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From: Joe Buck <jbuck@synopsys.COM>
To: mrs@wrs.com (Mike Stump)
Cc: gcc@gcc.gnu.org, jbuck@synopsys.com, rms@gnu.org
Subject: Re: type based aliasing again
Date: Thu, 30 Sep 1999 18:02:00 -0000	[thread overview]
Message-ID: <199909090229.TAA22893@atrus.synopsys.com> (raw)
Message-ID: <19990930180200.bxJjHr5vGAsWELAKdo2e4_VToQQsuis3GYytwgOk6Fw@z> (raw)
In-Reply-To: <199909090211.TAA03202@kankakee.wrs.com>

> My comment is similar to Mark's comment.  Documentation, what can we
> document as working?  Can users rely upon it working?

You misunderstood.  I am not proposing a language extension.  I am
proposing trying to detect that the user is breaking the rules.  If
we catch him, we issue a warning and declare that there is aliasing.
If we don't catch him, the user may lose.  If the user wants to
be assured of winning, she must follow ANSI rules.

(The original idea started in a discussion with RMS, so I shouldn't say
"I" here, but then I am currently writing this, not him).

> Is it less confusing to a user to have the compiler predictably
> generate wrong code, or for it to almost always generate right code,
> even for bad code, except in really obscure and hard to understand
> cases?

In this case, most users don't even know the rule, so they can't predict
that the compiler will generate wrong code.

> Anway, more questions from me than answers...  Off hand though, if we
> can make the compiler generate `right' code in more cases, even if the
> users code is wrong, I think we should probably do it.

Good, we agree.


  reply	other threads:[~1999-09-30 18:02 UTC|newest]

