diff --git a/scripts/mk_project.py b/scripts/mk_project.py
index 5645e3af1..21a00e697 100644
--- a/scripts/mk_project.py
+++ b/scripts/mk_project.py
@@ -59,7 +59,8 @@ def init_project_def():
     add_lib('qe', ['smt','sat'], 'qe')
     add_lib('duality', ['smt', 'interp', 'qe'])
     add_lib('muz', ['smt', 'sat', 'smt2parser', 'aig_tactic', 'qe'], 'muz/base')
-    add_lib('transforms', ['muz', 'hilbert'], 'muz/transforms')
+    add_lib('dataflow', ['muz'], 'muz/dataflow')
+    add_lib('transforms', ['muz', 'hilbert', 'dataflow'], 'muz/transforms')
     add_lib('rel', ['muz', 'transforms'], 'muz/rel')
     add_lib('pdr', ['muz', 'transforms', 'arith_tactics', 'core_tactics', 'smt_tactic'], 'muz/pdr')
     add_lib('clp', ['muz', 'transforms'], 'muz/clp')
diff --git a/src/muz/dataflow/dataflow.h b/src/muz/dataflow/dataflow.h
new file mode 100755
index 000000000..c68846b9e
--- /dev/null
+++ b/src/muz/dataflow/dataflow.h
@@ -0,0 +1,269 @@
+/*++
+Copyright (c) 2015 Microsoft Corporation
+
+Module Name:
+
+    dataflow.h
+
+Abstract:
+
+    Generic bottom-up and top-down data-flow engine for analysis
+    of rule sets.
+
+Author:
+    Henning Guenther (t-hennig)
+
+--*/
+
+#ifndef DATAFLOW_H_
+#define DATAFLOW_H_
+
+#include "dl_rule.h"
+#include "dl_rule_set.h"
+#include "hashtable.h"
+#include "vector.h"
+
+namespace datalog {
+    template <typename Fact> class fact_reader;
+    template <typename Fact> class fact_writer;
+    /* The structure of fact classes:
+    class fact {
+    public:
+        typedef ... ctx_t;
+        // Empty fact
+        static fact null_fact;
+        fact(); -- bottom
+        // Init (Top down)
+        void init_down(ctx_t& ctx, const rule* r);
+        // Init (Bottom up)
+        bool init_up(ctx_t& ctx, const rule* r);
+        // Step (Bottom up)
+        bool propagate_up(ctx_t& ctx, const rule* r, const fact_reader<fact>& tail_facts);
+        // Step (Top down)
+        void propagate_down(ctx_t& ctx, const rule* r, fact_writer<fact>& tail_facts) const;
+        // Debugging
+        void dump(ctx_t& ctx, std::ostream& outp) const;
+        // Union
+        void join(ctx_t& ctx, const Fact& oth);
+        // Intersection
+        void intersect(ctx_t& ctx, const Fact& oth);
+    }; */
+    template <typename Fact> class dataflow_engine {
+    public:
+        typedef map<func_decl*, Fact, obj_ptr_hash<func_decl>, ptr_eq<func_decl> > fact_db;
+        typedef hashtable<func_decl*, obj_ptr_hash<func_decl>, ptr_eq<func_decl> > todo_set;
+        typedef typename fact_db::iterator iterator;
+    private:
+        const rule_set& m_rules;
+        fact_db m_facts;
+        todo_set m_todo[2];
+        unsigned m_todo_idx;
+        typename Fact::ctx_t& m_context;
+        rule_set::decl2rules m_body2rules;
+
+        void init_bottom_up() {
+            for (rule_set::iterator it = m_rules.begin(); it != m_rules.end(); ++it) {
+                rule* cur = *it;
+                for (unsigned i = 0; i < cur->get_uninterpreted_tail_size(); ++i) {
+                    func_decl *d = cur->get_tail(i)->get_decl();
+                    rule_set::decl2rules::obj_map_entry *e = m_body2rules.insert_if_not_there2(d, 0);
+                    if (!e->get_data().m_value) {
+                        e->get_data().m_value = alloc(ptr_vector<rule>);
+                    }
+                    e->get_data().m_value->push_back(cur);
+                }
+                if (cur->get_uninterpreted_tail_size() == 0) {
+                    func_decl* sym = cur->get_head()->get_decl();
