xref: /llvm-project/llvm/unittests/Support/MathExtrasTest.cpp (revision ec116ea684b43aadfdda03cea2c2a86423e3fc27)
1 //===- unittests/Support/MathExtrasTest.cpp - math utils tests ------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/Support/MathExtras.h"
10 #include "gtest/gtest.h"
11 
12 using namespace llvm;
13 
14 namespace {
15 
16 TEST(MathExtras, onesMask) {
17   EXPECT_EQ(0U, maskLeadingOnes<uint8_t>(0));
18   EXPECT_EQ(0U, maskTrailingOnes<uint8_t>(0));
19   EXPECT_EQ(0U, maskLeadingOnes<uint16_t>(0));
20   EXPECT_EQ(0U, maskTrailingOnes<uint16_t>(0));
21   EXPECT_EQ(0U, maskLeadingOnes<uint32_t>(0));
22   EXPECT_EQ(0U, maskTrailingOnes<uint32_t>(0));
23   EXPECT_EQ(0U, maskLeadingOnes<uint64_t>(0));
24   EXPECT_EQ(0U, maskTrailingOnes<uint64_t>(0));
25 
26   EXPECT_EQ(0x00000003U, maskTrailingOnes<uint32_t>(2U));
27   EXPECT_EQ(0xC0000000U, maskLeadingOnes<uint32_t>(2U));
28 
29   EXPECT_EQ(0x000007FFU, maskTrailingOnes<uint32_t>(11U));
30   EXPECT_EQ(0xFFE00000U, maskLeadingOnes<uint32_t>(11U));
31 
32   EXPECT_EQ(0xFFFFFFFFU, maskTrailingOnes<uint32_t>(32U));
33   EXPECT_EQ(0xFFFFFFFFU, maskLeadingOnes<uint32_t>(32U));
34   EXPECT_EQ(0xFFFFFFFFFFFFFFFFULL, maskTrailingOnes<uint64_t>(64U));
35   EXPECT_EQ(0xFFFFFFFFFFFFFFFFULL, maskLeadingOnes<uint64_t>(64U));
36 
37   EXPECT_EQ(0x0000FFFFFFFFFFFFULL, maskTrailingOnes<uint64_t>(48U));
38   EXPECT_EQ(0xFFFFFFFFFFFF0000ULL, maskLeadingOnes<uint64_t>(48U));
39 }
40 
41 TEST(MathExtras, isIntN) {
42   EXPECT_TRUE(isIntN(16, 32767));
43   EXPECT_FALSE(isIntN(16, 32768));
44 }
45 
46 TEST(MathExtras, isUIntN) {
47   EXPECT_TRUE(isUIntN(16, 65535));
48   EXPECT_FALSE(isUIntN(16, 65536));
49   EXPECT_TRUE(isUIntN(1, 0));
50   EXPECT_TRUE(isUIntN(6, 63));
51 }
52 
53 TEST(MathExtras, maxIntN) {
54   EXPECT_EQ(32767, maxIntN(16));
55   EXPECT_EQ(2147483647, maxIntN(32));
56   EXPECT_EQ(std::numeric_limits<int32_t>::max(), maxIntN(32));
57   EXPECT_EQ(std::numeric_limits<int64_t>::max(), maxIntN(64));
58 }
59 
60 TEST(MathExtras, minIntN) {
61   EXPECT_EQ(-32768LL, minIntN(16));
62   EXPECT_EQ(-64LL, minIntN(7));
63   EXPECT_EQ(std::numeric_limits<int32_t>::min(), minIntN(32));
64   EXPECT_EQ(std::numeric_limits<int64_t>::min(), minIntN(64));
65 }
66 
67 TEST(MathExtras, maxUIntN) {
68   EXPECT_EQ(0xffffULL, maxUIntN(16));
69   EXPECT_EQ(0xffffffffULL, maxUIntN(32));
70   EXPECT_EQ(0xffffffffffffffffULL, maxUIntN(64));
71   EXPECT_EQ(1ULL, maxUIntN(1));
72   EXPECT_EQ(0x0fULL, maxUIntN(4));
73 }
