Earlier quoted context omitted.
Clang and the arm64 backend did literally originate at Apple. Not sure what you want me to tell you.
Apologies, I focused on LLVM as a whole. You are right about clang (and I didn’t know about the arm64 backend)
Actually the arm64 backend is a grey area. I knew some guys that worked on it in secret at Apple. They definitely created and Developed it at Apple and dropped it on the community after the iPhone 5s launched, replacing the existing aarch64 backend.
I’m not 100% certain if they started with any bits of the previous aarch64 backend or not though.