1 //===- unittests/Support/MathExtrasTest.cpp - math utils tests ------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "gtest/gtest.h"
11 #include "llvm/Support/MathExtras.h"
12
13 using namespace llvm;
14
15 namespace {
16
TEST(MathExtras,countTrailingZeros)17 TEST(MathExtras, countTrailingZeros) {
18 uint8_t Z8 = 0;
19 uint16_t Z16 = 0;
20 uint32_t Z32 = 0;
21 uint64_t Z64 = 0;
22 EXPECT_EQ(8u, countTrailingZeros(Z8));
23 EXPECT_EQ(16u, countTrailingZeros(Z16));
24 EXPECT_EQ(32u, countTrailingZeros(Z32));
25 EXPECT_EQ(64u, countTrailingZeros(Z64));
26
27 uint8_t NZ8 = 42;
28 uint16_t NZ16 = 42;
29 uint32_t NZ32 = 42;
30 uint64_t NZ64 = 42;
31 EXPECT_EQ(1u, countTrailingZeros(NZ8));
32 EXPECT_EQ(1u, countTrailingZeros(NZ16));
33 EXPECT_EQ(1u, countTrailingZeros(NZ32));
34 EXPECT_EQ(1u, countTrailingZeros(NZ64));
35 }
36
TEST(MathExtras,countLeadingZeros)37 TEST(MathExtras, countLeadingZeros) {
38 uint8_t Z8 = 0;
39 uint16_t Z16 = 0;
40 uint32_t Z32 = 0;
41 uint64_t Z64 = 0;
42 EXPECT_EQ(8u, countLeadingZeros(Z8));
43 EXPECT_EQ(16u, countLeadingZeros(Z16));
44 EXPECT_EQ(32u, countLeadingZeros(Z32));
45 EXPECT_EQ(64u, countLeadingZeros(Z64));
46
47 uint8_t NZ8 = 42;
48 uint16_t NZ16 = 42;
49 uint32_t NZ32 = 42;
50 uint64_t NZ64 = 42;
51 EXPECT_EQ(2u, countLeadingZeros(NZ8));
52 EXPECT_EQ(10u, countLeadingZeros(NZ16));
53 EXPECT_EQ(26u, countLeadingZeros(NZ32));
54 EXPECT_EQ(58u, countLeadingZeros(NZ64));
55
56 EXPECT_EQ(8u, countLeadingZeros(0x00F000FFu));
57 EXPECT_EQ(8u, countLeadingZeros(0x00F12345u));
58 for (unsigned i = 0; i <= 30; ++i) {
59 EXPECT_EQ(31 - i, countLeadingZeros(1u << i));
60 }
61
62 EXPECT_EQ(8u, countLeadingZeros(0x00F1234500F12345ULL));
63 EXPECT_EQ(1u, countLeadingZeros(1ULL << 62));
64 for (unsigned i = 0; i <= 62; ++i) {
65 EXPECT_EQ(63 - i, countLeadingZeros(1ULL << i));
66 }
67 }
68
TEST(MathExtras,findFirstSet)69 TEST(MathExtras, findFirstSet) {
70 uint8_t Z8 = 0;
71 uint16_t Z16 = 0;
72 uint32_t Z32 = 0;
73 uint64_t Z64 = 0;
74 EXPECT_EQ(0xFFULL, findFirstSet(Z8));
75 EXPECT_EQ(0xFFFFULL, findFirstSet(Z16));
76 EXPECT_EQ(0xFFFFFFFFULL, findFirstSet(Z32));
77 EXPECT_EQ(0xFFFFFFFFFFFFFFFFULL, findFirstSet(Z64));
78
79 uint8_t NZ8 = 42;
80 uint16_t NZ16 = 42;
81 uint32_t NZ32 = 42;
82 uint64_t NZ64 = 42;
83 EXPECT_EQ(1u, findFirstSet(NZ8));
84 EXPECT_EQ(1u, findFirstSet(NZ16));
85 EXPECT_EQ(1u, findFirstSet(NZ32));
