A method, apparatus, system, and signal-bearing medium that in an embodiment collect profile information about class-type checks, calculate a number of class-type checks that minimizes a cost of inlining, generate inline code for the number of class-type checks for a site in a method, and sort the inline code based on a frequency of the class types. Any remaining class-type checks at the site that are not handled by the inlined class-type checks are handled via an out-of-line function call. In this way, inlined code is used when it provides better performance than an out-of-line function, and the out-of-line function call is used when it provides better performance than the inlined code.