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fixing #4670 (#4682)

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* fixing #4670

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

* init

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

* arrays

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

* arrays

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

* arrays

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

* na

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
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Nikolaj Bjorner 2020-09-10 04:35:11 -07:00 • committed by GitHub
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src/sat/smt/array_solver.cpp Normal file
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/*++
Copyright (c) 2020 Microsoft Corporation
Module Name:
array_solver.h
Abstract:
Theory plugin for arrays
Author:
Nikolaj Bjorner (nbjorner) 2020-09-08
--*/
#include "ast/ast_ll_pp.h"
#include "sat/smt/array_solver.h"
#include "sat/smt/euf_solver.h"
namespace array {
solver::solver(euf::solver& ctx, theory_id id):
th_euf_solver(ctx, id),
a(m),
m_sort2epsilon(m),
m_sort2diag(m),
m_find(*this),
m_hash(*this),
m_eq(*this),
m_axioms(DEFAULT_HASHTABLE_INITIAL_CAPACITY, m_hash, m_eq)
{
m_constraint = alloc(sat::constraint_base);
m_constraint->initialize(m_constraint.get(), this);
}
sat::check_result solver::check() {
flet<bool> _is_redundant(m_is_redundant, true);
bool turn[2] = { false, false };
turn[s().rand()(2)] = true;
for (unsigned idx = 0; idx < 2; ++idx) {
if (turn[idx]) {
if (add_delayed_axioms())
return sat::CR_CONTINUE;
}
else {
if (add_interface_equalities())
return sat::CR_CONTINUE;
}
}
return sat::CR_DONE;
}
void solver::push() {
th_euf_solver::lazy_push();
}
void solver::pop(unsigned n) {
n = lazy_pop(n);
if (n == 0)
return;
m_var_data.resize(get_num_vars());
}
std::ostream& solver::display(std::ostream& out) const {
for (unsigned i = 0; i < get_num_vars(); ++i) {
out << var2enode(i)->get_expr_id() << " " << mk_bounded_pp(var2expr(i), m, 2) << "\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 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::fresh(sat::solver* s, euf::solver& ctx) {
auto* result = alloc(solver, ctx, get_id());
ast_translation tr(m, ctx.get_manager());
for (unsigned i = 0; i < get_num_vars(); ++i) {
expr* e1 = var2expr(i);
expr* e2 = tr(e1);
euf::enode* n = ctx.get_enode(e2);
result->mk_var(n);
}
return result;
}
void solver::new_eq_eh(euf::th_eq const& eq) {
m_find.merge(eq.m_v1, eq.m_v2);
}
bool solver::unit_propagate() {
if (m_qhead == m_axiom_trail.size())
return false;
bool prop = false;
ctx.push(value_trail<euf::solver, unsigned>(m_qhead));
for (; m_qhead < m_axiom_trail.size() && !s().inconsistent(); ++m_qhead)
if (assert_axiom(m_qhead))
prop = true;
return prop;
}
void solver::merge_eh(theory_var v1, theory_var v2, theory_var, theory_var) {
euf::enode* n1 = var2enode(v1);
euf::enode* n2 = var2enode(v2);
SASSERT(n1->get_root() == n2->get_root());
SASSERT(n1->is_root() || n2->is_root());
SASSERT(v1 == find(v1));
expr* e1 = n1->get_expr();
expr* e2 = n2->get_expr();
auto& d1 = get_var_data(v1);
auto& d2 = get_var_data(v2);
if (d2.m_prop_upward && !d1.m_prop_upward)
set_prop_upward(v1);
if (a.is_array(e1))
for (euf::enode* parent : d2.m_parents) {
add_parent(v1, parent);
if (a.is_store(parent->get_expr()))
add_store(v1, parent);
}
if (is_lambda(e1) || is_lambda(e2))
push_axiom(congruence_axiom(n1, n2));
}
void solver::unmerge_eh(theory_var v1, theory_var v2) {
auto& p1 = get_var_data(v1).m_parents;
auto& p2 = get_var_data(v2).m_parents;
p1.shrink(p1.size() - p2.size());
}
void solver::add_store(theory_var v, euf::enode* store) {
SASSERT(a.is_store(store->get_expr()));
auto& d = get_var_data(v);
unsigned lambda_equiv_class_size = get_lambda_equiv_size(d);
if (get_config().m_array_always_prop_upward || lambda_equiv_class_size >= 1)
set_prop_upward(d);
for (euf::enode* n : d.m_parents)
if (a.is_select(n->get_expr()))
push_axiom(select_axiom(n, store));
if (get_config().m_array_always_prop_upward || lambda_equiv_class_size >= 1)
set_prop_upward(store);
}
void solver::add_parent(theory_var v_child, euf::enode* parent) {
SASSERT(parent->is_root());
get_var_data(v_child).m_parents.push_back(parent);
euf::enode* child = var2enode(v_child);
euf::enode* r = child->get_root();
expr* p = parent->get_expr();
expr* c = child->get_expr();
if (a.is_select(p) && parent->get_arg(0)->get_root() == r) {
if (a.is_const(c) || a.is_as_array(c) || a.is_store(c) || is_lambda(c))
push_axiom(select_axiom(parent, child));
#if 0
if (!get_config().m_array_delay_exp_axiom && d.m_prop_upward) {
auto& d = get_var_data(v_child);
for (euf::enode* p2 : d.m_parents)
if (a.is_store(p2->get_expr()))
push_axiom(select_axiom(parent, p2));
}
#endif
}
else if (a.mk_default(p)) {
if (a.is_const(c) || a.is_store(c) || a.is_map(c) || a.is_as_array(c))
push_axiom(default_axiom(child));
}
}
void solver::set_prop_upward(theory_var v) {
auto& d = get_var_data(find(v));
if (!d.m_prop_upward) {
ctx.push(reset_flag_trail<euf::solver>(d.m_prop_upward));
d.m_prop_upward = true;
if (!get_config().m_array_delay_exp_axiom)
push_parent_select_store_axioms(v);
set_prop_upward(d);
}
}
void solver::set_prop_upward(euf::enode* n) {
if (a.is_store(n->get_expr()))
set_prop_upward(n->get_arg(0)->get_th_var(get_id()));
}
void solver::set_prop_upward(var_data& d) {
for (auto* p : d.m_parents)
set_prop_upward(p);
}
/**
\brief Return the size of the equivalence class for array terms
that can be expressed as \lambda i : Index . [.. (select a i) ..]
*/
unsigned solver::get_lambda_equiv_size(var_data const& d) {
unsigned sz = 0;
for (auto* p : d.m_parents)
if (a.is_store(p->get_expr()))
++sz;
return sz;
}
}