With the wide expansion of multiprocessor architectures, the analysis and reasoning for programs under weak memory models has become an important concern. This work presents an original constraint solver for detecting program behaviors respecting a particular memory model. It is implemented in Prolog using CHR (Constraint Handling Rules). The CHR formalism provides a convenient generic solution for specifying memory models, that benefits from the existing optimized implementations of CHR and can be easily extended to new models. We briefly present the solver design, illustrate the encoding of memory model constraints in CHR and discuss the benefits and limitations of the proposal.