A system and method for optimizing program code in dynamic languages includes gathering hot-type information from a program by employing inferencing or profiling to get the hot-type information for operator uses, and inserting guards in the program based on data flow in the program to guard against propagation failures during runtime where preconditions are violated or where the propagation is unlikely to return. The program is versioned into global versions including a hot path version and a cold path version, where the hot path version is expected to be executed if the values of variables in the code are expected types, and other exceptional cases are handled by the cold path version as triggered by the guards. Compiler optimizations are performed to remove redundant representations of values, and heavy overloading of operators to provide an optimized compiling of the code.