[Bug fortran/114355] New: Segfault passing missing optional dummy of bind(c) subroutine to optional assumed-rank dummy

["anlauf at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114355

            Bug ID: 114355
           Summary: Segfault passing missing optional dummy of bind(c)
                    subroutine to optional assumed-rank dummy
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: anlauf at gcc dot gnu.org
  Target Milestone: ---

Found while working out corner cases for pr101135:

program main
  implicit none
  call test_c
contains
  subroutine test_c (s) bind(c)
    real, dimension(:), optional :: s
    call test_ar (s)
  end

  subroutine test_ar (z)
    real, dimension(..), optional :: z
  end
end

This crashes at runtime when compiled with -O0 or -Og since gcc-9.

The dump-tree has in test_c:

  {
    integer(kind=8) D.4362;
    struct array01_real(kind=4) parm.1;
    integer(kind=8) D.4369;
    struct array01_real(kind=4) * D.4370;

    D.4362 = s->dim[0].ubound;
    parm.1.span = s->span;
    parm.1.dtype = {.elem_len=4, .version=0, .rank=1, .type=3};
    D.4369 = s->dim[0].stride;
    parm.1.dim[0].lbound = 1;
    parm.1.dim[0].ubound = D.4362;
    parm.1.dim[0].stride = NON_LVALUE_EXPR <D.4369>;
    parm.1.data = (void *) s->data;
    parm.1.offset = -NON_LVALUE_EXPR <D.4369>;
    D.4370 = s != 0B ? &parm.1 : 0B;
    test_ar (D.4370);
  }

Looks like there are several potential NULL pointer dereferences.