We've certainly tested all Float32 inputs to some functions in Julia's math packages. I'm unable to find the relevant issues this very moment, otherwise would certainly post them.
I suspect https://github.com/JuliaLang/julia/pull/29700 might be one of them. As the original post states, rounding is (a) amenable to hardware acceleration, (b) easy to get wrong or slow, and (c) possible to test exhaustively.