Thread overview: 408+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-09-08 19:13 Mike Stump
1999-09-08 19:31 ` Joe Buck [this message]
1999-09-30 18:02   ` Joe Buck
1999-09-09  7:12 ` Marc Espie
1999-09-09 20:35   ` Jeffrey A Law
1999-09-10 12:29     ` Sudish Joseph
1999-09-30 18:02       ` Sudish Joseph
1999-09-30 18:02     ` Jeffrey A Law
1999-09-30 18:02   ` Marc Espie
1999-09-09 23:25 ` Richard Stallman
1999-09-08 18:11   ` Joe Buck
1999-09-08 18:43     ` Mark Mitchell
1999-09-08 19:25       ` Joe Buck
1999-09-08 19:51         ` David Edelsohn
1999-09-30 18:02           ` David Edelsohn
1999-09-30 18:02         ` Joe Buck
1999-09-08 19:44       ` Joe Buck
1999-09-08 20:26         ` Mark Mitchell
1999-09-08 20:43           ` Joe Buck
1999-09-08 21:45             ` Mark Mitchell
1999-09-08 22:04               ` Joe Buck
1999-09-08 22:25                 ` Mark Mitchell
1999-09-30 18:02                   ` Mark Mitchell
1999-09-09  2:08                 ` Jeffrey A Law
1999-09-09 10:51                   ` Joe Buck
1999-09-09 16:51                     ` John Vickers
1999-09-09 17:04                       ` Joe Buck
1999-09-09 17:12                         ` John Vickers
1999-09-30 18:02                           ` John Vickers
1999-09-30 18:02                         ` Joe Buck
1999-09-30 18:02                       ` John Vickers
1999-09-15  2:07                     ` Jeffrey A Law
1999-09-30 18:02                       ` Jeffrey A Law
1999-09-30 18:02                     ` Joe Buck
1999-09-09 23:26                   ` Richard Stallman
1999-09-09 23:38                     ` Jeffrey A Law
1999-09-30 18:02                       ` Jeffrey A Law
1999-09-30 18:02                     ` Richard Stallman
1999-09-09 23:26                   ` Richard Stallman
1999-09-30 18:02                     ` Richard Stallman
1999-09-30 18:02                   ` Jeffrey A Law
1999-09-09 23:25                 ` Richard Stallman
1999-09-10  0:06                   ` Mark Mitchell
1999-09-10  0:13                     ` Joe Buck
1999-09-30 18:02                       ` Joe Buck
1999-09-11  0:17                     ` Richard Stallman
1999-09-30 18:02                       ` Richard Stallman
1999-09-30 18:02                     ` Mark Mitchell
1999-09-30 18:02                   ` Richard Stallman
1999-09-30 18:02                 ` Joe Buck
1999-09-08 23:20               ` Richard Henderson
1999-09-08 23:41                 ` Mark Mitchell
1999-09-08 23:44                   ` Richard Henderson
1999-09-08 23:51                     ` Mark Mitchell
1999-09-30 18:02                       ` Mark Mitchell
1999-09-09  2:45                     ` Jeffrey A Law
1999-09-30 18:02                       ` Jeffrey A Law
1999-09-30 18:02                     ` Richard Henderson
1999-09-30 18:02                   ` Mark Mitchell
1999-09-30 18:02                 ` Richard Henderson
1999-09-30 18:02               ` Mark Mitchell
1999-09-30 18:02             ` Joe Buck
1999-09-08 21:33           ` Joe Buck
1999-09-08 21:56             ` Mark Mitchell
1999-09-30 18:02               ` Mark Mitchell
1999-09-09  1:38             ` Martin v. Loewis
1999-09-30 18:02               ` Martin v. Loewis
1999-09-09 23:25             ` Richard Stallman
1999-09-30 18:02               ` Richard Stallman
1999-09-30 18:02             ` Joe Buck
1999-09-09  2:20           ` Jeffrey A Law
1999-09-09  7:58             ` craig
1999-09-09 10:36               ` Joe Buck
1999-09-09 10:55                 ` Mark Mitchell
1999-09-11  0:15                   ` Richard Stallman
1999-09-30 18:02                     ` Richard Stallman
1999-09-30 18:02                   ` Mark Mitchell
1999-09-09 11:51                 ` craig
1999-09-09 12:45                   ` Joe Buck
1999-09-30 18:02                     ` Joe Buck
1999-09-30 18:02                   ` craig
1999-09-30 18:02                 ` Joe Buck
1999-09-30 18:02               ` craig
1999-09-30 18:02             ` Jeffrey A Law
1999-09-09 23:26           ` Richard Stallman
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` Mark Mitchell
1999-09-30 18:02         ` Joe Buck
1999-09-09 23:25       ` Richard Stallman
1999-09-10  0:03         ` Mark Mitchell
1999-09-10  0:23           ` Joe Buck
1999-09-11  0:17             ` Richard Stallman
1999-09-30 18:02               ` Richard Stallman
1999-09-30 18:02             ` Joe Buck
