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We should not bypass checking primitive constraints being empty

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CEisenhofer 2026-05-28 15:29:43 +02:00
parent 54782e68e0
commit 2bbd75a186
3 changed files with 23 additions and 30 deletions
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31
src/smt/seq/seq_nielsen.cpp
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@ -35,6 +35,7 @@ NSB review:
#include "ast/rewriter/th_rewriter.h"
#include "ast/rewriter/seq_skolem.h"
#include "ast/rewriter/var_subst.h"
#include "smt/smt_enode.h"
#include "util/statistics.h"
#include <algorithm>
#include <complex>
@ -45,12 +46,16 @@ NSB review:
namespace seq {
void deps_to_lits(const dep_tracker deps, svector<enode_pair> &eqs, svector<sat::literal> &lits) {
vector<dep_source> vs;
dep_manager::s_linearize(deps, vs);
void deps_to_lits(dep_manager &dep_mgr, const dep_tracker deps,
svector<enode_pair> &eqs, svector<sat::literal> &lits) {
vector<dep_source, false> vs;
dep_mgr.linearize(deps, vs);
for (dep_source const &d : vs) {
if (std::holds_alternative<enode_pair>(d))
if (std::holds_alternative<enode_pair>(d)) {
eqs.push_back(std::get<enode_pair>(d));
SASSERT(eqs.back().first->get_root() == eqs.back().second->get_root());
}
else if (std::holds_alternative<sat::literal>(d))
lits.push_back(std::get<sat::literal>(d));
else
@ -1962,12 +1967,6 @@ namespace seq {
return search_result::unsat;
}
if (node->is_satisfied()) {
m_sat_node = node;
m_sat_path = cur_path;
return search_result::sat;
}
// simplify constraints (idempotent after first call)
const simplify_result sr = node->simplify_and_init(cur_path);
@ -3758,7 +3757,7 @@ namespace seq {
first_filter_dep = m_dep_mgr.mk_join(first_filter_dep, prev_mem.m_dep);
}
}
if (regexes_p.size() > 1 && m_seq_regex->check_intersection_emptiness(regexes_p, 100) == l_true) {
if (m_seq_regex->check_intersection_emptiness(regexes_p, 100) == l_true) {
eliminated_dep = m_dep_mgr.mk_join(eliminated_dep, first_filter_dep);
continue;
}
@ -4982,15 +4981,13 @@ namespace seq {
// -----------------------------------------------------------------------
bool nielsen_graph::check_leaf_regex(nielsen_node const& node, dep_tracker& dep) {
if (!m_seq_regex)
return true;
SASSERT(m_seq_regex);
// Group str_mem constraints by variable (primitive constraints only)
u_map<std::pair<ptr_vector<euf::snode>, dep_tracker>> var_regexes;
for (auto const& mem : node.str_mems()) {
if (!mem.is_primitive())
continue;
SASSERT(mem.is_primitive());
const euf::snode* const first = mem.m_str->first();
SASSERT(first && first->is_var());
auto& list = var_regexes.insert_if_not_there(first->id(), std::pair<ptr_vector<euf::snode>, dep_tracker>());
@ -4998,10 +4995,8 @@ namespace seq {
list.second = dep_mgr().mk_join(list.second, mem.m_dep);
}
// For each variable with 2+ regex constraints, check intersection non-emptiness
// check intersection non-emptiness (also for single occurrences; it could be empty)
for (auto& [var_id, regexes] : var_regexes) {
if (regexes.first.size() < 2)
continue;
const lbool result = m_seq_regex->check_intersection_emptiness(regexes.first, 5000);
if (result == l_true) {
TRACE(seq, tout << "empty intersection\n");