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fixed-size min-heap for tracking top-k literals (#7752)

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* very basic setup

* ensure solve_eqs is fully disabled when smt.solve_eqs=false, #7743

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* respect smt configuration parameter in elim_unconstrained simplifier

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* indentation

* add bash files for test runs

* add option to selectively disable variable solving for only ground expressions

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* remove verbose output

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix #7745

axioms for len(substr(...)) escaped due to nested rewriting

* ensure atomic constraints are processed by arithmetic solver

* #7739 optimization

add simplification rule for at(x, offset) = ""

Introducing j just postpones some rewrites that prevent useful simplifications. Z3 already uses common sub-expressions.
The example highlights some opportunities for simplification, noteworthy at(..) = "".
The example is solved in both versions after adding this simplification.

* fix unsound len(substr) axiom

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* FreshConst is_sort (#7748)

* #7750

add pre-processing simplification

* Add parameter validation for selected API functions

* updates to ac-plugin

fix incrementality bugs by allowing destructive updates during saturation at the cost of redoing saturation after a pop.

* enable passive, add check for bloom up-to-date

* add top-k fixed-sized min-heap priority queue for top scoring literals

---------

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
Co-authored-by: Nikolaj Bjorner <nbjorner@microsoft.com>
Co-authored-by: humnrdble <83878671+humnrdble@users.noreply.github.com>
This commit is contained in:
Ilana Shapiro 2025-07-28 19:54:01 -07:00 • committed by GitHub
parent a9b4e35938
commit 435ea6ea99
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24 changed files with 762 additions and 303 deletions
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434
src/ast/euf/euf_ac_plugin.cpp
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@ -14,7 +14,7 @@ Author:
Nikolaj Bjorner (nbjorner) 2023-11-11
Completion modulo AC
E set of eqs
pick critical pair xy = z by j1 xu = v by j2 in E
Add new equation zu = xyu = vy by j1, j2
@ -22,7 +22,7 @@ Completion modulo AC
Sets P - processed, R - reductions, S - to simplify
new equality l = r:
new equality l = r:
reduce l = r modulo R if equation is external
orient l = r - if it cannot be oriented, discard
if l = r is a reduction rule then reduce R, S using l = r, insert into R
@ -46,9 +46,9 @@ backward subsumption e as (l = r) using (l' = r') in P u S:
is reduction rule e as (l = r):
l is a unit, and r is unit, is empty, or is zero.
superpose e as (l = r) with (l' = r') in P:
if l and l' share a common subset x.
if l and l' share a common subset x.
forward simplify (l' = r') in P u S using e as (l = r):
@ -56,10 +56,10 @@ forward simplify (l' = r') in P u S using e as (l = r):
More notes:
Justifications for new equations are joined (requires extension to egraph/justification)
Process new merges so use list is updated
Justifications for processed merges are recorded
Updated equations are recorded for restoration on backtracking
Keep track of foreign / shared occurrences of AC functions.
@ -91,7 +91,7 @@ More notes:
TODOs:
- Efficiency of handling shared terms.
- The shared terms hash table is not incremental.
- The shared terms hash table is not incremental.
It could be made incremental by updating it on every merge similar to how the egraph handles it.
- V2 using multiplicities instead of repeated values in monomials.
- Squash trail updates when equations or monomials are modified within the same epoch.
@ -131,20 +131,18 @@ namespace euf {
return;
for (auto arg : enode_args(n))
if (is_op(arg))
register_shared(arg);
register_shared(arg);
}
// unit -> {}
void ac_plugin::add_unit(enode* u) {
m_units.push_back(u);
mk_node(u);
auto m_id = to_monomial(u, {});
init_equation(eq(to_monomial(u), m_id, justification::axiom(get_id())));
void ac_plugin::add_unit(enode* u) {
push_equation(u, nullptr);
}
// zero x -> zero
void ac_plugin::add_zero(enode* z) {
mk_node(z)->is_zero = true;
// zeros persist
}
void ac_plugin::register_shared(enode* n) {
@ -165,12 +163,16 @@ namespace euf {
push_undo(is_register_shared);
}
void ac_plugin::push_scope_eh() {
push_undo(is_push_scope);
}
void ac_plugin::undo() {
auto k = m_undo.back();
m_undo.pop_back();
switch (k) {
case is_add_eq: {
m_active.pop_back();
case is_queue_eq: {
m_queued.pop_back();
break;
}
case is_add_node: {
@ -180,14 +182,15 @@ namespace euf {
n->~node();
break;
}
case is_add_monomial: {
m_monomials.pop_back();
case is_push_scope: {
m_active.reset();
m_passive.reset();
m_units.reset();
m_queue_head = 0;
break;
}
case is_update_eq: {
auto const& [idx, eq] = m_update_eq_trail.back();
m_active[idx] = eq;
m_update_eq_trail.pop_back();
case is_add_monomial: {
