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From: Andrew Pinski <pinskia@gmail.com>
To: "gcc-bugzilla@gcc.gnu.org" <gcc-bugzilla@gcc.gnu.org>
Cc: "gcc-bugs@gcc.gnu.org" <gcc-bugs@gcc.gnu.org>
Subject: Re: [Bug c/44715] New: Break in increment expression of "for" statement inconsistent with g++
Date: Tue, 29 Jun 2010 16:40:00 -0000 [thread overview]
Message-ID: <DB7F85B0-5BEE-4034-9DE2-873E70B0B4BE@gmail.com> (raw)
In-Reply-To: <bug-44715-10727@http.gcc.gnu.org/bugzilla/>
What does a break with a statement expression do for each frontend? Is
it even valid to have a break there(without a statement expression)?
If it is valid, what does each standard say about the break there? If
they say the same thing then I say both frontends should behave the
same but if the c standard says a break should apply to the outer one
then we should follow that for statement expressions also.
On Jun 29, 2010, at 9:20 AM, "doug dot gregor at gmail dot com" <gcc-bugzilla@gcc.gnu.org
> wrote:
> The following program exhibits different behavior with gcc vs. g++:
>
> dgregor$ cat t.c
> #include <stdio.h>
>
> int main()
> {
> int i;
> for( i = 0; i < 3; )
> for( ; ; ({ i++; break; }) )
> printf( "%d\n", i );
> }
>
> With gcc, the break in the statement expression applies to the outer
> "for"
> loop, so we get just "0" as output:
>
> dgregor$ gcc t.c && ./a.out
> 0
>
> with g++, the break in the statement expression applies to the inner
> "for"
> loop, so we get "0" "1" and "2" as the output:
>
> dgregor$ g++ t.c && ./a.out
> 0
> 1
> 2
>
> g++ seems to have the right behavior here, and in any case g++ can't
> really be
> changed now: Qt's foreach macro depends on having "break" bind to
> the inner for
> loop.
>
>
> --
> Summary: Break in increment expression of "for" statement
> inconsistent with g++
> Product: gcc
> Version: 4.2.0
> Status: UNCONFIRMED
> Severity: normal
> Priority: P3
> Component: c
> AssignedTo: unassigned at gcc dot gnu dot org
> ReportedBy: doug dot gregor at gmail dot com
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44715
>
next prev parent reply other threads:[~2010-06-29 16:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-29 16:20 doug dot gregor at gmail dot com
2010-06-29 16:36 ` [Bug c/44715] " joseph at codesourcery dot com
2010-06-29 16:40 ` Andrew Pinski [this message]
2010-06-29 16:40 ` pinskia at gmail dot com
2010-06-29 16:47 ` joseph at codesourcery dot com
2010-07-06 5:28 ` ecyrbe at gmail dot com
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