move to get_sort as method, add opt_lns pass, disable xor simplification unless configured, fix perf bug in model converter update trail

src/sat/sat_big.cpp

@@ -198,7 +198,7 @@ namespace sat {
                         s.m_mc.stackv().reset(); // TBD: brittle code
                         s.add_ate(~u, v);
                         if (find_binary_watch(wlist, ~v)) {
-                            IF_VERBOSE(10, verbose_stream() << "binary: " << ~u << "\n");
+                            IF_VERBOSE(20, verbose_stream() << "binary: " << ~u << "\n");
                             s.assign_unit(~u);
                         }
                         // could turn non-learned non-binary tautology into learned binary.

src/sat/sat_config.cpp

@@ -60,6 +60,8 @@ namespace sat {
             m_phase = PS_SAT_CACHING;
         else if (s == symbol("random"))
             m_phase = PS_RANDOM;
+        else if (s == symbol("frozen"))
+            m_phase = PS_FROZEN;
         else
             throw sat_param_exception("invalid phase selection strategy: always_false, always_true, basic_caching, caching, random");
 

src/sat/sat_config.h

@@ -28,6 +28,7 @@ namespace sat {
         PS_ALWAYS_FALSE,
         PS_BASIC_CACHING,
         PS_SAT_CACHING,
+        PS_FROZEN,
         PS_RANDOM
     };
 

src/sat/sat_model_converter.cpp

@@ -222,7 +222,6 @@ namespace sat {
         e.m_clause.append(c.size(), c.begin());
     }
 
-
     void model_converter::insert(entry & e, clause const & c) {
         SASSERT(c.contains(e.var()));
         SASSERT(m_entries.begin() <= &e);
@@ -345,7 +344,7 @@ namespace sat {
     void model_converter::flush(model_converter & src) {
         VERIFY(this != &src);
         m_entries.append(src.m_entries);
-        m_exposed_lim = src.m_exposed_lim;
+        m_exposed_lim += src.m_exposed_lim;
         src.m_entries.reset();
         src.m_exposed_lim = 0;
     }

src/sat/sat_solver.cpp

@@ -1682,6 +1682,9 @@ namespace sat {
             case PS_BASIC_CACHING:
                 phase = m_phase[next];
                 break;
+            case PS_FROZEN:
+                phase = m_best_phase[next];
+                break;
             case PS_SAT_CACHING:
                 if (m_search_state == s_unsat) {
                     phase = m_phase[next];
@@ -2071,6 +2074,7 @@ namespace sat {
             if (!was_eliminated(v)) {
                 m_model[v] = value(v);
                 m_phase[v] = value(v) == l_true;
+                m_best_phase[v] = value(v) == l_true;
             }
         }
         TRACE("sat_mc_bug", m_mc.display(tout););
@@ -2847,6 +2851,8 @@ namespace sat {
     }
 
     void solver::updt_phase_of_vars() {
+        if (m_config.m_phase == PS_FROZEN)
+            return;
         unsigned from_lvl = m_conflict_lvl;
         unsigned head = from_lvl == 0 ? 0 : m_scopes[from_lvl - 1].m_trail_lim;
         unsigned sz   = m_trail.size();
@@ -2912,6 +2918,8 @@ namespace sat {
         case PS_ALWAYS_FALSE:
             for (auto& p : m_phase) p = false;
             break;
+        case PS_FROZEN:
+            break;
         case PS_BASIC_CACHING:
             switch (m_rephase_lim % 4) {
             case 0:

src/sat/smt/ba_solver.cpp

@@ -1437,6 +1437,10 @@ namespace sat {
 
 
     bool ba_solver::init_watch(constraint& c) {
+        if (c.is_xr()) {
+            std::cout << c.is_xr() << "\n";
+        }
+
         return !inconsistent() && c.init_watch(*this);
     }
 
@@ -2064,8 +2068,10 @@ namespace sat {
             for (unsigned sz = m_constraints.size(), i = 0; i < sz; ++i) subsumption(*m_constraints[i]);
             for (unsigned sz = m_learned.size(), i = 0; i < sz; ++i) subsumption(*m_learned[i]);    
             unit_strengthen();
-            extract_xor();
-            merge_xor();
+            if (s().get_config().m_xor_solver) {
+                extract_xor();
+                merge_xor();
+            }
             cleanup_clauses();
             cleanup_constraints();
             update_pure();
@@ -2073,6 +2079,8 @@ namespace sat {
         }        
         while (count < 10 && (m_simplify_change || trail_sz < s().init_trail_size()));
 
+        gc();
+
         // validate_eliminated();
 
         IF_VERBOSE(1, 

src/sat/tactic/goal2sat.cpp

@@ -72,7 +72,7 @@ struct goal2sat::imp : public sat::sat_internalizer {
     expr_ref_vector             m_trail;
     func_decl_ref_vector        m_unhandled_funs;
     bool                        m_default_external;
-    bool                        m_xor_solver;
+    bool                        m_xor_solver { false };
     bool                        m_euf { false };
     bool                        m_drat { false };
     bool                        m_is_redundant { false };
@@ -1020,6 +1020,7 @@ void sat2goal::mc::flush_gmc() {
     expr_ref_vector tail(m);
     expr_ref def(m);
     auto is_literal = [&](expr* e) { expr* r; return is_uninterp_const(e) || (m.is_not(e, r) && is_uninterp_const(r)); };
+    
     for (unsigned i = 0; i < updates.size(); ++i) {
         sat::literal l = updates[i];
         if (l == sat::null_literal) {