[clang] [AMDGPU][clang] provide device implementation for __builtin_logb and … (PR #129347)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 commented:

So this is just an IR lowering? We'd probably need some more conclusive tests that it works as expected for exceptional values, but I'm going to guess it was copied from an existing implementation so we could just refer to that one.

https://github.com/llvm/llvm-project/pull/129347