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8253407: Move max_pow2 from test to src

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Reviewed-by: kbarrett, tschatzl
This commit is contained in:
Stefan Karlsson 2020-09-21 13:02:04 +00:00
parent fbfb62dffe
commit 7e49eaecbc
2 changed files with 25 additions and 14 deletions
src/hotspot/share/utilities
powerOfTwo.hpp
test/hotspot/gtest/utilities
test_powerOfTwo.cpp

9
src/hotspot/share/utilities/powerOfTwo.hpp

@ -34,6 +34,12 @@
// Power of two convenience library.
template <typename T, ENABLE_IF(std::is_integral<T>::value)>
constexpr T max_power_of_2() {
T max_val = std::numeric_limits<T>::max();
return max_val - (max_val >> 1);
}
// Returns true iff there exists integer i such that (T(1) << i) == x.
template <typename T, ENABLE_IF(std::is_integral<T>::value)>
constexpr bool is_power_of_2(T x) {
@ -71,8 +77,7 @@ inline T round_down_power_of_2(T value) {
template<typename T, ENABLE_IF(std::is_integral<T>::value)>
inline T round_up_power_of_2(T value) {
assert(value > 0, "Invalid value");
const T max_value = std::numeric_limits<T>::max();
assert(value <= (max_value - (max_value >> 1)), "Overflow");
assert(value <= max_power_of_2<T>(), "Overflow");
if (is_power_of_2(value)) {
return value;
}

30
test/hotspot/gtest/utilities/test_powerOfTwo.cpp

@ -29,11 +29,6 @@
#include <type_traits>
#include "unittest.hpp"
template <typename T> static constexpr T max_pow2() {
T max_val = std::numeric_limits<T>::max();
return max_val - (max_val >> 1);
}
struct StaticTestIsPowerOf2Result {
uint64_t _value;
int _status; // 0: success, > 0 indicates which failure case
@ -60,7 +55,7 @@ static constexpr StaticTestIsPowerOf2Result static_test_is_power_of_2_aux(T v) {
template<typename T>
static void static_test_is_power_of_2() {
constexpr StaticTestIsPowerOf2Result result
= static_test_is_power_of_2_aux(max_pow2<T>());
= static_test_is_power_of_2_aux(max_power_of_2<T>());
EXPECT_EQ(0, result._status)
<< "value = " << result._value << ", status = " << result._status;
@ -78,17 +73,17 @@ template <typename T> static void test_is_power_of_2() {
static_assert(!is_power_of_2(std::numeric_limits<T>::min()), "");
// Test true
for (T i = max_pow2<T>(); i > 0; i = (i >> 1)) {
for (T i = max_power_of_2<T>(); i > 0; i = (i >> 1)) {
EXPECT_TRUE(is_power_of_2(i)) << "value = " << T(i);
}
// Test one less
for (T i = max_pow2<T>(); i > 2; i = (i >> 1)) {
for (T i = max_power_of_2<T>(); i > 2; i = (i >> 1)) {
EXPECT_FALSE(is_power_of_2(i - 1)) << "value = " << T(i - 1);
}
// Test one more
for (T i = max_pow2<T>(); i > 1; i = (i >> 1)) {
for (T i = max_power_of_2<T>(); i > 1; i = (i >> 1)) {
EXPECT_FALSE(is_power_of_2(i + 1)) << "value = " << T(i + 1);
}
@ -140,7 +135,7 @@ template <typename T> void round_up_power_of_2() {
EXPECT_EQ(round_up_power_of_2(T(9)), T(16)) << "value = " << T(9);
EXPECT_EQ(round_up_power_of_2(T(10)), T(16)) << "value = " << T(10);
T t_max_pow2 = max_pow2<T>();
T t_max_pow2 = max_power_of_2<T>();
// round_up(any power of two) should return input
for (T pow2 = T(1); pow2 < t_max_pow2; pow2 *= 2) {
@ -183,7 +178,7 @@ template <typename T> void round_down_power_of_2() {
EXPECT_EQ(round_down_power_of_2(T(9)), T(8)) << "value = " << T(9);
EXPECT_EQ(round_down_power_of_2(T(10)), T(8)) << "value = " << T(10);
T t_max_pow2 = max_pow2<T>();
T t_max_pow2 = max_power_of_2<T>();
// For each pow2 >= 2:
// - round_down(pow2) should return pow2
@ -229,7 +224,7 @@ template <typename T> void next_power_of_2() {
EXPECT_EQ(next_power_of_2(T(9)), T(16)) << "value = " << T(9);
EXPECT_EQ(next_power_of_2(T(10)), T(16)) << "value = " << T(10);
T t_max_pow2 = max_pow2<T>();
T t_max_pow2 = max_power_of_2<T>();
// next(pow2 - 1) should return pow2
for (T pow2 = T(1); pow2 < t_max_pow2; pow2 = pow2 * 2) {
@ -256,3 +251,14 @@ TEST(power_of_2, next_power_of_2) {
next_power_of_2<uint32_t>();
next_power_of_2<uint64_t>();
}
TEST(power_of_2, max) {
EXPECT_EQ(max_power_of_2<int8_t>(), 0x40);
EXPECT_EQ(max_power_of_2<int16_t>(), 0x4000);
EXPECT_EQ(max_power_of_2<int32_t>(), 0x40000000);
EXPECT_EQ(max_power_of_2<int64_t>(), CONST64(0x4000000000000000));
EXPECT_EQ(max_power_of_2<uint8_t>(), 0x80u);
EXPECT_EQ(max_power_of_2<uint16_t>(), 0x8000u);
EXPECT_EQ(max_power_of_2<uint32_t>(), 0x80000000u);
EXPECT_EQ(max_power_of_2<uint64_t>(), UCONST64(0x8000000000000000));
}