/
IntegerPolyhedronTest.cpp
1495 lines (1266 loc) · 56.3 KB
/
IntegerPolyhedronTest.cpp
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//===- IntegerPolyhedron.cpp - Tests for IntegerPolyhedron class ----------===//
//
// 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 "Parser.h"
#include "Utils.h"
#include "mlir/Analysis/Presburger/IntegerRelation.h"
#include "mlir/Analysis/Presburger/PWMAFunction.h"
#include "mlir/Analysis/Presburger/Simplex.h"
#include <gmock/gmock.h>
#include <gtest/gtest.h>
#include <numeric>
#include <optional>
using namespace mlir;
using namespace presburger;
using testing::ElementsAre;
enum class TestFunction { Sample, Empty };
/// Construct a IntegerPolyhedron from a set of inequality and
/// equality constraints.
static IntegerPolyhedron
makeSetFromConstraints(unsigned ids, ArrayRef<SmallVector<int64_t, 4>> ineqs,
ArrayRef<SmallVector<int64_t, 4>> eqs,
unsigned syms = 0) {
IntegerPolyhedron set(
ineqs.size(), eqs.size(), ids + 1,
PresburgerSpace::getSetSpace(ids - syms, syms, /*numLocals=*/0));
for (const auto &eq : eqs)
set.addEquality(eq);
for (const auto &ineq : ineqs)
set.addInequality(ineq);
return set;
}
static void dump(ArrayRef<MPInt> vec) {
for (const MPInt &x : vec)
llvm::errs() << x << ' ';
llvm::errs() << '\n';
}
/// If fn is TestFunction::Sample (default):
///
/// If hasSample is true, check that findIntegerSample returns a valid sample
/// for the IntegerPolyhedron poly. Also check that getIntegerLexmin finds a
/// non-empty lexmin.
///
/// If hasSample is false, check that findIntegerSample returns std::nullopt
/// and findIntegerLexMin returns Empty.
///
/// If fn is TestFunction::Empty, check that isIntegerEmpty returns the
/// opposite of hasSample.
static void checkSample(bool hasSample, const IntegerPolyhedron &poly,
TestFunction fn = TestFunction::Sample) {
std::optional<SmallVector<MPInt, 8>> maybeSample;
MaybeOptimum<SmallVector<MPInt, 8>> maybeLexMin;
switch (fn) {
case TestFunction::Sample:
maybeSample = poly.findIntegerSample();
maybeLexMin = poly.findIntegerLexMin();
if (!hasSample) {
EXPECT_FALSE(maybeSample.has_value());
if (maybeSample.has_value()) {
llvm::errs() << "findIntegerSample gave sample: ";
dump(*maybeSample);
}
EXPECT_TRUE(maybeLexMin.isEmpty());
if (maybeLexMin.isBounded()) {
llvm::errs() << "findIntegerLexMin gave sample: ";
dump(*maybeLexMin);
}
} else {
ASSERT_TRUE(maybeSample.has_value());
EXPECT_TRUE(poly.containsPoint(*maybeSample));
ASSERT_FALSE(maybeLexMin.isEmpty());
if (maybeLexMin.isUnbounded()) {
EXPECT_TRUE(Simplex(poly).isUnbounded());
}
if (maybeLexMin.isBounded()) {
EXPECT_TRUE(poly.containsPointNoLocal(*maybeLexMin));
}
}
break;
case TestFunction::Empty:
EXPECT_EQ(!hasSample, poly.isIntegerEmpty());
break;
}
}
/// Check sampling for all the permutations of the dimensions for the given
/// constraint set. Since the GBR algorithm progresses dimension-wise, different
/// orderings may cause the algorithm to proceed differently. At least some of
///.these permutations should make it past the heuristics and test the
/// implementation of the GBR algorithm itself.
/// Use TestFunction fn to test.
static void checkPermutationsSample(bool hasSample, unsigned nDim,
ArrayRef<SmallVector<int64_t, 4>> ineqs,
ArrayRef<SmallVector<int64_t, 4>> eqs,
TestFunction fn = TestFunction::Sample) {
SmallVector<unsigned, 4> perm(nDim);
std::iota(perm.begin(), perm.end(), 0);
auto permute = [&perm](ArrayRef<int64_t> coeffs) {
SmallVector<int64_t, 4> permuted;
for (unsigned id : perm)
permuted.push_back(coeffs[id]);
permuted.push_back(coeffs.back());
return permuted;
};
do {
SmallVector<SmallVector<int64_t, 4>, 4> permutedIneqs, permutedEqs;
for (const auto &ineq : ineqs)
permutedIneqs.push_back(permute(ineq));
for (const auto &eq : eqs)
permutedEqs.push_back(permute(eq));
checkSample(hasSample,
makeSetFromConstraints(nDim, permutedIneqs, permutedEqs), fn);
} while (std::next_permutation(perm.begin(), perm.end()));
}
TEST(IntegerPolyhedronTest, removeInequality) {
IntegerPolyhedron set =
makeSetFromConstraints(1, {{0, 0}, {1, 1}, {2, 2}, {3, 3}, {4, 4}}, {});
set.removeInequalityRange(0, 0);
EXPECT_EQ(set.getNumInequalities(), 5u);