86 EXPECT_EQ(1u, findFirstSet(NZ64));
87 }
88
TEST(MathExtras,findLastSet)89 TEST(MathExtras, findLastSet) {
90 uint8_t Z8 = 0;
91 uint16_t Z16 = 0;
92 uint32_t Z32 = 0;
93 uint64_t Z64 = 0;
94 EXPECT_EQ(0xFFULL, findLastSet(Z8));
95 EXPECT_EQ(0xFFFFULL, findLastSet(Z16));
96 EXPECT_EQ(0xFFFFFFFFULL, findLastSet(Z32));
97 EXPECT_EQ(0xFFFFFFFFFFFFFFFFULL, findLastSet(Z64));
98
99 uint8_t NZ8 = 42;
100 uint16_t NZ16 = 42;
101 uint32_t NZ32 = 42;
102 uint64_t NZ64 = 42;
103 EXPECT_EQ(5u, findLastSet(NZ8));
104 EXPECT_EQ(5u, findLastSet(NZ16));
105 EXPECT_EQ(5u, findLastSet(NZ32));
106 EXPECT_EQ(5u, findLastSet(NZ64));
107 }
108
TEST(MathExtras,reverseBits)109 TEST(MathExtras, reverseBits) {
110 uint8_t NZ8 = 42;
111 uint16_t NZ16 = 42;
112 uint32_t NZ32 = 42;
113 uint64_t NZ64 = 42;
114 EXPECT_EQ(0x54ULL, reverseBits(NZ8));
115 EXPECT_EQ(0x5400ULL, reverseBits(NZ16));
116 EXPECT_EQ(0x54000000ULL, reverseBits(NZ32));
117 EXPECT_EQ(0x5400000000000000ULL, reverseBits(NZ64));
118 }
119
TEST(MathExtras,isPowerOf2_32)120 TEST(MathExtras, isPowerOf2_32) {
121 EXPECT_TRUE(isPowerOf2_32(1 << 6));
122 EXPECT_TRUE(isPowerOf2_32(1 << 12));
123 EXPECT_FALSE(isPowerOf2_32((1 << 19) + 3));
124 EXPECT_FALSE(isPowerOf2_32(0xABCDEF0));
125 }
126
TEST(MathExtras,isPowerOf2_64)127 TEST(MathExtras, isPowerOf2_64) {
128 EXPECT_TRUE(isPowerOf2_64(1LL << 46));
129 EXPECT_TRUE(isPowerOf2_64(1LL << 12));
130 EXPECT_FALSE(isPowerOf2_64((1LL << 53) + 3));
131 EXPECT_FALSE(isPowerOf2_64(0xABCDEF0ABCDEF0LL));
132 }
133
TEST(MathExtras,ByteSwap_32)134 TEST(MathExtras, ByteSwap_32) {
135 EXPECT_EQ(0x44332211u, ByteSwap_32(0x11223344));
136 EXPECT_EQ(0xDDCCBBAAu, ByteSwap_32(0xAABBCCDD));
137 }
138
TEST(MathExtras,ByteSwap_64)139 TEST(MathExtras, ByteSwap_64) {
140 EXPECT_EQ(0x8877665544332211ULL, ByteSwap_64(0x1122334455667788LL));
141 EXPECT_EQ(0x1100FFEEDDCCBBAAULL, ByteSwap_64(0xAABBCCDDEEFF0011LL));
142 }
143
TEST(MathExtras,countLeadingOnes)144 TEST(MathExtras, countLeadingOnes) {
145 for (int i = 30; i >= 0; --i) {
146 // Start with all ones and unset some bit.
147 EXPECT_EQ(31u - i, countLeadingOnes(0xFFFFFFFF ^ (1 << i)));
148 }
149 for (int i = 62; i >= 0; --i) {
150 // Start with all ones and unset some bit.
151 EXPECT_EQ(63u - i, countLeadingOnes(0xFFFFFFFFFFFFFFFFULL ^ (1LL << i)));
152 }
153 for (int i = 30; i >= 0; --i) {
154 // Start with all ones and unset some bit.
