Do you use the LLVM_INCLUDE_TESTS setting? If so, what for?
It is documented to preclude the inclusion unittests in the build.
What it actually does in preclude all LLVM testing (unit and regression), but only unittests for Clang. The Clang regression tests continue to be built and run.
My preference is simply to remove it if none have an important use case. If they do, I would like to understand it and come up with some sane and consistent semantic model to support it.