74 
75 TEST(MathExtras, reverseBits) {
76   uint8_t NZ8 = 42;
77   uint16_t NZ16 = 42;
78   uint32_t NZ32 = 42;
79   uint64_t NZ64 = 42;
80   EXPECT_EQ(0x54ULL, reverseBits(NZ8));
81   EXPECT_EQ(0x5400ULL, reverseBits(NZ16));
82   EXPECT_EQ(0x54000000ULL, reverseBits(NZ32));
83   EXPECT_EQ(0x5400000000000000ULL, reverseBits(NZ64));
84 }
85 
86 TEST(MathExtras, isShiftedMask_32) {
87   EXPECT_FALSE(isShiftedMask_32(0x01010101));
88   EXPECT_TRUE(isShiftedMask_32(0xf0000000));
89   EXPECT_TRUE(isShiftedMask_32(0xffff0000));
90   EXPECT_TRUE(isShiftedMask_32(0xff << 1));
91 
92   unsigned MaskIdx, MaskLen;
93   EXPECT_FALSE(isShiftedMask_32(0x01010101, MaskIdx, MaskLen));
94   EXPECT_TRUE(isShiftedMask_32(0xf0000000, MaskIdx, MaskLen));
95   EXPECT_EQ(28, (int)MaskIdx);
96   EXPECT_EQ(4, (int)MaskLen);
97   EXPECT_TRUE(isShiftedMask_32(0xffff0000, MaskIdx, MaskLen));
98   EXPECT_EQ(16, (int)MaskIdx);
99   EXPECT_EQ(16, (int)MaskLen);
100   EXPECT_TRUE(isShiftedMask_32(0xff << 1, MaskIdx, MaskLen));
101   EXPECT_EQ(1, (int)MaskIdx);
102   EXPECT_EQ(8, (int)MaskLen);
103 }
104 
105 TEST(MathExtras, isShiftedMask_64) {
106   EXPECT_FALSE(isShiftedMask_64(0x0101010101010101ull));
107   EXPECT_TRUE(isShiftedMask_64(0xf000000000000000ull));
108   EXPECT_TRUE(isShiftedMask_64(0xffff000000000000ull));
109   EXPECT_TRUE(isShiftedMask_64(0xffull << 55));
110 
111   unsigned MaskIdx, MaskLen;
112   EXPECT_FALSE(isShiftedMask_64(0x0101010101010101ull, MaskIdx, MaskLen));
113   EXPECT_TRUE(isShiftedMask_64(0xf000000000000000ull, MaskIdx, MaskLen));
114   EXPECT_EQ(60, (int)MaskIdx);
115   EXPECT_EQ(4, (int)MaskLen);
116   EXPECT_TRUE(isShiftedMask_64(0xffff000000000000ull, MaskIdx, MaskLen));
117   EXPECT_EQ(48, (int)MaskIdx);
118   EXPECT_EQ(16, (int)MaskLen);
119   EXPECT_TRUE(isShiftedMask_64(0xffull << 55, MaskIdx, MaskLen));
120   EXPECT_EQ(55, (int)MaskIdx);
121   EXPECT_EQ(8, (int)MaskLen);
122 }
123 
124 TEST(MathExtras, isPowerOf2_32) {
125   EXPECT_FALSE(isPowerOf2_32(0));
126   EXPECT_TRUE(isPowerOf2_32(1 << 6));
127   EXPECT_TRUE(isPowerOf2_32(1 << 12));
128   EXPECT_FALSE(isPowerOf2_32((1 << 19) + 3));
129   EXPECT_FALSE(isPowerOf2_32(0xABCDEF0));
130 }
131 
132 TEST(MathExtras, isPowerOf2_64) {
133   EXPECT_FALSE(isPowerOf2_64(0));
134   EXPECT_TRUE(isPowerOf2_64(1LL << 46));
135   EXPECT_TRUE(isPowerOf2_64(1LL << 12));
136   EXPECT_FALSE(isPowerOf2_64((1LL << 53) + 3));
137   EXPECT_FALSE(isPowerOf2_64(0xABCDEF0ABCDEF0LL));
138 }
139 
140 TEST(MathExtras, PowerOf2Ceil) {