+                    bool new_info = m_facts.insert_if_not_there2(sym, Fact())->get_data().m_value.init_up(m_context, cur);
+                    if (new_info) {
+                        m_todo[m_todo_idx].insert(sym);
+                    }
+                }
+            }
+        }
+
+        void init_top_down() {
+            const func_decl_set& output_preds = m_rules.get_output_predicates();
+            for (func_decl_set::iterator I = output_preds.begin(),
+                E = output_preds.end(); I != E; ++I) {
+                func_decl* sym = *I;
+                const rule_vector& output_rules = m_rules.get_predicate_rules(sym);
+                for (unsigned i = 0; i < output_rules.size(); ++i) {
+                    m_facts.insert_if_not_there2(sym, Fact())->get_data().m_value.init_down(m_context, output_rules[i]);
+                    m_todo[m_todo_idx].insert(sym);
+                }
+            }
+        }
+
+        void step_bottom_up() {
+            for(todo_set::iterator I = m_todo[m_todo_idx].begin(),
+                E = m_todo[m_todo_idx].end(); I!=E; ++I) {
+                ptr_vector<rule> * rules; 
+                if (!m_body2rules.find(*I, rules))
+                    continue;
+
+                for (ptr_vector<rule>::iterator I2 = rules->begin(),
+                    E2 = rules->end(); I2 != E2; ++I2) {
+                    func_decl* head_sym = (*I2)->get_head()->get_decl();
+                    fact_reader<Fact> tail_facts(m_facts, *I2);
+                    bool new_info = m_facts.insert_if_not_there2(head_sym, Fact())->get_data().m_value.propagate_up(m_context, *I2, tail_facts);
+                    if (new_info) {
+                        m_todo[!m_todo_idx].insert(head_sym);
+                    }
+                }
+            }
+            // Update todo list
+            m_todo[m_todo_idx].reset();
+            m_todo_idx = !m_todo_idx;
+        }
+
+        void step_top_down() {
+            for(todo_set::iterator I = m_todo[m_todo_idx].begin(),
+                E = m_todo[m_todo_idx].end(); I!=E; ++I) {
+                func_decl* head_sym = *I;
+                // We can't use a reference here because we are changing the map while using the reference
+                const Fact head_fact = m_facts.get(head_sym, Fact::null_fact);
+                const rule_vector& deps = m_rules.get_predicate_rules(head_sym);
+                const unsigned deps_size = deps.size();
+                for (unsigned i = 0; i < deps_size; ++i) {
+                    rule* trg_rule = deps[i];
+                    const unsigned tail_size = trg_rule->get_uninterpreted_tail_size();
+                    fact_writer<Fact> writer(m_facts, trg_rule, m_todo[!m_todo_idx]);
+                    // Generate new facts
+                    head_fact.propagate_down(m_context, trg_rule, writer);
+                }
+            }
+            // Update todo list
+            m_todo[m_todo_idx].reset();
+            m_todo_idx = !m_todo_idx;
+        }
+
+        bool done() const {
+            return m_todo[m_todo_idx].empty();
+        }
+
+    public:
+        dataflow_engine(typename Fact::ctx_t& ctx, const rule_set& rules) : m_rules(rules), m_context(ctx), m_todo_idx(0) {}
+
+        ~dataflow_engine() {
+            for (rule_set::decl2rules::iterator it = m_body2rules.begin(); it != m_body2rules.end(); ++it) {
+                dealloc(it->m_value);
+            }
+        }
+
+        void dump(std::ostream& outp) {
+            obj_hashtable<func_decl> visited;
