From: mark@codesourcery.com
To: torvalds@transmeta.com
Cc: craig@jcb-sc.com, davem@redhat.com, chip@perlsupport.com,
egcs@egcs.cygnus.com
Subject: Re: Linux and aliasing?
Date: Wed, 30 Jun 1999 15:43:00 -0000 [thread overview]
Message-ID: <19990604071529Y.mitchell@codesourcery.com> (raw)
Message-ID: <19990630154300.WgrQsvBhp4O_hUJ8uQ7jd0dmMITvcFiSFfKSFNS37jI@z> (raw)
In-Reply-To: <Pine.LNX.3.95.990603235147.3026A-100000@penguin.transmeta.com>
>>>>> "Linus" == Linus Torvalds <torvalds@transmeta.com> writes:
Linus> On Thu, 3 Jun 1999 mark@codesourcery.com wrote:
>> I don't think the cast rule is by any means the right obvious
>> default. For one thing, it pessimizes object-oriented C code
>> that does downcasts through an inheritance hierarchy. There's
>> no reason that we shouldn't be able to use type-based alias
>> analysis in such situations, but your proposal would make it
>> not happen.
Linus> But those downcasts are implicit, not explicit, no? I think
Linus> only explicit casts should break the alias rule.
No, they are often explicit. In C, you don't have base classes, per
se, so you right them explicitly.
Linus> Have you actually ever tried? I don't think you realize
Linus> quite what a rat-hole it is. It's not worth ANYBODYS time.
Yes, I have done similar things.
Linus> I think it's a damn shame that instead of technical
Linus> arguments _everything_ revolves around people reading the
Linus> standard as if it was the bible, and trying to make people
Linus> feel guilty for not really caring. It's not a sin to just
Linus> want to get good code without having to do magic
Linus> contortions, guys.
I implemented the code, and I wouldn't say that I ignored real
programmers. In fact, my work was paid for by real programmers, who
noticed that GCC would generate markedly better code on some examples
they had if type-based aliasing were in use.
I've expressed the position that if we come up with a reasonable
localized rule, that does not pessimize conforming code, that I would
have no objection. In fact, I would be perfectly willing to work on
such a project.
With respect to your comments about prereleases, they're simply not
fair. I see no reason that I, or anyone else, should volunteer our
time to add features. Had I introduced a bug, I would feel duty-bound
to fix it.
I do listen to feedback, and I've heard your point of view. I respect
your opinion. That doesn't mean I'm going to sit down and to what you
would like on my own time.
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com
next prev parent reply other threads:[~1999-06-30 15:43 UTC|newest]
Thread overview: 218+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-06-03 10:23 Chip Salzenberg
1999-06-03 10:37 ` mark
1999-06-03 11:26 ` David S. Miller
1999-06-03 12:03 ` mark
1999-06-03 12:25 ` David S. Miller
1999-06-03 20:06 ` craig
1999-06-03 23:03 ` Linus Torvalds
1999-06-03 23:45 ` mark
1999-06-04 0:04 ` Linus Torvalds
1999-06-04 1:08 ` Branko Cibej
1999-06-30 15:43 ` Branko Cibej
1999-06-04 1:24 ` Joe Buck
1999-06-04 1:50 ` Linus Torvalds
1999-06-04 5:46 ` craig
1999-06-04 7:22 ` burley (was Re: Linux and aliasing?) Mark Hahn
1999-06-04 8:16 ` craig
1999-06-30 15:43 ` craig
1999-06-30 15:43 ` Mark Hahn