1999-09-11  0:17           ` Richard Stallman
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` Mark Mitchell
1999-09-10 14:29         ` Marc Lehmann
1999-09-30 18:02           ` Marc Lehmann
1999-09-15  2:05         ` Jeffrey A Law
1999-09-15  7:55           ` Nick Ing-Simmons
1999-09-30 18:02             ` Nick Ing-Simmons
1999-09-15 23:14           ` Richard Stallman
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` Jeffrey A Law
1999-09-30 18:02         ` Richard Stallman
1999-09-30 18:02       ` Mark Mitchell
1999-09-08 20:44     ` Joe Buck
1999-09-30 18:02       ` Joe Buck
1999-09-14  3:04     ` Alexandre Oliva
1999-09-14  5:34       ` Bernd Schmidt
1999-09-14  5:45         ` Alexandre Oliva
1999-09-14  5:52           ` Bernd Schmidt
1999-09-30 18:02             ` Bernd Schmidt
1999-09-21  1:16           ` Rask Ingemann Lambertsen
1999-09-21  2:02             ` Jamie Lokier
1999-09-30 18:02               ` Jamie Lokier
1999-09-30 18:02             ` Rask Ingemann Lambertsen
1999-09-30 18:02           ` Alexandre Oliva
1999-09-14  9:31         ` Andi Kleen
1999-09-30 18:02           ` Andi Kleen
1999-09-30 18:02         ` Bernd Schmidt
1999-09-14 22:22       ` Richard Stallman
1999-09-30 18:02         ` Richard Stallman
1999-09-30 18:02       ` Alexandre Oliva
1999-09-30 18:02     ` Joe Buck
1999-09-10  0:11   ` Joe Buck
1999-09-10  8:43     ` craig
1999-09-10 18:25       ` Jonathan Larmour
1999-09-11  3:50         ` craig
1999-09-30 18:02           ` craig
1999-09-30 18:02         ` Jonathan Larmour
1999-09-11  0:15       ` Richard Stallman
1999-09-11  3:51         ` craig
1999-09-12  0:51           ` Richard Stallman
1999-09-12  8:54             ` craig
1999-09-13  0:47               ` Richard Stallman
1999-09-30 18:02                 ` Richard Stallman
1999-09-30 18:02               ` craig
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` craig
1999-09-30 18:02         ` Richard Stallman
1999-09-30 18:02       ` craig
1999-09-11  0:14     ` Richard Stallman
1999-09-11 15:20       ` Mark Mitchell
1999-09-11 18:04         ` David Edelsohn
1999-09-11 18:20           ` Mark Mitchell
1999-09-11 23:40             ` Sudish Joseph
1999-09-30 18:02               ` Sudish Joseph
1999-09-12  8:16             ` Robert Lipe
1999-09-30 18:02               ` Robert Lipe
1999-09-30 18:02             ` Mark Mitchell
1999-09-13  0:47           ` Richard Stallman
1999-09-15  2:06             ` Jeffrey A Law
1999-09-15  8:02               ` Nick Ing-Simmons
1999-09-15  9:20                 ` Jeffrey A Law
1999-09-15  9:31                   ` David Edelsohn
1999-09-15 10:02                     ` craig
1999-09-16 23:13                       ` Richard Stallman
1999-09-17  1:51                         ` craig
1999-09-17 22:16                           ` Richard Stallman
1999-09-30 18:02                             ` Richard Stallman
1999-09-30 18:02                           ` craig
1999-09-30 18:02                         ` Richard Stallman
1999-09-30 18:02                       ` craig
1999-09-30 18:02                     ` David Edelsohn
1999-09-15  9:56                   ` Nick Ing-Simmons
1999-09-15 10:08                     ` craig
1999-09-15 10:48                       ` Nick Ing-Simmons
1999-09-15 14:32                         ` craig
1999-09-30 18:02                           ` craig
1999-09-30 18:02                         ` Nick Ing-Simmons
1999-09-16 10:54                       ` Andi Kleen
1999-09-16 12:08                         ` Joern Rennecke
1999-09-16 12:18                           ` Mark Mitchell
1999-09-17  7:07                             ` __typealias qualifier (was Re: type based aliasing again) patl
1999-09-17  8:32                               ` Mark Mitchell
1999-09-30 18:02                                 ` Mark Mitchell
1999-09-30 18:02                               ` Patrick J. LoPresti
1999-09-30 18:02                             ` type based aliasing again Mark Mitchell
1999-09-30 18:02                           ` Joern Rennecke
1999-09-16 14:29                         ` craig
1999-09-16 22:19                           ` Andi Kleen
1999-09-30 18:02                             ` Andi Kleen
1999-09-30 18:02                           ` craig
1999-09-30 18:02                         ` Andi Kleen
1999-09-16 23:13                       ` Richard Stallman