set.removeInequalityRange(1, 3);
EXPECT_EQ(set.getNumInequalities(), 3u);
EXPECT_THAT(set.getInequality(0), ElementsAre(0, 0));
EXPECT_THAT(set.getInequality(1), ElementsAre(3, 3));
EXPECT_THAT(set.getInequality(2), ElementsAre(4, 4));
set.removeInequality(1);
EXPECT_EQ(set.getNumInequalities(), 2u);
EXPECT_THAT(set.getInequality(0), ElementsAre(0, 0));
EXPECT_THAT(set.getInequality(1), ElementsAre(4, 4));
}
TEST(IntegerPolyhedronTest, removeEquality) {
IntegerPolyhedron set =
makeSetFromConstraints(1, {}, {{0, 0}, {1, 1}, {2, 2}, {3, 3}, {4, 4}});
set.removeEqualityRange(0, 0);
EXPECT_EQ(set.getNumEqualities(), 5u);
set.removeEqualityRange(1, 3);
EXPECT_EQ(set.getNumEqualities(), 3u);
EXPECT_THAT(set.getEquality(0), ElementsAre(0, 0));
EXPECT_THAT(set.getEquality(1), ElementsAre(3, 3));
EXPECT_THAT(set.getEquality(2), ElementsAre(4, 4));
set.removeEquality(1);
EXPECT_EQ(set.getNumEqualities(), 2u);
EXPECT_THAT(set.getEquality(0), ElementsAre(0, 0));
EXPECT_THAT(set.getEquality(1), ElementsAre(4, 4));
}
TEST(IntegerPolyhedronTest, clearConstraints) {
IntegerPolyhedron set = makeSetFromConstraints(1, {}, {});
set.addInequality({1, 0});
EXPECT_EQ(set.atIneq(0, 0), 1);
EXPECT_EQ(set.atIneq(0, 1), 0);
set.clearConstraints();
set.addInequality({1, 0});
EXPECT_EQ(set.atIneq(0, 0), 1);
EXPECT_EQ(set.atIneq(0, 1), 0);
}
TEST(IntegerPolyhedronTest, removeIdRange) {
IntegerPolyhedron set(PresburgerSpace::getSetSpace(3, 2, 1));
set.addInequality({10, 11, 12, 20, 21, 30, 40});
set.removeVar(VarKind::Symbol, 1);
EXPECT_THAT(set.getInequality(0),
testing::ElementsAre(10, 11, 12, 20, 30, 40));
set.removeVarRange(VarKind::SetDim, 0, 2);
EXPECT_THAT(set.getInequality(0), testing::ElementsAre(12, 20, 30, 40));
set.removeVarRange(VarKind::Local, 1, 1);
EXPECT_THAT(set.getInequality(0), testing::ElementsAre(12, 20, 30, 40));
set.removeVarRange(VarKind::Local, 0, 1);
EXPECT_THAT(set.getInequality(0), testing::ElementsAre(12, 20, 40));
}
TEST(IntegerPolyhedronTest, FindSampleTest) {
// Bounded sets with only inequalities.
// 0 <= 7x <= 5
checkSample(true,
parseIntegerPolyhedron("(x) : (7 * x >= 0, -7 * x + 5 >= 0)"));
// 1 <= 5x and 5x <= 4 (no solution).
checkSample(
false, parseIntegerPolyhedron("(x) : (5 * x - 1 >= 0, -5 * x + 4 >= 0)"));
// 1 <= 5x and 5x <= 9 (solution: x = 1).
checkSample(
true, parseIntegerPolyhedron("(x) : (5 * x - 1 >= 0, -5 * x + 9 >= 0)"));
// Bounded sets with equalities.
// x >= 8 and 40 >= y and x = y.
checkSample(true, parseIntegerPolyhedron(
"(x,y) : (x - 8 >= 0, -y + 40 >= 0, x - y == 0)"));
// x <= 10 and y <= 10 and 10 <= z and x + 2y = 3z.
// solution: x = y = z = 10.
checkSample(true,
parseIntegerPolyhedron("(x,y,z) : (-x + 10 >= 0, -y + 10 >= 0, "
"z - 10 >= 0, x + 2 * y - 3 * z == 0)"));
// x <= 10 and y <= 10 and 11 <= z and x + 2y = 3z.
// This implies x + 2y >= 33 and x + 2y <= 30, which has no solution.
checkSample(false,
parseIntegerPolyhedron("(x,y,z) : (-x + 10 >= 0, -y + 10 >= 0, "
"z - 11 >= 0, x + 2 * y - 3 * z == 0)"));
// 0 <= r and r <= 3 and 4q + r = 7.
// Solution: q = 1, r = 3.
checkSample(true, parseIntegerPolyhedron(
"(q,r) : (r >= 0, -r + 3 >= 0, 4 * q + r - 7 == 0)"));
// 4q + r = 7 and r = 0.
// Solution: q = 1, r = 3.
checkSample(false,
parseIntegerPolyhedron("(q,r) : (4 * q + r - 7 == 0, r == 0)"));
// The next two sets are large sets that should take a long time to sample
// with a naive branch and bound algorithm but can be sampled efficiently with
// the GBR algorithm.
//
// This is a triangle with vertices at (1/3, 0), (2/3, 0) and (10000, 10000).
checkSample(
true, parseIntegerPolyhedron("(x,y) : (y >= 0, "
"300000 * x - 299999 * y - 100000 >= 0, "
"-300000 * x + 299998 * y + 200000 >= 0)"));
// This is a tetrahedron with vertices at
// (1/3, 0, 0), (2/3, 0, 0), (2/3, 0, 10000), and (10000, 10000, 10000).
// The first three points form a triangular base on the xz plane with the
// apex at the fourth point, which is the only integer point.
checkPermutationsSample(
true, 3,
{
{0, 1, 0, 0}, // y >= 0
{0, -1, 1, 0}, // z >= y
{300000, -299998, -1,
-100000}, // -300000x + 299998y + 100000 + z <= 0.
{-150000, 149999, 0, 100000}, // -150000x + 149999y + 100000 >= 0.
