[llvm-dev] [RFC] Introducing classes for the codegen driven by new pass manager

[Robinson, Paul via llvm-dev]

> I'd just note that not every pass you can run with "opt" is actually part of the optimization pipeline. There are a few important IR-level passes that only run in the codegen pipeline, but are still nameable with opt to run individually for testing purposes. Switching over doesn't need to block on these passes being migrated. So I'm not sure this method of determining progress towards switching to NPM actually makes sense.

FTR, there are IR-level passes that only run in the codegen pipeline,
and are *not* available in opt, but are available in llc; for example 
the stack protector pass.  Just throwing that out there.
--paulr