m_monomials.pop_back();
break;
}
case is_add_shared_index: {
@ -203,7 +206,7 @@ namespace euf {
break;
}
case is_register_shared: {
auto s = m_shared.back();
auto s = m_shared.back();
m_shared_nodes[s.n->get_id()] = false;
m_shared.pop_back();
break;
@ -316,14 +319,24 @@ namespace euf {
}
void ac_plugin::merge_eh(enode* l, enode* r) {
if (l == r)
return;
push_equation(l, r);
}
void ac_plugin::pop_equation(enode* l, enode* r) {
m_fuel += m_fuel_inc;
auto j = justification::equality(l, r);
auto m1 = to_monomial(l);
auto m2 = to_monomial(r);
TRACE(plugin, tout << "merge: " << m_name << " " << g.bpp(l) << " == " << g.bpp(r) << " " << m_pp_ll(*this, monomial(m1)) << " == " << m_pp_ll(*this, monomial(m2)) << "\n");
init_equation(eq(m1, m2, j));
if (!r) {
m_units.push_back(l);
mk_node(l);
auto m_id = to_monomial(l, {});
init_equation(eq(to_monomial(l), m_id, justification::axiom(get_id())), true);
}
else {
auto j = justification::equality(l, r);
auto m1 = to_monomial(l);
auto m2 = to_monomial(r);
TRACE(plugin, tout << "merge: " << m_name << " " << g.bpp(l) << " == " << g.bpp(r) << " " << m_pp_ll(*this, monomial(m1)) << " == " << m_pp_ll(*this, monomial(m2)) << "\n");
init_equation(eq(m1, m2, j), true);
}
}
void ac_plugin::diseq_eh(enode* eq) {
@ -336,64 +349,80 @@ namespace euf {
register_shared(b);
}
bool ac_plugin::init_equation(eq const& e) {
m_active.push_back(e);
auto& eq = m_active.back();
deduplicate(monomial(eq.l).m_nodes, monomial(eq.r).m_nodes);
if (orient_equation(eq)) {
auto& ml = monomial(eq.l);
auto& mr = monomial(eq.r);
unsigned eq_id = m_active.size() - 1;
if (ml.size() == 1 && mr.size() == 1)
push_merge(ml[0]->n, mr[0]->n, eq.j);
for (auto n : ml) {
if (!n->n->is_marked2()) {
n->eqs.push_back(eq_id);
n->n->mark2();
push_undo(is_add_eq_index);
m_node_trail.push_back(n);
for (auto s : n->shared)
m_shared_todo.insert(s);
}
}
for (auto n : mr) {
if (!n->n->is_marked2()) {
n->eqs.push_back(eq_id);
n->n->mark2();
push_undo(is_add_eq_index);
m_node_trail.push_back(n);
for (auto s : n->shared)
m_shared_todo.insert(s);
}
}
for (auto n : ml)
n->n->unmark2();
for (auto n : mr)
n->n->unmark2();
SASSERT(well_formed(eq));
TRACE(plugin, display_equation_ll(tout, eq) << " shared: " << m_shared_todo << "\n");
m_to_simplify_todo.insert(eq_id);
m_new_eqs.push_back(eq_id);
//display_equation_ll(verbose_stream() << "init " << eq_id << ": ", eq) << "\n";
return true;
}
else {
m_active.pop_back();
return false;
}
void ac_plugin::push_equation(enode* l, enode* r) {
if (l == r)
return;
m_queued.push_back({ l, r });
push_undo(is_queue_eq);
}
bool ac_plugin::init_equation(eq eq, bool is_active) {
deduplicate(monomial(eq.l), monomial(eq.r));
if (!orient_equation(eq))
return false;
#if 1
if (is_reducing(eq))
is_active = true;
#else
is_active = true; // set to active by default
#endif
if (!is_active) {
m_passive.push_back(eq);
return true;
}
m_active.push_back(eq);
auto& ml = monomial(eq.l);
auto& mr = monomial(eq.r);
unsigned eq_id = m_active.size() - 1;
if (ml.size() == 1 && mr.size() == 1)
push_merge(ml[0]->n, mr[0]->n, eq.j);
for (auto n : ml) {
if (!n->n->is_marked2()) {
n->eqs.push_back(eq_id);
n->n->mark2();
push_undo(is_add_eq_index);
m_node_trail.push_back(n);
for (auto s : n->shared)
m_shared_todo.insert(s);
}
}
for (auto n : mr) {
if (!n->n->is_marked2()) {
n->eqs.push_back(eq_id);
n->n->mark2();
push_undo(is_add_eq_index);
m_node_trail.push_back(n);
for (auto s : n->shared)
m_shared_todo.insert(s);
}
}
for (auto n : ml)
n->n->unmark2();
for (auto n : mr)
n->n->unmark2();
SASSERT(well_formed(eq));
TRACE(plugin, display_equation_ll(tout, eq) << " shared: " << m_shared_todo << "\n");
m_to_simplify_todo.insert(eq_id);
m_new_eqs.push_back(eq_id);
//display_equation_ll(verbose_stream() << "init " << eq_id << ": ", eq) << "\n";
return true;
}
bool ac_plugin::orient_equation(eq& e) {
auto& ml = monomial(e.l);
auto& mr = monomial(e.r);
@ -402,7 +431,7 @@ namespace euf {
if (ml.size() < mr.size()) {
std::swap(e.l, e.r);
return true;
}
}
else {
sort(ml);
sort(mr);
@ -412,7 +441,7 @@ namespace euf {
if (ml[i]->id() < mr[i]->id())
std::swap(e.l, e.r);
return true;
}
}
return false;
}
}
@ -429,7 +458,7 @@ namespace euf {
return false;
if (!is_sorted(mr))
return false;
for (unsigned i = 0; i < ml.size(); ++i) {
for (unsigned i = 0; i < ml.size(); ++i) {
if (ml[i]->id() == mr[i]->id())
continue;
if (ml[i]->id() < mr[i]->id())
@ -455,8 +484,11 @@ namespace euf {
uint64_t ac_plugin::filter(monomial_t& m) {
auto& bloom = m.m_bloom;
if (bloom.m_tick == m_tick)
if (bloom.m_tick == m_tick) {
SASSERT(bloom_filter_is_correct(m.m_nodes, m.m_bloom));
return bloom.m_filter;
}
bloom.m_filter = 0;
for (auto n : m)
bloom.m_filter |= (1ull << (n->id() % 64ull));
@ -466,6 +498,13 @@ namespace euf {
return bloom.m_filter;
}
bool ac_plugin::bloom_filter_is_correct(ptr_vector<node> const& m, bloom const& b) const {
uint64_t f = 0;
for (auto n : m)
f |= (1ull << (n->id() % 64ull));
return b.m_filter == f;
}
bool ac_plugin::can_be_subset(monomial_t& subset, monomial_t& superset) {
if (subset.size() > superset.size())
