[Bug c++/32782] New: inconsistant overflow in implicit conversion warning with -sizeof()

[Bug c++/32782] New: inconsistant overflow in implicit conversion warning with -sizeof()

[Steve at Zook dot com]

When calling a procedure with signed char or short arguments using -sizeof() as
an expression, an "<filename>:<line#>: warning: overflow in implicit constant
conversion" is output. Arguments with int or long do not. This happens even
though there is no real overflow (e.g. if -sizeof() evaluates to -4). See
attached test program (compiled using command line m68k-elf-g++ -c
testcpp.cpp). Proper code is produced. Warning can be avoided by casting
sizeof() to int (i.e. -(int)sizeof() ). Similar results are obtained when
returning a -sizeof() value in procedures with return type signed char or
short. This warning does not occur in revision 3.4.6.


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           Summary: inconsistant overflow in implicit conversion warning
                    with -sizeof()
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: trivial
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: Steve at Zook dot com
  GCC host triplet: i386-pc-cygwin
GCC target triplet: m68k-elf-unknown


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32782

[Bug c++/32782] inconsistant overflow in implicit conversion warning with -sizeof()

[Steve at Zook dot com]

------- Comment #1 from Steve at Zook dot com  2007-07-16 19:05 -------
Created an attachment (id=13926)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13926&action=view)
Test code fragment compiled m68k-elf-g++ -c testpp.cpp

Lines end in \r\n.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32782

[Bug c++/32782] inconsistent overflow in implicit conversion warning with -sizeof()

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2007-07-16 19:30 -------
The type of sizeof is unsigned. So you really have (short)(unsigned)-4 .


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32782

[Bug c++/32782] inconsistent overflow in implicit conversion warning with -sizeof()

[schwab at suse dot de]

------- Comment #3 from schwab at suse dot de  2008-03-30 22:36 -------
Not a bug.


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schwab at suse dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
   GCC host triplet|i386-pc-cygwin              |
 GCC target triplet|m68k-elf-unknown            |
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32782