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1 | //===-- llvm/Support/MathExtras.h - Useful math functions -------*- C++ -*-===// |
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 | // This file contains some functions that are useful for math stuff. | |
11 | // | |
12 | //===----------------------------------------------------------------------===// | |
13 | ||
14 | #ifndef LLVM_SUPPORT_MATHEXTRAS_H | |
15 | #define LLVM_SUPPORT_MATHEXTRAS_H | |
16 | ||
1a4d82fc | 17 | #include "llvm/Support/Compiler.h" |
223e47cc | 18 | #include "llvm/Support/SwapByteOrder.h" |
1a4d82fc JJ |
19 | #include <cassert> |
20 | #include <cstring> | |
21 | #include <type_traits> | |
223e47cc | 22 | |
970d7e83 | 23 | #ifdef _MSC_VER |
1a4d82fc | 24 | #include <intrin.h> |
970d7e83 LB |
25 | #endif |
26 | ||
223e47cc | 27 | namespace llvm { |
1a4d82fc JJ |
28 | /// \brief The behavior an operation has on an input of 0. |
29 | enum ZeroBehavior { | |
30 | /// \brief The returned value is undefined. | |
31 | ZB_Undefined, | |
32 | /// \brief The returned value is numeric_limits<T>::max() | |
33 | ZB_Max, | |
34 | /// \brief The returned value is numeric_limits<T>::digits | |
35 | ZB_Width | |
36 | }; | |
37 | ||
38 | /// \brief Count number of 0's from the least significant bit to the most | |
39 | /// stopping at the first 1. | |
40 | /// | |
41 | /// Only unsigned integral types are allowed. | |
42 | /// | |
43 | /// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are | |
44 | /// valid arguments. | |
45 | template <typename T> | |
46 | typename std::enable_if<std::numeric_limits<T>::is_integer && | |
47 | !std::numeric_limits<T>::is_signed, std::size_t>::type | |
48 | countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) { | |
49 | (void)ZB; | |
50 | ||
51 | if (!Val) | |
52 | return std::numeric_limits<T>::digits; | |
53 | if (Val & 0x1) | |
54 | return 0; | |
55 | ||
56 | // Bisection method. | |
57 | std::size_t ZeroBits = 0; | |
58 | T Shift = std::numeric_limits<T>::digits >> 1; | |
59 | T Mask = std::numeric_limits<T>::max() >> Shift; | |
60 | while (Shift) { | |
61 | if ((Val & Mask) == 0) { | |
62 | Val >>= Shift; | |
63 | ZeroBits |= Shift; | |
64 | } | |
65 | Shift >>= 1; | |
66 | Mask >>= Shift; | |
67 | } | |
68 | return ZeroBits; | |
69 | } | |
70 | ||
71 | // Disable signed. | |
72 | template <typename T> | |
73 | typename std::enable_if<std::numeric_limits<T>::is_integer && | |
74 | std::numeric_limits<T>::is_signed, std::size_t>::type | |
75 | countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) LLVM_DELETED_FUNCTION; | |
76 | ||
77 | #if __GNUC__ >= 4 || _MSC_VER | |
78 | template <> | |
79 | inline std::size_t countTrailingZeros<uint32_t>(uint32_t Val, ZeroBehavior ZB) { | |
80 | if (ZB != ZB_Undefined && Val == 0) | |
81 | return 32; | |
82 | ||
83 | #if __has_builtin(__builtin_ctz) || __GNUC_PREREQ(4, 0) | |
84 | return __builtin_ctz(Val); | |
85 | #elif _MSC_VER | |
86 | unsigned long Index; | |
87 | _BitScanForward(&Index, Val); | |
88 | return Index; | |
89 | #endif | |
90 | } | |
91 | ||
92 | #if !defined(_MSC_VER) || defined(_M_X64) | |
93 | template <> | |
94 | inline std::size_t countTrailingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) { | |
95 | if (ZB != ZB_Undefined && Val == 0) | |
96 | return 64; | |
97 | ||
98 | #if __has_builtin(__builtin_ctzll) || __GNUC_PREREQ(4, 0) | |
99 | return __builtin_ctzll(Val); | |
