fix drat output for elim_eqs

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

src/sat/sat_elim_eqs.cpp

@@ -23,9 +23,15 @@ Revision History:
 namespace sat {
     
     elim_eqs::elim_eqs(solver & s):
-        m_solver(s) {
+        m_solver(s),
+        m_to_delete(nullptr) {
     }
 
+    elim_eqs::~elim_eqs() {
+        dealloc(m_to_delete);
+    }
+
+
     inline literal norm(literal_vector const & roots, literal l) {
         if (l.sign()) 
             return ~roots[l.var()];
@@ -86,6 +92,12 @@ namespace sat {
         m_new_bin.reset();
     }
 
+    void elim_eqs::drat_delete_clause() {
+        if (m_solver.m_config.m_drat) {
+            m_solver.m_drat.del(*m_to_delete->get()); 
+        }
+    }
+
     void elim_eqs::cleanup_clauses(literal_vector const & roots, clause_vector & cs) {
         clause_vector::iterator it  = cs.begin();
         clause_vector::iterator it2 = it;
@@ -107,8 +119,16 @@ namespace sat {
                 it2++;
                 continue;
             }
-            if (!c.frozen())
+            if (!c.frozen()) {
                 m_solver.detach_clause(c);
+            }
+            
+            // save clause to be deleted for drat
+            if (m_solver.m_config.m_drat) {
+                if (!m_to_delete) m_to_delete = alloc(tmp_clause);
+                m_to_delete->set(sz, c.begin(), c.is_learned());
+            }
+
             // apply substitution
             for (i = 0; i < sz; i++) {   
                 literal lit = c[i];
@@ -124,60 +144,69 @@ namespace sat {
                         CTRACE("sat", l != norm(roots, l), tout << l << " " << norm(roots, l) << "\n"; tout.flush(););
                         SASSERT(l == norm(roots, l));
                     } });
+
             // remove duplicates, and check if it is a tautology
-            literal l_prev = null_literal;
             unsigned j = 0;
+            literal l_prev = null_literal;
             for (i = 0; i < sz; i++) {
                 literal l = c[i];
-                if (l == l_prev)
+                if (l == ~l_prev) {
-                    continue;
-                if (l == ~l_prev)
                     break;
+                }
+                if (l == l_prev) {
+                    continue;
+                }
+                SASSERT(l != ~l_prev);
                 l_prev = l;
                 lbool val = m_solver.value(l);
-                if (val == l_true)
+                if (val == l_true) {
-                    break; // clause was satisfied
+                    break;
-                if (val == l_false)
+                }
+                if (val == l_false) {
                     continue; // skip
+                }
                 c[j] = l;                
                 j++;
             }
+            TRACE("elim_eqs", tout << "after removing duplicates: " << c << " j: " << j << "\n";);
+
             if (i < sz) {
-                // clause is a tautology or was simplified to true
+                drat_delete_clause();
-                m_solver.del_clause(c);
+                m_solver.del_clause(c, false);
                 continue; 
             }
-            if (j == 0) {
+
-                // empty clause
+            switch (j) {
+            case 0:
                 m_solver.set_conflict(justification());
                 for (; it != end; ++it) {
                     *it2 = *it;
                     it2++;
                 }
                 cs.set_end(it2);
-                return;
+                return;                
-            }
-            TRACE("elim_eqs", tout << "after removing duplicates: " << c << " j: " << j << "\n";);
-
-            SASSERT(j >= 1);
-            switch (j) {
             case 1:
                 m_solver.assign(c[0], justification());
-                m_solver.del_clause(c);
+                m_solver.del_clause(c, false);
+                drat_delete_clause();
                 break;
             case 2:
                 m_solver.mk_bin_clause(c[0], c[1], c.is_learned());
-                m_solver.del_clause(c);
+                m_solver.del_clause(c, false);
+                drat_delete_clause();
                 break;
             default:
                 SASSERT(*it == &c);
                 if (j < sz) {
-                    if (m_solver.m_config.m_drat) m_solver.m_drat.del(c); 
                     c.shrink(j);
-                    if (m_solver.m_config.m_drat) m_solver.m_drat.add(c, true); 
                 }
-                else
+                else {
                     c.update_approx();
+                }
+                if (m_solver.m_config.m_drat) {
+                    m_solver.m_drat.add(c, true); 
+                    drat_delete_clause();
+                }
 
                 DEBUG_CODE(for (literal l : c) VERIFY(l == norm(roots, l)););
                 

src/sat/sat_elim_eqs.h

@@ -23,6 +23,7 @@ Revision History:
 
 namespace sat {
     class solver;
+    class tmp_clause;
     
     class elim_eqs {
         struct bin {
@@ -32,6 +33,8 @@ namespace sat {
         };
         svector<bin> m_new_bin;
         solver & m_solver;
+        tmp_clause* m_to_delete;
+        void drat_delete_clause();
         void save_elim(literal_vector const & roots, bool_var_vector const & to_elim);
         void cleanup_clauses(literal_vector const & roots, clause_vector & cs);
         void cleanup_bin_watches(literal_vector const & roots);
@@ -39,6 +42,7 @@ namespace sat {
         bool check_clause(clause const& c, literal_vector const& roots) const;
     public:
         elim_eqs(solver & s);
+        ~elim_eqs();
         void operator()(literal_vector const & roots, bool_var_vector const & to_elim);
     };
 

src/sat/sat_solver.cpp

@@ -298,14 +298,14 @@ namespace sat {
         mk_clause(3, ls, learned);
     }
 
-    void solver::del_clause(clause& c) {
+    void solver::del_clause(clause& c, bool enable_drat) {
         if (!c.is_learned()) {
             m_stats.m_non_learned_generation++;
         } 
         if (c.frozen()) {
             --m_num_frozen;
         }
-        if (m_config.m_drat && !m_drat.is_cleaned(c)) {
+        if (enable_drat && m_config.m_drat && !m_drat.is_cleaned(c)) {
             m_drat.del(c);
         }
         dealloc_clause(&c);        

src/sat/sat_solver.h

@@ -232,7 +232,7 @@ namespace sat {
         void defrag_clauses();
         bool should_defrag();
         bool memory_pressure();
-        void del_clause(clause & c);
+        void del_clause(clause & c, bool enable_drat = true);
         clause * mk_clause_core(unsigned num_lits, literal * lits, bool learned);
         clause * mk_clause_core(literal_vector const& lits) { return mk_clause_core(lits.size(), lits.c_ptr()); }
         clause * mk_clause_core(unsigned num_lits, literal * lits) { return mk_clause_core(num_lits, lits, false); }