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https://github.com/RPCS3/llvm-mirror.git
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3b35892e68
Summary: Improve SaturatingAdd()/SaturatingMultiply() to use bool * to optionally return overflow result. This should make it clearer that the value is returned at callsites and reduces the size of the implementation. Reviewers: davidxl, silvas Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D15219 llvm-svn: 255128
308 lines
9.2 KiB
C++
308 lines
9.2 KiB
C++
//===- unittests/Support/MathExtrasTest.cpp - math utils tests ------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "gtest/gtest.h"
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#include "llvm/Support/MathExtras.h"
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using namespace llvm;
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namespace {
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TEST(MathExtras, countTrailingZeros) {
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uint8_t Z8 = 0;
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uint16_t Z16 = 0;
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uint32_t Z32 = 0;
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uint64_t Z64 = 0;
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EXPECT_EQ(8u, countTrailingZeros(Z8));
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EXPECT_EQ(16u, countTrailingZeros(Z16));
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EXPECT_EQ(32u, countTrailingZeros(Z32));
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EXPECT_EQ(64u, countTrailingZeros(Z64));
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uint8_t NZ8 = 42;
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uint16_t NZ16 = 42;
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uint32_t NZ32 = 42;
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uint64_t NZ64 = 42;
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EXPECT_EQ(1u, countTrailingZeros(NZ8));
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EXPECT_EQ(1u, countTrailingZeros(NZ16));
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EXPECT_EQ(1u, countTrailingZeros(NZ32));
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EXPECT_EQ(1u, countTrailingZeros(NZ64));
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}
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TEST(MathExtras, countLeadingZeros) {
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uint8_t Z8 = 0;
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uint16_t Z16 = 0;
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uint32_t Z32 = 0;
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uint64_t Z64 = 0;
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EXPECT_EQ(8u, countLeadingZeros(Z8));
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EXPECT_EQ(16u, countLeadingZeros(Z16));
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EXPECT_EQ(32u, countLeadingZeros(Z32));
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EXPECT_EQ(64u, countLeadingZeros(Z64));
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uint8_t NZ8 = 42;
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uint16_t NZ16 = 42;
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uint32_t NZ32 = 42;
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uint64_t NZ64 = 42;
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EXPECT_EQ(2u, countLeadingZeros(NZ8));
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EXPECT_EQ(10u, countLeadingZeros(NZ16));
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EXPECT_EQ(26u, countLeadingZeros(NZ32));
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EXPECT_EQ(58u, countLeadingZeros(NZ64));
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EXPECT_EQ(8u, countLeadingZeros(0x00F000FFu));
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EXPECT_EQ(8u, countLeadingZeros(0x00F12345u));
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for (unsigned i = 0; i <= 30; ++i) {
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EXPECT_EQ(31 - i, countLeadingZeros(1u << i));
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}
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EXPECT_EQ(8u, countLeadingZeros(0x00F1234500F12345ULL));
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EXPECT_EQ(1u, countLeadingZeros(1ULL << 62));
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for (unsigned i = 0; i <= 62; ++i) {
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EXPECT_EQ(63 - i, countLeadingZeros(1ULL << i));
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}
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}
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TEST(MathExtras, findFirstSet) {
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uint8_t Z8 = 0;
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uint16_t Z16 = 0;
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uint32_t Z32 = 0;
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uint64_t Z64 = 0;
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EXPECT_EQ(0xFFULL, findFirstSet(Z8));
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EXPECT_EQ(0xFFFFULL, findFirstSet(Z16));
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EXPECT_EQ(0xFFFFFFFFULL, findFirstSet(Z32));
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EXPECT_EQ(0xFFFFFFFFFFFFFFFFULL, findFirstSet(Z64));
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uint8_t NZ8 = 42;
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uint16_t NZ16 = 42;
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uint32_t NZ32 = 42;
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uint64_t NZ64 = 42;
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EXPECT_EQ(1u, findFirstSet(NZ8));
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EXPECT_EQ(1u, findFirstSet(NZ16));
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EXPECT_EQ(1u, findFirstSet(NZ32));
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EXPECT_EQ(1u, findFirstSet(NZ64));
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}
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TEST(MathExtras, findLastSet) {
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uint8_t Z8 = 0;
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uint16_t Z16 = 0;
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uint32_t Z32 = 0;
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uint64_t Z64 = 0;
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EXPECT_EQ(0xFFULL, findLastSet(Z8));
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EXPECT_EQ(0xFFFFULL, findLastSet(Z16));
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EXPECT_EQ(0xFFFFFFFFULL, findLastSet(Z32));
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EXPECT_EQ(0xFFFFFFFFFFFFFFFFULL, findLastSet(Z64));
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uint8_t NZ8 = 42;
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uint16_t NZ16 = 42;
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uint32_t NZ32 = 42;
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uint64_t NZ64 = 42;
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EXPECT_EQ(5u, findLastSet(NZ8));
