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* Re: c++/1920
@ 2001-04-01 0:00 Joe Buck
0 siblings, 0 replies; 4+ messages in thread
From: Joe Buck @ 2001-04-01 0:00 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c++/1920; it has been noted by GNATS.
From: Joe Buck <jbuck@synopsys.com>
To: mdejong@redhat.com, gcc-gnats@gcc.gnu.org, nobody@gcc.gnu.org,
ebb9@email.byu.edu
Cc:
Subject: Re: c++/1920
Date: Mon, 26 Feb 2001 15:02:39 -0800
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=1920&database=gcc
Eric's analysis is correct: this is not legal C++, and the bug is that
neither gcc 2.95.2 nor CVS gcc issue any diagnostics.
I've changed the status to "analyzed", "non-critical", "accepts-illegal"
as Eric suggested.
--
The reasonable man adapts himself to the world; the unreasonable man
persists in trying to adapt the world to himself. Therefore, all
progress
depends on the unreasonable man. -----George Bernard Shaw
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: c++/1920
@ 2001-04-01 0:00 Eric Blake
0 siblings, 0 replies; 4+ messages in thread
From: Eric Blake @ 2001-04-01 0:00 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c++/1920; it has been noted by GNATS.
From: Eric Blake <ebb9@email.byu.edu>
To: mdejong@redhat.com, gcc-gnats@gcc.gnu.org, nobody@gcc.gnu.org
Cc:
Subject: Re: c++/1920
Date: Fri, 09 Feb 2001 15:51:35 -0700
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=1920&database=gcc
Actually, it looks like this bug should be recategorized as
accepts-illegal. Consider this variation:
#include <stdio.h>
void foo(unsigned &bar)
{
bar = 1;
}
int main()
{
unsigned a = 0;
foo((unsigned) a);
if (a == 1)
printf("OK\n");
else {
printf("a = %d, expeceted 1", a);
return 1;
}
return 0;
}
$ g++ -o foo foo.cc
foo.cc: In function `int main()':
foo.cc:9: initialization of non-const reference type `unsigned int &'
foo.cc:9: from rvalue of type `unsigned int'
foo.cc:3: in passing argument 1 of `foo(unsigned int &)'
Therefore, the fact that changing the declaration of a from unsigned to
int allows the compiler to complete without warning or error is the true
bug. In line 10, (unsigned) a is an rvalue, which cannot be assigned to
the non-const unsigned & of foo(). The correct cast in this situation
would be (unsigned &) a, which does work as expected.
--
Eric Blake
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: c++/1920
@ 2001-04-01 0:00 jbuck
0 siblings, 0 replies; 4+ messages in thread
From: jbuck @ 2001-04-01 0:00 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c++/1920; it has been noted by GNATS.
From: jbuck@synopsys.com
To: gcc-gnats@gcc.gnu.org, mdejong@redhat.com, nobody@gcc.gnu.org
Cc:
Subject: Re: c++/1920
Date: 26 Feb 2001 23:00:53 -0000
Synopsis: g++ -O1 optimization bug in casting a reference argument
State-Changed-From-To: open->analyzed
State-Changed-By: jbuck
State-Changed-When: Mon Feb 26 15:00:53 2001
State-Changed-Why:
Eric Blake's analysis is correct.
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=1920&database=gcc
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: c++/1920
@ 2003-05-06 0:16 Wolfgang Bangerth
0 siblings, 0 replies; 4+ messages in thread
From: Wolfgang Bangerth @ 2003-05-06 0:16 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c++/1920; it has been noted by GNATS.
From: Wolfgang Bangerth <bangerth@ices.utexas.edu>
To: gcc-gnats@gcc.gnu.org
Cc:
Subject: Re: c++/1920
Date: Mon, 5 May 2003 19:15:46 -0500 (CDT)
Since 3.3, the programs also fails in non-optimized mode. I think it's all
about not issuing a warning if a cast-as-lvalue is passed by reference.
This extension is evil!
W.
-------------------------------------------------------------------------
Wolfgang Bangerth email: bangerth@ices.utexas.edu
www: http://www.ices.utexas.edu/~bangerth/
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2003-05-06 0:16 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2001-04-01 0:00 c++/1920 Joe Buck
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2003-05-06 0:16 c++/1920 Wolfgang Bangerth
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