[clang] [llvm] [APFloat] Add APFloat support for FP6 data types (PR #94735)

[Krzysztof Drewniak via cfe-commits]

https://github.com/krzysz00 commented:

I have no issues with the code as written but I'm rather confused by how it will be used

What's the motivation for this PR? Will anyone be trying to constant-fold these things?

(If it's for MLIR support, I'd like to have a discussion there, since I don't thisk these scalars belong in `FloatType` and that the long-term solution is to allow arbitrary newtypes / tags on bits / ... up there)

https://github.com/llvm/llvm-project/pull/94735