+1. I'm years away from fp-analysis, but do the transcendental expansions even converge in the presence of fast-math? No `sin()`, no `cos()`, no `exp()`, ...
Well there are library implementations of fast-math trancendentals that offer bounded error, and a million different fast sine approximation algorithms, so, yes? This is why you shouldn’t listen to FUD. The corner cases are indeed frustrating for a few people, but most never hit them, and the world doesn’t suddenly break when fast math is enabled. I am paid to do some FP analysis, btw.