@wolf480pl @saagar there's some low hanging fruit in C that's easy enough to define, but a lot of UB in C is very hard to define, at least on normal hardware.

(and you're probably not defining things differently at O0 and O3, I think?)

@lonjil @saagar no I actually mean define them only at O0 :P
Define them to do something dumb and potentially dangerous but predictable.
Bonus points if it matches most people's idea of a "a high-level assembly"

@lonjil @saagar for example, have -O0 imply -fwrapv

@saagar @lonjil but that's what you'd expect from a "high level assembly", right?

I'm not saying anyone should do that, just that there is a way to make O0 behave more like assembly