[clang] [llvm] [HIPSPV] Add in-tree SPIR-V backend support for chipStar (PR #206910)

[Paulius Velesko via cfe-commits]

pvelesko wrote:

> But it’s fine in case the backend is not yet good enough for chipStar

the native backend is preferred. The idea being that if you are planning on using the SPIR-V Translator, you build LLVM with it and then prefer using it. Otherwise we default to using the native backend. 

> I think, the choice of using either the translator or the backend should be configurable

Yeah that's probably a better option and something that we could handle on the chipStar side. Currently we use two separate builds for native-vs-translator 

https://github.com/llvm/llvm-project/pull/206910