Upstreaming clangIR PR: https://github.com/llvm/clangir/pull/2065 Support for lowering of `__builtin_amdgcn_logb` and `scalebn` for AMDGPU builtins to clangIR. Followed similar lowering from clang->llvmir: `clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp`.