return false;
@ -477,6 +516,7 @@ namespace euf {
bool ac_plugin::can_be_subset(monomial_t& subset, ptr_vector<node> const& m, bloom& bloom) {
if (subset.size() > m.size())
return false;
SASSERT(bloom.m_tick != m_tick || bloom_filter_is_correct(m, bloom));
if (bloom.m_tick != m_tick) {
bloom.m_filter = 0;
for (auto n : m)
@ -501,10 +541,10 @@ namespace euf {
ns.push_back(n);
for (unsigned i = 0; i < ns.size(); ++i) {
auto k = ns[i];
if (is_op(k))
ns.append(k->num_args(), k->args());
else
m.push_back(mk_node(k));
if (is_op(k))
ns.append(k->num_args(), k->args());
else
m.push_back(mk_node(k));
}
return to_monomial(n, m);
}
@ -562,6 +602,10 @@ namespace euf {
}
void ac_plugin::propagate() {
while (m_queue_head < m_queued.size()) {
auto [l, r] = m_queued[m_queue_head++];
pop_equation(l, r);
}
while (true) {
loop_start:
if (m_fuel == 0)
@ -575,15 +619,15 @@ namespace euf {
SASSERT(well_formed(m_active[eq_id]));
// simplify eq using processed
TRACE(plugin,
for (auto other_eq : forward_iterator(eq_id))
tout << "forward iterator " << eq_id << " vs " << other_eq << " " << is_processed(other_eq) << "\n");
TRACE(plugin,
for (auto other_eq : forward_iterator(eq_id))
tout << "forward iterator " << eq_id << " vs " << other_eq << " " << is_processed(other_eq) << "\n");
for (auto other_eq : forward_iterator(eq_id))
if (is_processed(other_eq) && forward_simplify(eq_id, other_eq))
goto loop_start;
auto& eq = m_active[eq_id];
deduplicate(monomial(eq.l).m_nodes, monomial(eq.r).m_nodes);
deduplicate(monomial(eq.l), monomial(eq.r));
if (monomial(eq.l).size() == 0) {
set_status(eq_id, eq_status::is_dead_eq);
continue;
@ -605,8 +649,8 @@ namespace euf {
for (auto other_eq : backward_iterator(eq_id))
if (is_active(other_eq))
backward_simplify(eq_id, other_eq);
forward_subsume_new_eqs();
forward_subsume_new_eqs();
// superpose, create new equations
unsigned new_sup = 0;
for (auto other_eq : superpose_iterator(eq_id))
@ -623,12 +667,20 @@ namespace euf {
}
unsigned ac_plugin::pick_next_eq() {
init_pick:
while (!m_to_simplify_todo.empty()) {
unsigned id = *m_to_simplify_todo.begin();
if (id < m_active.size() && is_to_simplify(id))
return id;
m_to_simplify_todo.remove(id);
}
if (!m_passive.empty()) {
auto eq = m_passive.back();
// verbose_stream() << "pick passive " << eq_pp_ll(*this, eq) << "\n";
m_passive.pop_back();
init_equation(eq, true);
goto init_pick;
}
return UINT_MAX;
}
@ -637,14 +689,10 @@ namespace euf {
auto& eq = m_active[id];
if (eq.status == eq_status::is_dead_eq)
return;
if (are_equal(monomial(eq.l), monomial(eq.r)))
if (are_equal(monomial(eq.l), monomial(eq.r)))
s = eq_status::is_dead_eq;
if (eq.status != s) {
m_update_eq_trail.push_back({ id, eq });
eq.status = s;
push_undo(is_update_eq);
}
eq.status = s;
switch (s) {
case eq_status::is_processed_eq:
case eq_status::is_reducing_eq:
@ -657,7 +705,7 @@ namespace euf {
set_status(id, eq_status::is_dead_eq);
}
break;
}
}
}
//
@ -673,7 +721,7 @@ namespace euf {
}
//
// backward iterator allows simplification of eq
// forward iterator allows simplification of eq
// The rhs of eq is a super-set of lhs of other eq.
//
unsigned_vector const& ac_plugin::forward_iterator(unsigned eq_id) {
@ -733,7 +781,7 @@ namespace euf {
unsigned j = 0;
m_eq_seen.reserve(m_active.size() + 1, false);
for (unsigned i = 0; i < m_eq_occurs.size(); ++i) {
unsigned id = m_eq_occurs[i];
unsigned id = m_eq_occurs[i];
if (m_eq_seen[id])
continue;
if (id == eq_id)
@ -749,7 +797,7 @@ namespace euf {
}
//
// forward iterator simplifies other eqs where their rhs is a superset of lhs of eq
// backward iterator simplifies other eqs where their rhs is a superset of lhs of eq
//
unsigned_vector const& ac_plugin::backward_iterator(unsigned eq_id) {
auto& eq = m_active[eq_id];
@ -768,7 +816,7 @@ namespace euf {
}
void ac_plugin::init_ref_counts(monomial_t const& monomial, ref_counts& counts) const {
init_ref_counts(monomial.m_nodes, counts);
init_ref_counts(monomial.m_nodes, counts);
}
void ac_plugin::init_ref_counts(ptr_vector<node> const& monomial, ref_counts& counts) const {
@ -786,7 +834,7 @@ namespace euf {
init_ref_counts(m, check);
return
all_of(counts, [&](unsigned i) { return check[i] == counts[i]; }) &&
all_of(check, [&](unsigned i) { return check[i] == counts[i]; });
all_of(check, [&](unsigned i) { return check[i] == counts[i]; });
}
void ac_plugin::backward_simplify(unsigned src_eq, unsigned dst_eq) {
@ -843,10 +891,8 @@ namespace euf {
reduce(m_src_r, j);
auto new_r = to_monomial(m_src_r);
index_new_r(dst_eq, monomial(m_active[dst_eq].r), monomial(new_r));
m_update_eq_trail.push_back({ dst_eq, m_active[dst_eq] });
m_active[dst_eq].r = new_r;
m_active[dst_eq].j = j;
push_undo(is_update_eq);
m_src_r.reset();
m_src_r.append(monomial(src.r).m_nodes);
TRACE(plugin_verbose, tout << "rewritten to " << m_pp_ll(*this, monomial(new_r)) << "\n");
@ -862,7 +908,7 @@ namespace euf {
//
// dst_ids, dst_count contain rhs of dst_eq
//
TRACE(plugin, tout << "backward simplify " << eq_pp_ll(*this, src) << " " << eq_pp_ll(*this, dst) << " can-be-subset: " << can_be_subset(monomial(src.l), monomial(dst.r)) << "\n");
