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[2603:7000:9500:2e39::1db4]) by smtp.gmail.com with ESMTPSA id h4-20020a05620a400400b006e702033b15sm10365045qko.66.2022.10.21.12.14.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Oct 2022 12:14:56 -0700 (PDT) Date: Fri, 21 Oct 2022 15:14:54 -0400 From: Marek Polacek To: Florian Weimer Cc: Joseph Myers , gcc@gcc.gnu.org Subject: Re: C2x features status Message-ID: References: <874jvx81w2.fsf@oldenburg.str.redhat.com> MIME-Version: 1.0 In-Reply-To: <874jvx81w2.fsf@oldenburg.str.redhat.com> User-Agent: Mutt/2.2.7 (2022-08-07) X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-6.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham 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, Oct 21, 2022 at 08:31:09PM +0200, Florian Weimer via Gcc wrote: > * Joseph Myers: > > > I'm working on adding various C2x features to the C front end (and > > elsewhere in GCC as applicable). > > > > I suspect I won't get all the C2x features done for GCC 13. If anyone > > else is interested in adding C2x features, I'd encourage looking at some > > of the following, which I may well not get to for GCC 13 (and posting here > > to avoid duplication of effort if working on such a feature): > > > > * Bit-precise integer types (_BitInt) (see bug 102989) (integrated version > > based on N2763, plus literal suffixes from N2775 and bit-fields from > > N2969). Would require working with back-end maintainers and upstream ABI > > groups, where available, to get ABIs defined for as many architectures as > > possible, as well as some default ABI choice in GCC for architectures that > > haven't defined the ABI for these types. > > > > * [[unsequenced]] and [[reproducible]] attributes for function types. See > > N2956. These are supposed to be similar to const and pure attributes, at > > least in the absence of pointer and array function parameters (but note > > they never affect type compatibility). > > > > * Tag compatibility (N3037, alternative wording). Martin Uecker might > > have patches for a draft version of this? > > > > * Preprocessor #embed (N3017) (see bug 105863). > > Do you have a list of C2X features that are likely to impact autoconf > tests? Or planned changes in the GCC 13 and 14 default language modes > that reject constructs previous accepted as an extension? At least this one: commit 0a91bdaf177409a2a5e7895bce4f0e7091b4b3ca Author: Joseph Myers Date: Wed Sep 7 13:56:25 2022 +0000 c: New C2x keywords which says: As with the removal of unprototyped functions, this change has a high risk of breaking some old code and people doing GNU/Linux distribution builds may wish to see how much is broken in a build with a -std=gnu2x default. > I'm asking because I'm working on the implicit function declaration > problem once more, and other things could be piggybacked on the tool > support over time. See the parallel “C89isms in the test suite” thread. > > I wonder if anything went into the default C2X language mode already > that could be similarly disruptive as the removal of implicit ints? In > that case, I should probably backport that change into my GCC test > version. (To avoid chasing ghosts, it's based off GCC 12, I've decided > to decouple it from our planned switch to GCC 13.) > > Thanks, > Florian > Marek