If the user provides code where the result should be +0.0 and the compiler emits code that results in -0.0 (and the user has not explicitly enabled relaxed IEEE754 conformance), that's a bug in the compiler.
That is correct. But we were talking about how the == operator compares zeros. According to IEEE 754, -0 == +0 even though their bit patterns are not identical. And, by the way, inf != inf even if their bit patterns are identical.
> But we were talking about how the == operator compares zeros
Well, you were and I wasn't, and it wasn't clear whether you meant to contradict my point. I guess I could've made it more clear that I meant "using == to denote bitwise equality here only" and not "btw, == is bitwise for floats", but either way it should be clear now.