Only those variables can be calculated at compile time whose address is fixed?

In Primer (while studying constexpr) I found that:

variables defined inside a function ordinarily are not stored at a fixed address. Hence, we cannot use a constexpr pointer to point to such variables

Is it valid for all the values calculated at compile time or is it just a constraint for using keyword constexpr? + Does const keyword not ensures that the object would be determined (evaluated its value) at compile time despite being initialised by a literal?