[Bug tree-optimization/21569] New: write to const variable ignored at -O[12]

["rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

const int i=0;
int foo(void)
{
        *(int *)&i = 1;
        return i;
}

with -O0 gcc returns 1, with -O1 and up it returns 0.

Is this a valid store to i?  If not, why doesn't gcc warn
even at -Wall?

-- 
           Summary: write to const variable ignored at -O[12]
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21569