[Bug c++/88362] attribute aligned silently ignored on C++ references

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88362

--- Comment #5 from Martin Sebor <msebor at gcc dot gnu.org> ---
I think the attribute on references needs to work the same way as on pointers
so that we get consistent behavior for reference members.  __alignof__ should
return the corresponding alignment.  For example, in the following all three
members are 32-byte aligned as expected:

  struct S {
    __attribute__ ((aligned (32))) int i;
    __attribute__ ((aligned (32))) int *p;
    __attribute__ ((aligned (32))) int &r;
  };

  S s = { 0, &s.i, s.i };

but in the following the last assertion fails with GCC (it passes with Clang):

  static_assert (__alignof__ (s.i) == 32);
  static_assert (__alignof__ (s.p) == 32);
  static_assert (__alignof__ (s.r) == 32);