I don't want to read through 11 years of comments, but what does observable effects does corrupting mxcsr have? Surely it's just enabling FTZ/DAZ mode for the FPU which could harm bit-exactness in floating point math... but in code that cares about it, it's not uncommon to see RAII guards to configure the behavior you want (and usually, it's desirable to not comply with IEEE754 w.r.t subnormal numbers).
Like it's a quirk that floating point math can be non-deterministic but how bad is it, and is it actually a bug?
Like it's a quirk that floating point math can be non-deterministic but how bad is it, and is it actually a bug?