TRACE(plugin, tout << "forward simplify " << eq_pp_ll(*this, src) << " " << eq_pp_ll(*this, dst) << " can-be-subset: " << can_be_subset(monomial(src.l), monomial(dst.r)) << "\n");
if (forward_subsumes(src_eq, dst_eq)) {
set_status(dst_eq, eq_status::is_dead_eq);
@ -873,11 +919,11 @@ namespace euf {
// check that src.l is a subset of dst.r
if (!can_be_subset(monomial(src.l), monomial(dst.r)))
return false;
if (!is_subset(m_dst_r_counts, m_src_l_counts, monomial(src.l)))
return false;
if (monomial(dst.r).size() == 0)
return false;
if (!is_subset(m_dst_r_counts, m_src_l_counts, monomial(src.l)))
return false;
if (monomial(dst.r).size() == 0)
return false;
SASSERT(is_correct_ref_count(monomial(dst.r), m_dst_r_counts));
@ -885,17 +931,15 @@ namespace euf {
init_ref_counts(monomial(src.l), m_src_l_counts);
//verbose_stream() << "forward simplify " << eq_pp_ll(*this, src_eq) << " for " << eq_pp_ll(*this, dst_eq) << "\n";
rewrite1(m_src_l_counts, monomial(src.r), m_dst_r_counts, m);
auto j = justify_rewrite(src_eq, dst_eq);
reduce(m, j);
auto new_r = to_monomial(m);
index_new_r(dst_eq, monomial(m_active[dst_eq].r), monomial(new_r));
m_update_eq_trail.push_back({ dst_eq, m_active[dst_eq] });
m_active[dst_eq].r = new_r;
m_active[dst_eq].j = j;
TRACE(plugin, tout << "rewritten to " << m_pp(*this, monomial(new_r)) << "\n");
push_undo(is_update_eq);
return true;
}
@ -913,7 +957,7 @@ namespace euf {
m_new_eqs.reset();
}
bool ac_plugin::is_forward_subsumed(unsigned eq_id) {
bool ac_plugin::is_forward_subsumed(unsigned eq_id) {
return any_of(forward_iterator(eq_id), [&](unsigned other_eq) { return forward_subsumes(other_eq, eq_id); });
}
@ -968,14 +1012,16 @@ namespace euf {
}
// now dst.r and src.r should align and have the same elements.
// since src.r is a subset of dst.r we iterate over dst.r
if (!all_of(monomial(src.r), [&](node* n) {
unsigned id = n->id();
if (!all_of(monomial(src.r), [&](node* n) {
unsigned id = n->id();
return m_src_r_counts[id] == m_dst_r_counts[id]; })) {
TRACE(plugin_verbose, tout << "dst.r and src.r do not align\n");
SASSERT(!are_equal(m_active[src_eq], m_active[dst_eq]));
return false;
}
return all_of(monomial(dst.r), [&](node* n) { unsigned id = n->id(); return m_src_r_counts[id] == m_dst_r_counts[id]; });
bool r = all_of(monomial(dst.r), [&](node* n) { unsigned id = n->id(); return m_src_r_counts[id] == m_dst_r_counts[id]; });
SASSERT(r || !are_equal(m_active[src_eq], m_active[dst_eq]));
return r;
}
// src_l_counts, src_r_counts are initialized for src.l, src.r
@ -990,7 +1036,7 @@ namespace euf {
return false;
unsigned size_diff = monomial(dst.l).size() - monomial(src.l).size();
if (size_diff != monomial(dst.r).size() - monomial(src.r).size())
return false;
return false;
if (!is_superset(m_src_l_counts, m_dst_l_counts, monomial(dst.l)))
return false;
if (!is_superset(m_src_r_counts, m_dst_r_counts, monomial(dst.r)))
@ -1026,14 +1072,14 @@ namespace euf {
unsigned dst_count = dst_counts[id];
unsigned src_count = src_l[id];
SASSERT(dst_count > 0);
if (src_count == 0) {
dst[j++] = n;
dst[j++] = n;
}
else if (src_count < dst_count) {
dst[j++] = n;
dst_counts.dec(id, 1);
}
}
}
dst.shrink(j);
dst.append(src_r.m_nodes);
@ -1047,11 +1093,11 @@ namespace euf {
init_loop:
if (m.size() == 1)
return change;
bloom b;
bloom b;
init_ref_counts(m, m_m_counts);
for (auto n : m) {
if (n->is_zero) {
m[0] = n;
m[0] = n;
m.shrink(1);
break;
}
@ -1060,9 +1106,9 @@ namespace euf {
if (!is_reducing(eq)) // also can use processed?
continue;
auto& src = m_active[eq];
if (!is_equation_oriented(src))
continue;
if (!is_equation_oriented(src))
continue;
if (!can_be_subset(monomial(src.l), m, b))
continue;
if (!is_subset(m_m_counts, m_eq_counts, monomial(src.l)))
@ -1078,9 +1124,8 @@ namespace euf {
change = true;
goto init_loop;
}
}
}
while (false);
}
} while (false);
VERIFY(sz >= m.size());
return change;
}
@ -1122,7 +1167,7 @@ namespace euf {
auto& src = m_active[src_eq];
auto& dst = m_active[dst_eq];
unsigned max_left = std::max(monomial(src.l).size(), monomial(dst.l).size());
unsigned max_left = std::max(monomial(src.l).size(), monomial(dst.l).size());
unsigned min_right = std::max(monomial(src.r).size(), monomial(dst.r).size());
@ -1151,7 +1196,7 @@ namespace euf {
m_src_r.shrink(src_r_size);
return false;
}
// compute CD
for (auto n : monomial(src.l)) {
unsigned id = n->id();
@ -1171,18 +1216,18 @@ namespace euf {
reduce(m_src_r, j);
deduplicate(m_src_r, m_dst_r);
bool added_eq = false;
auto src_r = src.r;
unsigned max_left_new = std::max(m_src_r.size(), m_dst_r.size());
unsigned min_right_new = std::min(m_src_r.size(), m_dst_r.size());
if (max_left_new <= max_left && min_right_new <= min_right)
added_eq = init_equation(eq(to_monomial(m_src_r), to_monomial(m_dst_r), j));
if (max_left_new <= max_left && min_right_new <= min_right)
added_eq = init_equation(eq(to_monomial(m_src_r), to_monomial(m_dst_r), j), false);
CTRACE(plugin, added_eq,
tout << "superpose: " << m_name << " " << eq_pp_ll(*this, src) << " " << eq_pp_ll(*this, dst) << " --> ";
