array solver fixes

src/ast/array_decl_plugin.h

@@ -182,30 +182,31 @@ public:
 
     bool is_as_array_tree(expr * n);
 
-    app * mk_store(unsigned num_args, expr * const * args) {
+    app * mk_store(unsigned num_args, expr * const * args) const {
         return m_manager.mk_app(m_fid, OP_STORE, 0, nullptr, num_args, args);
     }
 
-    app * mk_store(expr_ref_vector const& args) {
-        return mk_store(args.size(), args.c_ptr());
-    }
-    app * mk_store(ptr_vector<expr> const& args) {
+    app * mk_store(expr_ref_vector const& args) const {
         return mk_store(args.size(), args.c_ptr());
     }
 
-    app * mk_select(unsigned num_args, expr * const * args) {
+    app * mk_store(ptr_vector<expr> const& args) const {
+        return mk_store(args.size(), args.c_ptr());
+    }
+
+    app * mk_select(unsigned num_args, expr * const * args) const {
         return m_manager.mk_app(m_fid, OP_SELECT, 0, nullptr, num_args, args);
     }
 
-    app * mk_select(ptr_vector<expr> const& args) {
+    app * mk_select(ptr_vector<expr> const& args) const {
         return mk_select(args.size(), args.c_ptr());
     }
 
-    app * mk_select(ptr_buffer<expr> const& args) {
+    app * mk_select(ptr_buffer<expr> const& args) const {
         return mk_select(args.size(), args.c_ptr());
     }
 
-    app * mk_select(expr_ref_vector const& args) {
+    app * mk_select(expr_ref_vector const& args) const {
         return mk_select(args.size(), args.c_ptr());
     }
 

src/sat/smt/CMakeLists.txt

@@ -5,6 +5,7 @@ z3_add_component(sat_smt
     arith_internalize.cpp
     arith_solver.cpp
     array_axioms.cpp
+    array_diagnostics.cpp
     array_internalize.cpp
     array_model.cpp
     array_solver.cpp

src/sat/smt/arith_solver.cpp

@@ -78,7 +78,7 @@ namespace arith {
         }
 
         // clone rows into m_solver, m_nla, m_lia
-        NOT_IMPLEMENTED_YET();
+        // NOT_IMPLEMENTED_YET();
 
         return result;        
     }

src/sat/smt/array_axioms.cpp

@@ -25,22 +25,27 @@ namespace array {
     void solver::push_axiom(axiom_record const& r) { 
         unsigned idx = m_axiom_trail.size();
         m_axiom_trail.push_back(r); 
+        TRACE("array", display(tout, r) << " " << m_axioms.contains(idx) << "\n";);
         if (m_axioms.contains(idx))
             m_axiom_trail.pop_back();
         else
             ctx.push(push_back_vector<svector<axiom_record>>(m_axiom_trail));
     }
 
-    bool solver::propagate_axiom(unsigned idx) {
-        if (m_axioms.contains(idx))
+    bool solver::propagate_axiom(unsigned idx) {        
+        if (!m_axioms.contains(idx)) {
+            m_axioms.insert(idx);
+            ctx.push(insert_map<axiom_table_t, unsigned>(m_axioms, idx));
+        }
+        else if (!m_axiom_trail[idx].is_delayed())
             return false;
-        m_axioms.insert(idx);
-        ctx.push(insert_map<axiom_table_t, unsigned>(m_axioms, idx));
         return assert_axiom(idx);
     }
 
     bool solver::assert_axiom(unsigned idx) {
         axiom_record& r = m_axiom_trail[idx];
+        if (!is_relevant(r))
+            return false;
         switch (r.m_kind) {
         case axiom_record::kind_t::is_store:
             return assert_store_axiom(to_app(r.n->get_expr()));
@@ -62,8 +67,7 @@ namespace array {
     bool solver::assert_default(axiom_record& r) {
         expr* child = r.n->get_expr();
         SASSERT(can_beta_reduce(r.n));
-        if (!ctx.is_relevant(child))
-            return false;
+            
         TRACE("array", tout << "default-axiom: " << mk_bounded_pp(child, m, 2) << "\n";);
         if (a.is_const(child))
             return assert_default_const_axiom(to_app(child));
@@ -79,30 +83,47 @@ namespace array {
         solver& s;
         unsigned m_idx;
         set_delay_bit(solver& s, unsigned idx) : s(s), m_idx(idx) {}
-        void undo(/*euf::solver& euf*/) override {
+        void undo() override {
             s.m_axiom_trail[m_idx].m_delayed = false;
         }
     };
 
