[llvm] [NewPM][CodeGen][llc] Add NPM support (PR #70922)

[via llvm-commits]

paperchalice wrote:

> can we rework that option to be a std::string and lookup the pass on demand?

We could, current implementation is trying to compatible with the legacy version, may refactor it in future, it may involves `PassBuilder`, because register allocators are passes with parameters.

> definitely needs some tests in `llvm/test/tools/llc/`
Need stub code in some targets, e.g. X86.

https://github.com/llvm/llvm-project/pull/70922