[clang] [flang] [llvm] [mlir] [Support][NFC] Move OptimizationLevel to the Support directory (PR #157057)

[Sergei Barannikov via cfe-commits]

s-barannikov wrote:

> > And what's wrong with Passes anyway?
> 
> See #156802 for a motivation for this change. If anybody wants to reference a constant variable from OptimizationLevel (OptimizationLevel::O0, for example) they have to add the extra Passes dependency, which seems a bit much for one variable.

`Passes` library closely related (and is tiny btw). I don't see a problem in keeping OptimizationLevel there. If you move the definiton of `registerLateLoopOptimizationsEPCallback()` (used in #15602) from h to cpp file you would need to add the dependency on `Passes` anyway.


https://github.com/llvm/llvm-project/pull/157057