[Bug tree-optimization/119614] [15 regression] protobuf-29.4 fails to build with -O2 (error: cannot tail-call: call and return value are different)

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119614

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Slightly further simplified:
struct S {} a;
char *foo ();
int e, g;
void bar (int);
void freddy (S);

struct U {
  void baz ();
  template <int>
  void
  baz (int)
  {
    static const char *(*f) () { qux<true> };
    f ();
  }
  template <bool>
  static const char *qux ();
};

__attribute__((noinline)) char *
corge ()
{
  bar (1);
  return 0;
}

void
U::baz ()
{
  baz<1> (1);
}

template <bool>
const char *
U::qux ()
{
  if (e == 1)
    {
      S b = a;
      freddy (b);
      if (g)
        return nullptr;
      [[gnu::musttail]] return corge ();
    }
  return foo ();
}