},
{});
// Same thing with some spurious extra dimensions equated to constants.
checkSample(true,
parseIntegerPolyhedron(
"(a,b,c,d,e) : (b + d - e >= 0, -b + c - d + e >= 0, "
"300000 * a - 299998 * b - c - 9 * d + 21 * e - 112000 >= 0, "
"-150000 * a + 149999 * b - 15 * d + 47 * e + 68000 >= 0, "
"d - e == 0, d + e - 2000 == 0)"));
// This is a tetrahedron with vertices at
// (1/3, 0, 0), (2/3, 0, 0), (2/3, 0, 100), (100, 100 - 1/3, 100).
checkPermutationsSample(false, 3,
{
{0, 1, 0, 0},
{0, -300, 299, 0},
{300 * 299, -89400, -299, -100 * 299},
{-897, 894, 0, 598},
},
{});
// Two tests involving equalities that are integer empty but not rational
// empty.
// This is a line segment from (0, 1/3) to (100, 100 + 1/3).
checkSample(false,
parseIntegerPolyhedron(
"(x,y) : (x >= 0, -x + 100 >= 0, 3 * x - 3 * y + 1 == 0)"));
// A thin parallelogram. 0 <= x <= 100 and x + 1/3 <= y <= x + 2/3.
checkSample(false, parseIntegerPolyhedron(
"(x,y) : (x >= 0, -x + 100 >= 0, "
"3 * x - 3 * y + 2 >= 0, -3 * x + 3 * y - 1 >= 0)"));
checkSample(true,
parseIntegerPolyhedron("(x,y) : (2 * x >= 0, -2 * x + 99 >= 0, "
"2 * y >= 0, -2 * y + 99 >= 0)"));
// 2D cone with apex at (10000, 10000) and
// edges passing through (1/3, 0) and (2/3, 0).
checkSample(true, parseIntegerPolyhedron(
"(x,y) : (300000 * x - 299999 * y - 100000 >= 0, "
"-300000 * x + 299998 * y + 200000 >= 0)"));
// Cartesian product of a tetrahedron and a 2D cone.
// The tetrahedron has vertices at
// (1/3, 0, 0), (2/3, 0, 0), (2/3, 0, 10000), and (10000, 10000, 10000).
// The first three points form a triangular base on the xz plane with the
// apex at the fourth point, which is the only integer point.
// The cone has apex at (10000, 10000) and
// edges passing through (1/3, 0) and (2/3, 0).
checkPermutationsSample(
true /* not empty */, 5,
{
// Tetrahedron contraints:
{0, 1, 0, 0, 0, 0}, // y >= 0
{0, -1, 1, 0, 0, 0}, // z >= y
// -300000x + 299998y + 100000 + z <= 0.
{300000, -299998, -1, 0, 0, -100000},
// -150000x + 149999y + 100000 >= 0.
{-150000, 149999, 0, 0, 0, 100000},
// Triangle constraints:
// 300000p - 299999q >= 100000
{0, 0, 0, 300000, -299999, -100000},
// -300000p + 299998q + 200000 >= 0
{0, 0, 0, -300000, 299998, 200000},
},
{});
// Cartesian product of same tetrahedron as above and {(p, q) : 1/3 <= p <=
// 2/3}. Since the second set is empty, the whole set is too.
checkPermutationsSample(
false /* empty */, 5,
{
// Tetrahedron contraints:
{0, 1, 0, 0, 0, 0}, // y >= 0
{0, -1, 1, 0, 0, 0}, // z >= y
// -300000x + 299998y + 100000 + z <= 0.
{300000, -299998, -1, 0, 0, -100000},
// -150000x + 149999y + 100000 >= 0.
{-150000, 149999, 0, 0, 0, 100000},
// Second set constraints:
// 3p >= 1
{0, 0, 0, 3, 0, -1},
// 3p <= 2
{0, 0, 0, -3, 0, 2},
},
{});
// Cartesian product of same tetrahedron as above and
// {(p, q, r) : 1 <= p <= 2 and p = 3q + 3r}.
// Since the second set is empty, the whole set is too.
checkPermutationsSample(
false /* empty */, 5,
{
// Tetrahedron contraints:
{0, 1, 0, 0, 0, 0, 0}, // y >= 0
{0, -1, 1, 0, 0, 0, 0}, // z >= y
// -300000x + 299998y + 100000 + z <= 0.
{300000, -299998, -1, 0, 0, 0, -100000},
// -150000x + 149999y + 100000 >= 0.
{-150000, 149999, 0, 0, 0, 0, 100000},
// Second set constraints:
// p >= 1
{0, 0, 0, 1, 0, 0, -1},
// p <= 2
{0, 0, 0, -1, 0, 0, 2},
},
{
{0, 0, 0, 1, -3, -3, 0}, // p = 3q + 3r
});
// Cartesian product of a tetrahedron and a 2D cone.
// The tetrahedron is empty and has vertices at
// (1/3, 0, 0), (2/3, 0, 0), (2/3, 0, 100), and (100, 100 - 1/3, 100).
// The cone has apex at (10000, 10000) and
// edges passing through (1/3, 0) and (2/3, 0).
// Since the tetrahedron is empty, the Cartesian product is too.
checkPermutationsSample(false /* empty */, 5,
{
// Tetrahedron contraints:
{0, 1, 0, 0, 0, 0},
{0, -300, 299, 0, 0, 0},
{300 * 299, -89400, -299, 0, 0, -100 * 299},
{-897, 894, 0, 0, 0, 598},
// Triangle constraints:
// 300000p - 299999q >= 100000
{0, 0, 0, 300000, -299999, -100000},
// -300000p + 299998q + 200000 >= 0
{0, 0, 0, -300000, 299998, 200000},
},
{});
// Cartesian product of same tetrahedron as above and
// {(p, q) : 1/3 <= p <= 2/3}.