155 EXPECT_EQ(31u - i, countLeadingOnes(0xFFFFFFFF ^ (1 << i)));
156 }
157 }
158
TEST(MathExtras,FloatBits)159 TEST(MathExtras, FloatBits) {
160 static const float kValue = 5632.34f;
161 EXPECT_FLOAT_EQ(kValue, BitsToFloat(FloatToBits(kValue)));
162 }
163
TEST(MathExtras,DoubleBits)164 TEST(MathExtras, DoubleBits) {
165 static const double kValue = 87987234.983498;
166 EXPECT_FLOAT_EQ(kValue, BitsToDouble(DoubleToBits(kValue)));
167 }
168
TEST(MathExtras,MinAlign)169 TEST(MathExtras, MinAlign) {
170 EXPECT_EQ(1u, MinAlign(2, 3));
171 EXPECT_EQ(2u, MinAlign(2, 4));
172 EXPECT_EQ(1u, MinAlign(17, 64));
173 EXPECT_EQ(256u, MinAlign(256, 512));
174 }
175
TEST(MathExtras,NextPowerOf2)176 TEST(MathExtras, NextPowerOf2) {
177 EXPECT_EQ(4u, NextPowerOf2(3));
178 EXPECT_EQ(16u, NextPowerOf2(15));
179 EXPECT_EQ(256u, NextPowerOf2(128));
180 }
181
TEST(MathExtras,RoundUpToAlignment)182 TEST(MathExtras, RoundUpToAlignment) {
183 EXPECT_EQ(8u, RoundUpToAlignment(5, 8));
184 EXPECT_EQ(24u, RoundUpToAlignment(17, 8));
185 EXPECT_EQ(0u, RoundUpToAlignment(~0LL, 8));
186
187 EXPECT_EQ(7u, RoundUpToAlignment(5, 8, 7));
188 EXPECT_EQ(17u, RoundUpToAlignment(17, 8, 1));
189 EXPECT_EQ(3u, RoundUpToAlignment(~0LL, 8, 3));
190 EXPECT_EQ(552u, RoundUpToAlignment(321, 255, 42));
191 }
192
193 template<typename T>
SaturatingAddTestHelper()194 void SaturatingAddTestHelper()
195 {
196 const T Max = std::numeric_limits<T>::max();
197 bool ResultOverflowed;
198
199 EXPECT_EQ(T(3), SaturatingAdd(T(1), T(2)));
200 EXPECT_EQ(T(3), SaturatingAdd(T(1), T(2), &ResultOverflowed));
201 EXPECT_FALSE(ResultOverflowed);
202
203 EXPECT_EQ(Max, SaturatingAdd(Max, T(1)));
204 EXPECT_EQ(Max, SaturatingAdd(Max, T(1), &ResultOverflowed));
205 EXPECT_TRUE(ResultOverflowed);
206
207 EXPECT_EQ(Max, SaturatingAdd(T(1), T(Max - 1)));
208 EXPECT_EQ(Max, SaturatingAdd(T(1), T(Max - 1), &ResultOverflowed));
209 EXPECT_FALSE(ResultOverflowed);
210
211 EXPECT_EQ(Max, SaturatingAdd(T(1), Max));
212 EXPECT_EQ(Max, SaturatingAdd(T(1), Max, &ResultOverflowed));
213 EXPECT_TRUE(ResultOverflowed);
214
215 EXPECT_EQ(Max, SaturatingAdd(Max, Max));
216 EXPECT_EQ(Max, SaturatingAdd(Max, Max, &ResultOverflowed));
217 EXPECT_TRUE(ResultOverflowed);
218 }
219
TEST(MathExtras,SaturatingAdd)220 TEST(MathExtras, SaturatingAdd) {
221 SaturatingAddTestHelper<uint8_t>();
222 SaturatingAddTestHelper<uint16_t>();
223 SaturatingAddTestHelper<uint32_t>();
224 SaturatingAddTestHelper<uint64_t>();
225 }
226
227 template<typename T>
SaturatingMultiplyTestHelper()228 void SaturatingMultiplyTestHelper()
229 {
230 const T Max = std::numeric_limits<T>::max();
231 bool ResultOverflowed;
232
233 // Test basic multiplication.
