llvm-project/llvm/unittests/ADT/DenseMapTest.cpp

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//===- llvm/unittest/ADT/DenseMapMap.cpp - DenseMap unit tests --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "gtest/gtest.h"
#include "llvm/ADT/DenseMap.h"
#include <map>
#include <set>
using namespace llvm;
namespace {
Introduce a SmallDenseMap container that re-uses the existing DenseMap implementation. This type includes an inline bucket array which is used initially. Once it is exceeded, an array of 64 buckets is allocated on the heap. The bucket count grows from there as needed. Some highlights of this implementation: - The inline buffer is very carefully aligned, and so supports types with alignment constraints. - It works hard to avoid aliasing issues. - Supports types with non-trivial constructors, destructors, copy constructions, etc. It works reasonably hard to minimize copies and unnecessary initialization. The most common initialization is to set keys to the empty key, and so that should be fast if at all possible. This class has a performance / space trade-off. It tries to optimize for relatively small maps, and so packs the inline bucket array densely into the object. It will be marginally slower than a normal DenseMap in a few use patterns, so it isn't appropriate everywhere. The unit tests for DenseMap have been generalized a bit to support running over different map implementations in addition to different key/value types. They've then been automatically extended to cover the new container through the magic of GoogleTest's typed tests. All of this is still a bit rough though. I'm going to be cleaning up some aspects of the implementation, documenting things better, and adding tests which include non-trivial types. As soon as I'm comfortable with the correctness, I plan to switch existing users of SmallMap over to this class as it is already more correct w.r.t. construction and destruction of objects iin the map. Thanks to Benjamin Kramer for all the reviews of this and the lead-up patches. That said, more review on this would really be appreciated. As I've noted a few times, I'm quite surprised how hard it is to get the semantics for a hashtable-based map container with a small buffer optimization correct. =] llvm-svn: 158638
2012-06-17 17:05:09 +08:00
uint32_t getTestKey(int i, uint32_t *) { return i; }
uint32_t getTestValue(int i, uint32_t *) { return 42 + i; }
Introduce a SmallDenseMap container that re-uses the existing DenseMap implementation. This type includes an inline bucket array which is used initially. Once it is exceeded, an array of 64 buckets is allocated on the heap. The bucket count grows from there as needed. Some highlights of this implementation: - The inline buffer is very carefully aligned, and so supports types with alignment constraints. - It works hard to avoid aliasing issues. - Supports types with non-trivial constructors, destructors, copy constructions, etc. It works reasonably hard to minimize copies and unnecessary initialization. The most common initialization is to set keys to the empty key, and so that should be fast if at all possible. This class has a performance / space trade-off. It tries to optimize for relatively small maps, and so packs the inline bucket array densely into the object. It will be marginally slower than a normal DenseMap in a few use patterns, so it isn't appropriate everywhere. The unit tests for DenseMap have been generalized a bit to support running over different map implementations in addition to different key/value types. They've then been automatically extended to cover the new container through the magic of GoogleTest's typed tests. All of this is still a bit rough though. I'm going to be cleaning up some aspects of the implementation, documenting things better, and adding tests which include non-trivial types. As soon as I'm comfortable with the correctness, I plan to switch existing users of SmallMap over to this class as it is already more correct w.r.t. construction and destruction of objects iin the map. Thanks to Benjamin Kramer for all the reviews of this and the lead-up patches. That said, more review on this would really be appreciated. As I've noted a few times, I'm quite surprised how hard it is to get the semantics for a hashtable-based map container with a small buffer optimization correct. =] llvm-svn: 158638
2012-06-17 17:05:09 +08:00
uint32_t *getTestKey(int i, uint32_t **) {
static uint32_t dummy_arr1[8192];
assert(i < 8192 && "Only support 8192 dummy keys.");
return &dummy_arr1[i];
}
