We developed a compiler from SICStus Prolog CLP(FD) to Gecode and a compiler from MiniZinc to Gecode. We compared the running times of the executions of (standard) codes directly in the three languages and of the compiled codes for some classical problems. Performances of the compiled codes in Gecode improve those in the original languages and are comparable with running time of native Gecode code. This is a first step towards the definition of a unified declarative modeling tool for combinatorial problems. © 2008 Springer Berlin Heidelberg.