[Bug lto/83997] ICE with alias template and attribute

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83997

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
It is actually much worse than just some ICE with -flto.

template<int N>
using T = int __attribute__((vector_size (sizeof(int) * N)));

T<4> q;
template<int N>
int r __attribute__((vector_size (sizeof(int) * N)));
void *s = &r<4>;

T<4>
foo (T<4> a)
{
  return a + 1;
}

decltype (r<4>)
bar (decltype (r<4>) a)
{
  return a + 1;
}

shows that when using the T<4> we treat it as normal int, so sizeof (q) is
sizeof (int) and foo just adds to int argument 1 and returns that as int.
Compare that to the r case which is handled right.