+            for (rule_set::iterator I = m_rules.begin(),
+                E = m_rules.end(); I != E; ++I) {
+                const rule* r = *I;
+                func_decl* head_decl = r->get_decl();
+                obj_hashtable<func_decl>::entry *dummy;
+                if (visited.insert_if_not_there_core(head_decl, dummy)) {
+                    const Fact& fact = m_facts.get(head_decl, Fact::null_fact);
+                    outp << head_decl->get_name() << " -> ";
+                    fact.dump(m_context, outp);
+                    outp << "\n";
+                }
+                for (unsigned i = 0; i < r->get_uninterpreted_tail_size(); ++i) {
+                    func_decl* tail_decl = r->get_tail(i)->get_decl();
+                    if (visited.insert_if_not_there_core(tail_decl, dummy)) {
+                        const Fact& fact = m_facts.get(tail_decl, Fact::null_fact);
+                        outp << tail_decl->get_name() << " -> ";
+                        fact.dump(m_context, outp);
+                        outp << "\n";
+                    }
+                }
+            }
+        }
+
+        void run_bottom_up() {
+            init_bottom_up();
+            while (!done()) step_bottom_up();
+        }
+
+        void run_top_down() {
+            init_top_down();
+            while (!done()) step_top_down();
+        }
+
+        const Fact& get_fact(func_decl* decl) const {
+            return m_facts.get(decl, Fact::null_fact);
+        }
+
+        iterator begin() const { return m_facts.begin(); }
+        iterator end() const { return m_facts.end(); }
+
+        void join(const dataflow_engine<Fact>& oth) {
+            for (typename fact_db::iterator I = oth.m_facts.begin(),
+                E = oth.m_facts.end(); I != E; ++I) {
+                typename fact_db::entry* entry;
+                if (m_facts.insert_if_not_there_core(I->m_key, entry)) {
+                    entry->get_data().m_value = I->m_value;
+                } else {
+                    entry->get_data().m_value.join(m_context, I->m_value);
+                }
+            }
+        }
+
+        void intersect(const dataflow_engine<Fact>& oth) {
+            vector<func_decl*> to_delete;
+            for (typename fact_db::iterator I = m_facts.begin(),
+                E = m_facts.end(); I != E; ++I) {
+                
+                typename fact_db::entry* entry;
+                if (entry = oth.m_facts.find_core(I->m_key)) {
+                    I->m_value.intersect(m_context, entry->get_data().m_value);
+                } else {
+                     to_delete.push_back(I->m_key);
+                }
+            }
+            for (unsigned i = 0; i < to_delete.size(); ++i) {
+                m_facts.erase(to_delete[i]);
+            }
+        }
+    };
+
+    // This helper-class is used to look up facts for rule tails
+    template <typename Fact> class fact_reader {
+        typedef typename dataflow_engine<Fact>::fact_db fact_db;
+        const fact_db& m_facts;
+        const rule* m_rule;
+    public:
+        fact_reader(const fact_db& facts, const rule* r)
+            : m_facts(facts), m_rule(r) {
+
+        }
+        const Fact& get(unsigned idx) const {
+            return m_facts.get(m_rule->get_tail(idx)->get_decl(), Fact::null_fact);
+        }
+        unsigned size() const {
+            return m_rule->get_uninterpreted_tail_size();
+        }
+    };
+
+    template <typename Fact> class fact_writer {
+        friend class dataflow_engine<Fact>;
+        typedef typename dataflow_engine<Fact>::fact_db fact_db;