+    bool solver::is_relevant(axiom_record const& r) const {
+        return true;
+#if 0
+        // relevancy propagation is currently incomplete on terms
+
+        expr* child = r.n->get_expr();
+        switch (r.m_kind) {
+        case axiom_record::kind_t::is_select: {
+            app* select = r.select->get_app();
+            for (unsigned i = 1; i < select->get_num_args(); ++i)
+                if (!ctx.is_relevant(select->get_arg(i)))
+                    return false;
+            return ctx.is_relevant(child);            
+        }
+        case axiom_record::kind_t::is_default:
+            return ctx.is_relevant(child);            
+        default:
+            return true;
+        }
+#endif
+    }
+
     bool solver::assert_select(unsigned idx, axiom_record& r) {
         expr* child = r.n->get_expr();
         app* select = r.select->get_app();
         SASSERT(a.is_select(select));
         SASSERT(can_beta_reduce(r.n));
-        if (!ctx.is_relevant(child))
-            return false;
-        for (unsigned i = 1; i < select->get_num_args(); ++i)
-            if (!ctx.is_relevant(select->get_arg(i)))
-                return false;
-        TRACE("array", tout << "select-axiom: " << mk_bounded_pp(select, m, 2) << " " << mk_bounded_pp(child, m, 2) << "\n";);
-        if (get_config().m_array_delay_exp_axiom && r.select->get_arg(0)->get_root() != r.n->get_root() && !r.m_delayed) {
+        TRACE("array", display(tout << "select-axiom: ", r) << "\n";);
+
+        if (get_config().m_array_delay_exp_axiom && r.select->get_arg(0)->get_root() != r.n->get_root() && !r.m_delayed && m_enable_delay) {
             IF_VERBOSE(11, verbose_stream() << "delay: " << mk_bounded_pp(child, m) << " " << mk_bounded_pp(select, m) << "\n");
             ctx.push(set_delay_bit(*this, idx));
             r.m_delayed = true;
             return false;
         }
-        if (r.select->get_arg(0)->get_root() != r.n->get_root() && r.m_delayed)
-            return false;
+        r.m_delayed = false;
         if (a.is_const(child))
             return assert_select_const_axiom(select, to_app(child));
         else if (a.is_as_array(child))
@@ -163,8 +184,13 @@ namespace array {
         expr_ref sel_eq_e(m.mk_eq(sel1, sel2), m);
         euf::enode* s1 = e_internalize(sel1);
         euf::enode* s2 = e_internalize(sel2);
+        TRACE("array", 
+              tout << "select-store " << ctx.bpp(s1) << " " << ctx.bpp(s1->get_root()) << "\n";
+              tout << "select-store " << ctx.bpp(s2) << " " << ctx.bpp(s2->get_root()) << "\n";);
+
         if (s1->get_root() == s2->get_root())
             return false;
+
         sat::literal sel_eq = mk_literal(sel_eq_e);
         if (s().value(sel_eq) == l_true)
             return false;
@@ -173,8 +199,8 @@ namespace array {
         for (unsigned i = 1; i < num_args; i++) {
             expr* idx1 = store->get_arg(i);
             expr* idx2 = select->get_arg(i);
-            euf::enode* r1 = expr2enode(idx1)->get_root();
-            euf::enode* r2 = expr2enode(idx2)->get_root();
+            euf::enode* r1 = expr2enode(idx1);
+            euf::enode* r2 = expr2enode(idx2);
             if (r1 == r2)
                 continue;
             if (m.are_distinct(r1->get_expr(), r2->get_expr())) {
@@ -186,6 +212,7 @@ namespace array {
             if (add_clause(idx_eq, sel_eq))
                 new_prop = true;
         }
+        TRACE("array", tout << "select-stored " << new_prop << "\n";);
         return new_prop;
     }
 
