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| From | Melzzzzz <mel@zzzzz.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: faster than c |
| Date | 2015-03-26 01:06 +0100 |
| Organization | albasani.net |
| Message-ID | <20150326010636.720cbe5d@maxa-pc> (permalink) |
| References | (8 earlier) <kfnd23wc1r7.fsf@x-alumni2.alumni.caltech.edu> <e80eed4c-56f5-4f57-a533-629a1aaa3a93@googlegroups.com> <mev5bo$8u6$1@dont-email.me> <kfn1tkcac3z.fsf@x-alumni2.alumni.caltech.edu> <mevhs5$357$1@dont-email.me> |
On Thu, 26 Mar 2015 00:55:36 +0100 David Brown <david.brown@hesbynett.no> wrote: > On 26/03/15 00:30, Tim Rentsch wrote: > > David Brown <david.brown@hesbynett.no> writes: > > > >> On 25/03/15 20:45, Malcolm McLean wrote: > >>> On Wednesday, March 25, 2015 at 7:31:59 PM UTC, Tim Rentsch wrote: > >>> > >>>> (BTW I think the "well-written" qualifier is just weaseling, > >>>> since you could arbitrarily limit "well-written" code to be only > >>>> that code that is also legal C++. To give the statement any > >>>> meaning there must be an independent definition of what > >>>> "well-written" means, or better yet choose another qualifier that > >>>> can be measured objectively.) > >>> > >>> Stuff like implict int, functions without prototypes, functions > >>> called with arguments of a different type to that declared in > >>> the argument list, ignoring of const qualifiers, assignment of > >>> pointer variables to ints and back, all examples of things C > >>> supports for backwards compatibility. > >> > >> That's the sort of thing I was thinking of - C++ is a lot stricter > >> about that kind of detail (although of course newer C standards are > >> also stricter than the old ones). > >> > >> But I am happy to accept that "almost all" was an overstatement, > >> and consider "most" as a better choice of vague > >> pseudo-quantification. And I didn't specify whether I was talking > >> about "almost all programs written in C", "almost all C program > >> lines", or any other definition of what I was vaguely quantifying. > >> > >> The whole point of the claim was to show that C is very rarely > >> going to let you write code that is faster than the equivalent C++ > >> code - because the C code is already valid C++ code, or it can > >> easily be massaged into being valid C++ code. Missing features > >> (like designated initialisers, VLAs, etc.) may mean the C++ source > >> code is a little bulkier, but it is unlikely to change the speed > >> of the generated object code significantly. And most since most > >> modern compilers handle C and C++, and generate approximately the > >> same results when the source code is valid as C and as C++, the > >> conclusion has to be that for most practical purposes, C code is > >> not going to be faster than C++ code. > > > > Does C++ have 'restrict'? If C++ does not have 'restrict', then > > there are lots of cases where a C compiler can generate better > > code than C++ could. In fact I ran into such a case just the > > other day (depressing but true). > > > > Good point - C++ does not have "restrict", and that could make a > difference. In many cases, I think you could make messy code changes > to make code that disallows aliasing by changing types as a > workaround for missing "restrict". > > Many (most?) C++ compilers have a "__restrict__" extension that does > the same job as C99 "restrict", but that is not standard C++. > gcc has also local functions extension for C but not for C++.
