diff --git a/src/muz/rel/dl_mk_partial_equiv.h b/src/muz/rel/dl_mk_partial_equiv.h
index f982952f1..be871f53e 100644
--- a/src/muz/rel/dl_mk_partial_equiv.h
+++ b/src/muz/rel/dl_mk_partial_equiv.h
@@ -30,7 +30,7 @@ namespace datalog {
         ast_manager & m;
         context &     m_context;
     public:
-        mk_partial_equivalence_transformer(context & ctx, unsigned priority=45000)
+        mk_partial_equivalence_transformer(context & ctx, unsigned priority=30000)
             : plugin(priority),
             m(ctx.get_manager()),
             m_context(ctx) {}
diff --git a/src/muz/rel/rel_context.cpp b/src/muz/rel/rel_context.cpp
index 68bc25c27..6d167dfec 100644
--- a/src/muz/rel/rel_context.cpp
+++ b/src/muz/rel/rel_context.cpp
@@ -307,8 +307,8 @@ namespace datalog {
         if (m_context.similarity_compressor()) {
             transf.register_plugin(alloc(mk_similarity_compressor, m_context)); 
         }
-        transf.register_plugin(alloc(mk_partial_equivalence_transformer, m_context));
         transf.register_plugin(alloc(mk_rule_inliner, m_context));
+        transf.register_plugin(alloc(mk_partial_equivalence_transformer, m_context));
         transf.register_plugin(alloc(mk_interp_tail_simplifier, m_context));
         transf.register_plugin(alloc(mk_separate_negated_tails, m_context));
 
diff --git a/src/qe/qe.cpp b/src/qe/qe.cpp
index 150198bab..585944263 100644
--- a/src/qe/qe.cpp
+++ b/src/qe/qe.cpp
@@ -596,7 +596,7 @@ namespace qe {
                 p = m_pols.back();
                 if (!m_is_relevant(e)) {
                     pop();
-                    insert(e, p, p?e:m.mk_not(e));
+                    insert(e, p, p?e:mk_not(m, e));
                     continue;
                 }
                 if (!is_app(e)) {
@@ -634,7 +634,7 @@ namespace qe {
                 }
                 else {
                     pop();
-                    insert(e, p, p?e:m.mk_not(e));
+                    insert(e, p, p?e:mk_not(m, e));
                 }
 
             }
@@ -1208,7 +1208,7 @@ namespace qe {
                 }
                 bool_rewriter(m).mk_or(fmls.size(), fmls.c_ptr(), fml);
                 
-                fml = m.mk_not(m.mk_iff(q, fml));
+                fml = mk_not(m, m.mk_iff(q, fml));
                 ast_smt_pp pp(m);
                 out << "; eliminate " << mk_pp(m_var, m) << "\n";
                 out << "(push)\n";
@@ -1303,12 +1303,7 @@ namespace qe {
             }
         }
         TRACE("qe_verbose", tout << "No plugin for " << mk_ismt2_pp(e, m) << "\n";);
-        if (p || m.is_not(e, e)) {
-            result = e;
-        } 
-        else {
-            result = m.mk_not(e);
-        }
+        result = p?e:mk_not(m, e);
     }
 
     void i_solver_context::mk_atom_fn::operator()(expr* e, bool p, expr_ref& result) {
@@ -1436,7 +1431,7 @@ namespace qe {
                 m_fml = f;
                 f = m_subfml;                
                 m_solver.assert_expr(f);
-            }           
+            }
             m_root.init(f);                       
             TRACE("qe", 
                   for (unsigned i = 0; i < num_vars; ++i) tout << mk_ismt2_pp(vars[i], m) << "\n";
@@ -1591,7 +1586,7 @@ namespace qe {
             }
             m_literals.reset();
             while (node) {
-                m_literals.push_back(m.mk_not(node->assignment()));
+                m_literals.push_back(mk_not(m, node->assignment()));
                 node = node->parent();
             }    
             add_literal(l1);
@@ -1865,7 +1860,7 @@ namespace qe {
         //
         app* mk_eq_value(app* b, rational const& vl) {
             if (m.is_bool(b)) {
-                if (vl.is_zero()) return m.mk_not(b);
+                if (vl.is_zero()) return to_app(mk_not(m, b));
                 if (vl.is_one()) return b;
                 UNREACHABLE();
             }        
@@ -2604,12 +2599,12 @@ namespace qe {
             TRACE("qe", tout << "variables extracted" << mk_pp(result, m) << "\n";);
 
             if (old_q->is_forall()) {
-                result = m.mk_not(result);
+                result = mk_not(m, result);
             }
             m_ctx.solve(result, vars);
             if (old_q->is_forall()) {
                 expr* e = 0;
-                result = m.is_not(result, e)?e:m.mk_not(result);
+                result = m.is_not(result, e)?e:mk_not(m, result);
             }       
             var_shifter shift(m);
             shift(result, vars.size(), result);
diff --git a/src/tactic/bv/bv_bounds_tactic.cpp b/src/tactic/bv/bv_bounds_tactic.cpp
index 317c17f12..0a4411847 100644
--- a/src/tactic/bv/bv_bounds_tactic.cpp
+++ b/src/tactic/bv/bv_bounds_tactic.cpp
@@ -155,6 +155,8 @@ class bv_bounds_simplifier : public ctx_simplify_tactic::simplifier {
     typedef obj_map<expr, interval> map;
 
