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/***
* Bitwuzla: Satisfiability Modulo Theories (SMT) solver.
*
* Copyright (C) 2022 by the authors listed in the AUTHORS file at
* https://github.com/bitwuzla/bitwuzla/blob/main/AUTHORS
*
* This file is part of Bitwuzla under the MIT license. See COPYING for more
* information at https://github.com/bitwuzla/bitwuzla/blob/main/COPYING
*/
#include <gtest/gtest.h>
#include "option/option.h"
#include "preprocess/pass/variable_substitution.h"
#include "preprocess/preprocessor.h"
#include "solving_context.h"
#include "test/unit/preprocess/test_preprocess_pass.h"
namespace bzla::test {
using namespace preprocess;
using namespace backtrack;
using namespace node;
class TestPassVariableSubstitution : public TestPreprocessingPass
{
public:
TestPassVariableSubstitution() : d_env(d_nm), d_pass(d_env, &d_bm)
{
d_options.rewrite_level.set(0);
d_options.pp_embedded_constr.set(false);
d_options.pp_flatten_and.set(false);
d_options.pp_skeleton_preproc.set(false);
d_options.pp_normalize.set(false);
};
protected:
Env d_env;
preprocess::pass::PassVariableSubstitution d_pass;
};
TEST_F(TestPassVariableSubstitution, subst1)
{
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node t = d_nm.mk_const(d_nm.mk_bool_type(), "t");
Node eq = d_nm.mk_node(Kind::EQUAL, {x, t});
d_as.push_back(eq);
preprocess::AssertionVector assertions(d_as.view());
d_pass.apply(assertions);
ASSERT_EQ(d_as.size(), 1);
ASSERT_EQ(d_as[0], d_nm.mk_value(true));
ASSERT_EQ(d_pass.process(eq), d_nm.mk_value(true));
}
TEST_F(TestPassVariableSubstitution, subst2)
{
Node x = d_nm.mk_const(d_nm.mk_bool_type());
Node y = d_nm.mk_const(d_nm.mk_bool_type());
Node t = d_nm.mk_const(d_nm.mk_bool_type());
Node eq = d_nm.mk_node(Kind::EQUAL, {x, y});
Node di = d_nm.mk_node(Kind::NOT, {d_nm.mk_node(Kind::EQUAL, {x, t})});
d_as.push_back(eq);
d_as.push_back(di);
preprocess::AssertionVector assertions(d_as.view());
d_pass.apply(assertions);
Node expected = d_nm.mk_node(Kind::NOT, {d_nm.mk_node(Kind::EQUAL, {y, t})});
ASSERT_EQ(d_as.size(), 2);
ASSERT_EQ(d_as[0], d_nm.mk_value(true));
ASSERT_EQ(d_as[1], expected);
ASSERT_EQ(d_pass.process(eq), d_nm.mk_value(true));
ASSERT_EQ(d_pass.process(di), expected);
}
TEST_F(TestPassVariableSubstitution, cycle1)
{
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node eq = d_nm.mk_node(Kind::EQUAL, {x, x});
d_as.push_back(eq);
preprocess::AssertionVector assertions(d_as.view());
d_pass.apply(assertions);
ASSERT_EQ(assertions[0], eq);
}
TEST_F(TestPassVariableSubstitution, cycle2)
{
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node y = d_nm.mk_const(d_nm.mk_bool_type(), "y");
Node eq1 = d_nm.mk_node(Kind::EQUAL, {x, y});
Node x_and_y = d_nm.mk_node(Kind::AND, {x, y});
Node eq2 = d_nm.mk_node(Kind::EQUAL, {y, x_and_y});
d_as.push_back(eq1);
d_as.push_back(eq2);
d_as.push_back(x_and_y);
preprocess::AssertionVector assertions(d_as.view());
d_pass.apply(assertions);
ASSERT_EQ(d_as[0], d_nm.mk_value(true));
ASSERT_EQ(d_as[1], d_nm.mk_value(true));
ASSERT_EQ(d_as[2], y);
}
TEST_F(TestPassVariableSubstitution, cycle3)
{
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node y = d_nm.mk_const(d_nm.mk_bool_type(), "y");
Node z = d_nm.mk_const(d_nm.mk_bool_type(), "z");
Node x_and_z = d_nm.mk_node(Kind::AND, {x, z});
Node eq1 = d_nm.mk_node(Kind::EQUAL, {x, y});
Node eq2 = d_nm.mk_node(Kind::EQUAL, {y, x_and_z});