+        fact_db& m_facts;
+        const rule* m_rule;
+        typename dataflow_engine<Fact>::todo_set& m_todo;
+    public:
+        fact_writer(fact_db& facts, const rule* r, typename dataflow_engine<Fact>::todo_set& todo)
+            : m_facts(facts), m_rule(r), m_todo(todo) {}
+
+        Fact& get(unsigned idx) {
+            func_decl* sym = m_rule->get_tail(idx)->get_decl();
+            return m_facts.insert_if_not_there2(sym, Fact())->get_data().m_value;
+        }
+
+        void set_changed(unsigned idx) {
+            m_todo.insert(m_rule->get_tail(idx)->get_decl());
+        }
+
+        unsigned size() const {
+            return m_rule->get_uninterpreted_tail_size();
+        }
+    };
+}
+
+#endif
diff --git a/src/muz/dataflow/reachability.h b/src/muz/dataflow/reachability.h
new file mode 100755
index 000000000..54da04967
--- /dev/null
+++ b/src/muz/dataflow/reachability.h
@@ -0,0 +1,82 @@
+/*++
+Copyright (c) 2015 Microsoft Corporation
+
+Module Name:
+
+    reachability.h
+
+Abstract:
+
+    Abstract domain for tracking rule reachability.
+
+Author:
+    Henning Guenther (t-hennig)
+
+--*/
+
+#ifndef REACHABILITY_H_
+#define REACHABILITY_H_
+
+#include "dataflow.h"
+
+namespace datalog {
+    class reachability_info {
+        bool m_reachable;
+        reachability_info(bool r) : m_reachable(r) {}
+    public:
+        typedef ast_manager ctx_t;
+        static const reachability_info null_fact;
+        reachability_info() : m_reachable(false) {}
+
+        void init_down(const ctx_t& m, const rule* r) {
+            m_reachable = true;
+        }
+
+        bool init_up(const ctx_t& m, const rule* r) {
+            if (m_reachable) 
+                return false;
+            else {
+                m_reachable = true;
+                return true;
+            }
+        }
+
+        void propagate_down(const ctx_t& manager, const rule* r, fact_writer<reachability_info>& tail_facts) const {
+            SASSERT(m_reachable);
+            for (unsigned i = 0; i < r->get_uninterpreted_tail_size(); ++i) {
+                reachability_info& tail_fact = tail_facts.get(i);
+                if (!tail_fact.m_reachable) {
+                    tail_fact.m_reachable = true;
+                    tail_facts.set_changed(i);
+                }
+            }
+        }
+
+        bool propagate_up(const ctx_t& manager, const rule* r, const fact_reader<reachability_info>& tail_facts) {
+            if (m_reachable)
+                return false;
+
+            for (unsigned i = 0; i < r->get_positive_tail_size(); ++i) {
+                if (!tail_facts.get(i).m_reachable) {
+                    return false;
+                }
+            }
+            m_reachable = true;
+            return true;
+        }
+
+        void join(const ctx_t& manager, const reachability_info& oth) {
+            m_reachable |= oth.m_reachable;
+        }
+
+        void dump(const ctx_t& manager, std::ostream& outp) const {
+            outp << (m_reachable ? "reachable" : "unreachable");
+        }
+
+        bool is_reachable() const { return m_reachable; }
+    };
+
+    typedef dataflow_engine<reachability_info> reachability;
+}
+
+#endif
diff --git a/src/muz/transforms/dl_mk_coi_filter.cpp b/src/muz/transforms/dl_mk_coi_filter.cpp
index 477eda408..d9c1a9d19 100644
--- a/src/muz/transforms/dl_mk_coi_filter.cpp
+++ b/src/muz/transforms/dl_mk_coi_filter.cpp
@@ -1,5 +1,5 @@
 /*++
-Copyright (c) 2006 Microsoft Corporation
+Copyright (c) 2006-2015 Microsoft Corporation
 