Introduce a SmallDenseMap container that re-uses the existing DenseMap implementation. This type includes an inline bucket array which is used initially. Once it is exceeded, an array of 64 buckets is allocated on the heap. The bucket count grows from there as needed. Some highlights of this implementation: - The inline buffer is very carefully aligned, and so supports types with alignment constraints. - It works hard to avoid aliasing issues. - Supports types with non-trivial constructors, destructors, copy constructions, etc. It works reasonably hard to minimize copies and unnecessary initialization. The most common initialization is to set keys to the empty key, and so that should be fast if at all possible. This class has a performance / space trade-off. It tries to optimize for relatively small maps, and so packs the inline bucket array densely into the object. It will be marginally slower than a normal DenseMap in a few use patterns, so it isn't appropriate everywhere. The unit tests for DenseMap have been generalized a bit to support running over different map implementations in addition to different key/value types. They've then been automatically extended to cover the new container through the magic of GoogleTest's typed tests. All of this is still a bit rough though. I'm going to be cleaning up some aspects of the implementation, documenting things better, and adding tests which include non-trivial types. As soon as I'm comfortable with the correctness, I plan to switch existing users of SmallMap over to this class as it is already more correct w.r.t. construction and destruction of objects iin the map. Thanks to Benjamin Kramer for all the reviews of this and the lead-up patches. That said, more review on this would really be appreciated. As I've noted a few times, I'm quite surprised how hard it is to get the semantics for a hashtable-based map container with a small buffer optimization correct. =] llvm-svn: 158638
2012-06-17 17:05:09 +08:00
uint32_t *getTestValue(int i, uint32_t **) {
static uint32_t dummy_arr1[8192];
assert(i < 8192 && "Only support 8192 dummy keys.");
return &dummy_arr1[i];
}
/// \brief A test class that tries to check that construction and destruction
/// occur correctly.
class CtorTester {
static std::set<CtorTester *> Constructed;
int Value;
public:
explicit CtorTester(int Value = 0) : Value(Value) {
EXPECT_TRUE(Constructed.insert(this).second);
}
CtorTester(uint32_t Value) : Value(Value) {
EXPECT_TRUE(Constructed.insert(this).second);
}
CtorTester(const CtorTester &Arg) : Value(Arg.Value) {
EXPECT_TRUE(Constructed.insert(this).second);
}
~CtorTester() {
EXPECT_EQ(1u, Constructed.erase(this));
}
operator uint32_t() const { return Value; }
int getValue() const { return Value; }
bool operator==(const CtorTester &RHS) const { return Value == RHS.Value; }
};
std::set<CtorTester *> CtorTester::Constructed;
struct CtorTesterMapInfo {
static inline CtorTester getEmptyKey() { return CtorTester(-1); }
static inline CtorTester getTombstoneKey() { return CtorTester(-2); }
static unsigned getHashValue(const CtorTester &Val) {
return Val.getValue() * 37u;
}
static bool isEqual(const CtorTester &LHS, const CtorTester &RHS) {
return LHS == RHS;
}
};
CtorTester getTestKey(int i, CtorTester *) { return CtorTester(i); }
CtorTester getTestValue(int i, CtorTester *) { return CtorTester(42 + i); }
Introduce a SmallDenseMap container that re-uses the existing DenseMap implementation. This type includes an inline bucket array which is used initially. Once it is exceeded, an array of 64 buckets is allocated on the heap. The bucket count grows from there as needed. Some highlights of this implementation: - The inline buffer is very carefully aligned, and so supports types with alignment constraints. - It works hard to avoid aliasing issues. - Supports types with non-trivial constructors, destructors, copy constructions, etc. It works reasonably hard to minimize copies and unnecessary initialization. The most common initialization is to set keys to the empty key, and so that should be fast if at all possible. This class has a performance / space trade-off. It tries to optimize for relatively small maps, and so packs the inline bucket array densely into the object. It will be marginally slower than a normal DenseMap in a few use patterns, so it isn't appropriate everywhere. The unit tests for DenseMap have been generalized a bit to support running over different map implementations in addition to different key/value types. They've then been automatically extended to cover the new container through the magic of GoogleTest's typed tests. All of this is still a bit rough though. I'm going to be cleaning up some aspects of the implementation, documenting things better, and adding tests which include non-trivial types. As soon as I'm comfortable with the correctness, I plan to switch existing users of SmallMap over to this class as it is already more correct w.r.t. construction and destruction of objects iin the map. Thanks to Benjamin Kramer for all the reviews of this and the lead-up patches. That said, more review on this would really be appreciated. As I've noted a few times, I'm quite surprised how hard it is to get the semantics for a hashtable-based map container with a small buffer optimization correct. =] llvm-svn: 158638
2012-06-17 17:05:09 +08:00
// Test fixture, with helper functions implemented by forwarding to global
// function overloads selected by component types of the type parameter. This
// allows all of the map implementations to be tested with shared
// implementations of helper routines.