d_as.push_back(x_and_z);
d_as.push_back(eq2);
d_as.push_back(eq1);
preprocess::AssertionVector assertions(d_as.view());
d_pass.apply(assertions);
Node y_and_z = d_nm.mk_node(Kind::AND, {y, z});
ASSERT_EQ(d_as[0], y_and_z);
ASSERT_EQ(d_as[1], d_nm.mk_node(Kind::EQUAL, {y, y_and_z}));
ASSERT_EQ(d_as[2], d_nm.mk_value(true));
}
TEST_F(TestPassVariableSubstitution, cycle4)
{
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node y = d_nm.mk_const(d_nm.mk_bool_type(), "y");
Node z = d_nm.mk_const(d_nm.mk_bool_type(), "z");
Node eq1 = d_nm.mk_node(Kind::EQUAL, {x, y});
Node eq2 = d_nm.mk_node(Kind::EQUAL, {y, z});
Node eq3 = d_nm.mk_node(Kind::EQUAL, {z, x});
d_as.push_back(eq1);
d_as.push_back(eq2);
d_as.push_back(eq3);
preprocess::AssertionVector assertions(d_as.view());
d_pass.apply(assertions);
ASSERT_EQ(d_as[0], d_nm.mk_value(true));
ASSERT_EQ(d_as[1], d_nm.mk_value(true));
ASSERT_EQ(d_as[2], d_nm.mk_value(true));
}
TEST_F(TestPassVariableSubstitution, cycle5)
{
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node y = d_nm.mk_const(d_nm.mk_bool_type(), "y");
Node z = d_nm.mk_const(d_nm.mk_bool_type(), "z");
Node eq1 = d_nm.mk_node(Kind::EQUAL, {x, y});
Node eq2 = d_nm.mk_node(Kind::EQUAL, {y, z});
Node eq3 = d_nm.mk_node(Kind::EQUAL, {z, x});
d_as.push_back(eq1);
d_as.push_back(eq2);
preprocess::AssertionVector assertions(d_as.view());
d_pass.apply(assertions);
ASSERT_EQ(d_as[0], d_nm.mk_value(true));
ASSERT_EQ(d_as[1], d_nm.mk_value(true));
d_as.push_back(eq3);
preprocess::AssertionVector assertions2(d_as.view());
d_pass.apply(assertions);
ASSERT_EQ(d_as[2], d_nm.mk_value(true));
}
/* --- Incremental tests ---------------------------------------------------- */
TEST_F(TestPassVariableSubstitution, inc1)
{
SolvingContext ctx(d_nm, d_options);
Preprocessor& pp = ctx.preprocessor();
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node y = d_nm.mk_const(d_nm.mk_bool_type(), "y");
Node t = d_nm.mk_const(d_nm.mk_bool_type(), "t");
Node eq = d_nm.mk_node(Kind::EQUAL, {x, y});
Node di = d_nm.mk_node(Kind::NOT, {d_nm.mk_node(Kind::EQUAL, {x, t})});
ctx.assert_formula(eq);
ctx.push();
ctx.assert_formula(di);
ctx.preprocess();
auto as = ctx.assertions();
if (d_options.pp_variable_subst_norm_diseq())
{
Node not_t = d_nm.invert_node(t);
ASSERT_EQ(as.size(), 2);
ASSERT_EQ(as[0], d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(as[1], d_nm.mk_node(Kind::EQUAL, {y, not_t}));
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {not_t, not_t}));
ASSERT_EQ(pp.process(di),
d_nm.invert_node(d_nm.mk_node(Kind::EQUAL, {not_t, t})));
ctx.pop();
ctx.preprocess();
ASSERT_EQ(as.size(), 1);
ASSERT_EQ(as[0], d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(pp.process(di),
d_nm.mk_node(Kind::NOT, {d_nm.mk_node(Kind::EQUAL, {y, t})}));
}
else
{
Node expected =
d_nm.mk_node(Kind::NOT, {d_nm.mk_node(Kind::EQUAL, {y, t})});
ASSERT_EQ(as.size(), 2);
ASSERT_EQ(as[0], d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(as[1], expected);
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(pp.process(di), expected);
ctx.pop();
ctx.preprocess();
ASSERT_EQ(as.size(), 1);
ASSERT_EQ(as[0], d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(pp.process(di), expected);
}
}
TEST_F(TestPassVariableSubstitution, inc2)
{
SolvingContext ctx(d_nm, d_options);
Preprocessor& pp = ctx.preprocessor();
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node y = d_nm.mk_const(d_nm.mk_bool_type(), "y");
