[NeuroCoder]

From a non-technical point of view (since the technical answer was already provided) I think this sort of magic optimizations is a double edge sword in any language. No matter what you do there will be corner cases that need manual tuning that become inaccessible behind some init option.

[sundarurfriend]

That's especially true for `fastmath`, which shoves a bunch of optimization tradeoffs together, some of them "handle with care" territory, some of them in the "faulty live grenade that'll probably explode in your face" territory.

I was just wondering why the post said "impossible to use correctly in Julia" rather than just "impossible to use correctly", but writing it out now, I realize that "impossible" would be hyperbole for the latter, it would be more like "highly likely to go wrong".