From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 4EEE73858D32 for ; Tue, 13 Jun 2023 07:06:29 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 4EEE73858D32 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686639988; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=K84cBkgx1tw7oVtkvVQU7PjMXEHkKYiqrA/bPp1xYic=; b=asJGIGUr2UB6ywnJmVk7aCSmvfOGJ9Bzvtxde42iAp4D7wP4G2+QOTBkKg01P1NyupB3cY A7Jhc6vXrvXMgOKXVzCoPtGTwVcTk65V+kyRtaa0Ow9Y+J6qjXiUTihmexrmBQmknvj1f/ 1IDbkFGR5F19bqHzuOoo2XpRHRGnxIo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-66-ps73VAzQM4OPPFBeHdPwNA-1; Tue, 13 Jun 2023 03:06:27 -0400 X-MC-Unique: ps73VAzQM4OPPFBeHdPwNA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E8D4F8037AA; Tue, 13 Jun 2023 07:06:26 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.194.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AA9512166B26; Tue, 13 Jun 2023 07:06:26 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 35D76Nne2491951 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 13 Jun 2023 09:06:24 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 35D76MlP2491950; Tue, 13 Jun 2023 09:06:22 +0200 Date: Tue, 13 Jun 2023 09:06:22 +0200 From: Jakub Jelinek To: Richard Biener , Uros Bizjak , gcc-patches@gcc.gnu.org Subject: Patch ping (Re: [PATCH] middle-end, i386: Pattern recognize add/subtract with carry [PR79173]) Message-ID: Reply-To: Jakub Jelinek References: MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-3.4 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_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE 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: Hi! On Tue, Jun 06, 2023 at 11:42:07PM +0200, Jakub Jelinek via Gcc-patches wrote: > The following patch introduces {add,sub}c5_optab and pattern recognizes > various forms of add with carry and subtract with carry/borrow, see > pr79173-{1,2,3,4,5,6}.c tests on what is matched. > Primarily forms with 2 __builtin_add_overflow or __builtin_sub_overflow > calls per limb (with just one for the least significant one), for > add with carry even when it is hand written in C (for subtraction > reassoc seems to change it too much so that the pattern recognition > doesn't work). __builtin_{add,sub}_overflow are standardized in C23 > under ckd_{add,sub} names, so it isn't any longer a GNU only extension. > > Note, clang has for these has (IMHO badly designed) > __builtin_{add,sub}c{b,s,,l,ll} builtins which don't add/subtract just > a single bit of carry, but basically add 3 unsigned values or > subtract 2 unsigned values from one, and result in carry out of 0, 1, or 2 > because of that. If we wanted to introduce those for clang compatibility, > we could and lower them early to just two __builtin_{add,sub}_overflow > calls and let the pattern matching in this patch recognize it later. > > I've added expanders for this on ix86 and in addition to that > added various peephole2s to make sure we get nice (and small) code > for the common cases. I think there are other PRs which request that > e.g. for the _{addcarry,subborrow}_u{32,64} intrinsics, which the patch > also improves. I'd like to ping this patch. Thanks. Jakub