koenig , gcc-patches Subject: Re: [patch, Fortran] Enable -fwrapv for -std=legacy Message-ID: Reply-To: sgk@troutmask.apl.washington.edu References: <5C328B17-0588-45F4-8A39-F468F7E9F326@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5C328B17-0588-45F4-8A39-F468F7E9F326@gmail.com> X-Spam-Status: No, score=-1.6 required=5.0 tests=BAYES_00,KAM_DMARC_STATUS,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Fri, Mar 10, 2023 at 07:01:29PM +0100, Richard Biener via Fortran wrote: > > > > Am 10.03.2023 um 18:54 schrieb Thomas Koenig via Fortran : > > > > Hello world, here's the patch that was discussed. > > > > Regression-tested. OK for trunk? > > > > Since this appeared only in gcc13, I see no need for a backport. > > I will also document this in the changes file. > > The „problem“ is latent forever, I’m not sure it’s good to > amend the kitchen-sink std=legacy option with -fwrapv since > that has quite some negative effects on optimization. In that case, it would then seem logical to remove whatever patch was added to -O3 that causes the massive regression with rnflow.f90 and add it instead to -Ofast. -Ofast at least hints that is unsafe to use. -- Steve