[Bug fortran/14568] New: Gfortran should not warn about unused variables in common blocks

["schnetter at aei dot mpg dot de" <gcc-bugzilla at gcc dot gnu dot org>]

Gfortran should not warn about unused variables in common blocks.  (Unless, 
possibly, the whole common block is unused.)  The following piece of code 
shows the problem: 
 
subroutine a 
  implicit none 
  integer b, c 
  common /block/ b, c 
  c = 1 
end subroutine a 
 
The compiler says 
 
$ ~/gcc-3.5-tree-ssa/bin/gfortran -S unusedcommon.f90 -Wall 
unusedcommon.f90: In function `a': 
unusedcommon.f90:1: warning: unused variable `b' 
 
My build is 
 
$ ~/gcc-3.5-tree-ssa/bin/gfortran -v 
Reading specs 
from /home/eschnett/gcc-3.5-tree-ssa/lib/gcc/i686-pc-linux-gnu/3.5-tree-ssa/specs 
Configured with: ../gcc/configure --prefix=/home/eschnett/gcc-3.5-tree-ssa 
--enable-languages=c,c++,f95 
Thread model: posix 
gcc version 3.5-tree-ssa 20040312 (merged 20040307)

-- 
           Summary: Gfortran should not warn about unused variables in
                    common blocks
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Severity: minor
          Priority: P2
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: schnetter at aei dot mpg dot de
                CC: gcc-bugs 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=14568