220 33437 article Path: news.gmane.org!.POSTED!not-for-mail From: Howard Hinnant Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: [idea for proposal] Adding std::shift to Date: Fri, 28 Jul 2017 17:57:01 -0400 Lines: 58 Approved: news@gmane.org Message-ID: References: <3e77c029-bc79-424c-bdad-eba28ec10cdb@isocpp.org> <94CDFCD7-3F9D-4D7E-BDD7-58D27561C291@gmail.com> <96DEA673-B79C-4D08-AE8E-EFFCA3C5A0E8@gmail.com>

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[2607:f8b0:4001:c0b::231]) by mx.google.com with ESMTPS id m63si18221972itc.174.2017.07.28.14.57.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 28 Jul 2017 14:57:05 -0700 (PDT) Received-SPF: pass (google.com: domain of howard.hinnant@gmail.com designates 2607:f8b0:4001:c0b::231 as permitted sender) client-ip=2607:f8b0:4001:c0b::231; Original-Received: by mail-it0-x231.google.com with SMTP id v205so86863068itf.1 for ; Fri, 28 Jul 2017 14:57:04 -0700 (PDT) X-Received: by 10.36.53.141 with SMTP id k135mr10485648ita.176.1501279024115; Fri, 28 Jul 2017 14:57:04 -0700 (PDT) Original-Received: from [10.0.1.2] (cpe-67-241-68-255.twcny.res.rr.com. [67.241.68.255]) by smtp.gmail.com with ESMTPSA id d72sm10509353iod.46.2017.07.28.14.57.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 28 Jul 2017 14:57:03 -0700 (PDT) In-Reply-To: X-Mailer: Apple Mail (2.3273) X-Original-Sender: howard.hinnant@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=Iz5LNQWJ; spf=pass (google.com: domain of howard.hinnant@gmail.com designates 2607:f8b0:4001:c0b::231 as permitted sender) smtp.mailfrom=howard.hinnant@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com 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:33437 Archived-At: --Apple-Mail=_970DBBD2-DC67-43C8-81F6-5053ADAE2002 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" On Jul 28, 2017, at 5:45 PM, Dan Raviv wrote: >=20 > Ok, so why the need for copy_backward in addition to copy (since copy cou= ld be used instead with reverse iterators/pointers)? Is this mostly an opti= mization issue, as Nicol says? (I guess so because it seems he is always co= rrect) :) But it would be great to get your perspective on this too Howard. copy_backward predates my participation in the standardization process, and= I would prefer not to speculate. I do note that the code gen using the latest clang at -O3 is much worse for= copy+reverse_iterator than for copy_backward using int* as the base iterat= or. Howard --=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/DBD8279E-AB79-41D0-89D9-0695AF7A5D7D%40gmail.com= .. --Apple-Mail=_970DBBD2-DC67-43C8-81F6-5053ADAE2002 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJZe7MuAAoJEGbcHCxKqhWCAk0QAKmOlUsBHRftMlu0u37pUCTT gJWtkCLZzvwt7pdcxUf/ygmHxAbzzDocOw1ZlBb1Z+5om7ai49PLLb5sJ/QB8dSP AM4BBwqaqUEiBr3RD6p9OsNT4AEbRmwqchgoA5m9kWlmT0xyFfLMk1PgmdWxzOyu Sl/i1irDX+Ffc6Yk80VUpNssPu//jACIyCdNfxAoZ4dC79xpmbjsdQrwceTbt+uD IhQeefOAq478mHUFPMPsXWXgIdVqEo6qQTF9GMobG/a+2uOYm2NBBJnXS7ZwcaPD txvp7cVg+BSM+fW0CetQBjMKJwzZ3OBwpPg/2r9fkpeMhrzZJuO257WLFCDpD3OY hngXGpF/PJGk5Ubvl8wTqHsZZAJppTcpqdW2JiTRkFAY5D9cmOf0z/a59Xs7/pEj 1ETizyxgvHlAVdPj++V1LTFtzqFK4+Ts35+msjSn61CK26dfr2UwRK9OYMXujitB FX1eiQxwsKj+ylNic1S+CxOdZdlyJ6rRlC1JeO0LCWaFVZIi7zjGVNMN+oHbH815 9lHmI7hE3WpsUdiDqiSey88udWPa+YDa7a1Dtr+5FpLHjQ0Xl7kDGEtwGoM67s3B BZSVnIUSGrodc7Yqc1Kgnth2ftbl7O5HXFDVS2OljeioQIHMVBDSfbYbQ7x3qnv7 5+fCzs8BUUJ1DPxs/dRt =kJrx -----END PGP SIGNATURE----- --Apple-Mail=_970DBBD2-DC67-43C8-81F6-5053ADAE2002-- .