mirror of
https://github.com/Z3Prover/z3
synced 2025-04-07 01:54:08 +00:00
627 lines
20 KiB
C++
627 lines
20 KiB
C++
/*++
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Copyright (c) 2020 Microsoft Corporation
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Module Name:
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euf_solver.cpp
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Abstract:
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Solver plugin for EUF
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Author:
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Nikolaj Bjorner (nbjorner) 2020-08-25
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--*/
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#include "ast/pb_decl_plugin.h"
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#include "ast/ast_ll_pp.h"
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#include "sat/sat_solver.h"
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#include "sat/smt/sat_smt.h"
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#include "sat/smt/ba_solver.h"
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#include "sat/smt/bv_solver.h"
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#include "sat/smt/euf_solver.h"
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namespace euf {
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solver::solver(ast_manager& m, sat::sat_internalizer& si, params_ref const& p) :
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extension(m.mk_family_id("euf")),
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m(m),
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si(si),
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m_egraph(m),
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m_trail(*this),
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m_rewriter(m),
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m_unhandled_functions(m),
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m_solver(nullptr),
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m_lookahead(nullptr),
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m_to_m(&m),
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m_to_si(&si),
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m_reinit_exprs(m)
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{
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updt_params(p);
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std::function<void(std::ostream&, void*)> disp =
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[&](std::ostream& out, void* j) { display_justification_ptr(out, reinterpret_cast<size_t*>(j)); };
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m_egraph.set_display_justification(disp);
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}
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void solver::updt_params(params_ref const& p) {
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m_config.updt_params(p);
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}
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/**
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* retrieve extension that is associated with Boolean variable.
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*/
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th_solver* solver::bool_var2solver(sat::bool_var v) {
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if (v >= m_var2expr.size())
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return nullptr;
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expr* e = m_var2expr[v];
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if (!e)
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return nullptr;
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return expr2solver(e);
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}
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th_solver* solver::expr2solver(expr* e) {
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if (is_app(e))
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return func_decl2solver(to_app(e)->get_decl());
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return nullptr;
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}
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th_solver* solver::get_solver(family_id fid, func_decl* f) {
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if (fid == null_family_id)
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return nullptr;
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auto* ext = m_id2solver.get(fid, nullptr);
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if (ext)
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return ext;
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if (fid == m.get_basic_family_id())
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return nullptr;
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pb_util pb(m);
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bv_util bvu(m);
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if (pb.get_family_id() == fid) {
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ext = alloc(sat::ba_solver, *this, fid);
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if (use_drat())
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s().get_drat().add_theory(fid, symbol("ba"));
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}
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else if (bvu.get_family_id() == fid) {
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ext = alloc(bv::solver, *this, fid);
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if (use_drat())
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s().get_drat().add_theory(fid, symbol("bv"));
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}
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if (ext) {
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ext->set_solver(m_solver);
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ext->push_scopes(s().num_scopes());
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add_solver(fid, ext);
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}
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else if (f)
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unhandled_function(f);
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return ext;
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}
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void solver::add_solver(family_id fid, th_solver* th) {
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m_solvers.push_back(th);
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m_id2solver.setx(fid, th, nullptr);
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}
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void solver::unhandled_function(func_decl* f) {
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if (m_unhandled_functions.contains(f))
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return;
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m_unhandled_functions.push_back(f);
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m_trail.push(push_back_vector<solver, func_decl_ref_vector>(m_unhandled_functions));
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IF_VERBOSE(0, verbose_stream() << mk_pp(f, m) << " not handled\n");
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}
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void solver::init_search() {
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TRACE("before_search", s().display(tout););
