N1570 "An iteration statement whose controlling expression is not a constant expression, that performs no input/output operations, does not access volatile obje

N1570 "An iteration statement whose controlling expression is not a constant expression, that performs no input/output operations, does not access volatile objects, and performs no synchronization or atomic operations in its body, controlling expression, or (in the case of a for statement) its expression-3, may be assumed by the implementation to terminate." Doesn't seem like UB but optimizing effectless loops out is permitted.