1999-09-30 18:02                         ` Richard Stallman
1999-09-30 18:02                       ` craig
1999-09-30 18:02                     ` Nick Ing-Simmons
1999-09-30 18:02                   ` Jeffrey A Law
1999-09-30 18:02                 ` Nick Ing-Simmons
1999-09-15 23:14               ` Richard Stallman
1999-09-30 18:02                 ` Richard Stallman
1999-09-30 18:02               ` Jeffrey A Law
1999-09-30 18:02             ` Richard Stallman
1999-09-30 18:02           ` David Edelsohn
1999-09-12  9:45         ` Jonathan Larmour
1999-09-30 18:02           ` Jonathan Larmour
1999-09-13  0:47         ` Richard Stallman
1999-09-30 18:02           ` Richard Stallman
1999-09-13  4:05         ` Richard Earnshaw
1999-09-15  2:05           ` Jeffrey A Law
1999-09-30 18:02             ` Jeffrey A Law
1999-09-30 18:02           ` Richard Earnshaw
1999-09-30 18:02         ` Mark Mitchell
1999-09-30 18:02       ` Richard Stallman
1999-09-30 18:02     ` Joe Buck
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` Mike Stump
1999-09-09 14:26 Mike Stump
1999-09-09 14:38 ` Mark Mitchell
1999-09-11  0:16   ` Richard Stallman
1999-09-15  2:07     ` Jeffrey A Law
1999-09-30 18:02       ` Jeffrey A Law
1999-09-30 18:02     ` Richard Stallman
1999-09-30 18:02   ` Mark Mitchell
1999-09-30 18:02 ` Mike Stump
1999-09-09 15:40 Claus Fischer
1999-09-09 15:57 ` David Starner
1999-09-09 16:24   ` Claus Fischer
1999-09-09 16:55     ` Joe Buck
1999-09-09 17:31       ` Claus Fischer
1999-09-30 18:02         ` Claus Fischer
1999-09-30 18:02       ` Joe Buck
1999-09-10  8:42     ` craig
1999-09-30 18:02       ` craig
1999-09-30 18:02     ` Claus Fischer
1999-09-30 18:02   ` David Starner
1999-09-09 16:37 ` Jeffrey A Law
1999-09-09 17:15   ` Claus Fischer
1999-09-30 18:02     ` Claus Fischer
1999-09-30 18:02   ` Jeffrey A Law
1999-09-30 18:02 ` Claus Fischer
1999-09-09 21:54 Alex Rosenberg
1999-09-30 18:02 ` Alex Rosenberg
1999-09-10  8:43 craig
1999-09-12  0:49 ` Richard Stallman
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` craig
1999-09-11 18:21 Phil Edwards
1999-09-30 18:02 ` Phil Edwards
1999-09-11 21:48 N8TM
1999-09-30 18:02 ` N8TM
     [not found] <9377.936981585@upchuck.cygnus.com>
1999-09-12  0:52 ` Richard Stallman
1999-09-30 18:02   ` Richard Stallman
1999-09-12 11:20 Josh Stern
1999-09-30 18:02 ` Josh Stern
1999-09-13 10:55 R. Kelley Cook
1999-09-13 13:22 ` craig
1999-09-30 18:02   ` craig
1999-09-30 18:02 ` R. Kelley Cook
1999-09-13 16:34 Mike Stump
1999-09-14 22:20 ` Richard Stallman
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` Mike Stump
1999-09-13 21:45 N8TM
1999-09-14  4:01 ` Marc Espie
1999-09-14  9:56   ` David Edelsohn
1999-09-14 10:10     ` Richard Earnshaw
1999-09-14 10:31       ` Nick Ing-Simmons
1999-09-14 10:52         ` David Edelsohn
1999-09-14 11:11           ` craig
1999-09-14 14:44             ` David Edelsohn
1999-09-30 18:02               ` David Edelsohn
1999-09-14 15:06             ` David Edelsohn
1999-09-14 17:35               ` Marc Lehmann
1999-09-30 18:02                 ` Marc Lehmann
1999-09-14 23:41               ` craig
1999-09-15  8:28                 ` Marc Lehmann
1999-09-30 18:02                   ` Marc Lehmann
1999-09-15  9:19                 ` David Edelsohn
1999-09-15  9:59                   ` Nick Ing-Simmons
1999-09-15 15:33                     ` David Edelsohn
1999-09-30 18:02                       ` David Edelsohn
1999-09-30 18:02                     ` Nick Ing-Simmons
1999-09-15 10:01                   ` craig
1999-09-30 18:02                     ` craig
1999-09-30 18:02                   ` David Edelsohn
1999-09-30 18:02                 ` craig
1999-09-30 18:02               ` David Edelsohn
1999-09-30 18:02             ` craig
1999-09-14 11:58           ` Gerald Pfeifer
1999-09-30 18:02             ` Gerald Pfeifer
1999-09-30 18:02           ` David Edelsohn
1999-09-14 11:01         ` craig
1999-09-14 11:14           ` craig
1999-09-30 18:02             ` craig
1999-09-14 11:39           ` Mark Mitchell
1999-09-14 14:48             ` Toon Moene
1999-09-14 15:00               ` David Edelsohn
1999-09-14 16:01                 ` Toon Moene
1999-09-14 16:15                   ` David Edelsohn
1999-09-14 16:43                     ` Mark Mitchell
1999-09-30 18:02                       ` Mark Mitchell
1999-09-14 17:39                     ` Marc Lehmann
