[Bug fortran/30512] New: MAXVAL() incorrect for zero-size int arrays, and for -HUGE-1 maximum values.

[brooks at gcc dot gnu dot org]

Consider the following program:

debian-gfortran:~/test> cat maxval.f90
integer(1) :: i(3)
logical :: msk(3)

i = -huge(i)
i = i - 1
write(*,*) i
write(*,*) maxval(i)

msk = .false.
i = 1
write(*,*) i
write(*,*) -huge(i), maxval(i, msk)
end

In both of these cases, the result of the MAXVAL call should be -huge(i)-1. 
(For the latter case, see the standard on the definition of the intrinsic,
which says that the result is the negative number with the largest magnitude
possible within the representation).  However, the actual result is this:

debian-gfortran:~/test> ../bin-trunk/bin/gfortran maxval.f90 -o maxval
debian-gfortran:~/test> ./maxval
 -128 -128 -128
 -127
    1    1    1
 -127 -127

This error holds for larger integer kinds, as well.

The error seems to stem from the libgfortran implementation, in which the
initial search value is initialized as -GFC_INTEGER_<n>_HUGE, where it should
be one less than that.


-- 
           Summary: MAXVAL() incorrect for zero-size int arrays, and for -
                    HUGE-1 maximum values.
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: brooks at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30512