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}
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bool solver::is_external(bool_var v) {
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if (nullptr != m_var2expr.get(v, nullptr))
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return true;
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for (auto* s : m_solvers)
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if (s->is_external(v))
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return true;
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return false;
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}
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bool solver::propagate(literal l, ext_constraint_idx idx) {
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auto* ext = sat::constraint_base::to_extension(idx);
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SASSERT(ext != this);
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return ext->propagate(l, idx);
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}
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void solver::get_antecedents(literal l, ext_justification_idx idx, literal_vector& r, bool probing) {
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m_egraph.begin_explain();
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m_explain.reset();
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auto* ext = sat::constraint_base::to_extension(idx);
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if (ext == this)
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get_antecedents(l, constraint::from_idx(idx), r, probing);
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else
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ext->get_antecedents(l, idx, r, probing);
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for (unsigned qhead = 0; qhead < m_explain.size(); ++qhead) {
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size_t* e = m_explain[qhead];
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if (is_literal(e))
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r.push_back(get_literal(e));
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else {
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size_t idx = get_justification(e);
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auto* ext = sat::constraint_base::to_extension(idx);
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SASSERT(ext != this);
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sat::literal lit = sat::null_literal;
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ext->get_antecedents(lit, idx, r, probing);
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}
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}
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m_egraph.end_explain();
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TRACE("euf", tout << "eplain " << l << " <- " << r << " " << probing << "\n";);
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DEBUG_CODE(for (auto lit : r) SASSERT(s().value(lit) == l_true););
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if (!probing)
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log_antecedents(l, r);
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}
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void solver::add_antecedent(enode* a, enode* b) {
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m_egraph.explain_eq<size_t>(m_explain, a, b);
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}
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bool solver::propagate(enode* a, enode* b, ext_justification_idx idx) {
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if (a->get_root() == b->get_root())
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return false;
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m_egraph.merge(a, b, to_ptr(idx));
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return true;
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}
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void solver::get_antecedents(literal l, constraint& j, literal_vector& r, bool probing) {
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expr* e = nullptr;
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euf::enode* n = nullptr;
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if (!probing && !m_drating)
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init_ackerman();
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switch (j.kind()) {
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case constraint::kind_t::conflict:
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SASSERT(m_egraph.inconsistent());
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m_egraph.explain<size_t>(m_explain);
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break;
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case constraint::kind_t::eq:
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e = m_var2expr[l.var()];
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n = m_egraph.find(e);
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SASSERT(n);
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SASSERT(m_egraph.is_equality(n));
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SASSERT(!l.sign());
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m_egraph.explain_eq<size_t>(m_explain, n->get_arg(0), n->get_arg(1));
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break;
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case constraint::kind_t::lit:
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e = m_var2expr[l.var()];
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n = m_egraph.find(e);
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SASSERT(n);
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SASSERT(m.is_bool(n->get_expr()));
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m_egraph.explain_eq<size_t>(m_explain, n, (l.sign() ? mk_false() : mk_true()));
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break;
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default:
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IF_VERBOSE(0, verbose_stream() << (unsigned)j.kind() << "\n");
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UNREACHABLE();
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}
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}
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void solver::asserted(literal l) {
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expr* e = m_var2expr.get(l.var(), nullptr);
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if (!e) {
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return;
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}
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bool sign = l.sign();
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TRACE("euf", tout << "asserted: " << l << "@" << s().scope_lvl() << "\n";);
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euf::enode* n = m_egraph.find(e);
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if (!n)
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return;
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for (auto th : enode_th_vars(n))
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m_id2solver[th.get_id()]->asserted(l);
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if (!n->merge_enabled())
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return;
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size_t* c = to_ptr(l);
