[Bug rtl-optimization/21450] [3.4/4.0/4.1 regression] -fstrict-aliasing causes miscompilation

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-07 
22:19 -------
Confirmed, here is a testcase which makes it fail with 3.4.0:
extern "C" void abort (void) throw();

struct T {};
struct U : T {};
int size = 2;

int main ()
{
  struct T * * pretmp3;
  struct U * p;
  int i;
  int size1 = size;
 p  =(U*)1 ;


  pretmp3 = (struct T * *) &p;
  i = 0;
L0:;
  *pretmp3 = 0;
  if (p != 0) abort();
  i = i + 1;
  if (i != 2) goto L0;
L4:;
  return 0;
}

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
 GCC target triplet|                            |i686-pc-linux-gnu
      Known to fail|                            |3.2.3 3.3.4 3.4.2 4.0.0
                   |                            |4.1.0
      Known to work|                            |2.95.3 3.0.4
   Last reconfirmed|0000-00-00 00:00:00         |2005-05-07 22:19:39
               date|                            |
            Summary|[4.0/4.1 regression] -      |[3.4/4.0/4.1 regression] -
                   |fstrict-aliasing causes     |fstrict-aliasing causes
                   |miscompilation              |miscompilation
   Target Milestone|---                         |3.4.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21450