[LLVMdev] Contributing the Apple ARM64 compiler backend

[Eric Christopher]

>
> Getting to that idillic end-state of one AArch64 backend in the tree which encompasses the best of both is going to take a fair bit of work and a lot of discussion amongst the interested parties. To get there, I think a rough roadmap like the following makes sense:
>
> 1. Import the ARM64 backend into the public tree so it's easily accessible for everyone to investigate.
> 2. Test it. Benchmark it. Explore it. Get data for the community to work with about the state of the back end. ARM has some excellent data that will help guide us here.
> 3. Identify the core backend to build on and to merge features and tuning from the other to. The data I have seen so far leads me to believe ARM64 is the correct choice here, but that's a decision primarily for the contributors above.
> 4. Clean up the codebase (C++11-ify it, for example), fix any regressions and test failures identified in benchmarking.
>

Sounds great. It'd be good to get the target independent bits applied
separately (hopefully after the arm64 backend is committed so that
tests are more obvious), but I'm in favor of committing this as soon
as you can type svn ci with the appropriate splits for patches.

-eric