[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #10 from manu at gcc dot gnu dot org 2007-01-29 11:09 --- WONTFIX as decided here: http://gcc.gnu.org/ml/gcc/2007-01/msg01179.html -- manu at gcc dot gnu dot org changed: What|Removed |Added Status|NEW |RESOLVED Resolution||WONTFIX http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #9 from manu at gcc dot gnu dot org 2007-01-29 01:10 --- Pawel, I don't want to appear rude but as you see from the answers in the ML, control might reach the end of the function without an explicit return. Thus, the warning is valid and I think we should close this as INVALID. Don't you agree? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #5 from manu at gcc dot gnu dot org 2007-01-23 13:57 --- I don't get this. The enum value can be any integer apart from foo and bar. Moreover, since it is undefined, it can be literally anything! So you need a default: case to handle that. In the first testcase, without a default case, the function returns (when it reaches the end) without a value, so the warning is correct. In the second case, r is not initialized unless __e is X or Y (and if out-of-range enum values are undefined in C++, __e can be anything!), thus the warning seems correct as well. So, is this really a bug? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #6 from pluto at agmk dot net 2007-01-23 15:02 ---
(In reply to comment #5)
I don't get this. The enum value can be any integer apart from foo and bar.
3.9.1/7, subnote. 43) says that enum isn't an integral type
but can be promoted to {signed/unsigned} int/long.
an assignment of int to enum produces an error,
so how ( in defined non-hax0r way ) enum can be any integer?
if it can be, then what's difference between enum and int?
$ cat tmp.cpp
typedef enum { foo, bar } e;
e assign( int v__ ) { return v__; }
int promote( e e__ ) { return e__; }
$ x86_64-gnu-linux-g++ tmp.cpp -O2 -c -Wall
tmp.cpp: In function 'e assign(int)':
tmp.cpp:2: error: invalid conversion from 'int' to 'e'
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #7 from manu at gcc dot gnu dot org 2007-01-23 15:55 ---
(In reply to comment #6)
an assignment of int to enum produces an error,
so how ( in defined non-hax0r way ) enum can be any integer?
if it can be, then what's difference between enum and int?
Undefined behaviour exists. It can happen. It will happen. Is casting a hax0r
way?
[EMAIL PROTECTED]:~$ cat test.cc
#include stdio.h
typedef enum { foo, bar } e;
int zoo( e __e )
{
switch ( __e )
{
case foo: return -1;
case bar: return +1;
}
}
int main()
{
printf(%d\n, zoo((e)10));
return 0;
}
[EMAIL PROTECTED]:~$ g++ -pedantic test.cc -o test
[EMAIL PROTECTED]:~$ ./test
-1209364588
We have requests for warnings about out-of-range enum conversions in C++:
* PR 12242
* PR 27975
* PR 12242
Again, I am just trying to understand the issue here. You will get a more
expert opinion about the standard and whether this is an actual bug or you
should have a default: case in your switch statements in the gcc@gcc.gnu.org
mailing list.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #8 from manu at gcc dot gnu dot org 2007-01-23 15:57 --- (In reply to comment #7) * PR 12242 * PR 27975 * PR 12242 This should have been: * PR 12242 * PR 27975 * PR 30357 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #3 from pluto at agmk dot net 2006-07-31 14:35 ---
one more testcase that renders different warning.
typedef enum { X, Y } e;
e zoo( e __e )
{
e r;
switch ( __e )
{
case X: r = Y; break;
case Y: r = X; break;
}
return r;
}
bug.cpp: In function 'e zoo(e)':
bug.cpp:4: warning: 'r' may be used uninitialized in this function
e zoo(e) (__e)
{
e r;
e D.2076;
int __e.0;
bb 0:
switch ((int) __e)
{
case 0: goto L0;
case 1: goto L6;
default : goto L5;
}
L6:;
r = 0;
goto bb 3 (L2);
L5:;
goto bb 3 (L2);
L0:;
r = 1;
L2:;
return r;
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #4 from pluto at agmk dot net 2006-07-31 14:41 --- so, -Werror is useless now. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #2 from pinskia at gcc dot gnu dot org 2006-07-06 16:55 --- Values in enums that are out of range are undefined in C++ (while defined in C). -- pinskia at gcc dot gnu dot org changed: What|Removed |Added Severity|normal |minor Status|UNCONFIRMED |NEW Ever Confirmed|0 |1 Last reconfirmed|-00-00 00:00:00 |2006-07-06 16:55:34 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
[Bug c++/28236] wrong control reaches warning with enums.
--- Comment #1 from pluto at agmk dot net 2006-07-03 17:00 ---
zoo (__e)
{
int D.1616;
bb 0:
switch (__e)
{
case 0: goto L0;
case 1: goto L5;
default : goto L2;
}
L0:;
D.1616 = -1;
goto bb 3 (L3);
L2:;
return; problem.
L5:;
D.1616 = 1;
L3:;
return D.1616;
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28236