tout << m_pp_ll(*this, m_src_r) << "== " << m_pp_ll(*this, m_dst_r) << "\n";);
tout << m_pp_ll(*this, m_src_r) << "== " << m_pp_ll(*this, m_dst_r) << "\n";);
m_src_r.reset();
m_src_r.append(monomial(src_r).m_nodes);
return added_eq;
@ -1191,7 +1236,7 @@ namespace euf {
bool ac_plugin::is_reducing(eq const& e) const {
auto const& l = monomial(e.l);
auto const& r = monomial(e.r);
return l.size() == 1 && r.size() <= 1;
return l.size() == 1 && r.size() <= 1;
}
void ac_plugin::backward_reduce(unsigned eq_id) {
@ -1202,23 +1247,36 @@ namespace euf {
SASSERT(is_active(other_eq));
backward_reduce(eq, other_eq);
}
for (auto p : m_passive) {
bool change = false;
if (backward_reduce_monomial(eq, p, monomial(p.l)))
change = true;
if (backward_reduce_monomial(eq, p, monomial(p.r)))
change = true;
(void)change;
CTRACE(plugin, change,
verbose_stream() << "backward reduce " << eq_pp_ll(*this, eq) << " " << eq_pp_ll(*this, p) << "\n");
}
}
// TODO: this is destructive. It breaks reversibility.
// TODO: also need justifications from eq if there is a change.
void ac_plugin::backward_reduce(eq const& eq, unsigned other_eq_id) {
auto& other_eq = m_active[other_eq_id];
auto& other_eq = m_active[other_eq_id];
TRACE(plugin_verbose,
tout << "backward reduce " << eq_pp_ll(*this, eq) << " " << eq_pp_ll(*this, other_eq) << "\n");
bool change = false;
if (backward_reduce_monomial(eq, monomial(other_eq.l)))
if (backward_reduce_monomial(eq, other_eq, monomial(other_eq.l)))
change = true;
if (backward_reduce_monomial(eq, monomial(other_eq.r)))
if (backward_reduce_monomial(eq, other_eq, monomial(other_eq.r)))
change = true;
if (change)
set_status(other_eq_id, eq_status::is_to_simplify_eq);
CTRACE(plugin, change,
tout << "backward reduce " << eq_pp_ll(*this, eq) << " " << eq_pp_ll(*this, other_eq) << "\n");
if (change) {
set_status(other_eq_id, eq_status::is_to_simplify_eq);
}
}
bool ac_plugin::backward_reduce_monomial(eq const& eq, monomial_t& m) {
auto const& r = monomial(eq.r);
bool ac_plugin::backward_reduce_monomial(eq const& src, eq& dst, monomial_t& m) {
auto const& r = monomial(src.r);
unsigned j = 0;
bool change = false;
for (auto n : m) {
@ -1241,7 +1299,11 @@ namespace euf {
m.m_nodes[j++] = r[0];
}
m.m_nodes.shrink(j);
return change;
if (change) {
m.m_bloom.m_tick = 0;
dst.j = join(dst.j, src);
}
return change;
}
bool ac_plugin::are_equal(monomial_t& a, monomial_t& b) {
@ -1252,8 +1314,8 @@ namespace euf {
if (a.size() != b.size())
return false;
m_eq_counts.reset();
for (auto n : a)
m_eq_counts.inc(n->id(), 1);
for (auto n : a)
m_eq_counts.inc(n->id(), 1);
for (auto n : b) {
unsigned id = n->id();
if (m_eq_counts[id] == 0)
@ -1277,21 +1339,29 @@ namespace euf {
return true;
}
void ac_plugin::deduplicate(monomial_t& a, monomial_t& b) {
unsigned sza = a.size(), szb = b.size();
deduplicate(a.m_nodes, b.m_nodes);
if (sza != a.size())
a.m_bloom.m_tick = 0;
if (szb != b.size())
b.m_bloom.m_tick = 0;
}
void ac_plugin::deduplicate(ptr_vector<node>& a, ptr_vector<node>& b) {
{
for (auto n : a) {
if (n->is_zero) {
a[0] = n;
a.shrink(1);
break;
}
for (auto n : a) {
if (n->is_zero) {
a[0] = n;
a.shrink(1);
break;
}
for (auto n : b) {
if (n->is_zero) {
b[0] = n;
b.shrink(1);
break;
}
}
for (auto n : b) {
if (n->is_zero) {
b[0] = n;
b.shrink(1);
break;
}
}
@ -1340,14 +1410,14 @@ namespace euf {
while (!m_shared_todo.empty()) {
auto idx = *m_shared_todo.begin();
m_shared_todo.remove(idx);
if (idx < m_shared.size())
if (idx < m_shared.size())
simplify_shared(idx, m_shared[idx]);
}
m_monomial_table.reset();
for (auto const& s1 : m_shared) {
shared s2;
TRACE(plugin_verbose, tout << "shared " << s1.m << ": " << m_pp_ll(*this, monomial(s1.m)) << "\n");
if (!m_monomial_table.find(s1.m, s2))
if (!m_monomial_table.find(s1.m, s2))
m_monomial_table.insert(s1.m, s1);
else if (s2.n->get_root() != s1.n->get_root()) {
TRACE(plugin, tout << "merge shared " << g.bpp(s1.n->get_root()) << " and " << g.bpp(s2.n->get_root()) << "\n");
@ -1380,14 +1450,12 @@ namespace euf {
}
}
for (auto n : monomial(old_m))
n->n->unmark2();
n->n->unmark2();
m_update_shared_trail.push_back({ idx, s });
push_undo(is_update_shared);
m_shared[idx].m = new_m;
m_shared[idx].j = j;
TRACE(plugin_verbose, tout << "shared simplified to " << m_pp_ll(*this, monomial(new_m)) << "\n");
push_merge(old_n, new_n, j);
}
@ -1397,19 +1465,15 @@ namespace euf {
}
justification::dependency* ac_plugin::justify_equation(unsigned eq) {
auto const& e = m_active[eq];
auto* j = m_dep_manager.mk_leaf(e.j);
j = justify_monomial(j, monomial(e.l));
j = justify_monomial(j, monomial(e.r));
return j;
}
justification::dependency* ac_plugin::justify_monomial(justification::dependency* j, monomial_t const& m) {
return j;
return m_dep_manager.mk_leaf(m_active[eq].j);
}
justification ac_plugin::join(justification j, unsigned eq) {
return justification::dependent(m_dep_manager.mk_join(m_dep_manager.mk_leaf(j), justify_equation(eq)));
}
justification ac_plugin::join(justification j, eq const& eq) {
return justification::dependent(m_dep_manager.mk_join(m_dep_manager.mk_leaf(j), m_dep_manager.mk_leaf(eq.j)));
}
}

