[Bug fortran/27589] New: Add compiler flag to check for uninitalized values at runtime

[tobias dot burnus at physik dot fu-berlin dot de]

Currently, gfortran does not seem to have any option to catch uninitialized
variables at run time.

Example (from http://www.polyhedron.com/pb05/linux/diagnose.html):
--------<UNIN1>------------
        program uin1
        integer x,y,a,b
        x=y
        a=b
        print *,x,a
        b=1
        end
---------------------------

Other compilers have an options to catch those, e.g.:

ifort64-9.1 -C -check all -warn all,nodec,interfaces -gen_interfaces -traceback
-fpe0 -fpstkchk UIN1.F
./a.out
forrtl: severe (193): Run-Time Check Failure. The variable 'uin1_$Y' is being
used without being defined

NAG: f95 -C=all -C=undefined -info -g -gline UIN1.F
./a.out
Reference to undefined variable Y
Program terminated by fatal error
In UIN1, line 5 of UIN1.F


-- 
           Summary: Add compiler flag to check for uninitalized values at
                    runtime
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tobias dot burnus at physik dot fu-berlin dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27589