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We don't need to handle negative membership constraints explicitly

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CEisenhofer 2026-03-04 19:07:36 +01:00
parent 4e7d83f996
commit b2838b472d
7 changed files with 121 additions and 117 deletions
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24
src/smt/seq/seq_nielsen.cpp
View file

@ -260,6 +260,8 @@ namespace seq {
m_nodes.reset();
m_edges.reset();
m_root = nullptr;
m_sat_node = nullptr;
m_sat_path.reset();
m_run_idx = 0;
m_depth_bound = 0;
m_next_mem_id = 0;
@ -533,6 +535,8 @@ namespace seq {
return search_result::sat;
++m_stats.m_num_solve_calls;
m_sat_node = nullptr;
m_sat_path.reset();
// Iterative deepening: start at depth 3, increment by 1 on each failure.
// m_max_search_depth == 0 means unlimited; otherwise stop when bound exceeds it.
@ -541,7 +545,8 @@ namespace seq {
if (m_max_search_depth > 0 && m_depth_bound > m_max_search_depth)
break;
inc_run_idx();
search_result r = search_dfs(m_root, 0);
svector<nielsen_edge*> cur_path;
search_result r = search_dfs(m_root, 0, cur_path);
if (r == search_result::sat) {
++m_stats.m_num_sat;
return r;
@ -559,7 +564,7 @@ namespace seq {
return search_result::unknown;
}
nielsen_graph::search_result nielsen_graph::search_dfs(nielsen_node* node, unsigned depth) {
nielsen_graph::search_result nielsen_graph::search_dfs(nielsen_node* node, unsigned depth, svector<nielsen_edge*>& cur_path) {
++m_stats.m_num_dfs_nodes;
if (depth > m_stats.m_max_depth)
m_stats.m_max_depth = depth;
@ -567,8 +572,11 @@ namespace seq {
// cycle/revisit detection: if already visited this run, return cached status.
// mirrors ZIPT's NielsenNode.GraphExpansion() evalIdx check.
if (node->eval_idx() == m_run_idx) {
if (node->is_satisfied())
if (node->is_satisfied()) {
m_sat_node = node;
m_sat_path = cur_path;
return search_result::sat;
}
if (node->is_currently_conflict())
return search_result::unsat;
return search_result::unknown;
@ -583,8 +591,11 @@ namespace seq {
node->set_general_conflict(true);
return search_result::unsat;
}
if (sr == simplify_result::satisfied || node->is_satisfied())
if (sr == simplify_result::satisfied || node->is_satisfied()) {
m_sat_node = node;
m_sat_path = cur_path;
return search_result::sat;
}
// depth bound check
if (depth >= m_depth_bound)
@ -611,10 +622,11 @@ namespace seq {
// explore children
bool any_unknown = false;
for (nielsen_edge* e : node->outgoing()) {
nielsen_node* child = e->tgt();
search_result r = search_dfs(child, depth + 1);
cur_path.push_back(e);
search_result r = search_dfs(e->tgt(), depth + 1, cur_path);
if (r == search_result::sat)
return search_result::sat;
cur_path.pop_back();
if (r == search_result::unknown)
any_unknown = true;
}

13
src/smt/seq/seq_nielsen.h
View file

@ -425,6 +425,7 @@ namespace seq {
// edges
ptr_vector<nielsen_edge> m_outgoing;
nielsen_node* m_backedge = nullptr;
nielsen_edge* m_parent_edge = nullptr;
// status flags
bool m_is_general_conflict = false;
@ -457,6 +458,9 @@ namespace seq {
nielsen_node* backedge() const { return m_backedge; }
void set_backedge(nielsen_node* n) { m_backedge = n; }
nielsen_edge* parent_edge() const { return m_parent_edge; }
void set_parent_edge(nielsen_edge* e) { m_parent_edge = e; }
// status
bool is_general_conflict() const { return m_is_general_conflict; }
void set_general_conflict(bool v) { m_is_general_conflict = v; }
@ -532,6 +536,8 @@ namespace seq {
ptr_vector<nielsen_node> m_nodes;
ptr_vector<nielsen_edge> m_edges;
nielsen_node* m_root = nullptr;
nielsen_node* m_sat_node = nullptr;
svector<nielsen_edge*> m_sat_path;
unsigned m_run_idx = 0;
unsigned m_depth_bound = 0;
unsigned m_max_search_depth = 0;
@ -558,6 +564,11 @@ namespace seq {
nielsen_node* root() const { return m_root; }
void set_root(nielsen_node* n) { m_root = n; }
// satisfying leaf node (set by solve() when result is sat)
nielsen_node* sat_node() const { return m_sat_node; }
// path of edges from root to sat_node (set when sat_node is set)
svector<nielsen_edge*> const& sat_path() const { return m_sat_path; }
// add constraints to the root node from external solver
void add_str_eq(euf::snode* lhs, euf::snode* rhs);
void add_str_mem(euf::snode* str, euf::snode* regex);
@ -625,7 +636,7 @@ namespace seq {
void generate_length_constraints(vector<length_constraint>& constraints);
private:
search_result search_dfs(nielsen_node* node, unsigned depth);
search_result search_dfs(nielsen_node* node, unsigned depth, svector<nielsen_edge*>& cur_path);
// create a fresh variable with a unique name
euf::snode* mk_fresh_var();