I don't understand why this article invents and explains a phony ranged-float fix when the real fix from the footnotes would have been just as simple to explain. The deception needlessly undermines the main point of the article, which I completely agree with.
The real fix felt more complicated when I drafted this. Seems like it isn't; I'll think about updating the post
That fix has limited applicability. x * x is also a non-negative float. But abs(x * x) is not optimized. Or abs(abs(x)+1). GCC, for example, does know that.