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widen scope of der #5480

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-08-15 00:22:34 -07:00
parent 2704fb5fd5
commit b7d4501bc3
2 changed files with 14 additions and 18 deletions
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30
src/ast/rewriter/der.cpp
View file

@ -136,8 +136,12 @@ void der::reduce1(quantifier * q, expr_ref & r, proof_ref & pr) {
var * v = nullptr;
expr_ref t(m);
if (m.is_or(e)) {
unsigned num_args = to_app(e)->get_num_args();
if (is_var_diseq(e, num_decls, v, t) && !occurs(v, t))
r = m.mk_false();
else {
expr_ref_vector ors(m);
flatten_or(e, ors);
unsigned num_args = ors.size();
unsigned diseq_count = 0;
unsigned largest_vinx = 0;
@ -149,7 +153,7 @@ void der::reduce1(quantifier * q, expr_ref & r, proof_ref & pr) {
// Find all disequalities
for (unsigned i = 0; i < num_args; i++) {
if (is_var_diseq(to_app(e)->get_arg(i), num_decls, v, t)) {
if (is_var_diseq(ors.get(i), num_decls, v, t)) {
unsigned idx = v->get_idx();
if (m_map.get(idx, nullptr) == nullptr) {
m_map.reserve(idx + 1);
@ -170,7 +174,7 @@ void der::reduce1(quantifier * q, expr_ref & r, proof_ref & pr) {
if (!m_order.empty()) {
create_substitution(largest_vinx + 1);
apply_substitution(q, r);
apply_substitution(q, ors, r);
}
}
else {
@ -180,11 +184,6 @@ void der::reduce1(quantifier * q, expr_ref & r, proof_ref & pr) {
}
// Remark: get_elimination_order/top-sort checks for cycles, but it is not invoked for unit clauses.
// So, we must perform a occurs check here.
else if (is_var_diseq(e, num_decls, v, t) && !occurs(v, t)) {
r = m.mk_false();
}
else
r = q;
if (m.proofs_enabled()) {
pr = r == q ? nullptr : m.mk_der(q, r);
@ -327,9 +326,8 @@ void der::create_substitution(unsigned sz) {
}
}
void der::apply_substitution(quantifier * q, expr_ref & r) {
expr * e = q->get_expr();
unsigned num_args=to_app(e)->get_num_args();
void der::apply_substitution(quantifier * q, expr_ref_vector& ors, expr_ref & r) {
unsigned num_args = ors.size();
// get a new expression
m_new_args.reset();
@ -338,13 +336,11 @@ void der::apply_substitution(quantifier * q, expr_ref & r) {
if (x != -1 && m_map.get(x) != nullptr)
continue; // this is a disequality with definition (vanishes)
m_new_args.push_back(to_app(e)->get_arg(i));
m_new_args.push_back(ors.get(i));
}
unsigned sz = m_new_args.size();
expr_ref t(m);
t = (sz == 1) ? m_new_args[0] : m.mk_or(sz, m_new_args.data());
expr_ref new_e = m_subst(t, m_subst_map.size(), m_subst_map.data());
expr_ref t = mk_or(m, m_new_args.size(), m_new_args.data());
expr_ref new_e = m_subst(t, m_subst_map);
// don't forget to update the quantifier patterns
expr_ref_buffer new_patterns(m);

2
src/ast/rewriter/der.h
View file

@ -147,7 +147,7 @@ class der {
void get_elimination_order();
void create_substitution(unsigned sz);
void apply_substitution(quantifier * q, expr_ref & r);
void apply_substitution(quantifier * q, expr_ref_vector& ors, expr_ref & r);
void reduce1(quantifier * q, expr_ref & r, proof_ref & pr);