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SASSERT(is_literal(c));
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SASSERT(l == get_literal(c));
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if (m.is_eq(e) && n->num_args() == 2) {
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euf::enode* na = n->get_arg(0);
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euf::enode* nb = n->get_arg(1);
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if (!sign) {
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m_egraph.merge(na, nb, c);
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return;
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}
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else
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new_diseq(na, nb, l);
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}
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euf::enode* nb = sign ? mk_false() : mk_true();
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m_egraph.merge(n, nb, c);
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}
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void solver::new_diseq(enode* n1, enode* n2, literal lit) {
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enode * r1 = n1->get_root();
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enode * r2 = n2->get_root();
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if (r1 == r2)
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return;
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if (r1->has_one_th_var() && r2->has_one_th_var() && r1->get_first_th_id() == r2->get_first_th_id()) {
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theory_id id = r1->get_first_th_id();
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theory_var v1 = r1->get_th_var(id);
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theory_var v2 = r2->get_th_var(id);
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fid2solver(id)->new_diseq_eh(r1, r2);
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}
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}
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bool solver::unit_propagate() {
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bool propagated = false;
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while (!s().inconsistent()) {
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if (m_egraph.inconsistent()) {
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unsigned lvl = s().scope_lvl();
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s().set_conflict(sat::justification::mk_ext_justification(lvl, conflict_constraint().to_index()));
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return true;
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}
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bool propagated1 = false;
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if (m_egraph.propagate()) {
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propagate_literals();
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propagate_th_eqs();
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propagated1 = true;
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}
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for (auto* s : m_solvers) {
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if (s->unit_propagate())
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propagated1 = true;
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}
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if (!propagated1)
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break;
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propagated = true;
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}
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DEBUG_CODE(if (!s().inconsistent()) check_missing_eq_propagation(););
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return propagated;
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}
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void solver::propagate_literals() {
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for (; m_egraph.has_literal() && !s().inconsistent() && !m_egraph.inconsistent(); m_egraph.next_literal()) {
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euf::enode_bool_pair p = m_egraph.get_literal();
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euf::enode* n = p.first;
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bool is_eq = p.second;
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expr* e = n->get_expr();
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expr* a = nullptr, *b = nullptr;
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bool_var v = si.to_bool_var(e);
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SASSERT(m.is_bool(e));
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size_t cnstr;
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literal lit;
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if (is_eq) {
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VERIFY(m.is_eq(e, a, b));
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cnstr = eq_constraint().to_index();
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lit = literal(v, false);
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}
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else {
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a = e, b = n->get_root()->get_expr();
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SASSERT(m.is_true(b) || m.is_false(b));
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cnstr = lit_constraint().to_index();
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lit = literal(v, m.is_false(b));
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}
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unsigned lvl = s().scope_lvl();
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CTRACE("euf", s().value(lit) != l_true, tout << lit << " " << s().value(lit) << "@" << lvl << " " << is_eq << " " << mk_bounded_pp(a, m) << " = " << mk_bounded_pp(b, m) << "\n";);
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if (s().value(lit) == l_false && m_ackerman)
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m_ackerman->cg_conflict_eh(a, b);
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switch (s().value(lit)) {
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case l_true:
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break;
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case l_undef:
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case l_false:
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s().assign(lit, sat::justification::mk_ext_justification(lvl, cnstr));
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break;
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}
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}
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}
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void solver::propagate_th_eqs() {
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for (; m_egraph.has_th_eq() && !s().inconsistent() && !m_egraph.inconsistent(); m_egraph.next_th_eq()) {
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th_eq eq = m_egraph.get_th_eq();
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m_id2solver[eq.m_id]->new_eq_eh(eq);
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}
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}
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constraint& solver::mk_constraint(constraint*& c, constraint::kind_t k) {
