This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: Signed int overflow behavior in the security context

From: Robert Dewar <dewar at adacore dot com>
To: Paul Schlie <schlie at comcast dot net>
Cc: Richard Guenther <richard dot guenther at gmail dot com>, Joe Buck <Joe dot Buck at synopsys dot com>, Andreas Bogk <andreas at andreas dot org>, gcc at gcc dot gnu dot org
Date: Sat, 27 Jan 2007 20:31:48 -0500
Subject: Re: Signed int overflow behavior in the security context
References: <C1E0E69F.FAFF%schlie@comcast.net>

Paul Schlie wrote:

-  However x ^= x :: 0 for example is well defined because absent any
intervening assignments, all reference to x must semantically yield the same
value, regardless of what that value may be.

Nope, there is no such requirement in the standard. Undefined means undefined. Again you are confusing the language C defined in the C standard with some ill-defined language in your mind with different semantics. Furthermore, it is quite easy to see how in practice you might get different results on successive accesses.

Follow-Ups:
- Re: Signed int overflow behavior in the security context
  - From: Paul Schlie

References:
- Signed int overflow behavior in the security context
  - From: Paul Schlie

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]