141   EXPECT_EQ(0U, PowerOf2Ceil(0U));
142   EXPECT_EQ(8U, PowerOf2Ceil(8U));
143   EXPECT_EQ(8U, PowerOf2Ceil(7U));
144 }
145 
146 TEST(MathExtras, PowerOf2Floor) {
147   EXPECT_EQ(0U, PowerOf2Floor(0U));
148   EXPECT_EQ(8U, PowerOf2Floor(8U));
149   EXPECT_EQ(4U, PowerOf2Floor(7U));
150 }
151 
152 TEST(MathExtras, CTLog2) {
153   EXPECT_EQ(CTLog2<1ULL << 0>(), 0U);
154   EXPECT_EQ(CTLog2<1ULL << 1>(), 1U);
155   EXPECT_EQ(CTLog2<1ULL << 2>(), 2U);
156   EXPECT_EQ(CTLog2<1ULL << 3>(), 3U);
157   EXPECT_EQ(CTLog2<1ULL << 4>(), 4U);
158   EXPECT_EQ(CTLog2<1ULL << 5>(), 5U);
159   EXPECT_EQ(CTLog2<1ULL << 6>(), 6U);
160   EXPECT_EQ(CTLog2<1ULL << 7>(), 7U);
161   EXPECT_EQ(CTLog2<1ULL << 8>(), 8U);
162   EXPECT_EQ(CTLog2<1ULL << 9>(), 9U);
163   EXPECT_EQ(CTLog2<1ULL << 10>(), 10U);
164   EXPECT_EQ(CTLog2<1ULL << 11>(), 11U);
165   EXPECT_EQ(CTLog2<1ULL << 12>(), 12U);
166   EXPECT_EQ(CTLog2<1ULL << 13>(), 13U);
167   EXPECT_EQ(CTLog2<1ULL << 14>(), 14U);
168   EXPECT_EQ(CTLog2<1ULL << 15>(), 15U);
169 }
170 
171 TEST(MathExtras, FloatBits) {
172   static const float kValue = 5632.34f;
173   EXPECT_FLOAT_EQ(kValue, BitsToFloat(FloatToBits(kValue)));
174 }
175 
176 TEST(MathExtras, DoubleBits) {
177   static const double kValue = 87987234.983498;
178   EXPECT_DOUBLE_EQ(kValue, BitsToDouble(DoubleToBits(kValue)));
179 }
180 
181 TEST(MathExtras, MinAlign) {
182   EXPECT_EQ(1u, MinAlign(2, 3));
183   EXPECT_EQ(2u, MinAlign(2, 4));
184   EXPECT_EQ(1u, MinAlign(17, 64));
185   EXPECT_EQ(256u, MinAlign(256, 512));
186 }
187 
188 TEST(MathExtras, NextPowerOf2) {
189   EXPECT_EQ(4u, NextPowerOf2(3));
190   EXPECT_EQ(16u, NextPowerOf2(15));
191   EXPECT_EQ(256u, NextPowerOf2(128));
192 }
193 
194 TEST(MathExtras, alignTo) {
195   EXPECT_EQ(8u, alignTo(5, 8));
196   EXPECT_EQ(24u, alignTo(17, 8));
197   EXPECT_EQ(0u, alignTo(~0LL, 8));
198 
199   EXPECT_EQ(7u, alignTo(5, 8, 7));
200   EXPECT_EQ(17u, alignTo(17, 8, 1));
201   EXPECT_EQ(3u, alignTo(~0LL, 8, 3));
202   EXPECT_EQ(552u, alignTo(321, 255, 42));
203 }
204 
205 template <typename T> void SaturatingAddTestHelper() {
206   const T Max = std::numeric_limits<T>::max();
207   bool ResultOverflowed;
208 
209   EXPECT_EQ(T(3), SaturatingAdd(T(1), T(2)));
210   EXPECT_EQ(T(3), SaturatingAdd(T(1), T(2), &ResultOverflowed));
211   EXPECT_FALSE(ResultOverflowed);
212 
213   EXPECT_EQ(Max, SaturatingAdd(Max, T(1)));
214   EXPECT_EQ(Max, SaturatingAdd(Max, T(1), &ResultOverflowed));
215   EXPECT_TRUE(ResultOverflowed);
