[Bug c++/92893] Unhelpful -Wstringop-overflow warning

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92893

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
Defining Str like so works for the test case:

struct Str {
  template<typename T1, typename T2> Str(Cat<T1, T2> c)
  {
    struct Flex { char c, a[]; } *p = (Flex*)get();
    c.add(p->a);
  }
};

by changing the IL the warning sees to:

  <bb 2> [local count: 1073741824]:
  _8 = __builtin_strlen (p_2(D));
  _6 = get ();
  MEM[(char * {ref-all})_6 + 1B] = 0;
  _30 = &MEM <char[<unknown>]> [(void *)_6 + 2B];   <<< char[]
  __builtin_memcpy (_30, p_2(D), _8);
  _34 = _30 + _8;
  MEM <unsigned int> [(char * {ref-all})_34] = 7895160;