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faster than c fir <profesor.fir@gmail.com> - 2015-01-10 13:11 -0800
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-10 14:26 -0800
Re: faster than c Chad <cdalten@gmail.com> - 2015-01-10 14:43 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-10 15:20 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-10 15:39 -0800
Re: faster than c glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-11 09:23 +0000
Re: faster than c asetofsymbols@gmail.com - 2015-01-11 02:17 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-11 06:00 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-12 06:46 -0800
Re: faster than c Morris Dovey <mrdovey@iedu.com> - 2015-01-12 15:01 -0600
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-12 13:44 -0800
Re: faster than c Morris Dovey <mrdovey@iedu.com> - 2015-01-12 16:59 -0600
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-12 15:25 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-13 04:56 -0800
Re: faster than c glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-12 23:26 +0000
Re: faster than c jt@toerring.de (Jens Thoms Toerring) - 2015-01-13 01:10 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-13 05:16 -0800
faster than c Chad <cdalten@gmail.com> - 2015-01-10 14:42 -0800
Re: faster than c Cooler_x0a <c00f3r@gmail.com> - 2015-01-10 15:51 -0800
Re: faster than c Geoff <geoff@invalid.invalid> - 2015-01-11 00:21 -0800
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-11 02:27 -0800
Re: faster than c gamo <gamo@telecable.es> - 2015-01-11 12:17 +0100
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-11 21:02 +0100
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-21 03:44 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-21 05:08 -0800
Re: faster than c Richard Heathfield <invalid@see.sig.invalid> - 2015-01-21 13:53 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-21 06:03 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-22 15:06 +0100
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-22 06:57 -0800
Re: faster than c mark.bluemel@gmail.com - 2015-01-22 07:27 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-22 07:36 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-22 07:45 -0800
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-24 22:36 -0700
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-11 21:16 +0100
Re: faster than c Tim Prince <tprince@computer.org> - 2015-01-11 15:42 -0500
Re: faster than c Michael Angelo Ravera <maravera@prodigy.net> - 2015-01-14 12:25 -0800
Re: faster than c Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-17 13:29 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 05:32 -0800
Re: faster than c Melzzzzz <mel@zzzzz.com> - 2015-01-17 14:42 +0100
Re: faster than c Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-17 19:29 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 11:55 -0800
Re: faster than c "Osmium" <r124c4u102@comcast.net> - 2015-01-17 08:00 -0600
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-17 10:15 -0800
Re: faster than c wssimms@gmail.com - 2015-01-17 10:31 -0800
Re: faster than c glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-17 19:10 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 11:21 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 11:13 -0800
Re: faster than c Öö Tiib <ootiib@hot.ee> - 2015-01-17 12:32 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-19 11:01 +0100
Re: faster than c Keith Thompson <kst-u@mib.org> - 2015-01-19 08:24 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-19 22:52 +0100
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-01-20 00:04 -0600
Re: faster than c Öö Tiib <ootiib@hot.ee> - 2015-01-19 10:12 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-19 23:05 +0100
Re: faster than c Öö Tiib <ootiib@hot.ee> - 2015-01-19 16:23 -0800
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-24 09:32 -0700
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-03-24 19:08 +0100
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-25 12:31 -0700
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-03-25 12:45 -0700
Re: faster than c Keith Thompson <kst-u@mib.org> - 2015-03-25 12:58 -0700
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-03-25 21:22 +0100
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-25 16:30 -0700
Re: faster than c Melzzzzz <mel@zzzzz.com> - 2015-03-26 00:50 +0100
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-28 09:20 -0700
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-03-26 00:55 +0100
Re: faster than c Melzzzzz <mel@zzzzz.com> - 2015-03-26 01:06 +0100
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-03-26 11:34 +0100