216 
217   EXPECT_EQ(Max, SaturatingAdd(T(1), T(Max - 1)));
218   EXPECT_EQ(Max, SaturatingAdd(T(1), T(Max - 1), &ResultOverflowed));
219   EXPECT_FALSE(ResultOverflowed);
220 
221   EXPECT_EQ(Max, SaturatingAdd(T(1), Max));
222   EXPECT_EQ(Max, SaturatingAdd(T(1), Max, &ResultOverflowed));
223   EXPECT_TRUE(ResultOverflowed);
224 
225   EXPECT_EQ(Max, SaturatingAdd(Max, Max));
226   EXPECT_EQ(Max, SaturatingAdd(Max, Max, &ResultOverflowed));
227   EXPECT_TRUE(ResultOverflowed);
228 
229   EXPECT_EQ(T(6), SaturatingAdd(T(1), T(2), T(3)));
230   EXPECT_EQ(T(6), SaturatingAdd(T(1), T(2), T(3), &ResultOverflowed));
231   EXPECT_FALSE(ResultOverflowed);
232 
233   EXPECT_EQ(T(10), SaturatingAdd(T(1), T(2), T(3), T(4)));
234   EXPECT_EQ(T(10), SaturatingAdd(T(1), T(2), T(3), T(4), &ResultOverflowed));
235   EXPECT_FALSE(ResultOverflowed);
236 
237   EXPECT_EQ(Max, SaturatingAdd(Max, T(0), T(0)));
238   EXPECT_EQ(Max, SaturatingAdd(Max, T(0), T(0), &ResultOverflowed));
239   EXPECT_FALSE(ResultOverflowed);
240 
241   EXPECT_EQ(Max, SaturatingAdd(T(0), T(0), Max));
242   EXPECT_EQ(Max, SaturatingAdd(T(0), T(0), Max, &ResultOverflowed));
243   EXPECT_FALSE(ResultOverflowed);
244 
245   EXPECT_EQ(Max, SaturatingAdd(Max, T(0), T(1)));
246   EXPECT_EQ(Max, SaturatingAdd(Max, T(0), T(1), &ResultOverflowed));
247   EXPECT_TRUE(ResultOverflowed);
248 
249   EXPECT_EQ(Max, SaturatingAdd(T(0), T(1), Max));
250   EXPECT_EQ(Max, SaturatingAdd(T(0), T(1), Max, &ResultOverflowed));
251   EXPECT_TRUE(ResultOverflowed);
252 
253   EXPECT_EQ(Max, SaturatingAdd(T(1), T(Max - 2), T(1)));
254   EXPECT_EQ(Max, SaturatingAdd(T(1), T(Max - 2), T(1), &ResultOverflowed));
255   EXPECT_FALSE(ResultOverflowed);
256 
257   EXPECT_EQ(Max, SaturatingAdd(T(1), T(1), T(Max - 2)));
258   EXPECT_EQ(Max, SaturatingAdd(T(1), T(1), T(Max - 2), &ResultOverflowed));
259   EXPECT_FALSE(ResultOverflowed);
260 
261   EXPECT_EQ(Max, SaturatingAdd(Max, Max, Max));
262   EXPECT_EQ(Max, SaturatingAdd(Max, Max, Max, &ResultOverflowed));
263   EXPECT_TRUE(ResultOverflowed);
264 }
265 
266 TEST(MathExtras, SaturatingAdd) {
267   SaturatingAddTestHelper<uint8_t>();
268   SaturatingAddTestHelper<uint16_t>();
269   SaturatingAddTestHelper<uint32_t>();
270   SaturatingAddTestHelper<uint64_t>();
271 }
272 
273 template<typename T>
274 void SaturatingMultiplyTestHelper()
275 {
276   const T Max = std::numeric_limits<T>::max();
277   bool ResultOverflowed;
278 
279   // Test basic multiplication.
