UnsafePointUnsafe = -2 // Unsafe for async preemption

	// UnsafePointRestart1(2) apply on a sequence of instructions, within
	// which if an async preemption happens, we should back off the PC
	// to the start of the sequence when resuming.
	// We need two so we can distinguish the start/end of the sequence
	// in case that two sequences are next to each other.
	UnsafePointRestart1 = -3
	UnsafePointRestart2 = -4