Re: faster than c Keith Thompson <kst-u@mib.org> - 2015-03-25 20:29 -0700
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-25 16:34 -0700
Re: faster than c Ian Collins <ian-news@hotmail.com> - 2015-03-26 13:53 +1300
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-28 15:08 -0700
Re: faster than c Ian Collins <ian-news@hotmail.com> - 2015-03-29 11:28 +1300
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-30 12:42 -0700
Re: faster than c Kaz Kylheku <kaz@kylheku.com> - 2015-03-30 20:06 +0000
Re: faster than c Ian Collins <ian-news@hotmail.com> - 2015-03-31 16:37 +1300
Re: faster than c Kaz Kylheku <kaz@kylheku.com> - 2015-03-31 05:13 +0000
Re: faster than c Ian Collins <ian-news@hotmail.com> - 2015-03-31 16:33 +1300
Re: faster than c Philip Lantz <prl@canterey.us> - 2015-03-31 00:14 -0700
Re: faster than c wssimms@gmail.com - 2015-01-17 10:33 -0800
Re: faster than c Greg Martin <greg.at.softsprocket@dot.com> - 2015-01-17 20:03 +0000
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-19 11:07 +0100
Re: faster than c wpihughes@gmail.com - 2015-01-26 13:30 -0800
Re: faster than c Ian Collins <ian-news@hotmail.com> - 2015-01-18 16:36 +1300
Re: faster than c glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-17 19:02 +0000
Re: faster than c BartC <bc@freeuk.com> - 2015-01-17 19:14 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 11:41 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 12:06 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-17 20:36 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 13:01 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-17 21:18 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 13:36 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-19 11:17 +0100
Re: faster than c Richard Heathfield <invalid@see.sig.invalid> - 2015-01-19 10:40 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 03:29 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 03:41 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-19 12:45 +0100
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 04:00 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 04:31 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 04:48 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-19 15:23 +0100
Re: faster than c mark.bluemel@gmail.com - 2015-01-19 07:25 -0800
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-19 08:56 -0800
Re: faster than c Richard Heathfield <invalid@see.sig.invalid> - 2015-01-19 17:01 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 09:08 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 09:19 -0800
Re: faster than c Bartc <bc@freeuk.com> - 2015-01-19 17:46 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 10:19 -0800
Re: faster than c Geoff <geoff@invalid.invalid> - 2015-01-19 10:56 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 11:30 -0800
Re: faster than c Keith Thompson <kst-u@mib.org> - 2015-01-19 14:22 -0800
Re: faster than c mark.bluemel@gmail.com - 2015-01-20 00:45 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-20 01:20 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 08:25 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-20 00:57 -0800
Re: faster than c fmassei@gmail.com - 2015-01-19 03:58 -0800
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-01-20 00:05 -0600
Re: faster than c fmassei@gmail.com - 2015-01-20 02:11 -0800
Re: faster than c asetofsymbols@gmail.com - 2015-01-20 02:18 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-20 02:30 -0800
Re: faster than c asetofsymbols@gmail.com - 2015-01-20 05:16 -0800
Re: faster than c Melzzzzz <mel@zzzzz.com> - 2015-01-20 14:18 +0100
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-01-20 15:29 -0600
Re: faster than c Richard Heathfield <invalid@see.sig.invalid> - 2015-01-20 21:53 +0000
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-01-20 17:37 -0600
Re: faster than c Richard Heathfield <invalid@see.sig.invalid> - 2015-01-21 00:05 +0000
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-01-21 01:38 -0600
Re: faster than c Richard Heathfield <invalid@see.sig.invalid> - 2015-01-21 07:46 +0000
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-21 03:23 -0800
Re: faster than c Richard Heathfield <invalid@see.sig.invalid> - 2015-01-21 13:52 +0000
Re: faster than c Morris Dovey <mrdovey@iedu.com> - 2015-01-21 08:53 -0600
Re: faster than c Melzzzzz <mel@zzzzz.com> - 2015-01-21 01:18 +0100
Re: faster than c fmassei@gmail.com - 2015-01-20 16:41 -0800
Re: faster than c Melzzzzz <mel@zzzzz.com> - 2015-01-21 01:58 +0100
Re: faster than c fmassei@gmail.com - 2015-01-20 17:11 -0800
Re: faster than c Melzzzzz <mel@zzzzz.com> - 2015-01-21 02:18 +0100
Re: faster than c fmassei@gmail.com - 2015-01-20 17:38 -0800
Re: faster than c Keith Thompson <kst-u@mib.org> - 2015-01-21 08:48 -0800
