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//===--- ConstraintSystemTests.cpp ----------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ConstraintSystem.h"
#include "gtest/gtest.h"
using namespace llvm;
namespace {
TEST(ConstraintSolverTest, TestSolutionChecks) {
{
ConstraintSystem CS;
// x + y <= 10, x >= 5, y >= 6, x <= 10, y <= 10
CS.addVariableRow({10, 1, 1});
CS.addVariableRow({-5, -1, 0});
CS.addVariableRow({-6, 0, -1});
CS.addVariableRow({10, 1, 0});
CS.addVariableRow({10, 0, 1});
EXPECT_FALSE(CS.mayHaveSolution());
}
{
ConstraintSystem CS;
// x + y <= 10, x >= 2, y >= 3, x <= 10, y <= 10
CS.addVariableRow({10, 1, 1});
CS.addVariableRow({-2, -1, 0});
CS.addVariableRow({-3, 0, -1});
CS.addVariableRow({10, 1, 0});
CS.addVariableRow({10, 0, 1});
EXPECT_TRUE(CS.mayHaveSolution());
}
{
ConstraintSystem CS;
// x + y <= 10, 10 >= x, 10 >= y; does not have a solution.
CS.addVariableRow({10, 1, 1});
CS.addVariableRow({-10, -1, 0});
CS.addVariableRow({-10, 0, -1});
EXPECT_FALSE(CS.mayHaveSolution());
}
{
ConstraintSystem CS;
// x + y >= 20, 10 >= x, 10 >= y; does HAVE a solution.
CS.addVariableRow({-20, -1, -1});
CS.addVariableRow({-10, -1, 0});
CS.addVariableRow({-10, 0, -1});
EXPECT_TRUE(CS.mayHaveSolution());
}
{
ConstraintSystem CS;
// 2x + y + 3z <= 10, 2x + y >= 10, y >= 1
CS.addVariableRow({10, 2, 1, 3});
CS.addVariableRow({-10, -2, -1, 0});
CS.addVariableRow({-1, 0, 0, -1});
EXPECT_FALSE(CS.mayHaveSolution());
}
{
ConstraintSystem CS;
// 2x + y + 3z <= 10, 2x + y >= 10
CS.addVariableRow({10, 2, 1, 3});
CS.addVariableRow({-10, -2, -1, 0});
EXPECT_TRUE(CS.mayHaveSolution());
}
}
TEST(ConstraintSolverTest, IsConditionImplied) {
{
// For the test below, we assume we know
// x <= 5 && y <= 3
ConstraintSystem CS;
CS.addVariableRow({5, 1, 0});
CS.addVariableRow({3, 0, 1});
// x + y <= 6 does not hold.
EXPECT_FALSE(CS.isConditionImplied({6, 1, 1}));
// x + y <= 7 does not hold.
EXPECT_FALSE(CS.isConditionImplied({7, 1, 1}));
// x + y <= 8 does hold.
EXPECT_TRUE(CS.isConditionImplied({8, 1, 1}));
// 2 * x + y <= 12 does hold.
EXPECT_FALSE(CS.isConditionImplied({12, 2, 1}));
// 2 * x + y <= 13 does hold.
EXPECT_TRUE(CS.isConditionImplied({13, 2, 1}));
// x + y <= 12 does hold.
EXPECT_FALSE(CS.isConditionImplied({12, 2, 1}));
// 2 * x + y <= 13 does hold.
EXPECT_TRUE(CS.isConditionImplied({13, 2, 1}));
// x <= y == x - y <= 0 does not hold.
EXPECT_FALSE(CS.isConditionImplied({0, 1, -1}));
// y <= x == -x + y <= 0 does not hold.
EXPECT_FALSE(CS.isConditionImplied({0, -1, 1}));
}
{
// For the test below, we assume we know
// x + 1 <= y + 1 == x - y <= 0
ConstraintSystem CS;
CS.addVariableRow({0, 1, -1});
// x <= y == x - y <= 0 does hold.
EXPECT_TRUE(CS.isConditionImplied({0, 1, -1}));
// y <= x == -x + y <= 0 does not hold.
EXPECT_FALSE(CS.isConditionImplied({0, -1, 1}));
// x <= y + 10 == x - y <= 10 does hold.
EXPECT_TRUE(CS.isConditionImplied({10, 1, -1}));
// x + 10 <= y == x - y <= -10 does NOT hold.
EXPECT_FALSE(CS.isConditionImplied({-10, 1, -1}));
}
{
// For the test below, we assume we know
// x <= y == x - y <= 0
// y <= z == y - x <= 0
ConstraintSystem CS;
CS.addVariableRow({0, 1, -1, 0});
CS.addVariableRow({0, 0, 1, -1});
// z <= y == -y + z <= 0 does not hold.
EXPECT_FALSE(CS.isConditionImplied({0, 0, -1, 1}));
// x <= z == x - z <= 0 does hold.
EXPECT_TRUE(CS.isConditionImplied({0, 1, 0, -1}));
}
}
TEST(ConstraintSolverTest, IsConditionImpliedOverflow) {
ConstraintSystem CS;
// Make sure isConditionImplied returns false when there is an overflow.
int64_t Limit = std::numeric_limits<int64_t>::max();
CS.addVariableRow({Limit - 1, Limit - 2, Limit - 3});
EXPECT_FALSE(CS.isConditionImplied({Limit - 1, Limit - 2, Limit - 3}));
}
} // namespace
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