234 EXPECT_EQ(T(6), SaturatingMultiply(T(2), T(3)));
235 EXPECT_EQ(T(6), SaturatingMultiply(T(2), T(3), &ResultOverflowed));
236 EXPECT_FALSE(ResultOverflowed);
237
238 EXPECT_EQ(T(6), SaturatingMultiply(T(3), T(2)));
239 EXPECT_EQ(T(6), SaturatingMultiply(T(3), T(2), &ResultOverflowed));
240 EXPECT_FALSE(ResultOverflowed);
241
242 // Test multiplication by zero.
243 EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(0)));
244 EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(0), &ResultOverflowed));
245 EXPECT_FALSE(ResultOverflowed);
246
247 EXPECT_EQ(T(0), SaturatingMultiply(T(1), T(0)));
248 EXPECT_EQ(T(0), SaturatingMultiply(T(1), T(0), &ResultOverflowed));
249 EXPECT_FALSE(ResultOverflowed);
250
251 EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(1)));
252 EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(1), &ResultOverflowed));
253 EXPECT_FALSE(ResultOverflowed);
254
255 EXPECT_EQ(T(0), SaturatingMultiply(Max, T(0)));
256 EXPECT_EQ(T(0), SaturatingMultiply(Max, T(0), &ResultOverflowed));
257 EXPECT_FALSE(ResultOverflowed);
258
259 EXPECT_EQ(T(0), SaturatingMultiply(T(0), Max));
260 EXPECT_EQ(T(0), SaturatingMultiply(T(0), Max, &ResultOverflowed));
261 EXPECT_FALSE(ResultOverflowed);
262
263 // Test multiplication by maximum value.
264 EXPECT_EQ(Max, SaturatingMultiply(Max, T(2)));
265 EXPECT_EQ(Max, SaturatingMultiply(Max, T(2), &ResultOverflowed));
266 EXPECT_TRUE(ResultOverflowed);
267
268 EXPECT_EQ(Max, SaturatingMultiply(T(2), Max));
269 EXPECT_EQ(Max, SaturatingMultiply(T(2), Max, &ResultOverflowed));
270 EXPECT_TRUE(ResultOverflowed);
271
272 EXPECT_EQ(Max, SaturatingMultiply(Max, Max));
273 EXPECT_EQ(Max, SaturatingMultiply(Max, Max, &ResultOverflowed));
274 EXPECT_TRUE(ResultOverflowed);
275
276 // Test interesting boundary conditions for algorithm -
277 // ((1 << A) - 1) * ((1 << B) + K) for K in [-1, 0, 1]
278 // and A + B == std::numeric_limits<T>::digits.
279 // We expect overflow iff A > B and K = 1.
280 const int Digits = std::numeric_limits<T>::digits;
281 for (int A = 1, B = Digits - 1; B >= 1; ++A, --B) {
282 for (int K = -1; K <= 1; ++K) {
283 T X = (T(1) << A) - T(1);
284 T Y = (T(1) << B) + K;
285 bool OverflowExpected = A > B && K == 1;
286
287 if(OverflowExpected) {
288 EXPECT_EQ(Max, SaturatingMultiply(X, Y));
289 EXPECT_EQ(Max, SaturatingMultiply(X, Y, &ResultOverflowed));
290 EXPECT_TRUE(ResultOverflowed);
291 } else {
292 EXPECT_EQ(X * Y, SaturatingMultiply(X, Y));
293 EXPECT_EQ(X * Y, SaturatingMultiply(X, Y, &ResultOverflowed));
294 EXPECT_FALSE(ResultOverflowed);
295 }
296 }
297 }
298 }
299
TEST(MathExtras,SaturatingMultiply)300 TEST(MathExtras, SaturatingMultiply) {
301 SaturatingMultiplyTestHelper<uint8_t>();
302 SaturatingMultiplyTestHelper<uint16_t>();
303 SaturatingMultiplyTestHelper<uint32_t>();
304 SaturatingMultiplyTestHelper<uint64_t>();
305 }
306
307 }
308