     ast_manager& m;
+    params_ref   m_params;
+    bool         m_propagate_eq;
     bv_util      m_bv;
     vector<map>  m_scopes;
     map         *m_bound;
@@ -209,9 +211,19 @@ class bv_bounds_simplifier : public ctx_simplify_tactic::simplifier {
 
 public:
 
-    bv_bounds_simplifier(ast_manager& m) : m(m), m_bv(m) {
+    bv_bounds_simplifier(ast_manager& m, params_ref const& p) : m(m), m_params(p), m_bv(m) {
         m_scopes.push_back(map());
         m_bound = &m_scopes.back();
+        updt_params(p);
+    }
+
+
+    virtual void updt_params(params_ref const & p) {
+        m_propagate_eq = p.get_bool("propagate_eq", false);
+    }
+
+    static void get_param_descrs(param_descrs& r) {
+        r.insert("propagate-eq", CPK_BOOL, "(default: false) propagate equalities from inequalities");
     }
 
     virtual ~bv_bounds_simplifier() {}
@@ -262,7 +274,7 @@ public:
                 result = m.mk_true();
             } else if (!b.intersect(ctx, intr)) {
                 result = m.mk_false();
-            } else if (intr.l == intr.h) {
+            } else if (m_propagate_eq && intr.l == intr.h) {
                 result = m.mk_eq(t1, m_bv.mk_numeral(intr.l, m.get_sort(t1)));
             }
         } else if (b.is_full() && b.tight) {
@@ -291,7 +303,7 @@ public:
     }
 
     virtual simplifier * translate(ast_manager & m) {
-        return alloc(bv_bounds_simplifier, m);
+        return alloc(bv_bounds_simplifier, m, m_params);
     }
 
     virtual unsigned scope_level() const {
@@ -302,5 +314,5 @@ public:
 }
 
 tactic * mk_bv_bounds_tactic(ast_manager & m, params_ref const & p) {
-    return clean(alloc(ctx_simplify_tactic, m, alloc(bv_bounds_simplifier, m), p));
+    return clean(alloc(ctx_simplify_tactic, m, alloc(bv_bounds_simplifier, m, p), p));
 }
diff --git a/src/tactic/core/ctx_simplify_tactic.cpp b/src/tactic/core/ctx_simplify_tactic.cpp
index 3bcadb03d..e07f7417d 100644
--- a/src/tactic/core/ctx_simplify_tactic.cpp
+++ b/src/tactic/core/ctx_simplify_tactic.cpp
@@ -198,6 +198,7 @@ struct ctx_simplify_tactic::imp {
         m_max_steps    = p.get_uint("max_steps", UINT_MAX);
         m_max_depth    = p.get_uint("max_depth", 1024);
         m_bail_on_blowup = p.get_bool("bail_on_blowup", false);
+        m_simp->updt_params(p);
     }
 
     void checkpoint() {
@@ -373,7 +374,7 @@ struct ctx_simplify_tactic::imp {
             if (new_arg != arg)
                 modified = true;
             if (i < num_args - 1 && !m.is_true(new_arg) && !m.is_false(new_arg) && !assert_expr(new_arg, OR))
-                new_arg = m.mk_false();
+                new_arg = OR ? m.mk_true() : m.mk_false();
 
             if ((OR && m.is_false(new_arg)) ||
                 (!OR && m.is_true(new_arg))) {
@@ -402,7 +403,7 @@ struct ctx_simplify_tactic::imp {
             if (new_arg != arg)
                 modified = true;
             if (i > 0 && !m.is_true(new_arg) && !m.is_false(new_arg) && !assert_expr(new_arg, OR))
-                new_arg = m.mk_false();
+                new_arg = OR ? m.mk_true() : m.mk_false();
 
             if ((OR && m.is_false(new_arg)) ||
                 (!OR && m.is_true(new_arg))) {
@@ -529,6 +530,37 @@ struct ctx_simplify_tactic::imp {
         return sz;
     }
 
