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add sat-euf

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-08-25 12:16:45 -07:00
parent a7b51d04cd
commit ecd3315a74
11 changed files with 474 additions and 52 deletions
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105
src/ast/euf/euf_egraph.cpp
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@ -35,8 +35,7 @@ namespace euf {
unmerge_justification(n1);
}
enode* egraph::mk_enode(expr* f, enode * const* args) {
unsigned num_args = is_app(f) ? to_app(f)->get_num_args() : 0;
enode* egraph::mk_enode(expr* f, unsigned num_args, enode * const* args) {
enode* n = enode::mk(m_region, f, num_args, args);
m_nodes.push_back(n);
m_exprs.push_back(f);
@ -98,15 +97,15 @@ namespace euf {
n->set_update_children();
}
enode* egraph::mk(expr* f, enode *const* args) {
enode* egraph::mk(expr* f, unsigned num_args, enode *const* args) {
SASSERT(!find(f));
force_push();
enode *n = mk_enode(f, args);
enode *n = mk_enode(f, num_args, args);
SASSERT(n->class_size() == 1);
m_expr2enode.setx(f->get_id(), n, nullptr);
if (n->num_args() == 0 && m.is_unique_value(f))
if (num_args == 0 && m.is_unique_value(f))
n->mark_interpreted();
if (n->num_args() == 0)
if (num_args == 0)
return n;
if (is_equality(n)) {
update_children(n);
@ -171,6 +170,8 @@ namespace euf {
std::swap(r1, r2);
std::swap(n1, n2);
}
if ((m.is_true(r2->get_owner()) || m.is_false(r2->get_owner())) && j.is_congruence())
m_new_lits.push_back(n1);
for (enode* p : enode_parents(n1))
m_table.erase(p);
for (enode* p : enode_parents(n2))
@ -187,6 +188,7 @@ namespace euf {
void egraph::propagate() {
m_new_eqs.reset();
m_new_lits.reset();
SASSERT(m_num_scopes == 0 || m_worklist.empty());
unsigned head = 0, tail = m_worklist.size();
while (head < tail && m.limit().inc() && !inconsistent()) {
@ -239,6 +241,88 @@ namespace euf {
SASSERT(n1->get_root()->m_target == nullptr);
}
/**
\brief generate an explanation for a congruence.
Each pair of children under a congruence have the same roots
and therefore have a least common ancestor. We only need
explanations up to the least common ancestors.
*/
void egraph::push_congruence(enode* n1, enode* n2, bool comm) {
SASSERT(n1->get_decl() == n2->get_decl());
if (comm &&
n1->get_arg(0)->get_root() == n2->get_arg(1)->get_root() &&
n1->get_arg(1)->get_root() == n2->get_arg(0)->get_root()) {
push_lca(n1->get_arg(0), n2->get_arg(1));
push_lca(n1->get_arg(1), n2->get_arg(0));
return;
}
for (unsigned i = 0; i < n1->num_args(); ++i)
push_lca(n1->get_arg(i), n2->get_arg(i));
}
void egraph::push_lca(enode* a, enode* b) {
SASSERT(a->get_root() == b->get_root());
enode* n = a;
while (n) {
n->mark2();
n = n->m_target;
}
n = b;
while (n) {
if (n->is_marked2())
n->unmark2();
else if (!n->is_marked1())
m_todo.push_back(n);
n = n->m_target;
}
n = a;
while (n->is_marked2()) {
n->unmark2();
if (!n->is_marked1())
m_todo.push_back(n);
n = n->m_target;
}
}
void egraph::push_todo(enode* n) {
while (n) {
m_todo.push_back(n);
n = n->m_target;
}
}
template <typename T>
void egraph::explain(ptr_vector<T>& justifications) {
SASSERT(m_inconsistent);
SASSERT(m_todo.empty());
push_todo(m_n1);
push_todo(m_n2);
explain_eq(justifications, m_n1, m_n2, m_justification);
explain_todo(justifications);
}
template <typename T>
void egraph::explain_eq(ptr_vector<T>& justifications, enode* a, enode* b, bool comm) {
SASSERT(m_todo.empty());
push_congruence(a, b, comm);
explain_todo(justifications);
}
template <typename T>
void egraph::explain_todo(ptr_vector<T>& justifications) {
for (unsigned i = 0; i < m_todo.size(); ++i) {
enode* n = m_todo[i];
if (n->m_target && !n->is_marked1()) {
n->mark1();
explain_eq(justifications, n, n->m_target, n->m_justification);
}
}
for (enode* n : m_todo)
n->unmark1();
m_todo.reset();
}
void egraph::invariant() {
for (enode* n : m_nodes)
n->invariant();
@ -267,3 +351,12 @@ namespace euf {
return out;
}
}
template void euf::egraph::explain(ptr_vector<int>& justifications);
template void euf::egraph::explain_todo(ptr_vector<int>& justifications);
template void euf::egraph::explain_eq(ptr_vector<int>& justifications, enode* a, enode* b, bool comm);
template void euf::egraph::explain(ptr_vector<unsigned>& justifications);
template void euf::egraph::explain_todo(ptr_vector<unsigned>& justifications);
template void euf::egraph::explain_eq(ptr_vector<unsigned>& justifications, enode* a, enode* b, bool comm);