[llvm] [AArch64] Switch to soft promoting half types. (PR #80576)

[David Green via llvm-commits]

davemgreen wrote:

Hi - I don't personally thing this is worth a release note. It seems like just a standard backend codegen change/bugfix that we would not usually release note, especially when -fp-armv8 is less encouraged for AArch64 and this effects fp16. A general release note for the better support of -fp-armv8 might be good in the llvm 19 time frame, but that can be left for Olivers other work. Happy to hear alternative thoughts though.
If you remove that part then this LGTM.

https://github.com/llvm/llvm-project/pull/80576