The compiler is emitting calls as if these were separately-compiled functions instead of intrinsics that it should expand inline. This is not the case when installing LLVM 16.0.1 directly, so I suspect some kind of corruption of the VS in-box Clang. We need to figure out what's going on here, and communicate with the MS-internal folks who handle the in-box Clang to get it straightened out before 17.7 ships.

EDIT:
This bug has the same root cause as DevCom-10369658/VSO-1822920 "Clang 16.0 offsetof behavior difference". The issue is in how VS packages LLVM.