[Bug middle-end/49106] New: static variable is optimized away even though it is referenced by a nested constructor

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49106

           Summary: static variable is optimized away even though it is
                    referenced by a nested constructor
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org


In the following program, the function "test" is optimized way as the node is
not marked as needed. Thus, the static variable "a" is removed - even though it
is referenced in the nested constructor "_const_func".

Result: Link error:
/tmp/ccaIjMKk.o: In function `_const_func.1591':
test.c:(.text+0x6): undefined reference to `a.1589'

Expected: The local static should not be optimized way, i.e. the nested
function lowering should properly update the cgraph ipa reference list.


Side remark: For my purpose (coarray initialization in gfortran) it would be
best if in such a case both the function and the constructor could be optimized
away. Thus, if there would be some method on tree-level to tell this cgraph ...


main ()
{
  void test (void)
  {
    static int a;
    void __attribute__((constructor))
    _const_func(void)
    {
      a = 7;
    }
  }
  return 0;
}