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EXPECT_EQ(5u, findLastSet(NZ16));
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EXPECT_EQ(5u, findLastSet(NZ32));
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EXPECT_EQ(5u, findLastSet(NZ64));
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}
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TEST(MathExtras, reverseBits) {
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uint8_t NZ8 = 42;
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uint16_t NZ16 = 42;
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uint32_t NZ32 = 42;
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uint64_t NZ64 = 42;
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EXPECT_EQ(0x54ULL, reverseBits(NZ8));
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EXPECT_EQ(0x5400ULL, reverseBits(NZ16));
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EXPECT_EQ(0x54000000ULL, reverseBits(NZ32));
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EXPECT_EQ(0x5400000000000000ULL, reverseBits(NZ64));
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}
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TEST(MathExtras, isPowerOf2_32) {
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EXPECT_TRUE(isPowerOf2_32(1 << 6));
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EXPECT_TRUE(isPowerOf2_32(1 << 12));
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EXPECT_FALSE(isPowerOf2_32((1 << 19) + 3));
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EXPECT_FALSE(isPowerOf2_32(0xABCDEF0));
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}
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TEST(MathExtras, isPowerOf2_64) {
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EXPECT_TRUE(isPowerOf2_64(1LL << 46));
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EXPECT_TRUE(isPowerOf2_64(1LL << 12));
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EXPECT_FALSE(isPowerOf2_64((1LL << 53) + 3));
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EXPECT_FALSE(isPowerOf2_64(0xABCDEF0ABCDEF0LL));
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}
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TEST(MathExtras, ByteSwap_32) {
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EXPECT_EQ(0x44332211u, ByteSwap_32(0x11223344));
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EXPECT_EQ(0xDDCCBBAAu, ByteSwap_32(0xAABBCCDD));
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}
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TEST(MathExtras, ByteSwap_64) {
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EXPECT_EQ(0x8877665544332211ULL, ByteSwap_64(0x1122334455667788LL));
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EXPECT_EQ(0x1100FFEEDDCCBBAAULL, ByteSwap_64(0xAABBCCDDEEFF0011LL));
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}
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TEST(MathExtras, countLeadingOnes) {
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for (int i = 30; i >= 0; --i) {
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// Start with all ones and unset some bit.
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EXPECT_EQ(31u - i, countLeadingOnes(0xFFFFFFFF ^ (1 << i)));
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}
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for (int i = 62; i >= 0; --i) {
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// Start with all ones and unset some bit.
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EXPECT_EQ(63u - i, countLeadingOnes(0xFFFFFFFFFFFFFFFFULL ^ (1LL << i)));
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}
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for (int i = 30; i >= 0; --i) {
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// Start with all ones and unset some bit.
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EXPECT_EQ(31u - i, countLeadingOnes(0xFFFFFFFF ^ (1 << i)));
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}
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}
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TEST(MathExtras, FloatBits) {
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static const float kValue = 5632.34f;
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EXPECT_FLOAT_EQ(kValue, BitsToFloat(FloatToBits(kValue)));
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}
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TEST(MathExtras, DoubleBits) {
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static const double kValue = 87987234.983498;
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EXPECT_FLOAT_EQ(kValue, BitsToDouble(DoubleToBits(kValue)));
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}
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TEST(MathExtras, MinAlign) {
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EXPECT_EQ(1u, MinAlign(2, 3));
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EXPECT_EQ(2u, MinAlign(2, 4));
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EXPECT_EQ(1u, MinAlign(17, 64));
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EXPECT_EQ(256u, MinAlign(256, 512));
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}
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TEST(MathExtras, NextPowerOf2) {
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EXPECT_EQ(4u, NextPowerOf2(3));
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EXPECT_EQ(16u, NextPowerOf2(15));
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EXPECT_EQ(256u, NextPowerOf2(128));
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}
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TEST(MathExtras, RoundUpToAlignment) {
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EXPECT_EQ(8u, RoundUpToAlignment(5, 8));
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EXPECT_EQ(24u, RoundUpToAlignment(17, 8));
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EXPECT_EQ(0u, RoundUpToAlignment(~0LL, 8));
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EXPECT_EQ(7u, RoundUpToAlignment(5, 8, 7));
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EXPECT_EQ(17u, RoundUpToAlignment(17, 8, 1));
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EXPECT_EQ(3u, RoundUpToAlignment(~0LL, 8, 3));
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EXPECT_EQ(552u, RoundUpToAlignment(321, 255, 42));
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}
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template<typename T>
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void SaturatingAddTestHelper()
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{
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const T Max = std::numeric_limits<T>::max();
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bool ResultOverflowed;
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EXPECT_EQ(T(3), SaturatingAdd(T(1), T(2)));
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EXPECT_EQ(T(3), SaturatingAdd(T(1), T(2), &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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EXPECT_EQ(Max, SaturatingAdd(Max, T(1)));
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EXPECT_EQ(Max, SaturatingAdd(Max, T(1), &ResultOverflowed));