@@ -483,9 +510,11 @@ namespace array {
         bool change = false;
         unsigned sz = m_axiom_trail.size();
         m_delay_qhead = 0;
+        
         for (; m_delay_qhead < sz; ++m_delay_qhead) 
-            if (m_axiom_trail[m_delay_qhead].m_delayed && assert_axiom(m_delay_qhead))
-                change = true;        
+            if (m_axiom_trail[m_delay_qhead].is_delayed() && assert_axiom(m_delay_qhead))
+                change = true;  
+        flet<bool> _enable_delay(m_enable_delay, false);
         if (unit_propagate())
             change = true;
         return change;

src/sat/smt/array_diagnostics.cpp

@@ -0,0 +1,138 @@
+/*++
+Copyright (c) 2020 Microsoft Corporation
+
+Module Name:
+
+    array_diagnostics.cpp
+
+Abstract:
+
+    Theory plugin for arrays, diagnostics functions
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2020-09-08
+
+*/
+
+#include "sat/smt/array_solver.h"
+#include "sat/smt/euf_solver.h"
+
+namespace array {
+    std::ostream& solver::display(std::ostream& out) const {
+        if (get_num_vars() > 0)
+            out << "array\n";
+        for (unsigned i = 0; i < get_num_vars(); ++i) {
+            auto& d = get_var_data(i);
+            out << var2enode(i)->get_expr_id() << " " << (d.m_prop_upward?"up":"fx") << " " << mk_bounded_pp(var2expr(i), m, 2) << "\n";
+            display_info(out, "parent lambdas", d.m_parent_lambdas);
+            display_info(out, "parent select", d.m_parent_selects);
+            display_info(out, "lambdas", d.m_lambdas);
+        }
+        return out;
+    }
+
+    std::ostream& solver::display_info(std::ostream& out, char const* id, euf::enode_vector const& v) const {
+        if (v.empty())
+            return out;
+        out << id << ":\n";
+        for (euf::enode* p : v)
+            out << "   " << ctx.bpp(p) << "\n";
+        return out;
+    }
+
+    std::ostream& solver::display(std::ostream& out, axiom_record const& r) const {
+        if (r.is_delayed())
+            out << "delay ";
+        switch (r.m_kind) {
+        case axiom_record::kind_t::is_store:
+            return out << "store " << ctx.bpp(r.n);            
+        case axiom_record::kind_t::is_select:
+            return out << "select " << ctx.bpp(r.n) << " " << ctx.bpp(r.select);
+        case axiom_record::kind_t::is_default:
+            return out << "default " << ctx.bpp(r.n);
+        case axiom_record::kind_t::is_extensionality:
+            return out << "extensionality " << ctx.bpp(r.n) << " " << ctx.bpp(r.select);
+        case axiom_record::kind_t::is_congruence:
+            return out << "congruence " << ctx.bpp(r.n) << " " << ctx.bpp(r.select);
+        default:
+            UNREACHABLE();
+        }
+        return out;
+    }
+
+
+    std::ostream& solver::display_justification(std::ostream& out, sat::ext_justification_idx idx) const { return out; }
+    std::ostream& solver::display_constraint(std::ostream& out, sat::ext_constraint_idx idx) const { return out; }
+
+    void solver::collect_statistics(statistics& st) const {
+        st.update("array store",        m_stats.m_num_store_axiom);
+        st.update("array sel/store",    m_stats.m_num_select_store_axiom);
+        st.update("array sel/const",    m_stats.m_num_select_const_axiom);