26
src/ast/euf/euf_ac_plugin.h
View file

@ -123,6 +123,7 @@ namespace euf {
func_decl* m_decl = nullptr;
bool m_is_injective = false;
vector<eq> m_active, m_passive;
enode_pair_vector m_queued;
ptr_vector<node> m_nodes;
bool_vector m_shared_nodes;
vector<monomial_t> m_monomials;
@ -146,21 +147,21 @@ namespace euf {
// backtrackable state
enum undo_kind {
is_add_eq,
is_queue_eq,
is_add_monomial,
is_add_node,
is_update_eq,
is_add_shared_index,
is_add_eq_index,
is_register_shared,
is_update_shared
is_update_shared,
is_push_scope
};
svector<undo_kind> m_undo;
ptr_vector<node> m_node_trail;
unsigned m_queue_head = 0;
svector<std::pair<unsigned, shared>> m_update_shared_trail;
svector<std::tuple<node*, unsigned, unsigned>> m_merge_trail;
svector<std::pair<unsigned, eq>> m_update_eq_trail;
@ -178,6 +179,7 @@ namespace euf {
enode* from_monomial(ptr_vector<node> const& m);
monomial_t const& monomial(unsigned i) const { return m_monomials[i]; }
monomial_t& monomial(unsigned i) { return m_monomials[i]; }
void sort(monomial_t& monomial);
bool is_sorted(monomial_t const& monomial) const;
uint64_t filter(monomial_t& m);
@ -188,11 +190,12 @@ namespace euf {
bool are_equal(eq const& a, eq const& b) {
return are_equal(monomial(a.l), monomial(b.l)) && are_equal(monomial(a.r), monomial(b.r));
}
bool bloom_filter_is_correct(ptr_vector<node> const& m, bloom const& b) const;
bool well_formed(eq const& e) const;
bool is_reducing(eq const& e) const;
void backward_reduce(unsigned eq_id);
void backward_reduce(eq const& src, unsigned dst);
bool backward_reduce_monomial(eq const& eq, monomial_t& m);
void backward_reduce(eq const& eq, unsigned dst);
bool backward_reduce_monomial(eq const& src, eq & dst, monomial_t& m);
void forward_subsume_new_eqs();
bool is_forward_subsumed(unsigned dst_eq);
bool forward_subsumes(unsigned src_eq, unsigned dst_eq);
@ -207,8 +210,10 @@ namespace euf {
UNREACHABLE();
return nullptr;
}
bool init_equation(eq const& e);
bool init_equation(eq e, bool is_active);
void push_equation(enode* l, enode* r);
void pop_equation(enode* l, enode* r);
bool orient_equation(eq& e);
void set_status(unsigned eq_id, eq_status s);
unsigned pick_next_eq();
@ -217,6 +222,7 @@ namespace euf {
void backward_simplify(unsigned eq_id, unsigned using_eq);
bool forward_simplify(unsigned eq_id, unsigned using_eq);
bool superpose(unsigned src_eq, unsigned dst_eq);
void deduplicate(monomial_t& a, monomial_t& b);
void deduplicate(ptr_vector<node>& a, ptr_vector<node>& b);
ptr_vector<node> m_src_r, m_src_l, m_dst_r, m_dst_l;
@ -260,8 +266,8 @@ namespace euf {
justification justify_rewrite(unsigned eq1, unsigned eq2);
justification::dependency* justify_equation(unsigned eq);
justification::dependency* justify_monomial(justification::dependency* d, monomial_t const& m);
justification join(justification j1, unsigned eq);
justification join(justification j1, eq const& eq);
bool is_correct_ref_count(monomial_t const& m, ref_counts const& counts) const;
bool is_correct_ref_count(ptr_vector<node> const& m, ref_counts const& counts) const;
@ -301,6 +307,8 @@ namespace euf {
void undo() override;
void push_scope_eh() override;
void propagate() override;
std::ostream& display(std::ostream& out) const override;