template <typename T>
class DenseMapTest : public ::testing::Test {
protected:
T Map;
static typename T::key_type *const dummy_key_ptr;
static typename T::mapped_type *const dummy_value_ptr;
typename T::key_type getKey(int i = 0) {
return getTestKey(i, dummy_key_ptr);
}
typename T::mapped_type getValue(int i = 0) {
return getTestValue(i, dummy_value_ptr);
}
};
template <typename T>
typename T::key_type *const DenseMapTest<T>::dummy_key_ptr = 0;
template <typename T>
typename T::mapped_type *const DenseMapTest<T>::dummy_value_ptr = 0;
// Register these types for testing.
typedef ::testing::Types<DenseMap<uint32_t, uint32_t>,
Introduce a SmallDenseMap container that re-uses the existing DenseMap implementation. This type includes an inline bucket array which is used initially. Once it is exceeded, an array of 64 buckets is allocated on the heap. The bucket count grows from there as needed. Some highlights of this implementation: - The inline buffer is very carefully aligned, and so supports types with alignment constraints. - It works hard to avoid aliasing issues. - Supports types with non-trivial constructors, destructors, copy constructions, etc. It works reasonably hard to minimize copies and unnecessary initialization. The most common initialization is to set keys to the empty key, and so that should be fast if at all possible. This class has a performance / space trade-off. It tries to optimize for relatively small maps, and so packs the inline bucket array densely into the object. It will be marginally slower than a normal DenseMap in a few use patterns, so it isn't appropriate everywhere. The unit tests for DenseMap have been generalized a bit to support running over different map implementations in addition to different key/value types. They've then been automatically extended to cover the new container through the magic of GoogleTest's typed tests. All of this is still a bit rough though. I'm going to be cleaning up some aspects of the implementation, documenting things better, and adding tests which include non-trivial types. As soon as I'm comfortable with the correctness, I plan to switch existing users of SmallMap over to this class as it is already more correct w.r.t. construction and destruction of objects iin the map. Thanks to Benjamin Kramer for all the reviews of this and the lead-up patches. That said, more review on this would really be appreciated. As I've noted a few times, I'm quite surprised how hard it is to get the semantics for a hashtable-based map container with a small buffer optimization correct. =] llvm-svn: 158638
2012-06-17 17:05:09 +08:00
DenseMap<uint32_t *, uint32_t *>,
DenseMap<CtorTester, CtorTester, CtorTesterMapInfo>,
Introduce a SmallDenseMap container that re-uses the existing DenseMap implementation. This type includes an inline bucket array which is used initially. Once it is exceeded, an array of 64 buckets is allocated on the heap. The bucket count grows from there as needed. Some highlights of this implementation: - The inline buffer is very carefully aligned, and so supports types with alignment constraints. - It works hard to avoid aliasing issues. - Supports types with non-trivial constructors, destructors, copy constructions, etc. It works reasonably hard to minimize copies and unnecessary initialization. The most common initialization is to set keys to the empty key, and so that should be fast if at all possible. This class has a performance / space trade-off. It tries to optimize for relatively small maps, and so packs the inline bucket array densely into the object. It will be marginally slower than a normal DenseMap in a few use patterns, so it isn't appropriate everywhere. The unit tests for DenseMap have been generalized a bit to support running over different map implementations in addition to different