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-01-20 15:24 -0600
Re: faster than c fmassei@gmail.com - 2015-01-20 13:38 -0800
Re: faster than c Greg Martin <greg.at.softsprocket@dot.com> - 2015-01-21 16:43 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-21 10:09 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-24 01:15 -0800
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-01-21 23:59 -0600
Re: faster than c fmassei@gmail.com - 2015-01-22 01:17 -0800
Re: faster than c wssimms@gmail.com - 2015-01-22 05:16 -0800
Re: faster than c fmassei@gmail.com - 2015-01-22 05:27 -0800
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-22 05:36 -0800
Re: faster than c fmassei@gmail.com - 2015-01-22 05:54 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-22 05:55 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-22 15:18 +0100
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-01-23 00:53 -0600
Re: faster than c fmassei@gmail.com - 2015-01-23 00:36 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-23 01:09 -0800
Re: faster than c fmassei@gmail.com - 2015-01-23 01:33 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-23 01:55 -0800
Re: faster than c Ian Collins <ian-news@hotmail.com> - 2015-01-23 22:44 +1300
Re: faster than c fmassei@gmail.com - 2015-01-23 01:56 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-22 15:11 +0100
Re: faster than c fmassei@gmail.com - 2015-01-22 06:21 -0800
Re: faster than c David Brown <david.brown@hesbynett.no> - 2015-01-22 16:46 +0100
Re: faster than c fmassei@gmail.com - 2015-01-22 07:58 -0800
Re: faster than c Lowell Gilbert <lgusenet@be-well.ilk.org> - 2015-01-22 12:29 -0500
Re: faster than c fmassei@gmail.com - 2015-01-22 10:09 -0800
Re: faster than c "Chris M. Thomasson" <no@spam.invalid> - 2015-01-22 14:07 -0800
Re: faster than c asetofsymbols@gmail.com - 2015-01-24 00:40 -0800
Re: faster than c "Chris M. Thomasson" <no@spam.invalid> - 2015-01-24 12:53 -0800
Re: faster than c Greg Martin <greg.at.softsprocket@dot.com> - 2015-01-22 15:09 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-22 01:59 -0800
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-24 09:46 -0700
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-03-25 02:15 -0500
Re: faster than c asetofsymbols@gmail.com - 2015-03-25 02:45 -0700
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-25 11:30 -0700
Re: faster than c Robert Wessel <robertwessel2@yahoo.com> - 2015-03-26 00:42 -0500
Re: faster than c Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-28 11:35 -0700
Re: faster than c Keith Thompson <kst-u@mib.org> - 2015-01-17 14:42 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-17 22:53 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 15:13 -0800
Re: faster than c glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-17 22:02 +0000
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-17 16:21 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-18 01:27 +0000
Re: faster than c glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-18 01:41 +0000
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-18 00:11 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-18 11:23 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-18 05:55 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-18 20:11 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-18 13:12 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-18 23:11 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-18 15:49 -0800
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-18 16:06 -0800
Re: faster than c Bartc <bc@freeuk.com> - 2015-01-19 01:03 +0000
Re: faster than c Richard Heathfield <invalid@see.sig.invalid> - 2015-01-19 08:13 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-19 01:39 -0800
Re: faster than c Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-18 13:52 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-18 23:36 +0000
Re: faster than c Walter Banks <walter@bytecraft.com> - 2015-01-20 14:01 -0500
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-20 11:18 -0800
Re: faster than c Melzzzzz <mel@zzzzz.com> - 2015-01-17 22:30 +0100
Re: faster than c Ian Collins <ian-news@hotmail.com> - 2015-01-18 16:49 +1300
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 05:55 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-17 14:30 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 07:32 -0800
Re: faster than c BartC <bc@freeuk.com> - 2015-01-17 15:56 +0000
Re: faster than c fir <profesor.fir@gmail.com> - 2015-01-17 08:33 -0800
Re: faster than c fmassei@gmail.com - 2015-01-19 02:26 -0800
faster than c asetofsymbols@gmail.com - 2015-01-20 00:12 -0800
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