add option to persist clauses #7109

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/smt/params/smt_params.cpp

@@ -51,6 +51,7 @@ void smt_params::updt_local_params(params_ref const & _p) {
     m_core_validate = p.core_validate();
     m_logic = _p.get_sym("logic", m_logic);
     m_string_solver = p.string_solver();
+    m_up_persist_clauses = p.up_persist_clauses();
     validate_string_solver(m_string_solver);
     if (_p.get_bool("arith.greatest_error_pivot", false))
         m_arith_pivot_strategy = arith_pivot_strategy::ARITH_PIVOT_GREATEST_ERROR;
@@ -145,6 +146,7 @@ void smt_params::display(std::ostream & out) const {
     DISPLAY_PARAM(m_agility_factor);
     DISPLAY_PARAM(m_restart_agility_threshold);
 
+    DISPLAY_PARAM(m_up_persist_clauses);
     DISPLAY_PARAM(m_lemma_gc_strategy);
     DISPLAY_PARAM(m_lemma_gc_half);
     DISPLAY_PARAM(m_recent_lemmas_size);

src/smt/params/smt_params.h

@@ -170,6 +170,14 @@ struct smt_params : public preprocessor_params,
     unsigned          m_old_clause_relevancy = 6; //!< Max. number of unassigned literals to be considered relevant.
     double            m_inv_clause_decay = 1;     //!< clause activity decay
 
+    // -----------------------------------
+    //
+    // User propagator configuration
+    //
+    // -----------------------------------
+
+    bool             m_up_persist_clauses = false;
+
     // -----------------------------------
     //
     // SMT-LIB (debug) pretty printer

src/smt/params/smt_params_helper.pyg

@@ -102,6 +102,7 @@ def_module_params(module_name='smt',
                           ('arith.print_ext_var_names', BOOL, False, 'print external variable names'),
                           ('pb.conflict_frequency', UINT, 1000, 'conflict frequency for Pseudo-Boolean theory'),
                           ('pb.learn_complements', BOOL, True, 'learn complement literals for Pseudo-Boolean theory'),
+                          ('up.persist_clauses', BOOL, True, 'replay propagated clauses below the levels they are asserted'),
                           ('array.weak', BOOL, False, 'weak array theory'),
                           ('array.extensional', BOOL, True, 'extensional array theory'),
                           ('clause_proof', BOOL, False, 'record a clausal proof'),

src/smt/theory_user_propagator.cpp

@@ -293,7 +293,7 @@ void theory_user_propagator::pop_scope_eh(unsigned num_scopes) {
 }
 
 bool theory_user_propagator::can_propagate() {
-    return m_qhead < m_prop.size() || m_to_add_qhead < m_to_add.size();
+    return m_qhead < m_prop.size() || m_to_add_qhead < m_to_add.size() || m_replay_qhead < m_clauses_to_replay.size();
 }
 
 void theory_user_propagator::propagate_consequence(prop_info const& prop) {
@@ -321,12 +321,10 @@ void theory_user_propagator::propagate_consequence(prop_info const& prop) {
         ctx.set_conflict(js);
     }
     else {
-#if 1
         for (auto& lit : m_lits)
             lit.neg();
         for (auto const& [a,b] : m_eqs)
             m_lits.push_back(~mk_eq(a->get_expr(), b->get_expr(), false));
-#endif
 
         literal lit; 
         if (has_quantifiers(prop.m_conseq)) {
@@ -340,19 +338,17 @@ void theory_user_propagator::propagate_consequence(prop_info const& prop) {
             lit = mk_literal(prop.m_conseq);
         ctx.mark_as_relevant(lit);
 
-#if 0
-        justification* js =
-            ctx.mk_justification(
-                ext_theory_propagation_justification(
-                    get_id(), ctx, m_lits.size(), m_lits.data(), m_eqs.size(), m_eqs.data(), lit));
-
-        ctx.assign(lit, js);
-#endif
-
-#if 1
         m_lits.push_back(lit);
-        ctx.mk_th_lemma(get_id(), m_lits);
-#endif
+        if (ctx.get_fparams().m_up_persist_clauses) {
+            ctx.mk_th_axiom(get_id(), m_lits);
+            expr_ref_vector clause(m);
+            for (auto lit : m_lits)
+                clause.push_back(ctx.literal2expr(lit));
+            m_clauses_to_replay.push_back(clause);
+        }
+        else {
+            ctx.mk_th_lemma(get_id(), m_lits);
+        }
         TRACE("user_propagate", ctx.display(tout););
     }
 }
@@ -363,12 +359,20 @@ void theory_user_propagator::propagate_new_fixed(prop_info const& prop) {
 
 
 void theory_user_propagator::propagate() {
-    if (m_qhead == m_prop.size() && m_to_add_qhead == m_to_add.size())
+    if (m_qhead == m_prop.size() && m_to_add_qhead == m_to_add.size() && m_replay_qhead == m_clauses_to_replay.size())
         return;
     TRACE("user_propagate", tout << "propagating queue head: " << m_qhead << " prop queue: " << m_prop.size() << "\n");
     force_push();
 
-    unsigned qhead = m_to_add_qhead;
+    unsigned qhead = m_replay_qhead;
+    if (qhead < m_clauses_to_replay.size()) {
+        for (; qhead < m_clauses_to_replay.size() && !ctx.inconsistent(); ++qhead)
+            replay_clause(m_clauses_to_replay.get(qhead));
+        ctx.push_trail(value_trail<unsigned>(m_replay_qhead));
+        m_replay_qhead = qhead;
+    }
+
+    qhead = m_to_add_qhead;
     if (qhead < m_to_add.size()) {
         for (; qhead < m_to_add.size(); ++qhead)
             add_expr(m_to_add.get(qhead), true);
@@ -391,6 +395,13 @@ void theory_user_propagator::propagate() {
 }
 
 
+void theory_user_propagator::replay_clause(expr_ref_vector const& clause) {
+    m_lits.reset();
+    for (expr* e : clause)
+        m_lits.push_back(mk_literal(e));
+    ctx.mk_th_axiom(get_id(), m_lits);
+}
+
 bool theory_user_propagator::internalize_atom(app* atom, bool gate_ctx) {
     return internalize_term(atom);
 }

src/smt/theory_user_propagator.h

@@ -86,6 +86,8 @@ namespace smt {
         expr*                  m_next_split_var = nullptr;
         unsigned               m_next_split_idx = 0;
         lbool                  m_next_split_phase = l_undef;
+        vector<expr_ref_vector> m_clauses_to_replay;
+        unsigned                m_replay_qhead = 0;
 
         expr* var2expr(theory_var v) { return m_var2expr.get(v); }
         theory_var expr2var(expr* e) { check_defined(e); return m_expr2var[e->get_id()]; }
@@ -101,6 +103,8 @@ namespace smt {
 
         bool_var enode_to_bool(enode* n, unsigned bit);
 
+        void replay_clause(expr_ref_vector const& clause);
+
     public:
         theory_user_propagator(context& ctx);