100 | #elif _MSC_VER | |
101 | unsigned long Index; | |
102 | _BitScanForward64(&Index, Val); | |
103 | return Index; | |
104 | #endif | |
105 | } | |
106 | #endif | |
107 | #endif | |
108 | ||
109 | /// \brief Count number of 0's from the most significant bit to the least | |
110 | /// stopping at the first 1. | |
111 | /// | |
112 | /// Only unsigned integral types are allowed. | |
113 | /// | |
114 | /// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are | |
115 | /// valid arguments. | |
116 | template <typename T> | |
117 | typename std::enable_if<std::numeric_limits<T>::is_integer && | |
118 | !std::numeric_limits<T>::is_signed, std::size_t>::type | |
119 | countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) { | |
120 | (void)ZB; | |
121 | ||
122 | if (!Val) | |
123 | return std::numeric_limits<T>::digits; | |
124 | ||
125 | // Bisection method. | |
126 | std::size_t ZeroBits = 0; | |
127 | for (T Shift = std::numeric_limits<T>::digits >> 1; Shift; Shift >>= 1) { | |
128 | T Tmp = Val >> Shift; | |
129 | if (Tmp) | |
130 | Val = Tmp; | |
131 | else | |
132 | ZeroBits |= Shift; | |
133 | } | |
134 | return ZeroBits; | |
135 | } | |
136 | ||
137 | // Disable signed. | |
138 | template <typename T> | |
139 | typename std::enable_if<std::numeric_limits<T>::is_integer && | |
140 | std::numeric_limits<T>::is_signed, std::size_t>::type | |
141 | countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) LLVM_DELETED_FUNCTION; | |
142 | ||
143 | #if __GNUC__ >= 4 || _MSC_VER | |
144 | template <> | |
145 | inline std::size_t countLeadingZeros<uint32_t>(uint32_t Val, ZeroBehavior ZB) { | |
146 | if (ZB != ZB_Undefined && Val == 0) | |
147 | return 32; | |
148 | ||
149 | #if __has_builtin(__builtin_clz) || __GNUC_PREREQ(4, 0) | |
150 | return __builtin_clz(Val); | |
151 | #elif _MSC_VER | |
152 | unsigned long Index; | |
153 | _BitScanReverse(&Index, Val); | |
154 | return Index ^ 31; | |
155 | #endif | |
156 | } | |
157 | ||
158 | #if !defined(_MSC_VER) || defined(_M_X64) | |
159 | template <> | |
160 | inline std::size_t countLeadingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) { | |
161 | if (ZB != ZB_Undefined && Val == 0) | |
162 | return 64; | |
163 | ||
164 | #if __has_builtin(__builtin_clzll) || __GNUC_PREREQ(4, 0) | |
165 | return __builtin_clzll(Val); | |
166 | #elif _MSC_VER | |
167 | unsigned long Index; | |
168 | _BitScanReverse64(&Index, Val); | |
169 | return Index ^ 63; | |
170 | #endif | |
171 | } | |
172 | #endif | |
173 | #endif | |
174 | ||
175 | /// \brief Get the index of the first set bit starting from the least | |
176 | /// significant bit. | |
177 | /// | |
178 | /// Only unsigned integral types are allowed. | |
179 | /// | |
180 | /// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are | |
181 | /// valid arguments. | |
182 | template <typename T> | |
183 | typename std::enable_if<std::numeric_limits<T>::is_integer && | |
184 | !std::numeric_limits<T>::is_signed, T>::type | |
185 | findFirstSet(T Val, ZeroBehavior ZB = ZB_Max) { | |
186 | if (ZB == ZB_Max && Val == 0) | |
187 | return std::numeric_limits<T>::max(); | |
188 | ||
189 | return countTrailingZeros(Val, ZB_Undefined); | |
190 | } | |
191 | ||
192 | // Disable signed. | |
193 | template <typename T> | |
194 | typename std::enable_if<std::numeric_limits<T>::is_integer && | |
195 | std::numeric_limits<T>::is_signed, T>::type | |
196 | findFirstSet(T Val, ZeroBehavior ZB = ZB_Max) LLVM_DELETED_FUNCTION; | |