1999-06-04 8:35 ` Linux and aliasing? Linus Torvalds
1999-06-04 10:04 ` Joe Buck
1999-06-04 10:22 ` Jeffrey A Law
1999-06-04 10:31 ` Joe Buck
1999-06-04 10:53 ` Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
1999-06-30 15:43 ` Joe Buck
1999-07-11 10:55 ` Jeffrey A Law
1999-07-31 23:33 ` Jeffrey A Law
1999-06-04 11:11 ` Toon Moene
1999-06-04 12:20 ` Jeffrey A Law
1999-06-05 5:45 ` Toon Moene
1999-06-05 6:23 ` Andi Kleen
1999-06-05 10:32 ` Toon Moene
1999-06-05 13:26 ` Jamie Lokier
1999-06-05 19:35 ` Linus Torvalds
1999-06-06 1:18 ` Martin v. Loewis
1999-06-06 10:46 ` Linus Torvalds
1999-06-30 15:43 ` Linus Torvalds
1999-06-06 17:56 ` Jason Merrill
1999-06-06 19:24 ` Tim Hollebeek
1999-06-30 15:43 ` Tim Hollebeek
1999-06-06 22:23 ` Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
[not found] ` <199906070645.IAA00615@mira.isdn.cs.tu-berlin.de>
1999-06-07 2:14 ` Jason Merrill
1999-06-07 8:02 ` mark
1999-06-07 8:41 ` David S. Miller
1999-06-07 9:24 ` Jeffrey A Law
1999-06-07 9:29 ` David S. Miller
1999-06-30 15:43 ` David S. Miller
1999-06-30 15:43 ` Jeffrey A Law
1999-06-07 9:32 ` Joe Buck
1999-06-30 15:43 ` Joe Buck
1999-06-30 15:43 ` David S. Miller
1999-06-30 15:43 ` mark
1999-06-07 13:11 ` Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
1999-06-30 15:43 ` Jason Merrill
1999-06-30 15:43 ` Jason Merrill
1999-06-30 15:43 ` Martin v. Loewis
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` Jamie Lokier
1999-06-05 18:48 ` Linus Torvalds
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` Toon Moene
1999-06-05 10:37 ` mark
1999-06-05 11:09 ` David S. Miller
1999-06-05 12:11 ` Toon Moene
1999-06-05 12:21 ` David S. Miller
1999-06-05 16:51 ` mark
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` David S. Miller
1999-06-30 15:43 ` Toon Moene
1999-06-07 6:01 ` Joern Rennecke
1999-06-30 15:43 ` Joern Rennecke
1999-06-30 15:43 ` David S. Miller
1999-06-05 11:35 ` Andi Kleen
1999-06-30 15:43 ` Andi Kleen
1999-06-05 12:41 ` Jamie Lokier
1999-06-05 14:43 ` Martin v. Loewis
1999-06-30 15:43 ` Martin v. Loewis
1999-06-05 16:53 ` mark
1999-06-07 2:36 ` Jamie Lokier
1999-06-07 8:04 ` mark
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` Jamie Lokier
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` Jamie Lokier
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` Andi Kleen
1999-06-06 23:12 ` f77 vs type based alias analysis Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
1999-06-06 23:20 ` Linux and aliasing? Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
1999-06-30 15:43 ` Toon Moene
1999-06-30 15:43 ` Jeffrey A Law
1999-06-05 4:05 ` Andi Kleen
1999-06-30 15:43 ` Andi Kleen
1999-06-30 15:43 ` Toon Moene
1999-06-30 15:43 ` Jeffrey A Law
1999-06-04 11:49 ` Linus Torvalds
1999-06-04 13:03 ` Gabriel Dos_Reis
1999-06-04 13:13 ` Joe Buck
1999-06-30 15:43 ` Joe Buck
1999-06-30 15:43 ` Gabriel Dos_Reis
1999-06-30 15:43 ` Linus Torvalds
1999-06-04 12:59 ` Alexandre Oliva
1999-06-04 13:29 ` Joe Buck
1999-06-04 13:39 ` Alexandre Oliva
1999-06-30 15:43 ` Alexandre Oliva
1999-06-30 15:43 ` Joe Buck
1999-06-30 15:43 ` Alexandre Oliva
1999-06-30 15:43 ` Joe Buck
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` craig
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` Joe Buck