 Module Name:
 
@@ -7,181 +7,100 @@ Module Name:
 
 Abstract:
 
-    Rule transformer which removes relations which are out of the cone of 
+    Rule transformer which removes relations which are out of the cone of
     influence of output relations
 
 Author:
-
-    Krystof Hoder (t-khoder) 2011-10-01.
-
-Revision History:
-
-    Andrey Rybalchenko (rybal) 2013-8-8
-    Added bottom_up pruning.
+    Krystof Hoder (t-khoder)
+    Andrey Rybalchenko (rybal)
+    Henning Guenther (t-hennig)
 
 --*/
 
-
-#include <sstream>
-#include"ast_pp.h"
-#include"dl_mk_coi_filter.h"
-#include"extension_model_converter.h"
+#include "dl_mk_coi_filter.h"
+#include "dataflow.h"
+#include "reachability.h"
+#include "ast_pp.h"
+#include "extension_model_converter.h"
 
 namespace datalog {
-  
-    // -----------------------------------
-    //
-    // mk_coi_filter
-    //
-    // -----------------------------------
+    const reachability_info reachability_info::null_fact;
 
     rule_set * mk_coi_filter::operator()(rule_set const & source) {
-        if (!m_context.xform_coi()) {
-            return 0;
-        }
-        if (source.empty()) {
-            return 0;
-        }
         scoped_ptr<rule_set> result1 = top_down(source);
-        scoped_ptr<rule_set> result2 = bottom_up(result1?*result1:source);
-        if (!result2) {
-            result2 = result1.detach();
-        }
-        return result2.detach();
+        scoped_ptr<rule_set> result2 = bottom_up(result1 ? *result1 : source);
+        return result2 ? result2.detach() : result1.detach();
     }
 
     rule_set * mk_coi_filter::bottom_up(rule_set const & source) {
-        func_decl_set all, reached;
-        ptr_vector<func_decl> todo;
-        rule_set::decl2rules body2rules;
-        // initialization for reachability
-        for (rule_set::iterator it = source.begin(); it != source.end(); ++it) {
-            rule * r = *it;
-            all.insert(r->get_decl());
-            if (r->get_uninterpreted_tail_size() == 0) {
-                if (!reached.contains(r->get_decl())) {
-                    reached.insert(r->get_decl());
-                    todo.insert(r->get_decl());
-                }
-            } 
-            else {
-                for (unsigned i = 0; i < r->get_uninterpreted_tail_size(); ++i) {
-                    func_decl * d = r->get_tail(i)->get_decl();
-                    all.insert(d);
-                    rule_set::decl2rules::obj_map_entry * e = body2rules.insert_if_not_there2(d, 0);
-                    if (!e->get_data().m_value) {
-                        e->get_data().m_value = alloc(ptr_vector<rule>);
-                    }
-                    e->get_data().m_value->push_back(r);
-                    if (r->is_neg_tail(i)) {
-                        // don't try COI on rule with negation.
-                        return 0;
-                    }
-                }
-            }
-        }
-        rel_context_base* rc = m_context.get_rel_context();
-        if (rc) {
-            func_decl_set::iterator fit = all.begin(), fend = all.end();
-            for (; fit != fend; ++fit) {
-                if (!rc->is_empty_relation(*fit) &&
-                    !reached.contains(*fit)) {
-                    reached.insert(*fit);
-                    todo.insert(*fit);
-                }
-            }                 
-        }
-        // reachability computation
-        while (!todo.empty()) {
-            func_decl * d = todo.back();
-            todo.pop_back();
-            ptr_vector<rule> * rules; 
-            if (!body2rules.find(d, rules)) continue;
-            for (ptr_vector<rule>::iterator it = rules->begin(); it != rules->end(); ++it) {
-                rule * r = *it;
-                if (reached.contains(r->get_decl())) continue;
-                bool contained = true;
-                for (unsigned i = 0; contained && i < r->get_uninterpreted_tail_size(); ++i) {
-                    contained = reached.contains(r->get_tail(i)->get_decl());
-                }
-                if (!contained) continue;
-                reached.insert(r->get_decl());
-                todo.insert(r->get_decl());
-            }
-        }
-
-        // eliminate each rule when some body predicate is not reached
+        dataflow_engine<reachability_info> engine(source.get_manager(), source);
+        engine.run_bottom_up();
         scoped_ptr<rule_set> res = alloc(rule_set, m_context);
         res->inherit_predicates(source);
         for (rule_set::iterator it = source.begin(); it != source.end(); ++it) {
             rule * r = *it;
 