197 | ||
198 | /// \brief Get the index of the last set bit starting from the least | |
199 | /// significant bit. | |
200 | /// | |
201 | /// Only unsigned integral types are allowed. | |
202 | /// | |
203 | /// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are | |
204 | /// valid arguments. | |
205 | template <typename T> | |
206 | typename std::enable_if<std::numeric_limits<T>::is_integer && | |
207 | !std::numeric_limits<T>::is_signed, T>::type | |
208 | findLastSet(T Val, ZeroBehavior ZB = ZB_Max) { | |
209 | if (ZB == ZB_Max && Val == 0) | |
210 | return std::numeric_limits<T>::max(); | |
211 | ||
212 | // Use ^ instead of - because both gcc and llvm can remove the associated ^ | |
213 | // in the __builtin_clz intrinsic on x86. | |
214 | return countLeadingZeros(Val, ZB_Undefined) ^ | |
215 | (std::numeric_limits<T>::digits - 1); | |
216 | } | |
217 | ||
218 | // Disable signed. | |
219 | template <typename T> | |
220 | typename std::enable_if<std::numeric_limits<T>::is_integer && | |
221 | std::numeric_limits<T>::is_signed, T>::type | |
222 | findLastSet(T Val, ZeroBehavior ZB = ZB_Max) LLVM_DELETED_FUNCTION; | |
223 | ||
224 | /// \brief Macro compressed bit reversal table for 256 bits. | |
225 | /// | |
226 | /// http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable | |
227 | static const unsigned char BitReverseTable256[256] = { | |
228 | #define R2(n) n, n + 2 * 64, n + 1 * 64, n + 3 * 64 | |
229 | #define R4(n) R2(n), R2(n + 2 * 16), R2(n + 1 * 16), R2(n + 3 * 16) | |
230 | #define R6(n) R4(n), R4(n + 2 * 4), R4(n + 1 * 4), R4(n + 3 * 4) | |
231 | R6(0), R6(2), R6(1), R6(3) | |
232 | #undef R2 | |
233 | #undef R4 | |
234 | #undef R6 | |
235 | }; | |
236 | ||
237 | /// \brief Reverse the bits in \p Val. | |
238 | template <typename T> | |
239 | T reverseBits(T Val) { | |
240 | unsigned char in[sizeof(Val)]; | |
241 | unsigned char out[sizeof(Val)]; | |
242 | std::memcpy(in, &Val, sizeof(Val)); | |
243 | for (unsigned i = 0; i < sizeof(Val); ++i) | |
244 | out[(sizeof(Val) - i) - 1] = BitReverseTable256[in[i]]; | |
245 | std::memcpy(&Val, out, sizeof(Val)); | |
246 | return Val; | |
247 | } | |
223e47cc LB |
248 | |
249 | // NOTE: The following support functions use the _32/_64 extensions instead of | |
250 | // type overloading so that signed and unsigned integers can be used without | |
251 | // ambiguity. | |
252 | ||
253 | /// Hi_32 - This function returns the high 32 bits of a 64 bit value. | |
254 | inline uint32_t Hi_32(uint64_t Value) { | |
255 | return static_cast<uint32_t>(Value >> 32); | |
256 | } | |
257 | ||
258 | /// Lo_32 - This function returns the low 32 bits of a 64 bit value. | |
259 | inline uint32_t Lo_32(uint64_t Value) { | |
260 | return static_cast<uint32_t>(Value); | |
261 | } | |
262 | ||
1a4d82fc JJ |
263 | /// Make_64 - This functions makes a 64-bit integer from a high / low pair of |
264 | /// 32-bit integers. | |
265 | inline uint64_t Make_64(uint32_t High, uint32_t Low) { | |
266 | return ((uint64_t)High << 32) | (uint64_t)Low; | |
267 | } | |
268 | ||
223e47cc LB |
269 | /// isInt - Checks if an integer fits into the given bit width. |
270 | template<unsigned N> | |
271 | inline bool isInt(int64_t x) { | |
272 | return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1))); | |
273 | } | |
274 | // Template specializations to get better code for common cases. | |
275 | template<> | |