280   EXPECT_EQ(T(6), SaturatingMultiply(T(2), T(3)));
281   EXPECT_EQ(T(6), SaturatingMultiply(T(2), T(3), &ResultOverflowed));
282   EXPECT_FALSE(ResultOverflowed);
283 
284   EXPECT_EQ(T(6), SaturatingMultiply(T(3), T(2)));
285   EXPECT_EQ(T(6), SaturatingMultiply(T(3), T(2), &ResultOverflowed));
286   EXPECT_FALSE(ResultOverflowed);
287 
288   // Test multiplication by zero.
289   EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(0)));
290   EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(0), &ResultOverflowed));
291   EXPECT_FALSE(ResultOverflowed);
292 
293   EXPECT_EQ(T(0), SaturatingMultiply(T(1), T(0)));
294   EXPECT_EQ(T(0), SaturatingMultiply(T(1), T(0), &ResultOverflowed));
295   EXPECT_FALSE(ResultOverflowed);
296 
297   EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(1)));
298   EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(1), &ResultOverflowed));
299   EXPECT_FALSE(ResultOverflowed);
300 
301   EXPECT_EQ(T(0), SaturatingMultiply(Max, T(0)));
302   EXPECT_EQ(T(0), SaturatingMultiply(Max, T(0), &ResultOverflowed));
303   EXPECT_FALSE(ResultOverflowed);
304 
305   EXPECT_EQ(T(0), SaturatingMultiply(T(0), Max));
306   EXPECT_EQ(T(0), SaturatingMultiply(T(0), Max, &ResultOverflowed));
307   EXPECT_FALSE(ResultOverflowed);
308 
309   // Test multiplication by maximum value.
310   EXPECT_EQ(Max, SaturatingMultiply(Max, T(2)));
311   EXPECT_EQ(Max, SaturatingMultiply(Max, T(2), &ResultOverflowed));
312   EXPECT_TRUE(ResultOverflowed);
313 
314   EXPECT_EQ(Max, SaturatingMultiply(T(2), Max));
315   EXPECT_EQ(Max, SaturatingMultiply(T(2), Max, &ResultOverflowed));
316   EXPECT_TRUE(ResultOverflowed);
317 
318   EXPECT_EQ(Max, SaturatingMultiply(Max, Max));
319   EXPECT_EQ(Max, SaturatingMultiply(Max, Max, &ResultOverflowed));
320   EXPECT_TRUE(ResultOverflowed);
321 
322   // Test interesting boundary conditions for algorithm -
323   // ((1 << A) - 1) * ((1 << B) + K) for K in [-1, 0, 1]
324   // and A + B == std::numeric_limits<T>::digits.
325   // We expect overflow iff A > B and K = 1.
326   const int Digits = std::numeric_limits<T>::digits;
327   for (int A = 1, B = Digits - 1; B >= 1; ++A, --B) {
328     for (int K = -1; K <= 1; ++K) {
329       T X = (T(1) << A) - T(1);
330       T Y = (T(1) << B) + K;
331       bool OverflowExpected = A > B && K == 1;
332 
333       if(OverflowExpected) {
334         EXPECT_EQ(Max, SaturatingMultiply(X, Y));
335         EXPECT_EQ(Max, SaturatingMultiply(X, Y, &ResultOverflowed));
336         EXPECT_TRUE(ResultOverflowed);
337       } else {
338         EXPECT_EQ(X * Y, SaturatingMultiply(X, Y));
339         EXPECT_EQ(X * Y, SaturatingMultiply(X, Y, &ResultOverflowed));
340         EXPECT_FALSE(ResultOverflowed);
341       }
342     }
343   }
344 }
345 
346 TEST(MathExtras, SaturatingMultiply) {
347   SaturatingMultiplyTestHelper<uint8_t>();
348   SaturatingMultiplyTestHelper<uint16_t>();
349   SaturatingMultiplyTestHelper<uint32_t>();
350   SaturatingMultiplyTestHelper<uint64_t>();
351 }
352 
353 template<typename T>
354 void SaturatingMultiplyAddTestHelper()
355 {
356   const T Max = std::numeric_limits<T>::max();
357   bool ResultOverflowed;
358 
359   // Test basic multiply-add.