+            bool new_tail = false;
             bool contained = true;
-            for (unsigned i = 0; contained && i < r->get_uninterpreted_tail_size(); ++i) {
-                contained = reached.contains(r->get_tail(i)->get_decl());
+            for (unsigned i = 0; i < r->get_uninterpreted_tail_size(); ++i) {
+                if (r->is_neg_tail(i)) {
+                    if (!engine.get_fact(r->get_tail(i)->get_decl()).is_reachable()) {
+                        if (!new_tail) {
+                            for (unsigned j = 0; j < i; ++j) {
+                                m_new_tail.push_back(r->get_tail(j));
+                                m_new_tail_neg.push_back(r->is_neg_tail(j));
+                            }
+                            new_tail = true;
+                        }
+                    } else if (new_tail) {
+                        m_new_tail.push_back(r->get_tail(i));
+                        m_new_tail_neg.push_back(true);
+                    }
+                } else {
+                    SASSERT(!new_tail);
+                    if (!engine.get_fact(r->get_tail(i)->get_decl()).is_reachable()) {
+                        contained = false;
+                        break;
+                    }
+                }
             }
             if (contained) {
-                res->add_rule(r);
+                if (new_tail) {
+                    rule* new_r = m_context.get_rule_manager().mk(r->get_head(), m_new_tail.size(),
+                        m_new_tail.c_ptr(), m_new_tail_neg.c_ptr(), symbol::null, false);
+                    res->add_rule(new_r);
+                } else {
+                    res->add_rule(r);
+                }
             }
+            m_new_tail.reset();
+            m_new_tail_neg.reset();
         }
         if (res->get_num_rules() == source.get_num_rules()) {
             TRACE("dl", tout << "No transformation\n";);
             res = 0;
-        }
-        else {
+        } else {
             res->close();
         }
 
         // set to false each unreached predicate 
         if (m_context.get_model_converter()) {
             extension_model_converter* mc0 = alloc(extension_model_converter, m);
-            for (func_decl_set::iterator it = all.begin(); it != all.end(); ++it) {
-                if (!reached.contains(*it)) {
-                    mc0->insert(*it, m.mk_false());
+            for (dataflow_engine<reachability_info>::iterator it = engine.begin(); it != engine.end(); it++) {
+                if (!it->m_value.is_reachable()) {
+                    mc0->insert(it->m_key, m.mk_false());
                 }
-            }   
+            }
             m_context.add_model_converter(mc0);
         }
-        // clean up body2rules range resources
-        for (rule_set::decl2rules::iterator it = body2rules.begin(); it != body2rules.end(); ++it) {
-            dealloc(it->m_value);
-        }
         CTRACE("dl", 0 != res, res->display(tout););
         return res.detach();
     }
 
     rule_set * mk_coi_filter::top_down(rule_set const & source) {
-
-        func_decl_set interesting_preds;
         func_decl_set pruned_preds;
-        ptr_vector<func_decl> todo;
-        {
-            const func_decl_set& output_preds = source.get_output_predicates();
-            func_decl_set::iterator oend = output_preds.end();
-            for (func_decl_set::iterator it = output_preds.begin(); it!=oend; ++it) {
-                todo.push_back(*it);
-                interesting_preds.insert(*it);
-            }
-        }
-
-        const rule_dependencies& deps = source.get_dependencies();
-
-        while (!todo.empty()) {
-            func_decl * curr = todo.back();
-            todo.pop_back();
-            interesting_preds.insert(curr);
-
-            const rule_dependencies::item_set& cdeps = deps.get_deps(curr);
-            rule_dependencies::item_set::iterator dend = cdeps.end();
-            for (rule_dependencies::item_set::iterator it = cdeps.begin(); it != dend; ++it) {
-                func_decl * dep_pred = *it;
-                if (!interesting_preds.contains(dep_pred)) {
-                    interesting_preds.insert(dep_pred);
-                    todo.push_back(dep_pred);
-                }
-            }
-        }
-
+        dataflow_engine<reachability_info> engine(source.get_manager(), source);
+        engine.run_top_down();
         scoped_ptr<rule_set> res = alloc(rule_set, m_context);
         res->inherit_predicates(source);
 
