[llvm-dev] OptBisect implementation for new pass manager

[David Greene via llvm-dev]

"Kaylor, Andrew" <andrew.kaylor at intel.com> writes:

> What if in the registration interface we had three options: skippable,
> not skippable, and run at OptLevel::None.

I kind of like this idea.  If necessary, the pass could even query the
target (or some other entity) about what OptLevel::None means.

If we have such query hooks, do we need "not skippable?"  If a pass is
not skippable, then running at OptLevel::None should be fine, as long as
the pass can know what it needs to do at OptLevel::None (at minimum
produce functional code).

"Not skippable" seems to imply "run the pass at full(-ish) optimization
always."  Maybe that's a useful third state, I'm not sure.

                         -David