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From: "joseph at codesourcery dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/45034] [4.3/4.4/4.5/4.6 Regression] "safe" conversion from unsigned to signed char gives broken code
Date: Tue, 27 Jul 2010 22:43:00 -0000 [thread overview]
Message-ID: <20100727224251.25552.qmail@sourceware.org> (raw)
In-Reply-To: <bug-45034-7665@http.gcc.gnu.org/bugzilla/>
------- Comment #9 from joseph at codesourcery dot com 2010-07-27 22:42 -------
Subject: Re: [4.3/4.4/4.5/4.6 Regression] "safe"
conversion from unsigned to signed char gives broken code
On Tue, 27 Jul 2010, mikpe at it dot uu dot se wrote:
> Personally I think GCC should treat source-level casts as wrapping, regardless
> of -fstrict-overflow and -fno-wrapv. Perhaps it intends to, and we're just
> seeing the effects of bugs.
This implementation-defined behavior is already documented in
implement-c.texi:
@item
@cite{The result of, or the signal raised by, converting an integer to a
signed integer type when the value cannot be represented in an object of
that type (C90 6.2.1.2, C99 6.3.1.3).}
For conversion to a type of width @math{N}, the value is reduced
modulo @math{2^N} to be within range of the type; no signal is raised.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45034
next prev parent reply other threads:[~2010-07-27 22:43 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-22 21:13 [Bug c/45034] New: " mikpe at it dot uu dot se
2010-07-22 21:14 ` [Bug c/45034] " mikpe at it dot uu dot se
2010-07-22 21:26 ` [Bug tree-optimization/45034] " pinskia at gcc dot gnu dot org
2010-07-23 4:14 ` hjl dot tools at gmail dot com
2010-07-23 8:52 ` [Bug tree-optimization/45034] [4.3/4.4/4.5/4.6 Regression] " rguenth at gcc dot gnu dot org
2010-07-24 18:47 ` mikpe at it dot uu dot se
2010-07-25 10:56 ` mikpe at it dot uu dot se
2010-07-26 14:47 ` rakdver at gcc dot gnu dot org
2010-07-27 22:18 ` mikpe at it dot uu dot se
2010-07-27 22:43 ` joseph at codesourcery dot com [this message]
2010-07-27 23:09 ` rakdver at kam dot mff dot cuni dot cz
2010-07-28 9:32 ` rguenth at gcc dot gnu dot org
2010-07-28 12:24 ` rguenth at gcc dot gnu dot org
2010-07-28 14:14 ` mikpe at it dot uu dot se
2010-07-28 15:38 ` mikpe at it dot uu dot se
2010-07-28 23:32 ` mikpe at it dot uu dot se
2010-07-29 11:00 ` rguenth at gcc dot gnu dot org
2010-07-29 11:00 ` [Bug tree-optimization/45034] [4.3/4.4/4.5 " rguenth at gcc dot gnu dot org
2010-08-08 15:50 ` rguenth at gcc dot gnu dot org
2010-08-08 15:51 ` [Bug tree-optimization/45034] [4.3/4.4 " rguenth at gcc dot gnu dot org
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