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wip - dependent expr simpliifer

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- simplify iterator over current indices
- add more simplifiers used by asserted_formulas
- improve diagnostics printing
This commit is contained in:
Nikolaj Bjorner 2022-11-30 13:41:40 +07:00
parent bec3acd146
commit b084821a0c
25 changed files with 553 additions and 158 deletions
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57
src/ast/simplifiers/eliminate_predicates.cpp
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@ -129,6 +129,38 @@ bool eliminate_predicates::can_be_macro_head(expr* _head, unsigned num_bound) {
return true;
}
/**
* a quasi macro head is of the form
* f(x,x) where x is the only bound variable
* f(x,y,x+y+3,1) where x, y are the only bound variables
*/
bool eliminate_predicates::can_be_quasi_macro_head(expr* head, unsigned num_bound) {
if (!is_app(_head))
return false;
app* head = to_app(_head);
func_decl* f = head->get_decl();
if (m_fmls.frozen(f))
return false;
if (m_is_macro.is_marked(f))
return false;
if (f->is_associative())
return false;
uint_set indices;
for (expr* arg : *head) {
if (!is_var(arg))
return continue;
unsigned idx = to_var(arg)->get_idx();
if (indices.contains(idx))
return continue;
if (idx >= num_bound)
return false;
indices.insert(idx);
}
return indices.size() == num_bound;
}
expr_ref eliminate_predicates::bind_free_variables_in_def(clause& cl, app* head, expr* def) {
unsigned num_bound = cl.m_bound.size();
if (head->get_num_args() == num_bound)
@ -365,7 +397,6 @@ void eliminate_predicates::try_find_macro(clause& cl) {
// (= (+ (f x) s) t)
// becomes (= (f x) (- t s))
//
// TBD:
// (= (+ (* -1 (f x)) x) t)
// becomes (= (f x) (- (- t s)))
@ -473,10 +504,13 @@ void eliminate_predicates::try_find_macro(clause& cl) {
// becomes (= (f x) (- t s (k x))
// add (>= (k x) 0)
// why is this a real improvement?
//
//
//
// To review: quasi-macros
// (= (f x y (+ x y)) s), where x y are all bound variables.
// then ...?
// (= (f x y (+ x y)) s), where x y are all bound variables.
// then replace (f x y z) by (if (= z (+ x y)) s (f' x y))
//
}
@ -501,21 +535,18 @@ void eliminate_predicates::reduce_definitions() {
for (auto const& [k, v] : m_macros)
macro_expander.insert(v->m_head, v->m_def, v->m_dep);
for (unsigned i = qhead(); i < qtail(); ++i) {
for (unsigned i : indices()) {
auto [f, d] = m_fmls[i]();
expr_ref fml(f, m), new_fml(m);
expr_dependency_ref dep(m);
expr_dependency_ref dep(d, m);
while (true) {
macro_expander(fml, new_fml, dep);
macro_expander(fml, dep, new_fml, dep);
if (new_fml == fml)
break;
rewrite(new_fml);
fml = new_fml;
}
if (fml != f) {
dep = m.mk_join(d, dep);
m_fmls.update(i, dependent_expr(m, fml, dep));
}
m_fmls.update(i, dependent_expr(m, fml, dep));
}
reset();
init_clauses();
@ -772,7 +803,7 @@ void eliminate_predicates::init_clauses() {
m_fmls.freeze_suffix();
for (unsigned i = qhead(); i < qtail(); ++i) {
for (unsigned i : indices()) {
clause* cl = init_clause(i);
add_use_list(*cl);
m_clauses.push_back(cl);
@ -816,6 +847,8 @@ void eliminate_predicates::reset() {
void eliminate_predicates::reduce() {
if (!m_fmls.has_quantifiers())
return;
reset();
init_clauses();
find_definitions();