Node eq = d_nm.mk_node(Kind::EQUAL, {x, y});
Node di = d_nm.mk_node(Kind::NOT, {d_nm.mk_node(Kind::EQUAL, {x, y})});
Node x_and_y = d_nm.mk_node(Kind::AND, {x, y});
ctx.assert_formula(di);
ctx.push();
ctx.assert_formula(eq);
ctx.assert_formula(x_and_y);
ctx.preprocess();
auto as = ctx.assertions();
if (d_options.pp_variable_subst_norm_diseq())
{
Node not_y = d_nm.invert_node(y);
Node not_y_and_y = d_nm.mk_node(Kind::AND, {not_y, y});
ASSERT_EQ(as[0], d_nm.invert_node(d_nm.mk_node(Kind::EQUAL, {not_y, y})));
ASSERT_EQ(as[1], d_nm.mk_node(Kind::EQUAL, {not_y, y}));
ASSERT_EQ(as[2], not_y_and_y);
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {not_y, y}));
ASSERT_EQ(pp.process(x_and_y), not_y_and_y);
ctx.pop();
ctx.preprocess();
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {not_y, y}));
ASSERT_EQ(pp.process(x_and_y), not_y_and_y);
}
else
{
Node y_and_y = d_nm.mk_node(Kind::AND, {y, y});
ASSERT_EQ(as[0], di);
ASSERT_EQ(as[1], eq);
ASSERT_EQ(as[2], y_and_y);
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(pp.process(x_and_y), y_and_y);
ctx.pop();
ctx.preprocess();
ASSERT_EQ(pp.process(eq), eq);
ASSERT_EQ(pp.process(x_and_y), x_and_y);
}
}
TEST_F(TestPassVariableSubstitution, inc3)
{
SolvingContext ctx(d_nm, d_options);
Preprocessor& pp = ctx.preprocessor();
Node x = d_nm.mk_const(d_nm.mk_bool_type(), "x");
Node y = d_nm.mk_const(d_nm.mk_bool_type(), "y");
Node z = d_nm.mk_const(d_nm.mk_bool_type(), "y");
Node eq = d_nm.mk_node(Kind::EQUAL, {x, y});
Node di = d_nm.mk_node(Kind::NOT, {d_nm.mk_node(Kind::EQUAL, {x, y})});
Node x_and_y = d_nm.mk_node(Kind::AND, {x, y});
Node x_and_z = d_nm.mk_node(Kind::AND, {x, z});
ctx.assert_formula(di);
ctx.push();
ctx.assert_formula(eq);
ctx.assert_formula(x_and_y);
ctx.push();
ctx.push();
ctx.assert_formula(x_and_z);
ctx.preprocess();
auto as = ctx.assertions();
if (d_options.pp_variable_subst_norm_diseq())
{
Node not_y = d_nm.invert_node(y);
Node not_y_eq_y = d_nm.mk_node(Kind::EQUAL, {not_y, y});
Node not_y_and_z = d_nm.mk_node(Kind::AND, {not_y, z});
Node not_y_and_y = d_nm.mk_node(Kind::AND, {not_y, y});
ASSERT_EQ(as[0], d_nm.invert_node(not_y_eq_y));
ASSERT_EQ(as[1], not_y_eq_y);
ASSERT_EQ(as[2], not_y_and_y);
ASSERT_EQ(as[3], not_y_and_z);
ASSERT_EQ(pp.process(eq), not_y_eq_y);
ASSERT_EQ(pp.process(x_and_y), not_y_and_y);
ASSERT_EQ(pp.process(x_and_z), not_y_and_z);
ctx.pop();
ASSERT_EQ(pp.process(eq), not_y_eq_y);
ASSERT_EQ(pp.process(x_and_y), not_y_and_y);
ASSERT_EQ(pp.process(x_and_z), not_y_and_z);
ctx.pop();
ctx.pop();
ASSERT_EQ(pp.process(eq), not_y_eq_y);
ASSERT_EQ(pp.process(x_and_y), not_y_and_y);
ASSERT_EQ(pp.process(x_and_z), not_y_and_z);
}
else
{
Node y_and_z = d_nm.mk_node(Kind::AND, {y, z});
Node y_and_y = d_nm.mk_node(Kind::AND, {y, y});
ASSERT_EQ(as[0], di);
ASSERT_EQ(as[1], eq);
ASSERT_EQ(as[2], y_and_y);
ASSERT_EQ(as[3], y_and_z);
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(pp.process(x_and_y), y_and_y);
ASSERT_EQ(pp.process(x_and_z), y_and_z);
ctx.pop();
ASSERT_EQ(pp.process(eq), d_nm.mk_node(Kind::EQUAL, {y, y}));
ASSERT_EQ(pp.process(x_and_y), y_and_y);
ASSERT_EQ(pp.process(x_and_z), y_and_z);
ctx.pop();
ctx.pop();
ASSERT_EQ(pp.process(eq), eq);
ASSERT_EQ(pp.process(x_and_y), x_and_y);
ASSERT_EQ(pp.process(x_and_z), x_and_z);
}
}
} // namespace bzla::test
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