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if (!c) {
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void* mem = memory::allocate(sat::constraint_base::obj_size(sizeof(constraint)));
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c = new (sat::constraint_base::ptr2mem(mem)) constraint(k);
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sat::constraint_base::initialize(mem, this);
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}
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return *c;
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}
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enode* solver::mk_true() {
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VERIFY(visit(m.mk_true()));
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return m_egraph.find(m.mk_true());
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}
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enode* solver::mk_false() {
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VERIFY(visit(m.mk_false()));
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return m_egraph.find(m.mk_false());
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}
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sat::check_result solver::check() {
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TRACE("euf", s().display(tout););
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bool give_up = false;
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bool cont = false;
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for (auto* e : m_solvers)
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switch (e->check()) {
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case sat::check_result::CR_CONTINUE: cont = true; break;
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case sat::check_result::CR_GIVEUP: give_up = true; break;
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default: break;
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}
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if (cont)
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return sat::check_result::CR_CONTINUE;
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if (give_up)
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return sat::check_result::CR_GIVEUP;
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return sat::check_result::CR_DONE;
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}
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void solver::push() {
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si.push();
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scope s;
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s.m_var_lim = m_var_trail.size();
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m_scopes.push_back(s);
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m_trail.push_scope();
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for (auto* e : m_solvers)
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e->push();
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m_egraph.push();
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}
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void solver::pop(unsigned n) {
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start_reinit(n);
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m_egraph.pop(n);
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for (auto* e : m_solvers)
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e->pop(n);
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scope const & s = m_scopes[m_scopes.size() - n];
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for (unsigned i = m_var_trail.size(); i-- > s.m_var_lim; )
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m_var2expr[m_var_trail[i]] = nullptr;
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m_var_trail.shrink(s.m_var_lim);
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m_trail.pop_scope(n);
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m_scopes.shrink(m_scopes.size() - n);
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si.pop(n);
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SASSERT(m_egraph.num_scopes() == m_scopes.size());
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}
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void solver::start_reinit(unsigned n) {
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m_reinit_exprs.reset();
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for (sat::bool_var v : s().get_vars_to_reinit()) {
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expr* e = bool_var2expr(v);
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m_reinit_exprs.push_back(e);
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}
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}
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void solver::finish_reinit() {
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SASSERT(s().get_vars_to_reinit().size() == m_reinit_exprs.size());
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if (s().get_vars_to_reinit().empty())
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return;
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unsigned i = 0;
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obj_map<expr, sat::bool_var> expr2var_replay;
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for (sat::bool_var v : s().get_vars_to_reinit()) {
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expr* e = m_reinit_exprs.get(i++);
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if (!e)
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continue;
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expr2var_replay.insert(e, v);
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}
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if (expr2var_replay.empty())
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return;
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si.set_expr2var_replay(&expr2var_replay);
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for (auto const& kv : expr2var_replay)
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attach_lit(si.internalize(kv.m_key, true), kv.m_key);
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si.set_expr2var_replay(nullptr);
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}
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void solver::pre_simplify() {
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for (auto* e : m_solvers)
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e->pre_simplify();
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}
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void solver::simplify() {
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for (auto* e : m_solvers)
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e->simplify();
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if (m_ackerman)
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m_ackerman->propagate();
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}
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void solver::clauses_modifed() {
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for (auto* e : m_solvers)
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e->clauses_modifed();
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}
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lbool solver::get_phase(bool_var v) {
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auto* ext = bool_var2solver(v);
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if (ext)
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return ext->get_phase(v);