@@ -189,10 +108,9 @@ namespace datalog {
         for (rule_set::iterator rit = source.begin(); rit != rend; ++rit) {
             rule * r = *rit;
             func_decl * pred = r->get_decl();
-            if (interesting_preds.contains(pred)) {
+            if (engine.get_fact(pred).is_reachable()) {
                 res->add_rule(r);
-            }
-            else if (m_context.get_model_converter()) {
+            } else if (m_context.get_model_converter()) {
                 pruned_preds.insert(pred);
             }
         }
@@ -201,7 +119,6 @@ namespace datalog {
             TRACE("dl", tout << "No transformation\n";);
             res = 0;
         }
-
         if (res && m_context.get_model_converter()) {
             func_decl_set::iterator end = pruned_preds.end();
             func_decl_set::iterator it = pruned_preds.begin();
@@ -217,18 +134,16 @@ namespace datalog {
                         if (!is_var(arg)) {
                             conj.push_back(m.mk_eq(m.mk_var(j, m.get_sort(arg)), arg));
                         }
-                    }                    
+                    }
                     fmls.push_back(m.mk_and(conj.size(), conj.c_ptr()));
                 }
                 expr_ref fml(m);
                 fml = m.mk_or(fmls.size(), fmls.c_ptr());
                 mc0->insert(*it, fml);
-            }   
+            }
             m_context.add_model_converter(mc0);
         }
         CTRACE("dl", 0 != res, res->display(tout););
         return res.detach();
     }
-
-};
-
+}
diff --git a/src/muz/transforms/dl_mk_coi_filter.h b/src/muz/transforms/dl_mk_coi_filter.h
index 8ec7e80c4..16abe2f52 100644
--- a/src/muz/transforms/dl_mk_coi_filter.h
+++ b/src/muz/transforms/dl_mk_coi_filter.h
@@ -1,5 +1,5 @@
 /*++
-Copyright (c) 2006 Microsoft Corporation
+Copyright (c) 2006-2015 Microsoft Corporation
 
 Module Name:
 
@@ -7,22 +7,21 @@ Module Name:
 
 Abstract:
 
-    Rule transformer which removes relations which are out of the cone of 
+    Rule transformer which removes relations which are out of the cone of
     influence of output relations
 
 Author:
-
-    Krystof Hoder (t-khoder) 2011-10-01.
-
-Revision History:
+    Krystof Hoder (t-khoder)
+    Andrey Rybalchenko (rybal)
+    Henning Guenther (t-hennig)
 
 --*/
 
-#ifndef _DL_MK_COI_FILTER_H_
-#define _DL_MK_COI_FILTER_H_
+#ifndef DL_MK_COI_FILTER_H_
+#define DL_MK_COI_FILTER_H_
 
-#include "dl_context.h"
 #include "dl_rule_transformer.h"
+#include "dl_context.h"
 
 namespace datalog {
 
@@ -32,20 +31,19 @@ namespace datalog {
 
         ast_manager & m;
         context & m_context;
-
+        vector<app*> m_new_tail;
+        svector<bool> m_new_tail_neg;
         rule_set * bottom_up(rule_set const & source);
         rule_set * top_down(rule_set const & source);
 
     public:
-        mk_coi_filter(context & ctx, unsigned priority=45000)
+        mk_coi_filter(context & ctx, unsigned priority = 45000)
             : plugin(priority),
             m(ctx.get_manager()),
             m_context(ctx) {}
 
         rule_set * operator()(rule_set const & source);
     };
+}
 
-};
-
-#endif /* _DL_MK_COI_FILTER_H_ */
-
+#endif