[Bug c++/12963] New: Wrong and misleading warning encourages writing non-portable code

["bagnara at cs dot unipr dot it" <gcc-bugzilla at gcc dot gnu dot org>]

For the C++ function

unsigned char
foo(unsigned char c) {
  if (c <= 255)
    return 255;
  else
    return c;
}

g++ 3.4 20031102 (and also 3.3.2, but NOT 3.3.1) generates,
without any -W option, the following warning:

g++ -c bug.cc
bug.cc: In function `unsigned char foo(unsigned char)':
bug.cc:3: warning: comparison is always true due to limited range of data type

I believe this warning should not be issued, since unsigned chars may
be more than 8 bits wide.  The fact that in the particular implementation
of ISO C++ I am using right now unsigned chars are 8 bits wide should be
irrelevant (I certainly do not want to write unportable code to avoid that warning).

-- 
           Summary: Wrong and misleading warning encourages writing non-
                    portable code
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bagnara at cs dot unipr dot it
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12963