[Bug tree-optimization/28807] New: [4.2 Regression] wrong code with may_alias and structs

[pinskia at gcc dot gnu dot org]

Testcase:
#include <stdio.h>

struct S { short x; };
typedef struct S __attribute__((__may_alias__)) test;

int f() {
  int a=10;
  test *p=(test *)&a;
  test s={1};
  *p=s;
  return a;
}

int main() {
  if (f() == 10)
    __builtin_abort()
  return 0;
}

-------
Even though the struct is not the same size as int, this should still work as
the struct is marked as may_alias so we get an aliasing set of 0.


-- 
           Summary: [4.2 Regression] wrong code with may_alias and structs
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28807