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return l_undef;
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}
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bool solver::set_root(literal l, literal r) {
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bool ok = true;
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for (auto* s : m_solvers)
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if (!s->set_root(l, r))
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ok = false;
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expr* e = bool_var2expr(l.var());
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if (e) {
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if (m.is_eq(e) && !m.is_iff(e))
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ok = false;
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euf::enode* n = get_enode(e);
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if (n && n->merge_enabled())
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ok = false;
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}
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TRACE("euf", tout << ok << " " << l << " -> " << r << "\n";);
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return ok;
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}
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void solver::flush_roots() {
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for (auto* s : m_solvers)
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s->flush_roots();
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}
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std::ostream& solver::display(std::ostream& out) const {
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m_egraph.display(out);
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out << "bool-vars\n";
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for (unsigned v : m_var_trail) {
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expr* e = m_var2expr[v];
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out << v << ": " << e->get_id() << " " << m_solver->value(v) << " " << mk_bounded_pp(e, m, 1) << "\n";
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}
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for (auto* e : m_solvers)
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e->display(out);
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return out;
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}
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std::ostream& solver::display_justification_ptr(std::ostream& out, size_t* j) const {
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if (is_literal(j))
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return out << get_literal(j) << " ";
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else
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return display_justification(out, get_justification(j)) << " ";
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}
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std::ostream& solver::display_justification(std::ostream& out, ext_justification_idx idx) const {
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auto* ext = sat::constraint_base::to_extension(idx);
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|
if (ext != this)
|
|
return ext->display_justification(out, idx);
|
|
return out;
|
|
}
|
|
|
|
std::ostream& solver::display_constraint(std::ostream& out, ext_constraint_idx idx) const {
|
|
auto* ext = sat::constraint_base::to_extension(idx);
|
|
if (ext != this)
|
|
return ext->display_constraint(out, idx);
|
|
return out;
|
|
}
|
|
|
|
void solver::collect_statistics(statistics& st) const {
|
|
m_egraph.collect_statistics(st);
|
|
for (auto* e : m_solvers)
|
|
e->collect_statistics(st);
|
|
st.update("euf ackerman", m_stats.m_ackerman);
|
|
}
|
|
|
|
sat::extension* solver::copy(sat::solver* s) {
|
|
auto* r = alloc(solver, *m_to_m, *m_to_si);
|
|
r->m_config = m_config;
|
|
sat::literal true_lit = sat::null_literal;
|
|
if (s->init_trail_size() > 0)
|
|
true_lit = s->trail_literal(0);
|
|
std::function<void* (void*)> copy_justification = [&](void* x) {
|
|
SASSERT(true_lit != sat::null_literal);
|
|
return (void*)(r->to_ptr(true_lit));
|
|
};
|
|
r->m_egraph.copy_from(m_egraph, copy_justification);
|
|
r->set_solver(s);
|
|
for (unsigned i = 0; i < m_id2solver.size(); ++i) {
|
|
auto* e = m_id2solver[i];
|
|
if (e)
|
|
r->add_solver(i, e->fresh(s, *r));
|
|
}
|
|
return r;
|
|
}
|
|
|
|
void solver::find_mutexes(literal_vector& lits, vector<literal_vector> & mutexes) {
|
|
for (auto* e : m_solvers)
|
|
e->find_mutexes(lits, mutexes);
|
|
}
|
|
|
|
void solver::gc() {
|
|
for (auto* e : m_solvers)
|
|
e->gc();
|
|
}
|
|
|
|
void solver::pop_reinit() {
|
|
finish_reinit();
|
|
for (auto* e : m_solvers)
|
|
e->pop_reinit();
|
|
}
|
|
|
|
bool solver::validate() {
|
|
for (auto* e : m_solvers)
|
|
if (!e->validate())
|
|
return false;
|
|
check_eqc_bool_assignment();
|
|
check_missing_bool_enode_propagation();
|
|
check_missing_eq_propagation();
|
|
m_egraph.invariant();
|
|
return true;
|
|
}
|
|
|
|
void solver::init_use_list(sat::ext_use_list& ul) {
|
|
for (auto* e : m_solvers)
|
|
e->init_use_list(ul);
|
|
}
|
|
|
|
bool solver::is_blocked(literal l, ext_constraint_idx idx) {
|
|
auto* ext = sat::constraint_base::to_extension(idx);
|
|
if (ext != this)
|
|
return ext->is_blocked(l, idx);
|
|
return false;
|
|
}
|
|
|
|
bool solver::check_model(sat::model const& m) const {
|
|
for (auto* e : m_solvers)
|
|
if (!e->check_model(m))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
unsigned solver::max_var(unsigned w) const {
|
|
for (auto* e : m_solvers)
|
|
w = e->max_var(w);
|
|
for (unsigned sz = m_var2expr.size(); sz-- > 0; ) {
|
|
expr* n = m_var2expr[sz];
|
|
if (n && m.is_bool(n)) {
|
|
w = std::max(w, sz);
|
|
break;
|
|
}
|
|
}
|
|
return w;
|
|
}
|
|
|
|
double solver::get_reward(literal l, ext_constraint_idx idx, sat::literal_occs_fun& occs) const {
|
|
auto* ext = sat::constraint_base::to_extension(idx);
|
|
SASSERT(ext);
|
|
return (ext == this) ? 0 : ext->get_reward(l, idx, occs);
|
|
}
|
|
|
|
bool solver::is_extended_binary(ext_justification_idx idx, literal_vector& r) {
|
|
auto* ext = sat::constraint_base::to_extension(idx);
|
|
SASSERT(ext);
|
|
return (ext != this) && ext->is_extended_binary(idx, r);
|
|
}
|
|
|
|
void solver::init_ackerman() {
|
|
if (m_ackerman)
|
|
return;
|
|
if (m_config.m_dack == dyn_ack_strategy::DACK_DISABLED)
|
|
return;
|
|
m_ackerman = alloc(ackerman, *this, m);
|
|
std::function<void(expr*,expr*,expr*)> used_eq = [&](expr* a, expr* b, expr* lca) {
|
|
m_ackerman->used_eq_eh(a, b, lca);
|
|
};
|
|
std::function<void(app*,app*)> used_cc = [&](app* a, app* b) {
|
|
m_ackerman->used_cc_eh(a, b);
|
|
};
|
|
m_egraph.set_used_eq(used_eq);
|
|
m_egraph.set_used_cc(used_cc);
|
|
}
|
|
|
|
bool solver::to_formulas(std::function<expr_ref(sat::literal)>& l2e, expr_ref_vector& fmls) {
|
|
for (auto* th : m_solvers) {
|
|
if (!th->to_formulas(l2e, fmls))
|
|
return false;
|
|
}
|
|
for (euf::enode* n : m_egraph.nodes()) {
|
|
if (!n->is_root())
|
|
fmls.push_back(m.mk_eq(n->get_expr(), n->get_root()->get_expr()));
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool solver::extract_pb(std::function<void(unsigned sz, literal const* c, unsigned k)>& card,
|
|
std::function<void(unsigned sz, literal const* c, unsigned const* coeffs, unsigned k)>& pb) {
|
|
for (auto* e : m_solvers)
|
|
if (!e->extract_pb(card, pb))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
}
|