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Solve disequalities lazily

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This commit is contained in:
CEisenhofer 2026-05-27 17:25:39 +02:00
parent 4cd908345a
commit e74b235d87
10 changed files with 337 additions and 16 deletions
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46
src/smt/theory_nseq.cpp
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@ -36,7 +36,7 @@ namespace smt {
m_egraph(m),
m_sgraph(m, m_egraph),
m_length_solver(m),
m_context_solver(ctx),
m_context_solver(ctx, [this](expr* e1, expr* e2) { m_axioms.diseq_axiom(e1, e2); }),
m_nielsen(m_sgraph, m_length_solver, m_context_solver),
m_axioms(m_th_rewriter),
m_regex(m_sgraph),
@ -262,8 +262,19 @@ namespace smt {
break;
}
}
else if (m_seq.is_seq(e1) && !m_no_diseq_set.contains(e1) && !m_no_diseq_set.contains(e2))
m_axioms.diseq_axiom(e1, e2);
else if (m_seq.is_seq(e1) && !m_no_diseq_set.contains(e1) && !m_no_diseq_set.contains(e2)) {
if (get_fparams().m_nseq_axiomatize_diseq)
m_axioms.diseq_axiom(e1, e2);
else {
euf::snode *s1 = get_snode(e1);
euf::snode *s2 = get_snode(e2);
seq::dep_tracker dep = nullptr;
ctx.push_trail(restore_vector(m_prop_queue));
m_prop_queue.push_back(deq_item(s1, s2, get_enode(v1), get_enode(v2), dep));
m_last_constraint_added = ctx.get_scope_level();
m_can_hot_restart = false;
}
}
else
;
}
@ -408,6 +419,8 @@ namespace smt {
auto const& item = m_prop_queue[m_prop_qhead++];
if (std::holds_alternative<eq_item>(item))
propagate_eq(std::get<eq_item>(item));
else if (std::holds_alternative<deq_item>(item))
propagate_deq(std::get<deq_item>(item));
else if (std::holds_alternative<mem_item>(item))
propagate_pos_mem(std::get<mem_item>(item));
else if (std::holds_alternative<axiom_item>(item))
@ -432,6 +445,11 @@ namespace smt {
ensure_length_var(eq.m_r->get_expr());
}
void theory_nseq::propagate_deq(tracked_str_deq const& eq) {
ensure_length_var(eq.m_l->get_expr());
ensure_length_var(eq.m_r->get_expr());
}
void theory_nseq::propagate_pos_mem(tracked_str_mem const& mem) {
SASSERT(mem.well_formed());
@ -587,7 +605,7 @@ namespace smt {
m_nielsen.reset();
m_can_hot_restart = true;
unsigned num_eqs = 0, num_mems = 0;
unsigned num_eqs = 0, num_deqs = 0, num_mems = 0;
// transfer string equalities and regex memberships from prop_queue to nielsen graph root
for (auto const& item : m_prop_queue) {
@ -596,6 +614,12 @@ namespace smt {
m_nielsen.add_str_eq(eq.m_lhs, eq.m_rhs, eq.m_l, eq.m_r);
++num_eqs;
}
if (std::holds_alternative<deq_item>(item)) {
SASSERT(!get_fparams().m_nseq_axiomatize_diseq);
auto const& eq = std::get<deq_item>(item);
m_nielsen.add_str_deq(eq.m_lhs, eq.m_rhs, eq.m_l, eq.m_r);
++num_deqs;
}
else if (std::holds_alternative<mem_item>(item)) {
auto const& mem = std::get<mem_item>(item);
int triv = m_regex.check_trivial(mem);
@ -626,7 +650,7 @@ namespace smt {
}
TRACE(seq, tout << "nseq populate: " << num_eqs << " eqs, "
<< num_mems << " mems -> nielsen root\n");
<< num_deqs << " diseqs, " << num_mems << " mems -> nielsen root\n");
IF_VERBOSE(1, verbose_stream() << "nseq final_check: populating graph with "
<< num_eqs << " eqs, " << num_mems << " mems\n";);
}
@ -641,12 +665,12 @@ namespace smt {
}
// Check if there are any eq/mem items in the propagation queue.
bool has_eq_or_mem = any_of(m_prop_queue, [](auto const &item) {
return std::holds_alternative<eq_item>(item) || std::holds_alternative<mem_item>(item);
bool has_eq_or_diseq_or_mem = any_of(m_prop_queue, [](auto const &item) {
return std::holds_alternative<eq_item>(item) || std::holds_alternative<deq_item>(item) || std::holds_alternative<mem_item>(item);
});
// there is nothing to do for the string solver, as there are no string constraints
if (!has_eq_or_mem && m_ho_terms.empty() && !has_unhandled_preds()) {
if (!has_eq_or_diseq_or_mem && m_ho_terms.empty() && !has_unhandled_preds()) {
if (!check_stoi_coherence()) {
TRACE(seq, tout << "nseq final_check: stoi coherence added axioms, FC_CONTINUE\n");
return FC_CONTINUE;
@ -665,7 +689,7 @@ namespace smt {
return FC_CONTINUE;
}
if (!has_eq_or_mem && !has_unhandled_preds()) {
if (!has_eq_or_diseq_or_mem && !has_unhandled_preds()) {
if (!check_stoi_coherence()) {
TRACE(seq, tout << "nseq final_check: stoi coherence added axioms, FC_CONTINUE\n");
return FC_CONTINUE;
@ -678,7 +702,7 @@ namespace smt {
return FC_DONE;
}
if (!has_eq_or_mem && has_unhandled_preds()) {
if (!has_eq_or_diseq_or_mem && has_unhandled_preds()) {
TRACE(seq, tout << "nielsen root if null\n");
// this can happen for regex constraint only benchmarks
// qf_s\20250410-matching\wildcard-matching-regex-67.smt2
@ -803,7 +827,7 @@ namespace smt {
TRACE(seq, tout << "nseq final_check: solve SAT, sat_node="
<< (m_nielsen.sat_node() ? "set" : "null") << "\n");
// Nielsen found a consistent assignment for positive constraints.
SASSERT(has_eq_or_mem); // we should have axiomatized them
SASSERT(has_eq_or_diseq_or_mem); // we should have axiomatized them
bool all_sat = add_nielsen_assumptions();