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add recfun rewriting, remove quantifier based recfun

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This commit is contained in:
Nikolaj Bjorner 2020-04-26 12:59:51 -07:00
parent 7f1b147cba
commit f9193809ea
13 changed files with 94 additions and 143 deletions
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85
src/smt/smt_model_checker.cpp
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@ -47,7 +47,6 @@ namespace smt {
m_model_finder(mf),
m_max_cexs(1),
m_iteration_idx(0),
m_has_rec_fun(false),
m_curr_model(nullptr),
m_fresh_exprs(m),
m_pinned_exprs(m) {
@ -380,36 +379,6 @@ namespace smt {
return false;
}
bool model_checker::check_rec_fun(quantifier* q, bool strict_rec_fun) {
TRACE("model_checker", tout << mk_pp(q, m) << "\n";);
SASSERT(q->get_num_patterns() == 2); // first pattern is the function, second is the body.
func_decl* f = m.get_rec_fun_decl(q);
expr_ref_vector args(m);
unsigned num_decls = q->get_num_decls();
args.resize(num_decls, nullptr);
var_subst sub(m);
expr_ref tmp(m), result(m);
for (enode* n : m_context->enodes_of(f)) {
if (m_context->is_relevant(n)) {
app* e = n->get_owner();
SASSERT(e->get_num_args() == num_decls);
for (unsigned i = 0; i < num_decls; ++i) {
args[i] = e->get_arg(i);
}
tmp = sub(q->get_expr(), num_decls, args.c_ptr());
TRACE("model_checker", tout << "curr_model:\n"; model_pp(tout, *m_curr_model););
m_curr_model->eval(tmp, result, true);
if (strict_rec_fun ? !m.is_true(result) : m.is_false(result)) {
add_instance(q, args, 0, nullptr);
return false;
}
TRACE("model_checker", tout << tmp << "\nevaluates to:\n" << result << "\n";);
}
}
return true;
}
void model_checker::init_aux_context() {
if (!m_fparams) {
m_fparams = alloc(smt_params, m_context->get_fparams());
@ -458,7 +427,7 @@ namespace smt {
bool found_relevant = false;
unsigned num_failures = 0;
check_quantifiers(false, found_relevant, num_failures);
check_quantifiers(found_relevant, num_failures);
if (found_relevant)
m_iteration_idx++;
@ -467,11 +436,11 @@ namespace smt {
TRACE("model_checker", tout << "model checker result: " << (num_failures == 0) << "\n";);
m_max_cexs += m_params.m_mbqi_max_cexs;
if (num_failures == 0 && (!m_context->validate_model() || has_rec_under_quantifiers())) {
if (num_failures == 0 && (!m_context->validate_model())) {
num_failures = 1;
// this time force expanding recursive function definitions
// that are not forced true in the current model.
check_quantifiers(true, found_relevant, num_failures);
check_quantifiers(found_relevant, num_failures);
}
if (num_failures == 0)
m_curr_model->cleanup();
@ -484,43 +453,6 @@ namespace smt {
return num_failures == 0;
}
struct has_rec_fun_proc {
obj_hashtable<func_decl>& m_rec_funs;
bool m_has_rec_fun;
bool has_rec_fun() const { return m_has_rec_fun; }
has_rec_fun_proc(obj_hashtable<func_decl>& rec_funs):
m_rec_funs(rec_funs),
m_has_rec_fun(false) {}
void operator()(app* fn) {
m_has_rec_fun |= m_rec_funs.contains(fn->get_decl());
}
void operator()(expr*) {}
};
bool model_checker::has_rec_under_quantifiers() {
if (!m_has_rec_fun) {
return false;
}
obj_hashtable<func_decl> rec_funs;
for (quantifier * q : *m_qm) {
if (m.is_rec_fun_def(q)) {
rec_funs.insert(m.get_rec_fun_decl(q));
}
}
expr_fast_mark1 visited;
has_rec_fun_proc proc(rec_funs);
for (quantifier * q : *m_qm) {
if (!m.is_rec_fun_def(q)) {
quick_for_each_expr(proc, visited, q);
if (proc.has_rec_fun()) return true;
}
}
return false;
}
//
// (repeated from defined_names.cpp)
// NB. The pattern for lambdas is incomplete.
@ -532,7 +464,7 @@ namespace smt {
// using multi-patterns.
//
void model_checker::check_quantifiers(bool strict_rec_fun, bool& found_relevant, unsigned& num_failures) {
void model_checker::check_quantifiers(bool& found_relevant, unsigned& num_failures) {
for (quantifier * q : *m_qm) {
if (!(m_qm->mbqi_enabled(q) &&
m_context->is_relevant(q) &&
@ -549,14 +481,7 @@ namespace smt {
verbose_stream() << "(smt.mbqi :checking " << q->get_qid() << ")\n";
}
found_relevant = true;
if (m.is_rec_fun_def(q)) {
m_has_rec_fun = true;
if (!check_rec_fun(q, strict_rec_fun)) {
TRACE("model_checker", tout << "checking recursive function failed\n";);
num_failures++;
}
}
else if (!check(q)) {
if (!check(q)) {
if (m_params.m_mbqi_trace || get_verbosity_level() >= 5) {
IF_VERBOSE(0, verbose_stream() << "(smt.mbqi :failed " << q->get_qid() << ")\n");
}