[Bug fortran/60739] New: Maybe uninitialized with deferred length character

[vladimir.fuka at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60739

            Bug ID: 60739
           Summary: Maybe uninitialized with deferred length character
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vladimir.fuka at gmail dot com

subroutine sub(str)
  character(*) :: str
  character(:), allocatable :: tmp

  tmp = str
  print *,allocated(tmp)
end

gfortran-4.9 uninit.f90 -c -Wall
uninit.f90: In function ‘sub’:
uninit.f90:5:0: warning: ‘.tmp’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
   tmp = str
 ^

-fdump-tree-original:

  character(kind=1)[1:.tmp] * tmp;
  integer(kind=4) .tmp;
  bitsizetype D.2326;
  sizetype D.2327;

  try
    {
      D.2326 = (bitsizetype) (sizetype) NON_LVALUE_EXPR <_str> * 8;
      D.2327 = (sizetype) NON_LVALUE_EXPR <_str>;
      tmp = 0B;
      {
        integer(kind=4) D.2321;
        integer(kind=4) D.2320;
        integer(kind=4) D.2319;

        D.2319 = _str;
        if (tmp != 0B) goto L.1;
        tmp = (character(kind=1)[1:.tmp] *) __builtin_malloc (MAX_EXPR
<(sizetype) _str, 1>);
        goto L.2;
        L.1:;
        if (.tmp == _str) goto L.2;
        tmp = (character(kind=1)[1:.tmp] *) __builtin_realloc ((void *) tmp,
MAX_EXPR <(sizetype) _str, 1>);
        L.2:;
        .tmp = _str;
        D.2320 = _str;
        D.2321 = .tmp;
        if (D.2321 != 0)
          {
            if ((unsigned long) D.2320 >= (unsigned long) D.2321)
              {
                __builtin_memmove ((void *) tmp, (void *) str, (unsigned long)
D.2321);
              }
            else
              {
                __builtin_memmove ((void *) tmp, (void *) str, (unsigned long)
D.2320);
                __builtin_memset ((void *) tmp + (sizetype) D.2320, 32,
(unsigned long) D.2321 - (unsigned long) D.2320);
              }
          }
      }
...