Hi Ben, > if (ConstantInt *c = (ConstantInt *) dyn_cast<ConstantInt>(index)){ > errs()<< "And it's a constant!!!!!!1111oneone!! ("<<c->getZExtValue() > << ")\n"; > } I don't think you need the "(ConstantInt *)" cast. The getZExtValue will fail if the constant doesn't fit in 64 bits. Ciao, Duncan.