276 | inline bool isInt<8>(int64_t x) { | |
277 | return static_cast<int8_t>(x) == x; | |
278 | } | |
279 | template<> | |
280 | inline bool isInt<16>(int64_t x) { | |
281 | return static_cast<int16_t>(x) == x; | |
282 | } | |
283 | template<> | |
284 | inline bool isInt<32>(int64_t x) { | |
285 | return static_cast<int32_t>(x) == x; | |
286 | } | |
287 | ||
288 | /// isShiftedInt<N,S> - Checks if a signed integer is an N bit number shifted | |
289 | /// left by S. | |
290 | template<unsigned N, unsigned S> | |
291 | inline bool isShiftedInt(int64_t x) { | |
292 | return isInt<N+S>(x) && (x % (1<<S) == 0); | |
293 | } | |
294 | ||
295 | /// isUInt - Checks if an unsigned integer fits into the given bit width. | |
296 | template<unsigned N> | |
297 | inline bool isUInt(uint64_t x) { | |
970d7e83 | 298 | return N >= 64 || x < (UINT64_C(1)<<(N)); |
223e47cc LB |
299 | } |
300 | // Template specializations to get better code for common cases. | |
301 | template<> | |
302 | inline bool isUInt<8>(uint64_t x) { | |
303 | return static_cast<uint8_t>(x) == x; | |
304 | } | |
305 | template<> | |
306 | inline bool isUInt<16>(uint64_t x) { | |
307 | return static_cast<uint16_t>(x) == x; | |
308 | } | |
309 | template<> | |
310 | inline bool isUInt<32>(uint64_t x) { | |
311 | return static_cast<uint32_t>(x) == x; | |
312 | } | |
313 | ||
314 | /// isShiftedUInt<N,S> - Checks if a unsigned integer is an N bit number shifted | |
315 | /// left by S. | |
316 | template<unsigned N, unsigned S> | |
317 | inline bool isShiftedUInt(uint64_t x) { | |
318 | return isUInt<N+S>(x) && (x % (1<<S) == 0); | |
319 | } | |
320 | ||
321 | /// isUIntN - Checks if an unsigned integer fits into the given (dynamic) | |
322 | /// bit width. | |
323 | inline bool isUIntN(unsigned N, uint64_t x) { | |
324 | return x == (x & (~0ULL >> (64 - N))); | |
325 | } | |
326 | ||
327 | /// isIntN - Checks if an signed integer fits into the given (dynamic) | |
328 | /// bit width. | |
329 | inline bool isIntN(unsigned N, int64_t x) { | |
330 | return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1))); | |
331 | } | |
332 | ||
333 | /// isMask_32 - This function returns true if the argument is a sequence of ones | |
334 | /// starting at the least significant bit with the remainder zero (32 bit | |
335 | /// version). Ex. isMask_32(0x0000FFFFU) == true. | |
336 | inline bool isMask_32(uint32_t Value) { | |
337 | return Value && ((Value + 1) & Value) == 0; | |
338 | } | |
339 | ||
340 | /// isMask_64 - This function returns true if the argument is a sequence of ones | |
341 | /// starting at the least significant bit with the remainder zero (64 bit | |
342 | /// version). | |
343 | inline bool isMask_64(uint64_t Value) { | |
344 | return Value && ((Value + 1) & Value) == 0; | |
345 | } | |
346 | ||
347 | /// isShiftedMask_32 - This function returns true if the argument contains a | |
348 | /// sequence of ones with the remainder zero (32 bit version.) | |
349 | /// Ex. isShiftedMask_32(0x0000FF00U) == true. | |
350 | inline bool isShiftedMask_32(uint32_t Value) { | |
351 | return isMask_32((Value - 1) | Value); | |
352 | } | |
353 | ||
354 | /// isShiftedMask_64 - This function returns true if the argument contains a | |
355 | /// sequence of ones with the remainder zero (64 bit version.) | |
356 | inline bool isShiftedMask_64(uint64_t Value) { | |
357 | return isMask_64((Value - 1) | Value); | |
358 | } | |
359 | ||