+        st.update("array sel/map",      m_stats.m_num_select_map_axiom);
+        st.update("array sel/as array", m_stats.m_num_select_as_array_axiom);
+        st.update("array sel/lambda",   m_stats.m_num_select_lambda_axiom);
+        st.update("array def/map",      m_stats.m_num_default_map_axiom);
+        st.update("array def/const",    m_stats.m_num_default_const_axiom);
+        st.update("array def/store",    m_stats.m_num_default_store_axiom);
+        st.update("array ext ax",       m_stats.m_num_extensionality_axiom);
+        st.update("array cong ax",      m_stats.m_num_congruence_axiom);        
+        st.update("array exp ax2",      m_stats.m_num_select_store_axiom_delayed);
+        st.update("array splits",       m_stats.m_num_eq_splits);
+    }
+
+    void solver::validate_check() const {
+        for (euf::enode* n : ctx.get_egraph().nodes()) {
+            if (!ctx.is_relevant(n)) 
+                continue;
+            if (a.is_select(n->get_expr()) && a.is_store(n->get_arg(0)->get_expr()))
+                validate_select_store(n);
+            if (is_array(n) && n->is_root() && ctx.is_shared(n)) {
+                for (euf::enode* k : ctx.get_egraph().nodes())
+                    if (k->get_expr_id() > n->get_expr_id() && k->is_root() && is_array(k) && ctx.is_shared(k))
+                        validate_extensionality(n, k);
+            }
+            expr* x = nullptr, *y = nullptr;
+            if (m.is_eq(n->get_expr(), x, y) && a.is_array(x))
+                std::cout << ctx.bpp(n) << " " << s().value(n->bool_var()) << "\n";
+            if (m.is_eq(n->get_expr(), x, y) && a.is_array(x) && s().value(n->bool_var()) == l_false)
+                validate_extensionality(expr2enode(x), expr2enode(y));
+        }        
+    }
+
+
+    void solver::validate_select_store(euf::enode* n) const {
+        SASSERT(a.is_select(n->get_expr()));
+        SASSERT(a.is_store(n->get_arg(0)->get_expr()));
+        bool same_args = true;
+        for (unsigned i = 1; same_args && i < n->num_args(); ++i) 
+            same_args = n->get_arg(i)->get_root() == n->get_arg(0)->get_arg(i)->get_root(); 
+        if (same_args) {
+            VERIFY(n->get_arg(0)->get_arg(n->num_args())->get_root() == n->get_root());
+            return;
+        }
+        euf::enode_vector args;
+        ptr_vector<expr> eargs;
+        args.push_back(n->get_arg(0)->get_arg(0));
+        for (unsigned i = 1; i < n->num_args(); ++i)
+            args.push_back(n->get_arg(i));
+        for (euf::enode* n : args)
+            eargs.push_back(n->get_expr());
+        expr_ref sel(a.mk_select(eargs.size(), eargs.c_ptr()), m);
+        euf::enode* n1 = ctx.get_egraph().find(sel, args.size(), args.c_ptr());
+        if (n1 && n1->get_root() == n->get_root())
+            return;
+        IF_VERBOSE(0, 
+                   verbose_stream() << ctx.bpp(n) << "\n";
+                   verbose_stream() << sel << "\n";
+                   verbose_stream() << n1 << " " << n->get_root() << "\n";);
+    }
+
+    void solver::validate_extensionality(euf::enode* s, euf::enode* t) const {
+        if (s->get_sort() != t->get_sort())
+            return;
+        IF_VERBOSE(0, 
+                   verbose_stream() << "extensionality " << ctx.bpp(s) << " " << ctx.bpp(t) << "\n";);
+    }
+
+}

