diff --git a/src/ast/expr_substitution.h b/src/ast/expr_substitution.h
index 90154d163..1590f888c 100644
--- a/src/ast/expr_substitution.h
+++ b/src/ast/expr_substitution.h
@@ -80,6 +80,7 @@ public:
             m_trail_lim.resize(new_sz); 
         }
     }
+    unsigned scope_level() const { return m_trail_lim.size(); }
     bool empty() const { return m_subst.empty(); }
     expr* find(expr * e) { proof* pr; expr* d = 0; if (find(e, d, pr)) return d; else return e; }
     bool find(expr * s, expr * & def, proof * & def_pr) { return m_subst.find(s, def, def_pr); }
diff --git a/src/tactic/bv/bv_bounds_tactic.cpp b/src/tactic/bv/bv_bounds_tactic.cpp
index 44f920840..22b74db77 100644
--- a/src/tactic/bv/bv_bounds_tactic.cpp
+++ b/src/tactic/bv/bv_bounds_tactic.cpp
@@ -11,7 +11,9 @@ Abstract:
 
 Author:
 
-    Nikolaj Bjorner (nbjorner) 2016-2-12
+    Nuno Lopes (nlopes) 2016-2-12
+
+    Nikolaj Bjorner (nbjorner) 
 
 
 --*/
@@ -650,11 +652,11 @@ namespace {
                         return false;
                     if (old == intr)
                         return true;
-                    m_scopes.insert(undo_bound(t1, old, false));
+                    m_scopes.push_back(undo_bound(t1, old, false));
                     old = intr;
                 } else {
                     m_bound.insert(t1, b);
-                    m_scopes.insert(undo_bound(t1, interval(), true));
+                    m_scopes.push_back(undo_bound(t1, interval(), true));
                 }
             }
             return true;
@@ -801,6 +803,10 @@ namespace {
             return alloc(dom_bv_bounds_simplifier, m, m_params);
         }
 
+        virtual unsigned scope_level() const {
+            return m_scopes.size();
+        }
+
     };
 
 }
diff --git a/src/tactic/bv/bv_bounds_tactic.h b/src/tactic/bv/bv_bounds_tactic.h
index 6c2ce60ed..1d6748b27 100644
--- a/src/tactic/bv/bv_bounds_tactic.h
+++ b/src/tactic/bv/bv_bounds_tactic.h
@@ -11,7 +11,8 @@ Abstract:
 
 Author:
 
-    Nikolaj Bjorner (nbjorner) 2016-2-12
+    Nuno Lopes (nlopes) 2016-2-12
+    Nikolaj Bjorner (nbjorner)
 
 
 --*/
@@ -21,8 +22,15 @@ Author:
 
 tactic * mk_bv_bounds_tactic(ast_manager & m, params_ref const & p = params_ref());
 
+tactic * mk_dom_bv_bounds_tactic(ast_manager & m, params_ref const & p = params_ref());
+
 /*
   ADD_TACTIC("propagate-bv-bounds", "propagate bit-vector bounds by simplifying implied or contradictory bounds.", "mk_bv_bounds_tactic(m, p)")
+
+
+  ADD_TACTIC("propagate-bv-bounds-new", "propagate bit-vector bounds by simplifying implied or contradictory bounds.", "mk_dom_bv_bounds_tactic(m, p)")
+
+
 */
 
 #endif
diff --git a/src/tactic/core/dom_simplify_tactic.h b/src/tactic/core/dom_simplify_tactic.h
index 79bc9728c..6cd94a3c1 100644
--- a/src/tactic/core/dom_simplify_tactic.h
+++ b/src/tactic/core/dom_simplify_tactic.h
@@ -83,6 +83,8 @@ class dom_simplifier {
     virtual void pop(unsigned num_scopes) = 0;
     
     virtual dom_simplifier * translate(ast_manager & m) = 0;
+
+    virtual unsigned scope_level() const = 0;
     
 };
 
@@ -116,9 +118,9 @@ class dom_simplify_tactic : public tactic {
     ptr_vector<expr> const & tree(expr * e);
     expr* idom(expr *e) const { return m_dominators.idom(e); }
 
-    unsigned scope_level() { return m_scope_level; }
-    void pop(unsigned n) { SASSERT(n <= m_scope_level); m_scope_level -= n; m_simplifier->pop(n); }
-    bool assert_expr(expr* f, bool sign) { m_scope_level++; return m_simplifier->assert_expr(f, sign); }
+    unsigned scope_level() { return m_simplifier->scope_level(); }
+    void pop(unsigned n) { SASSERT(n <= m_simplifier->scope_level()); m_simplifier->pop(n); }
+    bool assert_expr(expr* f, bool sign) { return m_simplifier->assert_expr(f, sign); }
 
     bool init(goal& g);
 
@@ -169,6 +171,8 @@ public:
     
     virtual void pop(unsigned num_scopes) { m_scoped_substitution.pop(num_scopes); }
     
+    virtual unsigned scope_level() const { return m_scoped_substitution.scope_level(); }
+
     virtual dom_simplifier * translate(ast_manager & m) {
         SASSERT(m_subst.empty());
         return alloc(expr_substitution_simplifier, m);