[llvm-dev] Revisiting/refining the definition of optnone with interprocedural transformations

[via llvm-dev]

Because I put my constructive suggestion at the end of a long
email, I'll repeat it with more clarity here:

`optnone` is what it is.

Define a new `opt-sometimes` that means what Johannes suggests.
(A better name is more than welcome!)
Clang's __attribute__((optnone)) can migrate to meaning
{ opt-sometimes, noipa, noinline }.

`optnone` can be retired, existing only in the bitcode upgrader
which replaces it with { opt-sometimes, noipa, noinline }.

Changing Clang's attribute to mean something else can be put off
to another day.
--paulr