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First step towards not-reusing variables

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CEisenhofer 2026-05-20 10:11:50 +02:00
parent 9bb0f7e337
commit dd00dd7362
6 changed files with 90 additions and 10 deletions
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52
src/smt/seq/seq_nielsen.cpp
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@ -1155,6 +1155,37 @@ namespace seq {
return true;
}
euf::snode* nielsen_graph::get_slice(euf::snode* v, expr* left, expr* right) {
SASSERT(v && v->get_expr() && left && right);
SASSERT(v->is_var());
expr_ref new_arg(v->get_expr(), m);
expr_ref new_l(left, m), new_r(right, m);
expr* arg, *l, *r;
std::cout << "Creating slice for " << mk_pp(new_arg, m) << "; " << mk_pp(new_l, m) << "; " << mk_pp(new_r, m) << std::endl;
if (m_sk.is_slice(new_arg, arg, l, r)) {
new_l = a.mk_add(left, l);
m_rw(new_l);
new_r = a.mk_add(right, r);
m_rw(new_r);
new_arg = arg;
}
expr_ref slice = m_sk.mk_slice(new_arg, new_l, new_r);
std::cout << "Got " << mk_pp(slice, m) << std::endl;
return m_sg.mk(slice);
}
euf::snode* nielsen_graph::get_tail(euf::snode* v, expr* cnt, const bool fwd) {
if (fwd)
return get_slice(v, cnt, a.mk_int(0));
return get_slice(v, a.mk_int(0), cnt);
}
euf::snode* nielsen_graph::get_tail(euf::snode* v, const unsigned cnt, const bool fwd) {
return get_tail(v, a.mk_int(cnt), fwd);
}
simplify_result nielsen_node::simplify_and_init(ptr_vector<nielsen_edge> const& cur_path) {
if (m_is_extended)
@ -1680,7 +1711,7 @@ namespace seq {
inc_run_idx();
ptr_vector<nielsen_edge> cur_path;
// scoped_push _scoped_push(m_dep_mgr); // gc dependencies after search
const search_result r = search_dfs(m_root, cur_path);
const search_result r = search_dfs(m_root, cur_path); // the main search loop
IF_VERBOSE(1, verbose_stream()
<< " depth_bound=" << m_depth_bound << " dfs_nodes=" << m_stats.m_num_dfs_nodes
<< " max_depth=" << m_stats.m_max_depth << " extensions=" << m_stats.m_num_extensions
@ -1722,8 +1753,7 @@ namespace seq {
}
nielsen_graph::search_result nielsen_graph::search_dfs(nielsen_node* node,
ptr_vector<nielsen_edge>& cur_path,
const unsigned depth) {
ptr_vector<nielsen_edge>& cur_path, const unsigned depth) {
++m_stats.m_num_dfs_nodes;
// std::cout << m_stats.m_num_dfs_nodes << std::endl;
@ -1885,6 +1915,7 @@ namespace seq {
// explore children
bool any_unknown = false;
bool all_general_conflict = true;
for (nielsen_edge *e : node->outgoing()) {
cur_path.push_back(e);
// Push a solver scope for this edge and assert its side integer
@ -1922,8 +1953,15 @@ namespace seq {
cur_path.pop_back();
if (r == search_result::unknown)
any_unknown = true;
if (!e->tgt()->is_general_conflict())
all_general_conflict = false;
}
if (all_general_conflict) {
SASSERT(!any_unknown);
// mark it such that we do not have to reconsider it even after a hot-restart
node->set_general_conflict();
}
if (!any_unknown) {
node->set_child_conflict();
return search_result::unsat;
@ -2236,7 +2274,8 @@ namespace seq {
for (unsigned j = 1; j < i; ++j) {
prefix_sn = dir_concat(m_sg, prefix_sn, char_toks[j], fwd);
}
euf::snode* replacement = dir_concat(m_sg, prefix_sn, var_node, fwd);
euf::snode* replacement = dir_concat(m_sg, prefix_sn,
get_tail(var_node, compute_length_expr(prefix_sn).get(), fwd), fwd);
nielsen_subst s(var_node, replacement,
mk_rewrite(a.mk_sub(compute_length_expr(var_node), compute_length_expr(prefix_sn))),
eq.m_dep);
@ -2304,7 +2343,7 @@ namespace seq {
child->apply_subst(m_sg, s1);
euf::snode* replacement = dir_concat(m_sg, char_head, var_head, fwd);
euf::snode* replacement = dir_concat(m_sg, char_head, get_tail(var_head, a.mk_int(1), fwd), fwd);
child = mk_child(node);
e = mk_edge(node, child, false);
const nielsen_subst s2(var_head, replacement, mk_rewrite(a.mk_sub(compute_length_expr(var_head), a.mk_int(1))), eq.m_dep);
@ -4249,7 +4288,8 @@ namespace seq {
SASSERT(n->m_conflict_external_literal == sat::null_literal);
continue;
}
SASSERT(n->outgoing().empty());
// not true anymore since we might have done a hot-restart where we previously created the child:
//SASSERT(n->outgoing().empty());
SASSERT(n->is_currently_conflict());
if (n->m_conflict_external_literal != sat::null_literal)
// We know from the outer solver that this literal is assigned true and contradicts node constraint