From: Mark Mitchell <mark@codesourcery.com>
To: Michael Veksler <VEKSLER@il.ibm.com>
Cc: Paul Koning <pkoning@equallogic.com>,
gcc@gcc.gnu.org, gdr@integrable-solutions.net,
nathan@codesourcery.com
Subject: Re: Do C++ signed types have modulo semantics?
Date: Tue, 28 Jun 2005 03:06:00 -0000 [thread overview]
Message-ID: <42C0BE8C.4040308@codesourcery.com> (raw)
In-Reply-To: <OFF89CA957.1E322A19-ONC225702D.0052A8AF-C225702D.00546B33@il.ibm.com>
Michael Veksler wrote:
>> Most programmers "know" that arithmetic is modulo wordsize. And those few
>>who know the right answer (only unsigned arithmetic is modulo) will
>>from time to time slip up and omit the "unsigned" keyword in their
>>declarations.
I agree.
Although the standard clearly makes signed overflow undefined, I think
it would be better if GCC defined it to be modulo arithmetic. The
degree to which that would result in inferior code seems likely to be
somewhat small, and the amount of user confusion we would eliminate, and
the number of programs that would not break with GCC, even though they
work with other compilers, seems likely to be high.
--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304
next prev parent reply other threads:[~2005-06-28 3:06 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-27 5:09 Michael Veksler
2005-06-27 13:02 ` Nathan Sidwell
2005-06-27 14:10 ` Gabriel Dos Reis
2005-06-27 14:36 ` Nathan Sidwell
2005-06-27 14:47 ` Paul Koning
2005-06-27 15:21 ` Michael Veksler
2005-06-28 3:06 ` Mark Mitchell [this message]
2005-06-28 3:49 ` Gabriel Dos Reis
2005-06-28 10:08 ` Robert Dewar
2005-06-28 11:19 ` Steven Bosscher
2005-06-28 12:03 ` Ulrich Weigand
2005-06-28 12:09 ` Steven Bosscher
2005-06-29 16:46 ` Steven Bosscher
2005-06-29 18:01 ` Daniel Berlin
2005-06-29 18:32 ` Steven Bosscher
2005-06-29 18:45 ` Robert Dewar
2005-06-29 19:13 ` Nicholas Nethercote
2005-06-28 12:16 ` Paul Koning
2005-06-28 12:30 ` Steven Bosscher
2005-06-28 12:35 ` Michael Veksler
2005-06-28 12:38 ` Steven Bosscher
2005-06-28 16:54 ` Joe Buck
2005-06-28 17:02 ` Mark Mitchell
2005-06-28 17:08 ` Daniel Berlin
2005-06-28 18:12 ` Mark Mitchell
2005-06-28 17:46 ` Theodore Papadopoulo
2005-06-27 15:17 ` Gabriel Dos Reis
2005-06-30 20:53 ` Kai Henningsen
2005-06-27 14:39 Morten Welinder
2005-06-27 15:21 ` Gabriel Dos Reis
[not found] <OF0E4366CA.5D54868B-ON4325702E.0036D351-4325702E.003973C5@il.ibm.com>
[not found] ` <m3k6keeibo.fsf@uniton.integrable-solutions.net>
2005-06-28 13:29 ` Nathan Sidwell
2005-06-28 13:59 ` Gabriel Dos Reis
2005-06-28 14:05 ` Nathan Sidwell
2005-06-28 14:05 ` Andrew Pinski
2005-06-28 14:13 ` Gabriel Dos Reis
2005-06-28 15:30 ` Michael Veksler
2005-06-28 15:49 ` Nathan Sidwell
2005-06-28 15:58 ` Michael Veksler
2005-06-28 16:07 ` Andrew Pinski
2005-06-28 16:39 ` Gabriel Dos Reis
2005-06-28 15:55 ` Gabriel Dos Reis
2005-06-28 16:47 ` Joseph S. Myers
2005-06-28 17:58 ` Gabriel Dos Reis
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