360   EXPECT_EQ(T(16), SaturatingMultiplyAdd(T(2), T(3), T(10)));
361   EXPECT_EQ(T(16), SaturatingMultiplyAdd(T(2), T(3), T(10), &ResultOverflowed));
362   EXPECT_FALSE(ResultOverflowed);
363 
364   // Test multiply overflows, add doesn't overflow
365   EXPECT_EQ(Max, SaturatingMultiplyAdd(Max, Max, T(0), &ResultOverflowed));
366   EXPECT_TRUE(ResultOverflowed);
367 
368   // Test multiply doesn't overflow, add overflows
369   EXPECT_EQ(Max, SaturatingMultiplyAdd(T(1), T(1), Max, &ResultOverflowed));
370   EXPECT_TRUE(ResultOverflowed);
371 
372   // Test multiply-add with Max as operand
373   EXPECT_EQ(Max, SaturatingMultiplyAdd(T(1), T(1), Max, &ResultOverflowed));
374   EXPECT_TRUE(ResultOverflowed);
375 
376   EXPECT_EQ(Max, SaturatingMultiplyAdd(T(1), Max, T(1), &ResultOverflowed));
377   EXPECT_TRUE(ResultOverflowed);
378 
379   EXPECT_EQ(Max, SaturatingMultiplyAdd(Max, Max, T(1), &ResultOverflowed));
380   EXPECT_TRUE(ResultOverflowed);
381 
382   EXPECT_EQ(Max, SaturatingMultiplyAdd(Max, Max, Max, &ResultOverflowed));
383   EXPECT_TRUE(ResultOverflowed);
384 
385   // Test multiply-add with 0 as operand
386   EXPECT_EQ(T(1), SaturatingMultiplyAdd(T(1), T(1), T(0), &ResultOverflowed));
387   EXPECT_FALSE(ResultOverflowed);
388 
389   EXPECT_EQ(T(1), SaturatingMultiplyAdd(T(1), T(0), T(1), &ResultOverflowed));
390   EXPECT_FALSE(ResultOverflowed);
391 
392   EXPECT_EQ(T(1), SaturatingMultiplyAdd(T(0), T(0), T(1), &ResultOverflowed));
393   EXPECT_FALSE(ResultOverflowed);
394 
395   EXPECT_EQ(T(0), SaturatingMultiplyAdd(T(0), T(0), T(0), &ResultOverflowed));
396   EXPECT_FALSE(ResultOverflowed);
397 
398 }
399 
400 TEST(MathExtras, SaturatingMultiplyAdd) {
401   SaturatingMultiplyAddTestHelper<uint8_t>();
402   SaturatingMultiplyAddTestHelper<uint16_t>();
403   SaturatingMultiplyAddTestHelper<uint32_t>();
404   SaturatingMultiplyAddTestHelper<uint64_t>();
405 }
406 
407 TEST(MathExtras, IsShiftedUInt) {
408   EXPECT_TRUE((isShiftedUInt<1, 0>(0)));
409   EXPECT_TRUE((isShiftedUInt<1, 0>(1)));
410   EXPECT_FALSE((isShiftedUInt<1, 0>(2)));
411   EXPECT_FALSE((isShiftedUInt<1, 0>(3)));
412   EXPECT_FALSE((isShiftedUInt<1, 0>(0x8000000000000000)));
413   EXPECT_TRUE((isShiftedUInt<1, 63>(0x8000000000000000)));
414   EXPECT_TRUE((isShiftedUInt<2, 62>(0xC000000000000000)));
415   EXPECT_FALSE((isShiftedUInt<2, 62>(0xE000000000000000)));
416 
417   // 0x201 is ten bits long and has a 1 in the MSB and LSB.
