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add demodulator tactic based on demodulator-simplifier

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- some handling for commutative operators
- fix bug in demodulator_index where fwd and bwd are swapped
This commit is contained in:
Nikolaj Bjorner 2022-12-05 03:20:46 -08:00
parent 87095950cb
commit de916f50d6
5 changed files with 123 additions and 37 deletions
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92
src/ast/substitution/demodulator_rewriter.cpp
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@ -852,19 +852,45 @@ bool demodulator_match_subst::match_args(app * lhs, expr * const * args) {
m_cache.reset();
m_todo.reset();
auto fill_commutative = [&](app* lhs, expr * const* args) {
if (!lhs->get_decl()->is_commutative())
return false;
if (lhs->get_num_args() != 2)
return false;
expr* l1 = lhs->get_arg(0);
expr* l2 = lhs->get_arg(1);
expr* r1 = args[0];
expr* r2 = args[1];
if (is_app(l1) && is_app(r1) && to_app(l1)->get_decl() != to_app(r1)->get_decl()) {
m_all_args_eq = false;
m_todo.push_back(expr_pair(l1, r2));
m_todo.push_back(expr_pair(l2, r1));
return true;
}
if (is_app(l2) && is_app(r2) && to_app(l2)->get_decl() != to_app(r2)->get_decl()) {
m_all_args_eq = false;
m_todo.push_back(expr_pair(l1, r2));
m_todo.push_back(expr_pair(l2, r1));
return true;
}
return false;
};
// fill todo-list, and perform quick success/failure tests
m_all_args_eq = true;
unsigned num_args = lhs->get_num_args();
for (unsigned i = 0; i < num_args; i++) {
expr * t_arg = lhs->get_arg(i);
expr * i_arg = args[i];
if (t_arg != i_arg)
m_all_args_eq = false;
if (is_app(t_arg) && is_app(i_arg) && to_app(t_arg)->get_decl() != to_app(i_arg)->get_decl()) {
// quick failure...
return false;
if (!fill_commutative(lhs, args)) {
for (unsigned i = 0; i < num_args; i++) {
expr * t_arg = lhs->get_arg(i);
expr * i_arg = args[i];
if (t_arg != i_arg)
m_all_args_eq = false;
if (is_app(t_arg) && is_app(i_arg) && to_app(t_arg)->get_decl() != to_app(i_arg)->get_decl()) {
// quick failure...
return false;
}
m_todo.push_back(expr_pair(t_arg, i_arg));
}
m_todo.push_back(expr_pair(t_arg, i_arg));
}
if (m_all_args_eq) {
@ -875,48 +901,47 @@ bool demodulator_match_subst::match_args(app * lhs, expr * const * args) {
m_subst.reset();
while (!m_todo.empty()) {
expr_pair const & p = m_todo.back();
auto const & [a, b] = m_todo.back();
if (is_var(p.first)) {
if (is_var(a)) {
expr_offset r;
if (m_subst.find(to_var(p.first), 0, r)) {
if (r.get_expr() != p.second)
if (m_subst.find(to_var(a), 0, r)) {
if (r.get_expr() != b)
return false;
}
else {
m_subst.insert(to_var(p.first), 0, expr_offset(p.second, 1));
m_subst.insert(to_var(a), 0, expr_offset(b, 1));
}
m_todo.pop_back();
continue;
}
if (is_var(p.second))
if (is_var(b))
return false;
// we may have nested quantifiers.
if (is_quantifier(p.first) || is_quantifier(p.second))
if (is_quantifier(a) || is_quantifier(b))
return false;
SASSERT(is_app(p.first) && is_app(p.second));
SASSERT(is_app(a) && is_app(b));
if (to_app(p.first)->is_ground() && !to_app(p.second)->is_ground())
if (to_app(a)->is_ground() && !to_app(b)->is_ground())
return false;
if (p.first == p.second && to_app(p.first)->is_ground()) {
SASSERT(to_app(p.second)->is_ground());
if (a == b && to_app(a)->is_ground()) {
m_todo.pop_back();
continue;
}
if (m_cache.contains(p)) {
if (m_cache.contains(expr_pair(a, b))) {
m_todo.pop_back();
continue;
}
if (p.first == p.second) {
// p.first and p.second is not ground...
if (a == b) {
// a and b is not ground...
// Traverse p.first and check whether every variable X:0 in p.first
// Traverse a and check whether every variable X:0 in a
// 1) is unbounded (then we bind X:0 -> X:1)
// 2) or, is already bounded to X:1
// If that is, the case, we execute:
@ -927,10 +952,10 @@ bool demodulator_match_subst::match_args(app * lhs, expr * const * args) {
// return false;
match_args_aux_proc proc(m_subst);
try {
for_each_expr(proc, p.first);
for_each_expr(proc, a);
// succeeded
m_todo.pop_back();
m_cache.insert(p);
m_cache.insert(expr_pair(a, b));
continue;
}
catch (const match_args_aux_proc::no_match &) {
@ -938,8 +963,8 @@ bool demodulator_match_subst::match_args(app * lhs, expr * const * args) {
}
}
app * n1 = to_app(p.first);
app * n2 = to_app(p.second);
app * n1 = to_app(a);
app * n2 = to_app(b);
if (n1->get_decl() != n2->get_decl())
return false;
@ -953,12 +978,13 @@ bool demodulator_match_subst::match_args(app * lhs, expr * const * args) {
if (num_args1 == 0)
continue;
m_cache.insert(p);
unsigned j = num_args1;
while (j > 0) {
--j;
m_cache.insert(expr_pair(a, b));
if (fill_commutative(n1, n2->get_args()))
continue;
for (unsigned j = num_args1; j-- > 0; )
m_todo.push_back(expr_pair(n1->get_arg(j), n2->get_arg(j)));
}
}
return true;
}