Originally mentioned in this comment and this comment.
Regarding the repeated WARNING: Wrapping Vararg directly in UnionAll is deprecated (wrap the tuple instead) warnings that only come up during precompilation - I'm still seeing those warnings.
I'm on Julia master with LoopVectorization v0.9.8 and VectorizationBase v0.14.3 (with AFAICT are the latest versions), and I see these warnings when I do rm -rf ~/.julia/compiled/ and then run the Gaius.jl test suite.