src/sat/smt/array_solver.cpp

@@ -3,7 +3,7 @@ Copyright (c) 2020 Microsoft Corporation
 
 Module Name:
 
-    array_solver.h
+    array_solver.cpp
 
 Abstract:
 
@@ -101,6 +101,10 @@ namespace array {
             else if (!turn[idx] && add_interface_equalities())
                 return sat::check_result::CR_CONTINUE;
         }
+        if (m_delay_qhead < m_axiom_trail.size()) 
+            return sat::check_result::CR_CONTINUE;
+            
+        // validate_check();
         return sat::check_result::CR_DONE;
     }
 
@@ -109,48 +113,6 @@ namespace array {
         m_var_data.resize(get_num_vars());
     }
 
-    std::ostream& solver::display(std::ostream& out) const {
-        if (get_num_vars() > 0)
-            out << "array\n";
-        for (unsigned i = 0; i < get_num_vars(); ++i) {
-            auto& d = get_var_data(i);
-            out << var2enode(i)->get_expr_id() << " " << mk_bounded_pp(var2expr(i), m, 2) << "\n";
-            display_info(out, "parent lambdas", d.m_parent_lambdas);
-            display_info(out, "parent select",  d.m_parent_selects);
-            display_info(out, "lambdas",        d.m_lambdas);
-        }
-        return out;
-    }
-
-    std::ostream& solver::display_info(std::ostream& out, char const* id, euf::enode_vector const& v) const {
-        if (v.empty())
-            return out;
-        out << id << ": ";
-        for (euf::enode* p : v)
-            out << mk_bounded_pp(p->get_expr(), m, 2) << " ";
-        out << "\n";
-        return out;
-    }
-
-    std::ostream& solver::display_justification(std::ostream& out, sat::ext_justification_idx idx) const { return out; }
-    std::ostream& solver::display_constraint(std::ostream& out, sat::ext_constraint_idx idx) const { return out; }
-
-    void solver::collect_statistics(statistics& st) const {
-        st.update("array store",        m_stats.m_num_store_axiom);
-        st.update("array sel/store",    m_stats.m_num_select_store_axiom);
-        st.update("array sel/const",    m_stats.m_num_select_const_axiom);
-        st.update("array sel/map",      m_stats.m_num_select_map_axiom);
-        st.update("array sel/as array", m_stats.m_num_select_as_array_axiom);
-        st.update("array sel/lambda",   m_stats.m_num_select_lambda_axiom);
-        st.update("array def/map",      m_stats.m_num_default_map_axiom);
-        st.update("array def/const",    m_stats.m_num_default_const_axiom);
-        st.update("array def/store",    m_stats.m_num_default_store_axiom);
-        st.update("array ext ax",       m_stats.m_num_extensionality_axiom);
-        st.update("array cong ax",      m_stats.m_num_congruence_axiom);        
-        st.update("array exp ax2",      m_stats.m_num_select_store_axiom_delayed);
-        st.update("array splits",       m_stats.m_num_eq_splits);
-    }
-
     euf::th_solver* solver::clone(euf::solver& dst_ctx) {
         auto* result = alloc(solver, dst_ctx, get_id());
         for (unsigned i = 0; i < get_num_vars(); ++i)          
@@ -186,6 +148,7 @@ namespace array {
     void solver::merge_eh(theory_var v1, theory_var v2, theory_var, theory_var) {
         euf::enode* n1 = var2enode(v1);
         euf::enode* n2 = var2enode(v2);
+        TRACE("array", tout << "merge: " << ctx.bpp(n1) << " == " << ctx.bpp(n2) << "\n";);
         SASSERT(n1->get_root() == n2->get_root());
         SASSERT(v1 == find(v1));
         expr* e1 = n1->get_expr();
@@ -207,11 +170,11 @@ namespace array {
     void solver::add_parent_select(theory_var v_child, euf::enode* select) {
         SASSERT(a.is_select(select->get_expr()));
         SASSERT(select->get_arg(0)->get_sort() == var2expr(v_child)->get_sort());
-
         v_child = find(v_child);
         ctx.push_vec(get_var_data(v_child).m_parent_selects, select);
         euf::enode* child = var2enode(v_child);
-        if (can_beta_reduce(child) && child != select->get_arg(0))
+        TRACE("array", tout << "v" << v_child << " - " << ctx.bpp(select) << " " << ctx.bpp(child) << " prop: " << should_prop_upward(get_var_data(v_child)) << "\n";);
+        if (can_beta_reduce(child)) 
             push_axiom(select_axiom(select, child));
     }
 
@@ -260,7 +223,9 @@ namespace array {
         expr* e = var2expr(v);
         if (!a.is_array(e))
             return;
+        
         auto& d = get_var_data(v);
+
         for (euf::enode* lambda : d.m_parent_lambdas)
             propagate_select_axioms(d, lambda);
     }

src/sat/smt/array_solver.h

@@ -96,6 +96,8 @@ namespace array {
             bool        m_delayed { false };
             axiom_record(kind_t k, euf::enode* n, euf::enode* select = nullptr) : m_kind(k), n(n), select(select) {}
 
