[Bug fortran/78171] New: example with undefined symbol compiles with '-O1 -fcheck=pointer'

[patrick.seewald at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78171

            Bug ID: 78171
           Summary: example with undefined symbol compiles with '-O1
                    -fcheck=pointer'
           Product: gcc
           Version: 6.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: patrick.seewald at gmail dot com
  Target Milestone: ---

This should not compile because 'foo' is undefined:

PROGRAM example
IMPLICIT NONE
REAL, ALLOCATABLE, DIMENSION(:) :: array
CALL foo(array)
END PROGRAM example

However it compiles with 'gfortran -O1 -fcheck=pointer example.f90'. If I run
the executable, I get:

At line 4 of file example.f90
Fortran runtime error: Allocatable actual argument 'array' is not allocated