key/value types. They've then been automatically extended to cover the new container through the magic of GoogleTest's typed tests. All of this is still a bit rough though. I'm going to be cleaning up some aspects of the implementation, documenting things better, and adding tests which include non-trivial types. As soon as I'm comfortable with the correctness, I plan to switch existing users of SmallMap over to this class as it is already more correct w.r.t. construction and destruction of objects iin the map. Thanks to Benjamin Kramer for all the reviews of this and the lead-up patches. That said, more review on this would really be appreciated. As I've noted a few times, I'm quite surprised how hard it is to get the semantics for a hashtable-based map container with a small buffer optimization correct. =] llvm-svn: 158638
2012-06-17 17:05:09 +08:00
SmallDenseMap<uint32_t, uint32_t>,
SmallDenseMap<uint32_t *, uint32_t *>,
SmallDenseMap<CtorTester, CtorTester, 4,
CtorTesterMapInfo>
Introduce a SmallDenseMap container that re-uses the existing DenseMap implementation. This type includes an inline bucket array which is used initially. Once it is exceeded, an array of 64 buckets is allocated on the heap. The bucket count grows from there as needed. Some highlights of this implementation: - The inline buffer is very carefully aligned, and so supports types with alignment constraints. - It works hard to avoid aliasing issues. - Supports types with non-trivial constructors, destructors, copy constructions, etc. It works reasonably hard to minimize copies and unnecessary initialization. The most common initialization is to set keys to the empty key, and so that should be fast if at all possible. This class has a performance / space trade-off. It tries to optimize for relatively small maps, and so packs the inline bucket array densely into the object. It will be marginally slower than a normal DenseMap in a few use patterns, so it isn't appropriate everywhere. The unit tests for DenseMap have been generalized a bit to support running over different map implementations in addition to different key/value types. They've then been automatically extended to cover the new container through the magic of GoogleTest's typed tests. All of this is still a bit rough though. I'm going to be cleaning up some aspects of the implementation, documenting things better, and adding tests which include non-trivial types. As soon as I'm comfortable with the correctness, I plan to switch existing users of SmallMap over to this class as it is already more correct w.r.t. construction and destruction of objects iin the map. Thanks to Benjamin Kramer for all the reviews of this and the lead-up patches. That said, more review on this would really be appreciated. As I've noted a few times, I'm quite surprised how hard it is to get the semantics for a hashtable-based map container with a small buffer optimization correct. =] llvm-svn: 158638
2012-06-17 17:05:09 +08:00
> DenseMapTestTypes;
TYPED_TEST_CASE(DenseMapTest, DenseMapTestTypes);
// Empty map tests
TYPED_TEST(DenseMapTest, EmptyIntMapTest) {
// Size tests
EXPECT_EQ(0u, this->Map.size());
EXPECT_TRUE(this->Map.empty());
// Iterator tests
EXPECT_TRUE(this->Map.begin() == this->Map.end());
// Lookup tests
EXPECT_FALSE(this->Map.count(this->getKey()));
EXPECT_TRUE(this->Map.find(this->getKey()) == this->Map.end());
#if !defined(_MSC_VER) || defined(__clang__)
EXPECT_EQ(typename TypeParam::mapped_type(),
this->Map.lookup(this->getKey()));
#else
// MSVC, at least old versions, cannot parse the typename to disambiguate
// TypeParam::mapped_type as a type. However, because MSVC doesn't implement
// two-phase name lookup, it also doesn't require the typename. Deal with
// this mutual incompatibility through specialized code.
EXPECT_EQ(TypeParam::mapped_type(),