checkPermutationsSample(false /* empty */, 5,
{
// Tetrahedron contraints:
{0, 1, 0, 0, 0, 0},
{0, -300, 299, 0, 0, 0},
{300 * 299, -89400, -299, 0, 0, -100 * 299},
{-897, 894, 0, 0, 0, 598},
// Second set constraints:
// 3p >= 1
{0, 0, 0, 3, 0, -1},
// 3p <= 2
{0, 0, 0, -3, 0, 2},
},
{});
checkSample(true, parseIntegerPolyhedron(
"(x, y, z) : (2 * x - 1 >= 0, x - y - 1 == 0, "
"y - z == 0)"));
// Test with a local id.
checkSample(true, parseIntegerPolyhedron("(x) : (x == 5*(x floordiv 2))"));
// Regression tests for the computation of dual coefficients.
checkSample(false, parseIntegerPolyhedron("(x, y, z) : ("
"6*x - 4*y + 9*z + 2 >= 0,"
"x + 5*y + z + 5 >= 0,"
"-4*x + y + 2*z - 1 >= 0,"
"-3*x - 2*y - 7*z - 1 >= 0,"
"-7*x - 5*y - 9*z - 1 >= 0)"));
checkSample(true, parseIntegerPolyhedron("(x, y, z) : ("
"3*x + 3*y + 3 >= 0,"
"-4*x - 8*y - z + 4 >= 0,"
"-7*x - 4*y + z + 1 >= 0,"
"2*x - 7*y - 8*z - 7 >= 0,"
"9*x + 8*y - 9*z - 7 >= 0)"));
}
TEST(IntegerPolyhedronTest, IsIntegerEmptyTest) {
// 1 <= 5x and 5x <= 4 (no solution).
EXPECT_TRUE(parseIntegerPolyhedron("(x) : (5 * x - 1 >= 0, -5 * x + 4 >= 0)")
.isIntegerEmpty());
// 1 <= 5x and 5x <= 9 (solution: x = 1).
EXPECT_FALSE(parseIntegerPolyhedron("(x) : (5 * x - 1 >= 0, -5 * x + 9 >= 0)")
.isIntegerEmpty());
// Unbounded sets.
EXPECT_TRUE(
parseIntegerPolyhedron("(x,y,z) : (2 * y - 1 >= 0, -2 * y + 1 >= 0, "
"2 * z - 1 >= 0, 2 * x - 1 == 0)")
.isIntegerEmpty());
EXPECT_FALSE(parseIntegerPolyhedron(
"(x,y,z) : (2 * x - 1 >= 0, -3 * x + 3 >= 0, "
"5 * z - 6 >= 0, -7 * z + 17 >= 0, 3 * y - 2 >= 0)")
.isIntegerEmpty());
EXPECT_FALSE(parseIntegerPolyhedron(
"(x,y,z) : (2 * x - 1 >= 0, x - y - 1 == 0, y - z == 0)")
.isIntegerEmpty());
// IntegerPolyhedron::isEmpty() does not detect the following sets to be
// empty.
// 3x + 7y = 1 and 0 <= x, y <= 10.
// Since x and y are non-negative, 3x + 7y can never be 1.
EXPECT_TRUE(parseIntegerPolyhedron(
"(x,y) : (x >= 0, -x + 10 >= 0, y >= 0, -y + 10 >= 0, "
"3 * x + 7 * y - 1 == 0)")
.isIntegerEmpty());
// 2x = 3y and y = x - 1 and x + y = 6z + 2 and 0 <= x, y <= 100.
// Substituting y = x - 1 in 3y = 2x, we obtain x = 3 and hence y = 2.
// Since x + y = 5 cannot be equal to 6z + 2 for any z, the set is empty.
EXPECT_TRUE(parseIntegerPolyhedron(
"(x,y,z) : (x >= 0, -x + 100 >= 0, y >= 0, -y + 100 >= 0, "
"2 * x - 3 * y == 0, x - y - 1 == 0, x + y - 6 * z - 2 == 0)")
.isIntegerEmpty());
// 2x = 3y and y = x - 1 + 6z and x + y = 6q + 2 and 0 <= x, y <= 100.
// 2x = 3y implies x is a multiple of 3 and y is even.
// Now y = x - 1 + 6z implies y = 2 mod 3. In fact, since y is even, we have
// y = 2 mod 6. Then since x = y + 1 + 6z, we have x = 3 mod 6, implying
// x + y = 5 mod 6, which contradicts x + y = 6q + 2, so the set is empty.
EXPECT_TRUE(
parseIntegerPolyhedron(
"(x,y,z,q) : (x >= 0, -x + 100 >= 0, y >= 0, -y + 100 >= 0, "
"2 * x - 3 * y == 0, x - y + 6 * z - 1 == 0, x + y - 6 * q - 2 == 0)")
.isIntegerEmpty());
// Set with symbols.
EXPECT_FALSE(parseIntegerPolyhedron("(x)[s] : (x + s >= 0, x - s == 0)")
.isIntegerEmpty());
}
TEST(IntegerPolyhedronTest, removeRedundantConstraintsTest) {
IntegerPolyhedron poly =
parseIntegerPolyhedron("(x) : (x - 2 >= 0, -x + 2 >= 0, x - 2 == 0)");
poly.removeRedundantConstraints();
// Both inequalities are redundant given the equality. Both have been removed.
EXPECT_EQ(poly.getNumInequalities(), 0u);
EXPECT_EQ(poly.getNumEqualities(), 1u);
IntegerPolyhedron poly2 =
parseIntegerPolyhedron("(x,y) : (x - 3 >= 0, y - 2 >= 0, x - y == 0)");
poly2.removeRedundantConstraints();
// The second inequality is redundant and should have been removed. The
// remaining inequality should be the first one.
EXPECT_EQ(poly2.getNumInequalities(), 1u);
EXPECT_THAT(poly2.getInequality(0), ElementsAre(1, 0, -3));
EXPECT_EQ(poly2.getNumEqualities(), 1u);
IntegerPolyhedron poly3 =
parseIntegerPolyhedron("(x,y,z) : (x - y == 0, x - z == 0, y - z == 0)");
poly3.removeRedundantConstraints();
// One of the three equalities can be removed.
