Why does __float80 depend on -mmmx/-msse?

[H. J. Lu]

There are

ix86_init_mmx_sse_builtins ()
{
  ..
  /* The __float80 type.  */
  if (TYPE_MODE (long_double_type_node) == XFmode)
    (*lang_hooks.types.register_builtin_type) (long_double_type_node,
                                               "__float80");
  else
    {
      /* The __float80 type.  */
      float80_type = make_node (REAL_TYPE);
      TYPE_PRECISION (float80_type) = 80;
      layout_type (float80_type);
      (*lang_hooks.types.register_builtin_type) (float80_type,
"__float80");
    }

That means __float80 is only available when -mmmx/-msse is used for
32bit compiler. Why does __float80 have to depend on -mmmx/-msse?


H.J.