[Bug tree-optimization/109968] False Warning stringop-overread at -O2

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109968

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> Reduced testcase without -fsanitize=address:

Sorry missed one undefined type.
Here is the corrected reduced testcase:
```
extern int write1 (int __fd, const void *__buf, int __n) 
    __attribute__ ((__access__ (__read_only__, 2, 3)));

typedef struct {
 struct {
  int b;
  int c;
 } s2;
} S;

void f1(int *a);

int f(S *s )
{
 int err;
f1(&s->s2.b);

 err = write1( 1, (const void *)&(s->s2), 6);
 return err;
}
```