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Groups > comp.lang.c++ > #70106
| From | "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: A question about if constexpr |
| Date | 2019-11-29 07:41 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <qrqeip$dbp$1@dont-email.me> (permalink) |
| References | <9d930f21-6639-49a3-8ef2-5de724f18255@googlegroups.com> <cone.1574898034.956666.129095.1004@monster.email-scan.com> <qro3p4$gd7$1@dont-email.me> <2f0c5b1c-897c-4de9-bd28-1e06b6128045@googlegroups.com> |
On 29.11.2019 06:09, Daniel wrote: > On Thursday, November 28, 2019 at 4:25:03 AM UTC-5, David Brown wrote: >> >> If the compiler is not >> generating identical code for an "if constexpr" and an "if" where the >> expression happens to be known at compile time (whether it is >> technically a C++ constant or not), then the compiler is doing a poor >> job at optimising. >> > Which raises the question, what is the point of the constexpr if statement anyway? Two main points: * It communicates to a human reader that the expression is evaluated at compile time, guaranteed. * In a function template the path not taken in a given instantiation, can contain code that wouldn't compile in that instantiation. Maybe more, but it's late in the day for me. - Alf
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A question about if constexpr Daniel <danielaparker@gmail.com> - 2019-11-27 05:45 -0800
Re: A question about if constexpr "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-27 15:03 +0100
Re: A question about if constexpr Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-11-29 16:33 +0000
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-29 16:52 -0800
Re: A question about if constexpr David Brown <david.brown@hesbynett.no> - 2019-11-30 12:03 +0100
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-30 03:47 -0800
Re: A question about if constexpr David Brown <david.brown@hesbynett.no> - 2019-11-30 15:08 +0100
Re: A question about if constexpr Sam <sam@email-scan.com> - 2019-11-27 18:40 -0500
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-27 23:16 -0800
Re: A question about if constexpr Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-11-29 16:35 +0000
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-29 16:41 -0800
Re: A question about if constexpr David Brown <david.brown@hesbynett.no> - 2019-11-28 10:24 +0100
Re: A question about if constexpr Bo Persson <bo@bo-persson.se> - 2019-11-28 11:58 +0100
Re: A question about if constexpr David Brown <david.brown@hesbynett.no> - 2019-11-28 12:37 +0100
Re: A question about if constexpr Robert Wessel <robertwessel2@yahoo.com> - 2019-11-28 14:04 -0600
Re: A question about if constexpr David Brown <david.brown@hesbynett.no> - 2019-11-29 09:23 +0100
Re: A question about if constexpr Robert Wessel <robertwessel2@yahoo.com> - 2019-11-29 14:42 -0600
Re: A question about if constexpr Daniel <danielaparker@gmail.com> - 2019-11-28 21:09 -0800
Re: A question about if constexpr "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-29 07:41 +0100
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-28 23:50 -0800
Re: A question about if constexpr David Brown <david.brown@hesbynett.no> - 2019-11-29 09:38 +0100
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-29 17:15 -0800
Re: A question about if constexpr Paavo Helde <myfirstname@osa.pri.ee> - 2019-11-30 08:19 +0200
Re: A question about if constexpr Ned Latham <nedlatham@woden.valhalla.oz> - 2019-11-30 00:24 -0600
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-30 02:13 -0800
Re: A question about if constexpr Ned Latham <nedlatham@woden.valhalla.oz> - 2019-11-30 04:56 -0600
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-30 03:20 -0800
Re: A question about if constexpr Ned Latham <nedlatham@woden.valhalla.oz> - 2019-11-30 05:38 -0600
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-30 04:57 -0800
Re: A question about if constexpr Ned Latham <nedlatham@woden.valhalla.oz> - 2019-11-30 09:46 -0600
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-30 11:09 -0800
Re: A question about if constexpr Ned Latham <nedlatham@woden.valhalla.oz> - 2019-11-30 20:03 -0600
Re: A question about if constexpr Öö Tiib <ootiib@hot.ee> - 2019-11-30 23:43 -0800
Re: A question about if constexpr Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-01 04:56 -0600
Re: A question about if constexpr Christian Gollwitzer <auriocus@gmx.de> - 2019-12-01 18:33 +0100
Re: A question about if constexpr Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-01 19:27 -0600
Re: A question about if constexpr boltar@nowhere.co.uk - 2019-12-02 08:34 +0000
Re: A question about if constexpr Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-02 04:21 -0600
Re: A question about if constexpr boltar@nowhere.co.uk - 2019-12-02 08:33 +0000
Re: A question about if constexpr Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-12-03 17:05 +0000
Re: A question about if constexpr boltar@nowhere.co.uk - 2019-12-03 17:09 +0000
Re: A question about if constexpr Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-12-03 18:03 +0000
Re: A question about if constexpr boltar@nowhere.co.uk - 2019-12-04 16:49 +0000
Re: A question about if constexpr Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-12-04 18:36 +0000
Re: A question about if constexpr boltar@nowhere.co.uk - 2019-12-05 12:51 +0000
Re: A question about if constexpr David Brown <david.brown@hesbynett.no> - 2019-11-29 09:30 +0100
Re: A question about if constexpr Paavo Helde <myfirstname@osa.pri.ee> - 2019-11-29 10:51 +0200
Re: A question about if constexpr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-28 13:52 -0800
Re: A question about if constexpr Bonita Montero <Bonita.Montero@gmail.com> - 2019-12-01 14:42 +0100
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