EXPECT_EQ(poly3.getNumInequalities(), 0u);
EXPECT_EQ(poly3.getNumEqualities(), 2u);
IntegerPolyhedron poly4 = parseIntegerPolyhedron(
"(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q) : ("
"b - 1 >= 0,"
"-b + 500 >= 0,"
"-16 * d + f >= 0,"
"f - 1 >= 0,"
"-f + 998 >= 0,"
"16 * d - f + 15 >= 0,"
"-16 * e + g >= 0,"
"g - 1 >= 0,"
"-g + 998 >= 0,"
"16 * e - g + 15 >= 0,"
"h >= 0,"
"-h + 1 >= 0,"
"j - 1 >= 0,"
"-j + 500 >= 0,"
"-f + 16 * l + 15 >= 0,"
"f - 16 * l >= 0,"
"-16 * m + o >= 0,"
"o - 1 >= 0,"
"-o + 998 >= 0,"
"16 * m - o + 15 >= 0,"
"p >= 0,"
"-p + 1 >= 0,"
"-g - h + 8 * q + 8 >= 0,"
"-o - p + 8 * q + 8 >= 0,"
"o + p - 8 * q - 1 >= 0,"
"g + h - 8 * q - 1 >= 0,"
"-f + n >= 0,"
"f - n >= 0,"
"k - 10 >= 0,"
"-k + 10 >= 0,"
"i - 13 >= 0,"
"-i + 13 >= 0,"
"c - 10 >= 0,"
"-c + 10 >= 0,"
"a - 13 >= 0,"
"-a + 13 >= 0"
")");
// The above is a large set of constraints without any redundant constraints,
// as verified by the Fourier-Motzkin based removeRedundantInequalities.
unsigned nIneq = poly4.getNumInequalities();
unsigned nEq = poly4.getNumEqualities();
poly4.removeRedundantInequalities();
ASSERT_EQ(poly4.getNumInequalities(), nIneq);
ASSERT_EQ(poly4.getNumEqualities(), nEq);
// Now we test that removeRedundantConstraints does not find any constraints
// to be redundant either.
poly4.removeRedundantConstraints();
EXPECT_EQ(poly4.getNumInequalities(), nIneq);
EXPECT_EQ(poly4.getNumEqualities(), nEq);
IntegerPolyhedron poly5 = parseIntegerPolyhedron(
"(x,y) : (128 * x + 127 >= 0, -x + 7 >= 0, -128 * x + y >= 0, y >= 0)");
// 128x + 127 >= 0 implies that 128x >= 0, since x has to be an integer.
// (This should be caught by GCDTightenInqualities().)
// So -128x + y >= 0 and 128x + 127 >= 0 imply y >= 0 since we have
// y >= 128x >= 0.
poly5.removeRedundantConstraints();
EXPECT_EQ(poly5.getNumInequalities(), 3u);
SmallVector<MPInt, 8> redundantConstraint = getMPIntVec({0, 1, 0});
for (unsigned i = 0; i < 3; ++i) {
// Ensure that the removed constraint was the redundant constraint [3].
EXPECT_NE(poly5.getInequality(i), ArrayRef<MPInt>(redundantConstraint));
}
}
TEST(IntegerPolyhedronTest, addConstantUpperBound) {
IntegerPolyhedron poly(PresburgerSpace::getSetSpace(2));
poly.addBound(BoundType::UB, 0, 1);
EXPECT_EQ(poly.atIneq(0, 0), -1);
EXPECT_EQ(poly.atIneq(0, 1), 0);
EXPECT_EQ(poly.atIneq(0, 2), 1);
poly.addBound(BoundType::UB, {1, 2, 3}, 1);
EXPECT_EQ(poly.atIneq(1, 0), -1);
EXPECT_EQ(poly.atIneq(1, 1), -2);
EXPECT_EQ(poly.atIneq(1, 2), -2);
}
TEST(IntegerPolyhedronTest, addConstantLowerBound) {
IntegerPolyhedron poly(PresburgerSpace::getSetSpace(2));
poly.addBound(BoundType::LB, 0, 1);
EXPECT_EQ(poly.atIneq(0, 0), 1);
EXPECT_EQ(poly.atIneq(0, 1), 0);
EXPECT_EQ(poly.atIneq(0, 2), -1);
poly.addBound(BoundType::LB, {1, 2, 3}, 1);
EXPECT_EQ(poly.atIneq(1, 0), 1);
EXPECT_EQ(poly.atIneq(1, 1), 2);
EXPECT_EQ(poly.atIneq(1, 2), 2);
}
/// Check if the expected division representation of local variables matches the
/// computed representation. The expected division representation is given as
/// a vector of expressions set in `expectedDividends` and the corressponding
/// denominator in `expectedDenominators`. The `denominators` and `dividends`
/// obtained through `getLocalRepr` function is verified against the
/// `expectedDenominators` and `expectedDividends` respectively.
static void checkDivisionRepresentation(
IntegerPolyhedron &poly,
const std::vector<SmallVector<int64_t, 8>> &expectedDividends,
ArrayRef<int64_t> expectedDenominators) {
DivisionRepr divs = poly.getLocalReprs();
// Check that the `denominators` and `expectedDenominators` match.
EXPECT_EQ(ArrayRef<MPInt>(getMPIntVec(expectedDenominators)),
divs.getDenoms());
// Check that the `dividends` and `expectedDividends` match. If the
// denominator for a division is zero, we ignore its dividend.