1999-09-30 18:02                       ` Marc Lehmann
1999-09-30 18:02                     ` David Edelsohn
1999-09-14 16:19                   ` dvv
1999-09-14 17:38                     ` Michael Meissner
1999-09-30 18:02                       ` Michael Meissner
1999-09-30 18:02                     ` Dima Volodin
1999-09-30 18:02                   ` Toon Moene
1999-09-30 18:02                 ` David Edelsohn
1999-09-14 15:08               ` Mark Mitchell
1999-09-30 18:02                 ` Mark Mitchell
1999-09-30 18:02               ` Toon Moene
1999-09-30 18:02             ` Mark Mitchell
1999-09-30 18:02           ` craig
1999-09-14 23:46         ` Geoff Keating
1999-09-15  7:47           ` Nick Ing-Simmons
1999-09-30 18:02             ` Nick Ing-Simmons
1999-09-30 18:02           ` Geoff Keating
1999-09-30 18:02         ` Nick Ing-Simmons
1999-09-30 18:02       ` Richard Earnshaw
1999-09-14 17:22     ` Marc Lehmann
1999-09-30 18:02       ` Marc Lehmann
1999-09-30 18:02     ` David Edelsohn
1999-09-14 17:23   ` Marc Lehmann
1999-09-15  1:59     ` Marc Espie
1999-09-15  8:28       ` Marc Lehmann
1999-09-30 18:02         ` Marc Lehmann
1999-09-30 18:02       ` Marc Espie
1999-09-30 18:02     ` Marc Lehmann
1999-09-15  2:01   ` Jeffrey A Law
1999-09-30 18:02     ` Jeffrey A Law
1999-09-30 18:02   ` Marc Espie
1999-09-30 18:02 ` N8TM
1999-09-14  6:46 Marcel Cox
1999-09-14  6:50 ` Bernd Schmidt
1999-09-14  7:14   ` Marcel Cox
1999-09-14  8:45     ` Jamie Lokier
1999-09-30 18:02       ` Jamie Lokier
1999-09-30 18:02     ` Marcel Cox
1999-09-30 18:02   ` Bernd Schmidt
1999-09-30 18:02 ` Marcel Cox
1999-09-15  7:02 David Ronis
1999-09-30 18:02 ` David Ronis
1999-09-15  8:27 Kaveh R. Ghazi
1999-09-15  8:57 ` Nathan Sidwell
1999-09-30 18:02   ` Nathan Sidwell
1999-09-30 18:02 ` Kaveh R. Ghazi
1999-09-15 11:42 Michael J. Bedy
1999-09-15 14:32 ` craig
1999-09-16 23:14   ` Richard Stallman
1999-09-30 18:02     ` Richard Stallman
1999-09-30 18:02   ` craig
1999-09-30 18:02 ` Michael J. Bedy
1999-09-15 21:47 Florin Mateoc
1999-09-16  2:18 ` craig
1999-09-30 18:02   ` craig
1999-09-30 18:02 ` Florin Mateoc
     [not found] <Pine.SO4.4.05.9909160153420.23533-100000@tamarack.cs.mtu.edu>
1999-09-16  2:19 ` craig
1999-09-30 18:02   ` craig
1999-09-16  6:12 Artem Hodyush
1999-09-16 23:15 ` Richard Stallman
1999-09-16 23:38   ` Gabriel Dos_Reis
1999-09-17 22:16     ` Richard Stallman
1999-09-30 18:02       ` Richard Stallman
1999-09-30 18:02     ` Gabriel Dos_Reis
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` Artem Hodyush
     [not found] <199909161750.LAA12073@basho.fc.hp.com>
1999-09-16 14:29 ` craig
1999-09-20 15:17   ` John W. Stevens
1999-09-30 18:02     ` John W. Stevens
1999-09-30 18:02   ` craig
1999-09-17  9:02 Harvey J. Stein
1999-09-30 18:02 ` Harvey J. Stein
1999-09-18  2:51 Ross Morgan-Linial
     [not found] ` <19990918151905.F1650@cerebro.laendle>
1999-09-18 22:18   ` Ross Morgan-Linial
1999-09-30 18:02     ` Ross Morgan-Linial
1999-09-30 18:02 ` Ross Morgan-Linial
1999-09-18  3:25 Artem Hodyush
1999-09-18 11:29 ` Russ Allbery
1999-09-20  5:54   ` Joern Rennecke
1999-09-30 18:02     ` Joern Rennecke
1999-09-30 18:02   ` Russ Allbery
1999-09-19 13:54 ` Richard Stallman
1999-09-30 18:02   ` Richard Stallman
1999-09-21  8:50 ` Harvey J. Stein
1999-09-30 18:02   ` Harvey J. Stein
1999-09-30 18:02 ` Artem Hodyush
1999-09-18  7:30 Stephen L Moshier
1999-09-30 18:02 ` Stephen L Moshier
1999-09-18  8:33 N8TM
1999-09-30 18:02 ` N8TM
1999-09-21  8:48 Harvey J. Stein
1999-09-22 12:15 ` Richard Stallman
1999-09-22 13:08   ` Harvey J. Stein
1999-09-24 23:37     ` Richard Stallman
1999-09-30 18:02       ` Richard Stallman
1999-09-30 18:02     ` Harvey J. Stein
1999-09-30 18:02   ` Richard Stallman
1999-09-30 18:02 ` Harvey J. Stein
     [not found] <19990921182843.25292.qmail@deer>
1999-09-21 15:47 ` John W. Stevens
1999-09-21 16:15   ` craig
1999-09-21 20:37     ` David Edelsohn
1999-09-30 18:02       ` David Edelsohn
1999-09-23  9:06     ` John W. Stevens
1999-09-23 11:06       ` craig
1999-09-30 18:02         ` craig
1999-09-30 18:02       ` John W. Stevens
1999-09-30 18:02     ` craig
1999-09-27  6:56   ` Rask Ingemann Lambertsen
1999-09-27  8:32     ` Joe Buck
1999-09-30 18:02       ` Joe Buck
1999-09-30 18:02     ` Rask Ingemann Lambertsen
1999-09-30 18:02   ` John W. Stevens

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