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EXPECT_TRUE(ResultOverflowed);
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EXPECT_EQ(Max, SaturatingAdd(T(1), T(Max - 1)));
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EXPECT_EQ(Max, SaturatingAdd(T(1), T(Max - 1), &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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EXPECT_EQ(Max, SaturatingAdd(T(1), Max));
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EXPECT_EQ(Max, SaturatingAdd(T(1), Max, &ResultOverflowed));
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EXPECT_TRUE(ResultOverflowed);
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EXPECT_EQ(Max, SaturatingAdd(Max, Max));
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EXPECT_EQ(Max, SaturatingAdd(Max, Max, &ResultOverflowed));
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EXPECT_TRUE(ResultOverflowed);
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}
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TEST(MathExtras, SaturatingAdd) {
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SaturatingAddTestHelper<uint8_t>();
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SaturatingAddTestHelper<uint16_t>();
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SaturatingAddTestHelper<uint32_t>();
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SaturatingAddTestHelper<uint64_t>();
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}
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template<typename T>
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void SaturatingMultiplyTestHelper()
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{
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const T Max = std::numeric_limits<T>::max();
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bool ResultOverflowed;
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// Test basic multiplication.
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EXPECT_EQ(T(6), SaturatingMultiply(T(2), T(3)));
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EXPECT_EQ(T(6), SaturatingMultiply(T(2), T(3), &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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EXPECT_EQ(T(6), SaturatingMultiply(T(3), T(2)));
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EXPECT_EQ(T(6), SaturatingMultiply(T(3), T(2), &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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// Test multiplication by zero.
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EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(0)));
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EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(0), &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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EXPECT_EQ(T(0), SaturatingMultiply(T(1), T(0)));
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EXPECT_EQ(T(0), SaturatingMultiply(T(1), T(0), &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(1)));
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EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(1), &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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EXPECT_EQ(T(0), SaturatingMultiply(Max, T(0)));
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EXPECT_EQ(T(0), SaturatingMultiply(Max, T(0), &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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EXPECT_EQ(T(0), SaturatingMultiply(T(0), Max));
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EXPECT_EQ(T(0), SaturatingMultiply(T(0), Max, &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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// Test multiplication by maximum value.
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EXPECT_EQ(Max, SaturatingMultiply(Max, T(2)));
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EXPECT_EQ(Max, SaturatingMultiply(Max, T(2), &ResultOverflowed));
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EXPECT_TRUE(ResultOverflowed);
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EXPECT_EQ(Max, SaturatingMultiply(T(2), Max));
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EXPECT_EQ(Max, SaturatingMultiply(T(2), Max, &ResultOverflowed));
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EXPECT_TRUE(ResultOverflowed);
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EXPECT_EQ(Max, SaturatingMultiply(Max, Max));
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EXPECT_EQ(Max, SaturatingMultiply(Max, Max, &ResultOverflowed));
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EXPECT_TRUE(ResultOverflowed);
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// Test interesting boundary conditions for algorithm -
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// ((1 << A) - 1) * ((1 << B) + K) for K in [-1, 0, 1]
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// and A + B == std::numeric_limits<T>::digits.
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// We expect overflow iff A > B and K = 1.
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const int Digits = std::numeric_limits<T>::digits;
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for (int A = 1, B = Digits - 1; B >= 1; ++A, --B) {
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for (int K = -1; K <= 1; ++K) {
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T X = (T(1) << A) - T(1);
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T Y = (T(1) << B) + K;
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bool OverflowExpected = A > B && K == 1;
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if(OverflowExpected) {
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EXPECT_EQ(Max, SaturatingMultiply(X, Y));
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EXPECT_EQ(Max, SaturatingMultiply(X, Y, &ResultOverflowed));
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EXPECT_TRUE(ResultOverflowed);
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} else {
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EXPECT_EQ(X * Y, SaturatingMultiply(X, Y));
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EXPECT_EQ(X * Y, SaturatingMultiply(X, Y, &ResultOverflowed));
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EXPECT_FALSE(ResultOverflowed);
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}
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}
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}
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}
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TEST(MathExtras, SaturatingMultiply) {
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SaturatingMultiplyTestHelper<uint8_t>();
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SaturatingMultiplyTestHelper<uint16_t>();
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SaturatingMultiplyTestHelper<uint32_t>();
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SaturatingMultiplyTestHelper<uint64_t>();
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}
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}
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