LATCH Primitive
The LATCH
primitive.
Note: When the 
         ENA (latch enable) input is high, the latch passes a signal
            from D to Q. When the ENA input is
            low, the state of Q is maintained, regardless of the D
            input.Note:  For information about Quartus® Prime primitive instantiation, go to Using a Quartus® Prime
            Logic Function.