418   EXPECT_TRUE((isShiftedUInt<10, 5>(uint64_t(0x201) << 5)));
419   EXPECT_FALSE((isShiftedUInt<10, 5>(uint64_t(0x201) << 4)));
420   EXPECT_FALSE((isShiftedUInt<10, 5>(uint64_t(0x201) << 6)));
421 }
422 
423 TEST(MathExtras, IsShiftedInt) {
424   EXPECT_TRUE((isShiftedInt<1, 0>(0)));
425   EXPECT_TRUE((isShiftedInt<1, 0>(-1)));
426   EXPECT_FALSE((isShiftedInt<1, 0>(2)));
427   EXPECT_FALSE((isShiftedInt<1, 0>(3)));
428   EXPECT_FALSE((isShiftedInt<1, 0>(0x8000000000000000)));
429   EXPECT_TRUE((isShiftedInt<1, 63>(0x8000000000000000)));
430   EXPECT_TRUE((isShiftedInt<2, 62>(0xC000000000000000)));
431   EXPECT_FALSE((isShiftedInt<2, 62>(0xE000000000000000)));
432 
433   // 0x201 is ten bits long and has a 1 in the MSB and LSB.
434   EXPECT_TRUE((isShiftedInt<11, 5>(int64_t(0x201) << 5)));
435   EXPECT_FALSE((isShiftedInt<11, 5>(int64_t(0x201) << 3)));
436   EXPECT_FALSE((isShiftedInt<11, 5>(int64_t(0x201) << 6)));
437   EXPECT_TRUE((isShiftedInt<11, 5>(-(int64_t(0x201) << 5))));
438   EXPECT_FALSE((isShiftedInt<11, 5>(-(int64_t(0x201) << 3))));
439   EXPECT_FALSE((isShiftedInt<11, 5>(-(int64_t(0x201) << 6))));
440 
441   EXPECT_TRUE((isShiftedInt<6, 10>(-(int64_t(1) << 15))));
442   EXPECT_FALSE((isShiftedInt<6, 10>(int64_t(1) << 15)));
443 }
444 
445 template <typename T>
446 class OverflowTest : public ::testing::Test { };
447 
448 using OverflowTestTypes = ::testing::Types<signed char, short, int, long,
449                                            long long>;
450 
451 TYPED_TEST_SUITE(OverflowTest, OverflowTestTypes, );
452 
453 TYPED_TEST(OverflowTest, AddNoOverflow) {
454   TypeParam Result;
455   EXPECT_FALSE(AddOverflow<TypeParam>(1, 2, Result));
456   EXPECT_EQ(Result, TypeParam(3));
457 }
458 
459 TYPED_TEST(OverflowTest, AddOverflowToNegative) {
460   TypeParam Result;
461   auto MaxValue = std::numeric_limits<TypeParam>::max();
462   EXPECT_TRUE(AddOverflow<TypeParam>(MaxValue, MaxValue, Result));
463   EXPECT_EQ(Result, TypeParam(-2));
464 }
465 
466 TYPED_TEST(OverflowTest, AddOverflowToMin) {
467   TypeParam Result;
468   auto MaxValue = std::numeric_limits<TypeParam>::max();
469   EXPECT_TRUE(AddOverflow<TypeParam>(MaxValue, TypeParam(1), Result));
470   EXPECT_EQ(Result, std::numeric_limits<TypeParam>::min());
471 }
472 
473 TYPED_TEST(OverflowTest, AddOverflowToZero) {
474   TypeParam Result;
475   auto MinValue = std::numeric_limits<TypeParam>::min();
476   EXPECT_TRUE(AddOverflow<TypeParam>(MinValue, MinValue, Result));
477   EXPECT_EQ(Result, TypeParam(0));
478 }
479 
480 TYPED_TEST(OverflowTest, AddOverflowToMax) {
481   TypeParam Result;
482   auto MinValue = std::numeric_limits<TypeParam>::min();
483   EXPECT_TRUE(AddOverflow<TypeParam>(MinValue, TypeParam(-1), Result));
484   EXPECT_EQ(Result, std::numeric_limits<TypeParam>::max());
485 }
486 
487 TYPED_TEST(OverflowTest, SubNoOverflow) {
488   TypeParam Result;
489   EXPECT_FALSE(SubOverflow<TypeParam>(1, 2, Result));
490   EXPECT_EQ(Result, TypeParam(-1));
491 }
492 
