[cfe-dev] why does non-const stateless tag value require global variable, but constexpr does not.

[Larry Evans via cfe-dev]

This godbolt example code:

   https://godbolt.org/z/tiZ4jZ

shows that, depending on the value of #defined(TAG_CE),
a global variable, i.e.:

   tag_nc:
         .zero   1

is created.  Why can't the compiler see there's no need for this
tag_nc global variable since the code behaves the same as when
!defined(TAG_CE)?