Fix iterator equality check bug in ai.h

Author: reuk

src/analyses/ai.h

@@ -409,7 +409,9 @@ class ait:public ai_baset
   }
 
 protected:
-  typedef std::unordered_map<locationt, domainT, const_target_hash> state_mapt;
+  typedef std::
+    unordered_map<locationt, domainT, const_target_hash, pointee_address_equalt>
+      state_mapt;
   state_mapt state_map;
 
   // this one creates states, if need be

src/goto-programs/goto_program_template.h

@@ -810,4 +810,15 @@ struct const_target_hash_templatet
   { return t->location_number; }
 };
 
+/// Functor to check whether iterators from different collections point at the
+/// same object.
+struct pointee_address_equalt
+{
+  template <class A, class B>
+  bool operator()(const A &a, const B &b) const
+  {
+    return &(*a) == &(*b);
+  }
+};
+
 #endif // CPROVER_GOTO_PROGRAMS_GOTO_PROGRAM_TEMPLATE_H