493 TYPED_TEST(OverflowTest, SubOverflowToMax) {
494   TypeParam Result;
495   auto MinValue = std::numeric_limits<TypeParam>::min();
496   EXPECT_TRUE(SubOverflow<TypeParam>(0, MinValue, Result));
497   EXPECT_EQ(Result, MinValue);
498 }
499 
500 TYPED_TEST(OverflowTest, SubOverflowToMin) {
501   TypeParam Result;
502   auto MinValue = std::numeric_limits<TypeParam>::min();
503   EXPECT_TRUE(SubOverflow<TypeParam>(0, MinValue, Result));
504   EXPECT_EQ(Result, MinValue);
505 }
506 
507 TYPED_TEST(OverflowTest, SubOverflowToNegative) {
508   TypeParam Result;
509   auto MaxValue = std::numeric_limits<TypeParam>::max();
510   auto MinValue = std::numeric_limits<TypeParam>::min();
511   EXPECT_TRUE(SubOverflow<TypeParam>(MaxValue, MinValue, Result));
512   EXPECT_EQ(Result, TypeParam(-1));
513 }
514 
515 TYPED_TEST(OverflowTest, SubOverflowToPositive) {
516   TypeParam Result;
517   auto MaxValue = std::numeric_limits<TypeParam>::max();
518   auto MinValue = std::numeric_limits<TypeParam>::min();
519   EXPECT_TRUE(SubOverflow<TypeParam>(MinValue, MaxValue, Result));
520   EXPECT_EQ(Result, TypeParam(1));
521 }
522 
523 TYPED_TEST(OverflowTest, MulNoOverflow) {
524   TypeParam Result;
525   EXPECT_FALSE(MulOverflow<TypeParam>(1, 2, Result));
526   EXPECT_EQ(Result, 2);
527   EXPECT_FALSE(MulOverflow<TypeParam>(-1, 3, Result));
528   EXPECT_EQ(Result, -3);
529   EXPECT_FALSE(MulOverflow<TypeParam>(4, -2, Result));
530   EXPECT_EQ(Result, -8);
531   EXPECT_FALSE(MulOverflow<TypeParam>(-6, -5, Result));
532   EXPECT_EQ(Result, 30);
533 }
534 
535 TYPED_TEST(OverflowTest, MulNoOverflowToMax) {
536   TypeParam Result;
537   auto MaxValue = std::numeric_limits<TypeParam>::max();
538   auto MinValue = std::numeric_limits<TypeParam>::min();
539   EXPECT_FALSE(MulOverflow<TypeParam>(MinValue + 1, -1, Result));
540   EXPECT_EQ(Result, MaxValue);
541 }
542 
543 TYPED_TEST(OverflowTest, MulOverflowToMin) {
544   TypeParam Result;
545   auto MinValue = std::numeric_limits<TypeParam>::min();
546   EXPECT_TRUE(MulOverflow<TypeParam>(MinValue, -1, Result));
547   EXPECT_EQ(Result, MinValue);
548 }
549 
550 TYPED_TEST(OverflowTest, MulOverflowMax) {
551   TypeParam Result;
552   auto MinValue = std::numeric_limits<TypeParam>::min();
553   auto MaxValue = std::numeric_limits<TypeParam>::max();
554   EXPECT_TRUE(MulOverflow<TypeParam>(MinValue, MinValue, Result));
555   EXPECT_EQ(Result, 0);
556   EXPECT_TRUE(MulOverflow<TypeParam>(MaxValue, MaxValue, Result));
557   EXPECT_EQ(Result, 1);
558 }
559 
560 TYPED_TEST(OverflowTest, MulResultZero) {
561   TypeParam Result;
562   EXPECT_FALSE(MulOverflow<TypeParam>(4, 0, Result));
563   EXPECT_EQ(Result, TypeParam(0));
564   EXPECT_FALSE(MulOverflow<TypeParam>(-5, 0, Result));
565   EXPECT_EQ(Result, TypeParam(0));
566   EXPECT_FALSE(MulOverflow<TypeParam>(0, 5, Result));
567   EXPECT_EQ(Result, TypeParam(0));
568   EXPECT_FALSE(MulOverflow<TypeParam>(0, -5, Result));
569   EXPECT_EQ(Result, TypeParam(0));
570 }
571 
572 } // namespace
573