[Bug fortran/31119] -fbounds-check: Check for presence of optional arguments before bound checking

[fxcoudert at gcc dot gnu dot org]

------- Comment #3 from fxcoudert at gcc dot gnu dot org  2007-03-19 09:05 -------
Created an attachment (id=13229)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13229&action=view)
Patch that fixes the issue reported

The attached patch fixes the issue for the reported testcase. I checked that we
still issue errors when the optional parameter is present and has the wrong
size; the code below will error out as expected if one of the commented lines
is uncommented:

module sub_mod
contains
elemental subroutine set_optional(i,idef,iopt)
! set i to (iopt,idef) if iopt (is,is not) PRESENT
integer, intent(out)          :: i
integer, intent(in)           :: idef
integer, intent(in), optional :: iopt
if (present(iopt)) then
   i = iopt
else
   i = idef
end if
end subroutine set_optional

  subroutine sub(ivec)
    integer          , intent(in), optional :: ivec(:)
    integer                                 :: ivec_(2)
    call set_optional(ivec_,(/1,2/))
    print*,"ivec_=",ivec_
    call set_optional(ivec_,(/1,2/),ivec)
    print*,"ivec_=",ivec_
  end subroutine sub
end module sub_mod

program main
  use sub_mod, only: sub
  call sub()
  call sub((/4,5/))
!  call sub((/4/))
!  call sub((/4,5,6/))
end program main


Anyway, the other calls to checking routines need to be audited for similar
problems with optional args. That probably includes making a testcase for each
situation, and see if optional arg can be used in each context.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31119