+            bool is_delayed() const { return m_delayed; }
+
             struct hash {
                 solver& s;
                 hash(solver& s) :s(s) {}
@@ -122,12 +124,14 @@ namespace array {
         svector<axiom_record> m_axiom_trail;
         unsigned              m_qhead { 0 };
         unsigned              m_delay_qhead { 0 };
+        bool                  m_enable_delay { true };
         struct set_delay_bit;
         void push_axiom(axiom_record const& r);
         bool propagate_axiom(unsigned idx);
         bool assert_axiom(unsigned idx);
         bool assert_select(unsigned idx, axiom_record & r);
         bool assert_default(axiom_record & r);
+        bool is_relevant(axiom_record const& r) const;
 
         axiom_record select_axiom(euf::enode* s, euf::enode* n) { return axiom_record(axiom_record::kind_t::is_select, n, s); }
         axiom_record default_axiom(euf::enode* n) { return axiom_record(axiom_record::kind_t::is_default, n); }
@@ -188,7 +192,11 @@ namespace array {
         bool have_different_model_values(theory_var v1, theory_var v2);
 
         // diagnostics
-        std::ostream& display_info(std::ostream& out, char const* id, euf::enode_vector const& v) const;
+        std::ostream& display_info(std::ostream& out, char const* id, euf::enode_vector const& v) const; 
+        std::ostream& display(std::ostream& out, axiom_record const& r) const;
+        void validate_check() const;
+        void validate_select_store(euf::enode* n) const;
+        void validate_extensionality(euf::enode* s, euf::enode* t) const;
     public:
         solver(euf::solver& ctx, theory_id id);
         ~solver() override;

src/sat/smt/euf_model.cpp

@@ -236,13 +236,16 @@ namespace euf {
             expr* e = n->get_expr();
             if (!m.is_bool(e))
                 continue;
-            unsigned id = n->get_root_id();
-            if (!m_values.get(id))
+            if (!is_relevant(n))
                 continue;
-            bool tt = m.is_true(m_values.get(id));
-            if (mdl.is_true(e) != tt) {
-                IF_VERBOSE(0, verbose_stream() << "Failed to evaluate " << id << " " << mk_bounded_pp(e, m) << " " << mdl(e) << " " << mk_bounded_pp(m_values.get(id), m) << "\n");
+            bool tt = l_true == s().value(n->bool_var());
+            if (tt && mdl.is_false(e)) {
+                IF_VERBOSE(0, verbose_stream() << "Failed to validate " << bpp(n) << " " << mdl(e) << "\n");
+                for (auto* arg : euf::enode_args(n))
+                    IF_VERBOSE(0, verbose_stream() << bpp(arg) << "\n" << mdl(arg->get_expr()) << "\n");
             }
+            if (!tt && mdl.is_true(e))
+                IF_VERBOSE(0, verbose_stream() << "Failed to validate " << bpp(n) << " " << mdl(e) << "\n");
         }
         
     }

src/sat/smt/euf_solver.h

@@ -359,6 +359,7 @@ namespace euf {
         bool relevancy_enabled() const { return get_config().m_relevancy_lvl > 0; }
         void add_root(unsigned n, sat::literal const* lits);
         void add_aux(unsigned n, sat::literal const* lits);
+        void add_aux(sat::literal a, sat::literal b) { sat::literal lits[2] = {a, b}; add_aux(2, lits); }
         void track_relevancy(sat::bool_var v);
         bool is_relevant(expr* e) const;
         bool is_relevant(enode* n) const;

src/smt/params/theory_array_params.h

@@ -59,23 +59,6 @@ struct theory_array_params {
 
     void updt_params(params_ref const & _p);
 
-#if 0
-    void register_params(ini_params & p) {
-        p.register_int_param("array_solver", 0, 3, reinterpret_cast<int&>(m_array_mode), "0 - no array, 1 - simple, 2 - model based, 3 - full");
-        p.register_bool_param("array_weak", m_array_weak);
-        p.register_bool_param("array_extensional", m_array_extensional);
-        p.register_unsigned_param("array_laziness", m_array_laziness);
-        p.register_bool_param("array_delay_exp_axiom", m_array_delay_exp_axiom);
-        p.register_bool_param("array_cg", m_array_cg);
-        p.register_bool_param("array_always_prop_upward", m_array_always_prop_upward, 
-                              "Disable the built-in filter upwards propagation");
-        p.register_bool_param("array_lazy_ieq", m_array_lazy_ieq);
-        p.register_unsigned_param("array_lazy_ieq_delay", m_array_lazy_ieq_delay);
-        p.register_bool_param("array_canonize", m_array_canonize_simplify, 
-                              "Normalize arrays into normal form during simplification");
-    }
-#endif
-
     void display(std::ostream & out) const;
 };