gcc/testsuite/gcc.dg/torture/pr70740.c

/* { dg-do compile } */

extern int foo (void);
extern void *memcpy (void *, const void *, __SIZE_TYPE__);

struct
{
  char a[6];
} d;
struct
{
  int a1[0];
  int a2[0];
  int a3[0];
  int a4[];
} a, c;
int b;

int *
bar ()
{
  if (b)
    return a.a4;
  return a.a2;
}

void
baz ()
{
  int *e, *f;
  if (foo ())
    e = c.a3;
  else
    e = c.a1;
  memcpy (d.a, e, 6);
  f = bar ();
  memcpy (d.a, f, 1);
}