+    void process_goal(goal & g) {
+        SASSERT(scope_level() == 0);
+        // go forwards
+        unsigned old_lvl = scope_level();
+        unsigned sz = g.size();
+        expr_ref r(m);
+        for (unsigned i = 0; !g.inconsistent() && i < sz; ++i) {
+            m_depth = 0;            
+            simplify(g.form(i), r);
+            if (i < sz - 1 && !m.is_true(r) && !m.is_false(r) && !g.dep(i) && !assert_expr(r, false)) {
+                r = m.mk_false();
+            }
+            g.update(i, r, 0, g.dep(i));
+        }
+        pop(scope_level() - old_lvl);
+
+        // go backwards
+        sz = g.size();
+        for (unsigned i = sz; !g.inconsistent() && i > 0; ) {
+            m_depth = 0;
+            --i;
+            simplify(g.form(i), r);
+            if (i > 0 && !m.is_true(r) && !m.is_false(r) && !g.dep(i) && !assert_expr(r, false)) {
+                r = m.mk_false();
+            }
+            g.update(i, r, 0, g.dep(i));
+        }
+        pop(scope_level() - old_lvl);
+        SASSERT(scope_level() == 0);
+    }
+
     void process(expr * s, expr_ref & r) {
         TRACE("ctx_simplify_tactic", tout << "simplifying:\n" << mk_ismt2_pp(s, m) << "\n";);
         SASSERT(scope_level() == 0);
@@ -546,24 +578,22 @@ struct ctx_simplify_tactic::imp {
 
     void operator()(goal & g) {
         SASSERT(g.is_well_sorted());
-        bool proofs_enabled = g.proofs_enabled();
         m_occs.reset();
         m_occs(g);
         m_num_steps = 0;
-        expr_ref r(m);
-        proof * new_pr = 0;
         tactic_report report("ctx-simplify", g);
-        unsigned sz = g.size();
-        for (unsigned i = 0; i < sz; i++) {
-            if (g.inconsistent())
-                return;
-            expr * t = g.form(i);
-            process(t, r);
-            if (proofs_enabled) {
-                proof * pr = g.pr(i);
-                new_pr     = m.mk_modus_ponens(pr, m.mk_rewrite_star(t, r, 0, 0)); // TODO :-)
+        if (g.proofs_enabled()) {
+            expr_ref r(m);
+            unsigned sz = g.size();
+            for (unsigned i = 0; !g.inconsistent() && i < sz; ++i) {
+                expr * t = g.form(i);
+                process(t, r);
+                proof* new_pr = m.mk_modus_ponens(g.pr(i), m.mk_rewrite_star(t, r, 0, 0)); // TODO :-)
+                g.update(i, r, new_pr, g.dep(i));
             }
-            g.update(i, r, new_pr, g.dep(i));
+        }
+        else {
+            process_goal(g);
         }
         IF_VERBOSE(TACTIC_VERBOSITY_LVL, verbose_stream() << "(ctx-simplify :num-steps " << m_num_steps << ")\n";);
         SASSERT(g.is_well_sorted());
@@ -593,6 +623,7 @@ void ctx_simplify_tactic::get_param_descrs(param_descrs & r) {
     insert_max_memory(r);
     insert_max_steps(r);
     r.insert("max_depth", CPK_UINT, "(default: 1024) maximum term depth.");
+    r.insert("propagate_eq", CPK_BOOL, "(default: false) enable equality propagation from bounds.");
 }
 
 void ctx_simplify_tactic::operator()(goal_ref const & in, 
diff --git a/src/tactic/core/ctx_simplify_tactic.h b/src/tactic/core/ctx_simplify_tactic.h
index 5689a64b7..34258362b 100644
--- a/src/tactic/core/ctx_simplify_tactic.h
+++ b/src/tactic/core/ctx_simplify_tactic.h
@@ -34,6 +34,7 @@ public:
         virtual void pop(unsigned num_scopes) = 0;
         virtual simplifier * translate(ast_manager & m) = 0;
         virtual unsigned scope_level() const = 0;
+        virtual void updt_params(params_ref const & p) {}
         void set_occs(goal_num_occurs& occs) { m_occs = &occs; };
         bool shared(expr* t) const;
     };
diff --git a/src/tactic/smtlogics/qfufbv_tactic.cpp b/src/tactic/smtlogics/qfufbv_tactic.cpp
index f943b68c9..421a76cc7 100644
--- a/src/tactic/smtlogics/qfufbv_tactic.cpp
+++ b/src/tactic/smtlogics/qfufbv_tactic.cpp
@@ -124,7 +124,7 @@ private:
 
 };
 
-tactic * mk_qfufbv_preamble1(ast_manager & m, params_ref const & p) {
+static tactic * mk_qfufbv_preamble1(ast_manager & m, params_ref const & p) {
     params_ref simp2_p = p;
     simp2_p.set_bool("pull_cheap_ite", true);
     simp2_p.set_bool("push_ite_bv", false);
@@ -150,11 +150,7 @@ tactic * mk_qfufbv_preamble1(ast_manager & m, params_ref const & p) {
         );
 }
 
-tactic * mk_qfufbv_preamble(ast_manager & m, params_ref const & p) {
-    params_ref main_p;
-    main_p.set_bool("elim_and", true);
-    main_p.set_bool("blast_distinct", true);
-
+static tactic * mk_qfufbv_preamble(ast_manager & m, params_ref const & p) {
     return and_then(mk_simplify_tactic(m),
         mk_propagate_values_tactic(m),
         mk_solve_eqs_tactic(m),