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

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

can we add a llvm-test-suite test for these builtin functions? we can compare their value with host results for typical and corner inputs, like the test added in this PR https://github.com/llvm/llvm-test-suite/pull/230 . This will give us some confidence that the clang codegen works.

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