I think the x87 status/config registers you’re alluding to are a great example of power to the compiler that function colouring can potentially grant. “De-colou

I think the x87 status/config registers you’re alluding to are a great example of power to the compiler that function colouring can potentially grant. “De-colouring” the function requires gating around preserving these registers but within that colour/monad there’s no need to preserve them. That’s an upside, not a downside