A method for significantly reducing compilation time of an application program is provided for compiling the program using profile-directed feedback (PDF). The method applies an additional analysis process between a training run of the application program and a whole program compilation of the application. This analysis process examines a PDF profile file(s) produced during the training run and aggregates data from the PDF file to determine a maximum block counter associated with each source file of the application. Only those source files having maximum block counters in a specified top percent of all the source files of the application have their fat binaries included in the whole program compilation.