1999-06-04 5:47 ` craig
1999-06-30 15:43 ` craig
1999-06-04 7:11 ` mark [this message]
1999-06-04 8:38 ` Linus Torvalds
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` mark
1999-06-04 8:41 ` Tim Hollebeek
1999-06-04 8:53 ` Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
1999-06-30 15:43 ` Tim Hollebeek
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` mark
1999-06-04 5:47 ` craig
1999-06-04 8:17 ` Linus Torvalds
1999-06-04 8:49 ` craig
1999-06-04 8:57 ` Linus Torvalds
1999-06-04 9:02 ` Jean-Pierre Radley
1999-06-30 15:43 ` Jean-Pierre Radley
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` craig
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` craig
1999-06-04 8:39 ` Tim Hollebeek
1999-06-04 8:55 ` Linus Torvalds
1999-06-04 15:20 ` Richard Henderson
1999-06-05 9:50 ` Linus Torvalds
1999-06-05 11:00 ` mark
1999-06-06 10:30 ` Linus Torvalds
1999-06-06 10:44 ` mark
1999-06-06 14:17 ` Linus Torvalds
1999-06-06 17:41 ` mark
1999-06-07 8:58 ` Linus Torvalds
1999-06-07 9:18 ` mark
1999-06-07 9:29 ` Linus Torvalds
1999-06-07 9:38 ` Tim Hollebeek
1999-06-07 10:05 ` Jamie Lokier
1999-06-30 15:43 ` Jamie Lokier
1999-06-07 10:44 ` Linus Torvalds
1999-06-07 11:22 ` Jeffrey A Law
1999-06-08 1:34 ` Nick Ing-Simmons
1999-06-08 1:48 ` Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
1999-06-30 15:43 ` Nick Ing-Simmons
1999-06-30 15:43 ` Jeffrey A Law
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` Tim Hollebeek
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` mark
1999-06-07 13:34 ` Jamie Lokier
1999-06-30 15:43 ` Jamie Lokier
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` Richard Henderson
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` Tim Hollebeek
1999-06-04 15:02 ` Richard Henderson
1999-06-04 16:50 ` Bernd Schmidt
1999-06-30 15:43 ` Bernd Schmidt
1999-06-05 9:35 ` Linus Torvalds
1999-06-05 13:34 ` Richard Henderson
1999-06-05 18:40 ` Linus Torvalds
1999-06-30 15:43 ` Linus Torvalds
1999-06-05 21:38 ` Jakub Jelinek
1999-06-30 15:43 ` Jakub Jelinek
1999-06-30 15:43 ` Richard Henderson
1999-06-30 15:43 ` Linus Torvalds
1999-06-30 15:43 ` Richard Henderson
1999-06-30 15:43 ` Linus Torvalds
1999-06-03 23:53 ` Martin v. Loewis
1999-06-30 15:43 ` Martin v. Loewis
[not found] ` <v04205101b37d700fbf8d@[192.168.1.254]>
1999-06-04 7:01 ` craig
1999-06-30 15:43 ` craig
1999-06-30 15:43 ` craig
1999-06-30 15:43 ` David S. Miller
1999-06-03 13:31 ` Andi Kleen
1999-06-30 15:43 ` Andi Kleen
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` David S. Miller
1999-06-03 12:02 ` Andi Kleen
1999-06-03 15:38 ` Martin v. Loewis
1999-06-30 15:43 ` Martin v. Loewis
1999-06-30 15:43 ` Andi Kleen
1999-06-30 15:43 ` mark
1999-06-30 15:43 ` Chip Salzenberg
1999-06-04 11:54 Mike Stump
1999-06-04 12:13 ` Jeffrey A Law
1999-06-04 13:25 ` Sylvain Pion
1999-06-04 13:32 ` Jeffrey A Law
1999-06-30 15:43 ` Jeffrey A Law
1999-06-30 15:43 ` Sylvain Pion
1999-06-30 15:43 ` Jeffrey A Law
1999-06-30 15:43 ` Mike Stump
1999-06-06 15:08 Ross Harvey
1999-06-06 15:46 ` Linus Torvalds
1999-06-30 15:43 ` Linus Torvalds
1999-06-06 17:29 ` David S. Miller
1999-06-30 15:43 ` David S. Miller
1999-06-30 15:43 ` Ross Harvey
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