> The "trap values" concept is interesting. They're thinking that some floating point values are signaling NaNs, which will cause an exception if processed. An

> The "trap values" concept is interesting. They're thinking that some floating point values are signaling NaNs, which will cause an exception if processed. And then there's Itanium: https://blogs.msdn.microsoft.com/oldnewthing/20040119-00/?p=41003 https://blogs.msdn.microsoft.com/oldnewthing/20040119-00/?p=... Consider that any particular local variable might be allocated to a register. If the local variable has not been initialized, it might have junk from a previous use, and that junk might have the NaT bit set. Reading from that local variable, or even spilling it to the stack, can cause an exception.