EXPECT_TRUE(divs.getNumDivs() == expectedDividends.size());
for (unsigned i = 0, e = divs.getNumDivs(); i < e; ++i) {
if (divs.hasRepr(i)) {
for (unsigned j = 0, f = divs.getNumVars() + 1; j < f; ++j) {
EXPECT_TRUE(expectedDividends[i][j] == divs.getDividend(i)[j]);
}
}
}
}
TEST(IntegerPolyhedronTest, computeLocalReprSimple) {
IntegerPolyhedron poly(PresburgerSpace::getSetSpace(1));
poly.addLocalFloorDiv({1, 4}, 10);
poly.addLocalFloorDiv({1, 0, 100}, 10);
std::vector<SmallVector<int64_t, 8>> divisions = {{1, 0, 0, 4},
{1, 0, 0, 100}};
SmallVector<int64_t, 8> denoms = {10, 10};
// Check if floordivs can be computed when no other inequalities exist
// and floor divs do not depend on each other.
checkDivisionRepresentation(poly, divisions, denoms);
}
TEST(IntegerPolyhedronTest, computeLocalReprConstantFloorDiv) {
IntegerPolyhedron poly(PresburgerSpace::getSetSpace(4));
poly.addInequality({1, 0, 3, 1, 2});
poly.addInequality({1, 2, -8, 1, 10});
poly.addEquality({1, 2, -4, 1, 10});
poly.addLocalFloorDiv({0, 0, 0, 0, 100}, 30);
poly.addLocalFloorDiv({0, 0, 0, 0, 0, 206}, 101);
std::vector<SmallVector<int64_t, 8>> divisions = {{0, 0, 0, 0, 0, 0, 3},
{0, 0, 0, 0, 0, 0, 2}};
SmallVector<int64_t, 8> denoms = {1, 1};
// Check if floordivs with constant numerator can be computed.
checkDivisionRepresentation(poly, divisions, denoms);
}
TEST(IntegerPolyhedronTest, computeLocalReprRecursive) {
IntegerPolyhedron poly(PresburgerSpace::getSetSpace(4));
poly.addInequality({1, 0, 3, 1, 2});
poly.addInequality({1, 2, -8, 1, 10});
poly.addEquality({1, 2, -4, 1, 10});
poly.addLocalFloorDiv({0, -2, 7, 2, 10}, 3);
poly.addLocalFloorDiv({3, 0, 9, 2, 2, 10}, 5);
poly.addLocalFloorDiv({0, 1, -123, 2, 0, -4, 10}, 3);
poly.addInequality({1, 2, -2, 1, -5, 0, 6, 100});
poly.addInequality({1, 2, -8, 1, 3, 7, 0, -9});
std::vector<SmallVector<int64_t, 8>> divisions = {
{0, -2, 7, 2, 0, 0, 0, 10},
{3, 0, 9, 2, 2, 0, 0, 10},
{0, 1, -123, 2, 0, -4, 0, 10}};
SmallVector<int64_t, 8> denoms = {3, 5, 3};
// Check if floordivs which may depend on other floordivs can be computed.
checkDivisionRepresentation(poly, divisions, denoms);
}
TEST(IntegerPolyhedronTest, computeLocalReprTightUpperBound) {
{
IntegerPolyhedron poly = parseIntegerPolyhedron("(i) : (i mod 3 - 1 >= 0)");
// The set formed by the poly is:
// 3q - i + 2 >= 0 <-- Division lower bound
// -3q + i - 1 >= 0
// -3q + i >= 0 <-- Division upper bound
// We remove redundant constraints to get the set:
// 3q - i + 2 >= 0 <-- Division lower bound
// -3q + i - 1 >= 0 <-- Tighter division upper bound
// thus, making the upper bound tighter.
poly.removeRedundantConstraints();
std::vector<SmallVector<int64_t, 8>> divisions = {{1, 0, 0}};
SmallVector<int64_t, 8> denoms = {3};
// Check if the divisions can be computed even with a tighter upper bound.
checkDivisionRepresentation(poly, divisions, denoms);
}
{
IntegerPolyhedron poly = parseIntegerPolyhedron(
"(i, j, q) : (4*q - i - j + 2 >= 0, -4*q + i + j >= 0)");
// Convert `q` to a local variable.
poly.convertToLocal(VarKind::SetDim, 2, 3);
std::vector<SmallVector<int64_t, 8>> divisions = {{1, 1, 0, 1}};
SmallVector<int64_t, 8> denoms = {4};
// Check if the divisions can be computed even with a tighter upper bound.
checkDivisionRepresentation(poly, divisions, denoms);
}
}
TEST(IntegerPolyhedronTest, computeLocalReprFromEquality) {
{
IntegerPolyhedron poly =
parseIntegerPolyhedron("(i, j, q) : (-4*q + i + j == 0)");
// Convert `q` to a local variable.
poly.convertToLocal(VarKind::SetDim, 2, 3);
std::vector<SmallVector<int64_t, 8>> divisions = {{1, 1, 0, 0}};
SmallVector<int64_t, 8> denoms = {4};
checkDivisionRepresentation(poly, divisions, denoms);
}
{
IntegerPolyhedron poly =
parseIntegerPolyhedron("(i, j, q) : (4*q - i - j == 0)");
// Convert `q` to a local variable.
poly.convertToLocal(VarKind::SetDim, 2, 3);
std::vector<SmallVector<int64_t, 8>> divisions = {{1, 1, 0, 0}};
SmallVector<int64_t, 8> denoms = {4};
checkDivisionRepresentation(poly, divisions, denoms);
}
{
IntegerPolyhedron poly =
parseIntegerPolyhedron("(i, j, q) : (3*q + i + j - 2 == 0)");
// Convert `q` to a local variable.
poly.convertToLocal(VarKind::SetDim, 2, 3);
std::vector<SmallVector<int64_t, 8>> divisions = {{-1, -1, 0, 2}};
SmallVector<int64_t, 8> denoms = {3};
checkDivisionRepresentation(poly, divisions, denoms);
}
}
TEST(IntegerPolyhedronTest, computeLocalReprFromEqualityAndInequality) {
{
IntegerPolyhedron poly =
parseIntegerPolyhedron("(i, j, q, k) : (-3*k + i + j == 0, 4*q - "
"i - j + 2 >= 0, -4*q + i + j >= 0)");
// Convert `q` and `k` to local variables.