this->Map.lookup(this->getKey()));
#endif
}
// Constant map tests
TYPED_TEST(DenseMapTest, ConstEmptyMapTest) {
const TypeParam &ConstMap = this->Map;
EXPECT_EQ(0u, ConstMap.size());
EXPECT_TRUE(ConstMap.empty());
EXPECT_TRUE(ConstMap.begin() == ConstMap.end());
}
// A map with a single entry
TYPED_TEST(DenseMapTest, SingleEntryMapTest) {
this->Map[this->getKey()] = this->getValue();
// Size tests
EXPECT_EQ(1u, this->Map.size());
EXPECT_FALSE(this->Map.begin() == this->Map.end());
EXPECT_FALSE(this->Map.empty());
// Iterator tests
typename TypeParam::iterator it = this->Map.begin();
EXPECT_EQ(this->getKey(), it->first);
EXPECT_EQ(this->getValue(), it->second);
++it;
EXPECT_TRUE(it == this->Map.end());
// Lookup tests
EXPECT_TRUE(this->Map.count(this->getKey()));
EXPECT_TRUE(this->Map.find(this->getKey()) == this->Map.begin());
EXPECT_EQ(this->getValue(), this->Map.lookup(this->getKey()));
EXPECT_EQ(this->getValue(), this->Map[this->getKey()]);
}
// Test clear() method
TYPED_TEST(DenseMapTest, ClearTest) {
this->Map[this->getKey()] = this->getValue();
this->Map.clear();
EXPECT_EQ(0u, this->Map.size());
EXPECT_TRUE(this->Map.empty());
EXPECT_TRUE(this->Map.begin() == this->Map.end());
}
// Test erase(iterator) method
TYPED_TEST(DenseMapTest, EraseTest) {
this->Map[this->getKey()] = this->getValue();
this->Map.erase(this->Map.begin());
EXPECT_EQ(0u, this->Map.size());
EXPECT_TRUE(this->Map.empty());
EXPECT_TRUE(this->Map.begin() == this->Map.end());
}
// Test erase(value) method
TYPED_TEST(DenseMapTest, EraseTest2) {
this->Map[this->getKey()] = this->getValue();
this->Map.erase(this->getKey());
EXPECT_EQ(0u, this->Map.size());
EXPECT_TRUE(this->Map.empty());
EXPECT_TRUE(this->Map.begin() == this->Map.end());
}
// Test insert() method
TYPED_TEST(DenseMapTest, InsertTest) {
this->Map.insert(std::make_pair(this->getKey(), this->getValue()));
EXPECT_EQ(1u, this->Map.size());
EXPECT_EQ(this->getValue(), this->Map[this->getKey()]);
}
// Test copy constructor method
TYPED_TEST(DenseMapTest, CopyConstructorTest) {
this->Map[this->getKey()] = this->getValue();
TypeParam copyMap(this->Map);
EXPECT_EQ(1u, copyMap.size());
EXPECT_EQ(this->getValue(), copyMap[this->getKey()]);
}
// Test copy constructor method where SmallDenseMap isn't small.
TYPED_TEST(DenseMapTest, CopyConstructorNotSmallTest) {
for (int Key = 0; Key < 5; ++Key)
this->Map[this->getKey(Key)] = this->getValue(Key);
TypeParam copyMap(this->Map);
EXPECT_EQ(5u, copyMap.size());
for (int Key = 0; Key < 5; ++Key)
EXPECT_EQ(this->getValue(Key), copyMap[this->getKey(Key)]);
}
// Test copying from a default-constructed map.
TYPED_TEST(DenseMapTest, CopyConstructorFromDefaultTest) {
TypeParam copyMap(this->Map);
EXPECT_TRUE(copyMap.empty());
}
// Test copying from an empty map where SmallDenseMap isn't small.
TYPED_TEST(DenseMapTest, CopyConstructorFromEmptyTest) {
for (int Key = 0; Key < 5; ++Key)
this->Map[this->getKey(Key)] = this->getValue(Key);
this->Map.clear();
TypeParam copyMap(this->Map);
EXPECT_TRUE(copyMap.empty());
}
// Test assignment operator method
TYPED_TEST(DenseMapTest, AssignmentTest) {
this->Map[this->getKey()] = this->getValue();
TypeParam copyMap = this->Map;
EXPECT_EQ(1u, copyMap.size());
EXPECT_EQ(this->getValue(), copyMap[this->getKey()]);
}
// Test swap method
TYPED_TEST(DenseMapTest, SwapTest) {
this->Map[this->getKey()] = this->getValue();
TypeParam otherMap;
this->Map.swap(otherMap);
EXPECT_EQ(0u, this->Map.size());
EXPECT_TRUE(this->Map.empty());
EXPECT_EQ(1u, otherMap.size());
EXPECT_EQ(this->getValue(), otherMap[this->getKey()]);
this->Map.swap(otherMap);
EXPECT_EQ(0u, otherMap.size());
EXPECT_TRUE(otherMap.empty());
EXPECT_EQ(1u, this->Map.size());
EXPECT_EQ(this->getValue(), this->Map[this->getKey()]);
// Make this more interesting by inserting 100 numbers into the map.
