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remove nested booleans during pre-processing. issue #837

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-12-11 05:16:31 +01:00
parent ff46a925a2
commit 70bb92d016
1 changed files with 37 additions and 20 deletions
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57
src/qe/qe_mbp.cpp
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@ -29,6 +29,7 @@ Revision History:
#include "model_v2_pp.h"
#include "expr_functors.h"
#include "for_each_expr.h"
#include "model_evaluator.h"
using namespace qe;
@ -125,6 +126,7 @@ class mbp::impl {
th_rewriter m_rw;
ptr_vector<project_plugin> m_plugins;
expr_mark m_visited;
expr_mark m_bool_visited;
void add_plugin(project_plugin* p) {
family_id fid = p->get_family_id();
@ -212,10 +214,12 @@ class mbp::impl {
}
}
void extract_bools(model& model, expr_ref_vector& fmls, expr* fml) {
bool extract_bools(model_evaluator& eval, expr_ref_vector& fmls, expr* fml) {
TRACE("qe", tout << "extract bools: " << mk_pp(fml, m) << "\n";);
ptr_vector<expr> todo;
expr_safe_replace sub(m);
m_visited.reset();
bool found_bool = false;
if (is_app(fml)) {
todo.append(to_app(fml)->get_num_args(), to_app(fml)->get_args());
}
@ -226,16 +230,16 @@ class mbp::impl {
continue;
}
m_visited.mark(e);
if (m.is_bool(e)) {
expr_ref val(m);
VERIFY(model.eval(e, val));
if (m.is_bool(e) && !m.is_true(e) && !m.is_false(e)) {
expr_ref val = eval(e);
TRACE("qe", tout << "found: " << mk_pp(e, m) << "\n";);
if (m.is_true(val)) {
fmls.push_back(e);
}
else {
fmls.push_back(mk_not(m, e));
SASSERT(m.is_true(val) || m.is_false(val));
if (!m_bool_visited.is_marked(e)) {
fmls.push_back(m.is_true(val) ? e : mk_not(m, e));
}
sub.insert(e, val);
m_bool_visited.mark(e);
found_bool = true;
}
else if (is_app(e)) {
todo.append(to_app(e)->get_num_args(), to_app(e)->get_args());
@ -244,6 +248,14 @@ class mbp::impl {
TRACE("qe", tout << "expression not handled " << mk_pp(e, m) << "\n";);
}
}
if (found_bool) {
expr_ref tmp(m);
sub(fml, tmp);
expr_ref val = eval(tmp);
SASSERT(m.is_true(val) || m.is_false(val));
fmls.push_back(m.is_true(val) ? tmp : mk_not(m, tmp));
}
return found_bool;
}
void project_bools(model& model, app_ref_vector& vars, expr_ref_vector& fmls) {
@ -294,6 +306,7 @@ public:
void extract_literals(model& model, expr_ref_vector& fmls) {
expr_ref val(m);
model_evaluator eval(model);
TRACE("qe", tout << fmls << "\n";);
for (unsigned i = 0; i < fmls.size(); ++i) {
expr* fml = fmls[i].get(), *nfml, *f1, *f2, *f3;
@ -304,7 +317,7 @@ public:
}
else if (m.is_or(fml)) {
for (unsigned j = 0; j < to_app(fml)->get_num_args(); ++j) {
VERIFY (model.eval(to_app(fml)->get_arg(j), val));
val = eval(to_app(fml)->get_arg(j));
if (m.is_true(val)) {
fmls[i] = to_app(fml)->get_arg(j);
--i;
@ -317,7 +330,7 @@ public:
project_plugin::erase(fmls, i);
}
else if (m.is_iff(fml, f1, f2) || (m.is_not(fml, nfml) && m.is_xor(nfml, f1, f2))) {
VERIFY (model.eval(f1, val));
val = eval(f1);
if (m.is_false(val)) {
f1 = mk_not(m, f1);
f2 = mk_not(m, f2);
@ -327,7 +340,7 @@ public:
--i;
}
else if (m.is_implies(fml, f1, f2)) {
VERIFY (model.eval(f2, val));
val = eval(f2);
if (m.is_true(val)) {
fmls[i] = f2;
}
@ -337,7 +350,7 @@ public:
--i;
}
else if (m.is_ite(fml, f1, f2, f3)) {
VERIFY (model.eval(f1, val));
val = eval(f1);
if (m.is_true(val)) {
project_plugin::push_back(fmls, f1);
project_plugin::push_back(fmls, f2);
@ -354,7 +367,7 @@ public:
}
else if (m.is_not(fml, nfml) && m.is_and(nfml)) {
for (unsigned j = 0; j < to_app(nfml)->get_num_args(); ++j) {
VERIFY (model.eval(to_app(nfml)->get_arg(j), val));
val = eval(to_app(nfml)->get_arg(j));
if (m.is_false(val)) {
fmls[i] = mk_not(m, to_app(nfml)->get_arg(j));
--i;
@ -369,7 +382,7 @@ public:
project_plugin::erase(fmls, i);
}
else if ((m.is_not(fml, nfml) && m.is_iff(nfml, f1, f2)) || m.is_xor(fml, f1, f2)) {
VERIFY (model.eval(f1, val));
val = eval(f1);
if (m.is_true(val)) {
f2 = mk_not(m, f2);
}
@ -386,7 +399,7 @@ public:
project_plugin::erase(fmls, i);
}
else if (m.is_not(fml, nfml) && m.is_ite(nfml, f1, f2, f3)) {
VERIFY (model.eval(f1, val));
val = eval(f1);
if (m.is_true(val)) {
project_plugin::push_back(fmls, f1);
project_plugin::push_back(fmls, mk_not(m, f2));
@ -398,15 +411,19 @@ public:
project_plugin::erase(fmls, i);
}
else if (m.is_not(fml, nfml)) {
extract_bools(model, fmls, nfml);
if (extract_bools(eval, fmls, nfml)) {
project_plugin::erase(fmls, i);
}
}
else {
extract_bools(model, fmls, fml);
if (extract_bools(eval, fmls, fml)) {
project_plugin::erase(fmls, i);
}
// TBD other Boolean operations.
}
}
TRACE("qe", tout << fmls << "\n";);
m_visited.reset();
m_bool_visited.reset();
}
impl(ast_manager& m):m(m), m_rw(m) {