[Bug middle-end/31688] New: Bogus "may be used uninitialized" warning

[burnus at gcc dot gnu dot org]

[Based on PR 31683]
Compiling the following program with "gfortran -O -Wall" gives the bogus
warning:

foo2.f90:4: warning: 'offset.7' may be used uninitialized in this function
foo2.f90:4: warning: 'stride.6' may be used uninitialized in this function
foo2.f90:4: warning: 'pab.0' may be used uninitialized in this function

However, this part of code is not reachable if uninitialized.

The code is essentially:

int offset.7;
if(pab != 0B)
    offset.7 = -stride.6;
if (pab == 0B) return;
*force_a = (*pab.0)[offset.7]

Full Fortran source:

MODULE test
  IMPLICIT NONE
CONTAINS
  SUBROUTINE overlap(s, lds, pab, force_a)
    INTEGER, INTENT(IN)                         :: lds
    REAL, DIMENSION(lds, lds, *), INTENT(INOUT) :: s
    REAL, DIMENSION(:), INTENT(IN), OPTIONAL    :: pab
    REAL, INTENT(OUT)                           :: force_a

    if(.not.present(pab)) return
    force_a = pab(1)*s(1,1,1)
  END SUBROUTINE
END MODULE test


-- 
           Summary: Bogus "may be used uninitialized" warning
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31688