poly.convertToLocal(VarKind::SetDim, 2, 4);
std::vector<SmallVector<int64_t, 8>> divisions = {{1, 1, 0, 0, 1},
{1, 1, 0, 0, 0}};
SmallVector<int64_t, 8> denoms = {4, 3};
checkDivisionRepresentation(poly, divisions, denoms);
}
}
TEST(IntegerPolyhedronTest, computeLocalReprNoRepr) {
IntegerPolyhedron poly =
parseIntegerPolyhedron("(x, q) : (x - 3 * q >= 0, -x + 3 * q + 3 >= 0)");
// Convert q to a local variable.
poly.convertToLocal(VarKind::SetDim, 1, 2);
std::vector<SmallVector<int64_t, 8>> divisions = {{0, 0, 0}};
SmallVector<int64_t, 8> denoms = {0};
// Check that no division is computed.
checkDivisionRepresentation(poly, divisions, denoms);
}
TEST(IntegerPolyhedronTest, computeLocalReprNegConstNormalize) {
IntegerPolyhedron poly = parseIntegerPolyhedron(
"(x, q) : (-1 - 3*x - 6 * q >= 0, 6 + 3*x + 6*q >= 0)");
// Convert q to a local variable.
poly.convertToLocal(VarKind::SetDim, 1, 2);
// q = floor((-1/3 - x)/2)
// = floor((1/3) + (-1 - x)/2)
// = floor((-1 - x)/2).
std::vector<SmallVector<int64_t, 8>> divisions = {{-1, 0, -1}};
SmallVector<int64_t, 8> denoms = {2};
checkDivisionRepresentation(poly, divisions, denoms);
}
TEST(IntegerPolyhedronTest, simplifyLocalsTest) {
// (x) : (exists y: 2x + y = 1 and y = 2).
IntegerPolyhedron poly(PresburgerSpace::getSetSpace(1, 0, 1));
poly.addEquality({2, 1, -1});
poly.addEquality({0, 1, -2});
EXPECT_TRUE(poly.isEmpty());
// (x) : (exists y, z, w: 3x + y = 1 and 2y = z and 3y = w and z = w).
IntegerPolyhedron poly2(PresburgerSpace::getSetSpace(1, 0, 3));
poly2.addEquality({3, 1, 0, 0, -1});
poly2.addEquality({0, 2, -1, 0, 0});
poly2.addEquality({0, 3, 0, -1, 0});
poly2.addEquality({0, 0, 1, -1, 0});
EXPECT_TRUE(poly2.isEmpty());
// (x) : (exists y: x >= y + 1 and 2x + y = 0 and y >= -1).
IntegerPolyhedron poly3(PresburgerSpace::getSetSpace(1, 0, 1));
poly3.addInequality({1, -1, -1});
poly3.addInequality({0, 1, 1});
poly3.addEquality({2, 1, 0});
EXPECT_TRUE(poly3.isEmpty());
}
TEST(IntegerPolyhedronTest, mergeDivisionsSimple) {
{
// (x) : (exists z, y = [x / 2] : x = 3y and x + z + 1 >= 0).
IntegerPolyhedron poly1(PresburgerSpace::getSetSpace(1, 0, 1));
poly1.addLocalFloorDiv({1, 0, 0}, 2); // y = [x / 2].
poly1.addEquality({1, 0, -3, 0}); // x = 3y.
poly1.addInequality({1, 1, 0, 1}); // x + z + 1 >= 0.
// (x) : (exists y = [x / 2], z : x = 5y).
IntegerPolyhedron poly2(PresburgerSpace::getSetSpace(1));
poly2.addLocalFloorDiv({1, 0}, 2); // y = [x / 2].
poly2.addEquality({1, -5, 0}); // x = 5y.
poly2.appendVar(VarKind::Local); // Add local id z.
poly1.mergeLocalVars(poly2);
// Local space should be same.
EXPECT_EQ(poly1.getNumLocalVars(), poly2.getNumLocalVars());
// 1 division should be matched + 2 unmatched local ids.
EXPECT_EQ(poly1.getNumLocalVars(), 3u);
EXPECT_EQ(poly2.getNumLocalVars(), 3u);
}
{
// (x) : (exists z = [x / 5], y = [x / 2] : x = 3y).
IntegerPolyhedron poly1(PresburgerSpace::getSetSpace(1));
poly1.addLocalFloorDiv({1, 0}, 5); // z = [x / 5].
poly1.addLocalFloorDiv({1, 0, 0}, 2); // y = [x / 2].
poly1.addEquality({1, 0, -3, 0}); // x = 3y.
// (x) : (exists y = [x / 2], z = [x / 5]: x = 5z).
IntegerPolyhedron poly2(PresburgerSpace::getSetSpace(1));
poly2.addLocalFloorDiv({1, 0}, 2); // y = [x / 2].
poly2.addLocalFloorDiv({1, 0, 0}, 5); // z = [x / 5].
poly2.addEquality({1, 0, -5, 0}); // x = 5z.
poly1.mergeLocalVars(poly2);
// Local space should be same.
EXPECT_EQ(poly1.getNumLocalVars(), poly2.getNumLocalVars());
// 2 divisions should be matched.
EXPECT_EQ(poly1.getNumLocalVars(), 2u);
EXPECT_EQ(poly2.getNumLocalVars(), 2u);
}
{
// Division Normalization test.
// (x) : (exists z, y = [x / 2] : x = 3y and x + z + 1 >= 0).
