not_tail_called interaction with LTO and merging of decls on LTO

[pinskia]

This is more of a semantic question rather than a bug report (though it might turn into a bug report due to what is thought about).

Anyways take these 2 TUs:

int f(void) __attribute__((not_tail_called));
int g1(void);
int h(void)
{
  return g1();
}
int g(void)
{
  return f();
}

and

int f(void);
int g(void);
int g1(void)
{
  return f();
}
int h1(void)
{
  return g();
}

When g gets inlined into h1, will f cause a tail call or not? Likewise for g1 inlined into h?

[pinskia]

I should make a mention this came up when I started to think about how to implement this attribute in GCC and there is no documentation on how this works or is expected to work.