5
src/ast/euf/euf_arith_plugin.h
View file

@ -43,6 +43,11 @@ namespace euf {
void undo() override;
void push_scope_eh() override {
m_add.push_scope_eh();
m_mul.push_scope_eh();
}
void propagate() override;
std::ostream& display(std::ostream& out) const override;

3
src/ast/euf/euf_egraph.cpp
View file

@ -103,6 +103,9 @@ namespace euf {
m_scopes.push_back(m_updates.size());
m_region.push_scope();
m_updates.push_back(update_record(m_new_th_eqs_qhead, update_record::new_th_eq_qhead()));
for (auto p : m_plugins)
if (p)
p->push_scope_eh();
}
SASSERT(m_new_th_eqs_qhead <= m_new_th_eqs.size());
}

2
src/ast/euf/euf_plugin.h
View file

@ -52,6 +52,8 @@ namespace euf {
virtual void propagate() = 0;
virtual void undo() = 0;
virtual void push_scope_eh() {}
virtual std::ostream& display(std::ostream& out) const = 0;

28
src/ast/rewriter/bv_rewriter.cpp
View file

@ -2265,6 +2265,20 @@ br_status bv_rewriter::mk_bv_ext_rotate_left(expr * arg1, expr * arg2, expr_ref
unsigned shift = static_cast<unsigned>((r2 % numeral(bv_size)).get_uint64() % static_cast<uint64_t>(bv_size));
return mk_bv_rotate_left(shift, arg1, result);
}
expr* x = nullptr, * y = nullptr;
if (m_util.is_ext_rotate_right(arg1, x, y) && arg2 == y) {
// bv_ext_rotate_left(bv_ext_rotate_right(x, y), y) --> x
result = x;
return BR_DONE;
}
if (m_util.is_ext_rotate_left(arg1, x, y)) {
result = m_util.mk_bv_rotate_left(x, m_util.mk_bv_add(y, arg2));
return BR_REWRITE2;
}
if (m_util.is_ext_rotate_right(arg1, x, y)) {
result = m_util.mk_bv_rotate_left(x, m_util.mk_bv_sub(arg2, y));
return BR_REWRITE2;
}
return BR_FAILED;
}
@ -2275,6 +2289,20 @@ br_status bv_rewriter::mk_bv_ext_rotate_right(expr * arg1, expr * arg2, expr_ref
unsigned shift = static_cast<unsigned>((r2 % numeral(bv_size)).get_uint64() % static_cast<uint64_t>(bv_size));
return mk_bv_rotate_right(shift, arg1, result);
}
expr* x = nullptr, * y = nullptr;
if (m_util.is_ext_rotate_left(arg1, x, y) && arg2 == y) {
// bv_ext_rotate_right(bv_ext_rotate_left(x, y), y) --> x
result = x;
return BR_DONE;
}
if (m_util.is_ext_rotate_right(arg1, x, y)) {
result = m_util.mk_bv_rotate_right(x, m_util.mk_bv_add(y, arg2));
return BR_REWRITE2;
}
if (m_util.is_ext_rotate_left(arg1, x, y)) {
result = m_util.mk_bv_rotate_right(x, m_util.mk_bv_sub(arg2, y));
return BR_REWRITE2;
}
return BR_FAILED;
}

30
src/ast/rewriter/seq_axioms.cpp
View file

@ -1224,16 +1224,40 @@ namespace seq {
let n = len(x)
- len(a ++ b) = len(a) + len(b) if x = a ++ b
- len(unit(u)) = 1 if x = unit(u)
- len(extract(x, o, l)) = l if len(x) >= o + l etc
- len(str) = str.length() if x = str
- len(empty) = 0 if x = empty
- len(int.to.str(i)) >= 1 if x = int.to.str(i) and more generally if i = 0 then 1 else 1+floor(log(|i|))
- len(x) >= 0 otherwise
*/
void axioms::length_axiom(expr* n) {
expr* x = nullptr;
expr* x = nullptr, * y = nullptr, * offs = nullptr, * l = nullptr;
VERIFY(seq.str.is_length(n, x));
if (seq.str.is_concat(x) ||
seq.str.is_unit(x) ||
if (seq.str.is_concat(x) && to_app(x)->get_num_args() != 0) {
ptr_vector<expr> args;
for (auto arg : *to_app(x))
args.push_back(seq.str.mk_length(arg));
expr_ref len(a.mk_add(args), m);
add_clause(mk_eq(len, n));
}
else if (seq.str.is_extract(x, y, offs, l)) {
// len(extract(y, o, l)) = l if len(y) >= o + l, o >= 0, l >= 0
// len(extract(y, o, l)) = 0 if o < 0 or l <= 0 or len(y) < o
// len(extract(y, o, l)) = len(y) - o if o <= len(y) < o + l
expr_ref len_y(mk_len(y), m);
expr_ref z(a.mk_int(0), m);
expr_ref y_ge_l = mk_ge(a.mk_sub(len_y, a.mk_add(offs, l)), 0);
expr_ref y_ge_o = mk_ge(a.mk_sub(len_y, offs), 0);
expr_ref offs_ge_0 = mk_ge(offs, 0);
expr_ref l_ge_0 = mk_ge(l, 0);
add_clause(~offs_ge_0, ~l_ge_0, ~y_ge_l, mk_eq(n, l));
add_clause(offs_ge_0, mk_eq(n, z));
add_clause(l_ge_0, mk_eq(n, z));
add_clause(y_ge_o, mk_eq(n, z));
add_clause(~y_ge_o, y_ge_l, mk_eq(n, a.mk_sub(len_y, offs)));
}
else if (seq.str.is_unit(x) ||
seq.str.is_empty(x) ||
seq.str.is_string(x)) {
expr_ref len(n, m);