IntegerPolyhedron poly1(PresburgerSpace::getSetSpace(1, 0, 1));
// This division would be normalized.
poly1.addLocalFloorDiv({3, 0, 0}, 6); // y = [3x / 6] -> [x/2].
poly1.addEquality({1, 0, -3, 0}); // x = 3z.
poly1.addInequality({1, 1, 0, 1}); // x + y + 1 >= 0.
// (x) : (exists y = [x / 2], z : x = 5y).
IntegerPolyhedron poly2(PresburgerSpace::getSetSpace(1));
poly2.addLocalFloorDiv({1, 0}, 2); // y = [x / 2].
poly2.addEquality({1, -5, 0}); // x = 5y.
poly2.appendVar(VarKind::Local); // Add local id z.
poly1.mergeLocalVars(poly2);
// Local space should be same.
EXPECT_EQ(poly1.getNumLocalVars(), poly2.getNumLocalVars());
// One division should be matched + 2 unmatched local ids.
EXPECT_EQ(poly1.getNumLocalVars(), 3u);
EXPECT_EQ(poly2.getNumLocalVars(), 3u);
}
}
TEST(IntegerPolyhedronTest, mergeDivisionsNestedDivsions) {
{
// (x) : (exists y = [x / 2], z = [x + y / 3]: y + z >= x).
IntegerPolyhedron poly1(PresburgerSpace::getSetSpace(1));
poly1.addLocalFloorDiv({1, 0}, 2); // y = [x / 2].
poly1.addLocalFloorDiv({1, 1, 0}, 3); // z = [x + y / 3].
poly1.addInequality({-1, 1, 1, 0}); // y + z >= x.
// (x) : (exists y = [x / 2], z = [x + y / 3]: y + z <= x).
IntegerPolyhedron poly2(PresburgerSpace::getSetSpace(1));
poly2.addLocalFloorDiv({1, 0}, 2); // y = [x / 2].
poly2.addLocalFloorDiv({1, 1, 0}, 3); // z = [x + y / 3].
poly2.addInequality({1, -1, -1, 0}); // y + z <= x.
poly1.mergeLocalVars(poly2);
// Local space should be same.
EXPECT_EQ(poly1.getNumLocalVars(), poly2.getNumLocalVars());
// 2 divisions should be matched.
EXPECT_EQ(poly1.getNumLocalVars(), 2u);
EXPECT_EQ(poly2.getNumLocalVars(), 2u);
}
{
// (x) : (exists y = [x / 2], z = [x + y / 3], w = [z + 1 / 5]: y + z >= x).
IntegerPolyhedron poly1(PresburgerSpace::getSetSpace(1));
poly1.addLocalFloorDiv({1, 0}, 2); // y = [x / 2].
poly1.addLocalFloorDiv({1, 1, 0}, 3); // z = [x + y / 3].
poly1.addLocalFloorDiv({0, 0, 1, 1}, 5); // w = [z + 1 / 5].
poly1.addInequality({-1, 1, 1, 0, 0}); // y + z >= x.
// (x) : (exists y = [x / 2], z = [x + y / 3], w = [z + 1 / 5]: y + z <= x).
IntegerPolyhedron poly2(PresburgerSpace::getSetSpace(1));
poly2.addLocalFloorDiv({1, 0}, 2); // y = [x / 2].
poly2.addLocalFloorDiv({1, 1, 0}, 3); // z = [x + y / 3].
poly2.addLocalFloorDiv({0, 0, 1, 1}, 5); // w = [z + 1 / 5].
poly2.addInequality({1, -1, -1, 0, 0}); // y + z <= x.
poly1.mergeLocalVars(poly2);
// Local space should be same.
EXPECT_EQ(poly1.getNumLocalVars(), poly2.getNumLocalVars());
// 3 divisions should be matched.
EXPECT_EQ(poly1.getNumLocalVars(), 3u);
EXPECT_EQ(poly2.getNumLocalVars(), 3u);
}
{
// (x) : (exists y = [x / 2], z = [x + y / 3]: y + z >= x).
IntegerPolyhedron poly1(PresburgerSpace::getSetSpace(1));
poly1.addLocalFloorDiv({2, 0}, 4); // y = [2x / 4] -> [x / 2].
poly1.addLocalFloorDiv({1, 1, 0}, 3); // z = [x + y / 3].
poly1.addInequality({-1, 1, 1, 0}); // y + z >= x.
// (x) : (exists y = [x / 2], z = [x + y / 3]: y + z <= x).
IntegerPolyhedron poly2(PresburgerSpace::getSetSpace(1));
poly2.addLocalFloorDiv({1, 0}, 2); // y = [x / 2].
// This division would be normalized.
poly2.addLocalFloorDiv({3, 3, 0}, 9); // z = [3x + 3y / 9] -> [x + y / 3].
poly2.addInequality({1, -1, -1, 0}); // y + z <= x.
poly1.mergeLocalVars(poly2);
// Local space should be same.
EXPECT_EQ(poly1.getNumLocalVars(), poly2.getNumLocalVars());
// 2 divisions should be matched.
EXPECT_EQ(poly1.getNumLocalVars(), 2u);
EXPECT_EQ(poly2.getNumLocalVars(), 2u);
}
}
TEST(IntegerPolyhedronTest, mergeDivisionsConstants) {
{
// (x) : (exists y = [x + 1 / 3], z = [x + 2 / 3]: y + z >= x).
IntegerPolyhedron poly1(PresburgerSpace::getSetSpace(1));
poly1.addLocalFloorDiv({1, 1}, 2); // y = [x + 1 / 2].
poly1.addLocalFloorDiv({1, 0, 2}, 3); // z = [x + 2 / 3].
poly1.addInequality({-1, 1, 1, 0}); // y + z >= x.
// (x) : (exists y = [x + 1 / 3], z = [x + 2 / 3]: y + z <= x).