220 35519 <4569243.5CL4mZyDPR@tjmaciei-mobl1> article Path: news.gmane.org!.POSTED!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Rotational shift operator Date: Sat, 25 Nov 2017 12:24:21 -0800 Lines: 44 Approved: news@gmane.org Message-ID: <4569243.5CL4mZyDPR@tjmaciei-mobl1> References: <69593098-e2cc-487e-bd14-9001b27aa7c1@isocpp.org> <3031585.uCQqKE2Qzv@tjmaciei-mobl1> <9a7a898c-9e14-532f-fc4a-11d0aa5a1bf7@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1511641473 14842 195.159.176.226 (25 Nov 2017 20:24:33 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 25 Nov 2017 20:24:33 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRB7NC47IAKGQEJGQUGSI@isocpp.org Sat Nov 25 21:24:27 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wr0-f198.google.com ([209.85.128.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eIgzu-00035Y-VX for gclcip-std-proposals@m.gmane.org; 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[78.47.120.188]) by mx.google.com with ESMTP id l53si14540700wrl.149.2017.11.25.12.24.28 for ; Sat, 25 Nov 2017 12:24:28 -0800 (PST) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 78.47.120.188 as permitted sender) client-ip=78.47.120.188; Original-Received: from tjmaciei-mobl1.localnet (unknown [IPv6:2601:1c0:4501:5f9f:10a8:5dac:57fd:2747]) by gondolin.macieira.info (Postfix) with ESMTPSA id 95F0011A634 for ; Sat, 25 Nov 2017 12:24:24 -0800 (PST) In-Reply-To: <9a7a898c-9e14-532f-fc4a-11d0aa5a1bf7@gmail.com> X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 78.47.120.188 as permitted sender) smtp.mailfrom=thiago@macieira.org Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:35519 Archived-At: On s=C3=A1bado, 25 de novembro de 2017 04:08:07 PST Andrey Semashev wrote: > > The high-level language doesn't need that because the compilers are sma= rt > > enough to notice the pattern of two-shifts-and-or as a rotation and wri= te > > assembly accordingly. >=20 > Well, the compilers were not always that smart, and if we had the > standard rotation functions or operators from the start, people wouldn't > have to write assembler code and compilers wouldn't need to be taught to > recognize certain code patterns. Reliability of this recognition has > always been and will be a question of QoI, i.e. something that cannot be > relied on. True, chicken-and-the-egg: if the operators had been available, perhaps the= y=20 would have been used more often. But my assertion remains: if they had really been needed, they'd have been= =20 standardised and added to some language by now. For now, they only exist as= =20 intrinsics in . > I'm not arguing for operators or functions approach here. I'm saying > that dedicated rotation operations are long overdue in C and C++. I dispute that. They can only be overdue if you needed them and didn't have= =20 them. Since you can do rotation right now, you have them. --=20 Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center --=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/4569243.5CL4mZyDPR%40tjmaciei-mobl1. .