for (int i = 0; i < 100; ++i)
this->Map[this->getKey(i)] = this->getValue(i);
this->Map.swap(otherMap);
EXPECT_EQ(0u, this->Map.size());
EXPECT_TRUE(this->Map.empty());
EXPECT_EQ(100u, otherMap.size());
for (int i = 0; i < 100; ++i)
EXPECT_EQ(this->getValue(i), otherMap[this->getKey(i)]);
this->Map.swap(otherMap);
EXPECT_EQ(0u, otherMap.size());
EXPECT_TRUE(otherMap.empty());
EXPECT_EQ(100u, this->Map.size());
for (int i = 0; i < 100; ++i)
EXPECT_EQ(this->getValue(i), this->Map[this->getKey(i)]);
}
// A more complex iteration test
TYPED_TEST(DenseMapTest, IterationTest) {
bool visited[100];
std::map<typename TypeParam::key_type, unsigned> visitedIndex;
// Insert 100 numbers into the map
for (int i = 0; i < 100; ++i) {
visited[i] = false;
visitedIndex[this->getKey(i)] = i;
this->Map[this->getKey(i)] = this->getValue(i);
}
// Iterate over all numbers and mark each one found.
for (typename TypeParam::iterator it = this->Map.begin();
it != this->Map.end(); ++it)
visited[visitedIndex[it->first]] = true;
// Ensure every number was visited.
for (int i = 0; i < 100; ++i)
ASSERT_TRUE(visited[i]) << "Entry #" << i << " was never visited";
}
// const_iterator test
TYPED_TEST(DenseMapTest, ConstIteratorTest) {
// Check conversion from iterator to const_iterator.
typename TypeParam::iterator it = this->Map.begin();
typename TypeParam::const_iterator cit(it);
EXPECT_TRUE(it == cit);
// Check copying of const_iterators.
typename TypeParam::const_iterator cit2(cit);
EXPECT_TRUE(cit == cit2);
}
// Key traits that allows lookup with either an unsigned or char* key;
// In the latter case, "a" == 0, "b" == 1 and so on.
struct TestDenseMapInfo {
static inline unsigned getEmptyKey() { return ~0; }
static inline unsigned getTombstoneKey() { return ~0U - 1; }
static unsigned getHashValue(const unsigned& Val) { return Val * 37U; }
static unsigned getHashValue(const char* Val) {
return (unsigned)(Val[0] - 'a') * 37U;
}
static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
return LHS == RHS;
}
static bool isEqual(const char* LHS, const unsigned& RHS) {
return (unsigned)(LHS[0] - 'a') == RHS;
}
};
// find_as() tests
TEST(DenseMapCustomTest, FindAsTest) {
DenseMap<unsigned, unsigned, TestDenseMapInfo> map;
map[0] = 1;
map[1] = 2;
map[2] = 3;
// Size tests
EXPECT_EQ(3u, map.size());
// Normal lookup tests
EXPECT_EQ(1, map.count(1));
EXPECT_EQ(1u, map.find(0)->second);
EXPECT_EQ(2u, map.find(1)->second);
EXPECT_EQ(3u, map.find(2)->second);
EXPECT_TRUE(map.find(3) == map.end());
// find_as() tests
EXPECT_EQ(1u, map.find_as("a")->second);
EXPECT_EQ(2u, map.find_as("b")->second);
EXPECT_EQ(3u, map.find_as("c")->second);
EXPECT_TRUE(map.find_as("d") == map.end());
}
struct ContiguousDenseMapInfo {
static inline unsigned getEmptyKey() { return ~0; }
static inline unsigned getTombstoneKey() { return ~0U - 1; }
static unsigned getHashValue(const unsigned& Val) { return Val; }
static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
return LHS == RHS;
}
};
// Test that filling a small dense map with exactly the number of elements in
// the map grows to have enough space for an empty bucket.
TEST(DenseMapCustomTest, SmallDenseMapGrowTest) {
SmallDenseMap<unsigned, unsigned, 32, ContiguousDenseMapInfo> map;
// Add some number of elements, then delete a few to leave us some tombstones.
// If we just filled the map with 32 elements we'd grow because of not enough
// tombstones which masks the issue here.
for (unsigned i = 0; i < 20; ++i)
map[i] = i + 1;
for (unsigned i = 0; i < 10; ++i)
map.erase(i);
for (unsigned i = 20; i < 32; ++i)
map[i] = i + 1;
// Size tests
EXPECT_EQ(22u, map.size());
// Try to find an element which doesn't exist. There was a bug in
// SmallDenseMap which led to a map with num elements == small capacity not
// having an empty bucket any more. Finding an element not in the map would
// therefore never terminate.
EXPECT_TRUE(map.find(32) == map.end());
}
}