Apparatus and method for memorizing repeat function calls are described herein. An apparatus embodiment includes: uop buffer circuitry to identify a function for memorization based on retiring micro-operations (uops) from a processing pipeline; memorization retirement circuitry to generate a signature of the function which includes input and output data of the function; a memorization data structure to store the signature; and predictor circuitry to detect an instance of the function to be executed by the processing pipeline and to responsively exclude a first subset of uops associated with the instance from execution when a confidence level associated with the function is above a threshold. One or more instructions that are data-dependent on execution of the instance is then provided with the output data of the function from the memorization data structure.