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Regex factorization missed some justifications

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CEisenhofer 2026-04-14 17:19:07 +02:00
parent 2db99473a3
commit 0c4e4ad702
1 changed files with 45 additions and 26 deletions
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71
src/smt/seq/seq_nielsen.cpp
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@ -2901,6 +2901,12 @@ namespace seq {
if (!m_regex_factorization)
return false;
struct rf_split {
euf::snode* m_p;
euf::snode* m_q;
dep_tracker m_dep;
};
for (str_mem const& mem : node->str_mems()) {
SASSERT(mem.m_str && mem.m_regex);
@ -2909,49 +2915,62 @@ namespace seq {
euf::snode* first = mem.m_str->first();
SASSERT(first);
SASSERT(!first->is_char());
euf::snode* tail = m_sg.drop_first(mem.m_str);
SASSERT(tail);
tau_pairs pairs;
compute_tau(m, m_seq, m_sg, mem.m_regex->get_expr(), pairs);
vector<rf_split> feasible;
dep_tracker eliminated_dep = mem.m_dep;
for (auto const& pair : pairs) {
euf::snode* sn_p = m_sg.mk(pair.m_p);
euf::snode* sn_q = m_sg.mk(pair.m_q);
// Eagerly eliminate contradictory cases
// e.g. check intersection emptiness with max_states = 100
if (m_seq_regex->is_empty_bfs(sn_p, 100) == l_true)
continue;
if (m_seq_regex->is_empty_bfs(sn_q, 100) == l_true)
continue;
// Also check intersection with other primitive constraints on `first`
ptr_vector<euf::snode> regexes_p;
regexes_p.push_back(sn_p);
dep_tracker first_filter_dep = nullptr;
for (auto const& prev_mem : node->str_mems()) {
if (prev_mem.m_str == first)
if (prev_mem.m_str == first) {
regexes_p.push_back(prev_mem.m_regex);
}
if (regexes_p.size() > 1 && m_seq_regex->check_intersection_emptiness(regexes_p, 100) == l_true)
continue;
nielsen_node* child = mk_child(node);
mk_edge(node, child, true);
// remove the original mem from child
auto& child_mems = child->str_mems();
for (unsigned k = 0; k < child_mems.size(); ++k) {
if (child_mems[k] == mem) {
child_mems[k] = child_mems.back();
child_mems.pop_back();
break;
first_filter_dep = m_dep_mgr.mk_join(first_filter_dep, prev_mem.m_dep);
}
}
child->add_str_mem(str_mem(first, sn_p, mem.m_dep));
child->add_str_mem(str_mem(tail, sn_q, mem.m_dep));
if (regexes_p.size() > 1 && m_seq_regex->check_intersection_emptiness(regexes_p, 100) == l_true) {
eliminated_dep = m_dep_mgr.mk_join(eliminated_dep, first_filter_dep);
continue;
}
feasible.push_back({ sn_p, sn_q, m_dep_mgr.mk_join(mem.m_dep, first_filter_dep) });
}
if (feasible.empty()) {
node->set_general_conflict();
node->set_conflict(backtrack_reason::regex, eliminated_dep);
return true;
}
if (feasible.size() > 1)
continue;
nielsen_node* child = mk_child(node);
mk_edge(node, child, true);
// remove the original mem from child
auto& child_mems = child->str_mems();
for (unsigned k = 0; k < child_mems.size(); ++k) {
if (child_mems[k] == mem) {
child_mems[k] = child_mems.back();
child_mems.pop_back();
break;
}
}
child->add_str_mem(str_mem(first, feasible[0].m_p, feasible[0].m_dep));
child->add_str_mem(str_mem(tail, feasible[0].m_q, feasible[0].m_dep));
return true;
}