6
src/ast/rewriter/seq_rewriter.cpp
View file

@ -6021,6 +6021,12 @@ bool seq_rewriter::reduce_eq_empty(expr* l, expr* r, expr_ref& result) {
result = m_autil.mk_lt(s, zero());
return true;
}
// at(s, offset) = "" <=> len(s) <= offset or offset < 0
if (str().is_at(r, s, offset)) {
expr_ref len_s(str().mk_length(s), m());
result = m().mk_or(m_autil.mk_le(len_s, offset), m_autil.mk_lt(offset, zero()));
return true;
}
return false;
}

17
src/ast/simplifiers/elim_unconstrained.cpp
View file

@ -112,7 +112,7 @@ eliminate:
--*/
#include "params/smt_params_helper.hpp"
#include "ast/ast_ll_pp.h"
#include "ast/ast_pp.h"
#include "ast/recfun_decl_plugin.h"
@ -166,7 +166,7 @@ void elim_unconstrained::eliminate() {
expr_ref rr(m.mk_app(t->get_decl(), t->get_num_args(), m_args.data() + sz), m);
bool inverted = m_inverter(t->get_decl(), t->get_num_args(), m_args.data() + sz, r);
proof_ref pr(m);
if (inverted && m_enable_proofs) {
if (inverted && m_config.m_enable_proofs) {
expr * s = m.mk_app(t->get_decl(), t->get_num_args(), m_args.data() + sz);
expr * eq = m.mk_eq(s, r);
proof * pr1 = m.mk_def_intro(eq);
@ -267,7 +267,7 @@ void elim_unconstrained::reset_nodes() {
*/
void elim_unconstrained::init_nodes() {
m_enable_proofs = false;
m_config.m_enable_proofs = false;
m_trail.reset();
m_fmls.freeze_suffix();
@ -276,7 +276,7 @@ void elim_unconstrained::init_nodes() {
auto [f, p, d] = m_fmls[i]();
terms.push_back(f);
if (p)
m_enable_proofs = true;
m_config.m_enable_proofs = true;
}
m_heap.reset();
@ -303,7 +303,7 @@ void elim_unconstrained::init_nodes() {
for (expr* e : terms)
get_node(e).set_top();
m_inverter.set_produce_proofs(m_enable_proofs);
m_inverter.set_produce_proofs(m_config.m_enable_proofs);
}
@ -422,6 +422,8 @@ void elim_unconstrained::update_model_trail(generic_model_converter& mc, vector<
}
void elim_unconstrained::reduce() {
if (!m_config.m_enabled)
return;
generic_model_converter_ref mc = alloc(generic_model_converter, m, "elim-unconstrained");
m_inverter.set_model_converter(mc.get());
m_created_compound = true;
@ -436,3 +438,8 @@ void elim_unconstrained::reduce() {
mc->reset();
}
}
void elim_unconstrained::updt_params(params_ref const& p) {
smt_params_helper sp(p);
m_config.m_enabled = sp.elim_unconstrained();
}

9
src/ast/simplifiers/elim_unconstrained.h
View file

@ -79,6 +79,10 @@ class elim_unconstrained : public dependent_expr_simplifier {
unsigned m_num_eliminated = 0;
void reset() { m_num_eliminated = 0; }
};
struct config {
bool m_enabled = true;
bool m_enable_proofs = false;
};
expr_inverter m_inverter;
ptr_vector<node> m_nodes;
var_lt m_lt;
@ -86,8 +90,8 @@ class elim_unconstrained : public dependent_expr_simplifier {
expr_ref_vector m_trail;
expr_ref_vector m_args;
stats m_stats;
config m_config;
bool m_created_compound = false;
bool m_enable_proofs = false;
bool is_var_lt(int v1, int v2) const;
node& get_node(unsigned n) const { return *m_nodes[n]; }
@ -119,4 +123,7 @@ public:
void collect_statistics(statistics& st) const override { st.update("elim-unconstrained", m_stats.m_num_eliminated); }
void reset_statistics() override { m_stats.reset(); }
void updt_params(params_ref const& p) override;
};

14
src/ast/simplifiers/solve_eqs.cpp
View file

@ -46,6 +46,7 @@ Outline of a presumably better scheme:
#include "ast/simplifiers/solve_context_eqs.h"
#include "ast/converters/generic_model_converter.h"
#include "params/tactic_params.hpp"
#include "params/smt_params_helper.hpp"
namespace euf {
@ -118,7 +119,10 @@ namespace euf {
SASSERT(j == var2id(v));
if (m_fmls.frozen(v))
continue;
if (!m_config.m_enable_non_ground && has_quantifiers(t))
continue;
bool is_safe = true;
unsigned todo_sz = todo.size();
@ -126,6 +130,8 @@ namespace euf {
// all time-stamps must be at or above current level
// unexplored variables that are part of substitution are appended to work list.
SASSERT(m_todo.empty());
m_todo.push_back(t);
expr_fast_mark1 visited;
while (!m_todo.empty()) {
@ -224,6 +230,9 @@ namespace euf {
void solve_eqs::reduce() {
if (!m_config.m_enabled)
return;
m_fmls.freeze_suffix();
for (extract_eq* ex : m_extract_plugins)
@ -330,6 +339,9 @@ namespace euf {
for (auto* ex : m_extract_plugins)
ex->updt_params(p);
m_rewriter.updt_params(p);
smt_params_helper sp(p);
m_config.m_enabled = sp.solve_eqs();
m_config.m_enable_non_ground = sp.solve_eqs_non_ground();
}
void solve_eqs::collect_param_descrs(param_descrs& r) {

2
src/ast/simplifiers/solve_eqs.h
View file

@ -41,6 +41,8 @@ namespace euf {
struct config {
bool m_context_solve = true;
unsigned m_max_occs = UINT_MAX;
bool m_enabled = true;
bool m_enable_non_ground = true;
};
stats m_stats;