Extending logic programming to constraint logic programming has substantially broadened the range of problems solvable in a declarative style. However experiments with the Prolog III system showed that the generality of the constraint solving often incurs a heavy performance penalty for the — often occurring — special cases in which the problem has a simple algorithmic solution. This paper investigates — in the context of Prolog III — the feasibility of automatically extracting specialized versions. This is illustrated on some examples. Extraction of the specialized version is based on a transformation technique “compiling control” which was originally devised for transforming logic programs requiring a special computation rule into Prolog programs.