360 | /// isPowerOf2_32 - This function returns true if the argument is a power of | |
361 | /// two > 0. Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.) | |
362 | inline bool isPowerOf2_32(uint32_t Value) { | |
363 | return Value && !(Value & (Value - 1)); | |
364 | } | |
365 | ||
366 | /// isPowerOf2_64 - This function returns true if the argument is a power of two | |
367 | /// > 0 (64 bit edition.) | |
368 | inline bool isPowerOf2_64(uint64_t Value) { | |
369 | return Value && !(Value & (Value - int64_t(1L))); | |
370 | } | |
371 | ||
372 | /// ByteSwap_16 - This function returns a byte-swapped representation of the | |
373 | /// 16-bit argument, Value. | |
374 | inline uint16_t ByteSwap_16(uint16_t Value) { | |
375 | return sys::SwapByteOrder_16(Value); | |
376 | } | |
377 | ||
378 | /// ByteSwap_32 - This function returns a byte-swapped representation of the | |
379 | /// 32-bit argument, Value. | |
380 | inline uint32_t ByteSwap_32(uint32_t Value) { | |
381 | return sys::SwapByteOrder_32(Value); | |
382 | } | |
383 | ||
384 | /// ByteSwap_64 - This function returns a byte-swapped representation of the | |
385 | /// 64-bit argument, Value. | |
386 | inline uint64_t ByteSwap_64(uint64_t Value) { | |
387 | return sys::SwapByteOrder_64(Value); | |
388 | } | |
389 | ||
223e47cc LB |
390 | /// CountLeadingOnes_32 - this function performs the operation of |
391 | /// counting the number of ones from the most significant bit to the first zero | |
392 | /// bit. Ex. CountLeadingOnes_32(0xFF0FFF00) == 8. | |
393 | /// Returns 32 if the word is all ones. | |
394 | inline unsigned CountLeadingOnes_32(uint32_t Value) { | |
1a4d82fc | 395 | return countLeadingZeros(~Value); |
223e47cc LB |
396 | } |
397 | ||
398 | /// CountLeadingOnes_64 - This function performs the operation | |
399 | /// of counting the number of ones from the most significant bit to the first | |
400 | /// zero bit (64 bit edition.) | |
401 | /// Returns 64 if the word is all ones. | |
402 | inline unsigned CountLeadingOnes_64(uint64_t Value) { | |
1a4d82fc | 403 | return countLeadingZeros(~Value); |
223e47cc LB |
404 | } |
405 | ||
406 | /// CountTrailingOnes_32 - this function performs the operation of | |
407 | /// counting the number of ones from the least significant bit to the first zero | |
408 | /// bit. Ex. CountTrailingOnes_32(0x00FF00FF) == 8. | |
409 | /// Returns 32 if the word is all ones. | |
410 | inline unsigned CountTrailingOnes_32(uint32_t Value) { | |
1a4d82fc | 411 | return countTrailingZeros(~Value); |
223e47cc LB |
412 | } |
413 | ||
414 | /// CountTrailingOnes_64 - This function performs the operation | |
415 | /// of counting the number of ones from the least significant bit to the first | |
416 | /// zero bit (64 bit edition.) | |
417 | /// Returns 64 if the word is all ones. | |
418 | inline unsigned CountTrailingOnes_64(uint64_t Value) { | |
1a4d82fc | 419 | return countTrailingZeros(~Value); |
223e47cc LB |
420 | } |
421 | ||
422 | /// CountPopulation_32 - this function counts the number of set bits in a value. | |
423 | /// Ex. CountPopulation(0xF000F000) = 8 | |
424 | /// Returns 0 if the word is zero. | |
425 | inline unsigned CountPopulation_32(uint32_t Value) { | |
426 | #if __GNUC__ >= 4 | |
427 | return __builtin_popcount(Value); | |
428 | #else | |
429 | uint32_t v = Value - ((Value >> 1) & 0x55555555); | |
430 | v = (v & 0x33333333) + ((v >> 2) & 0x33333333); | |
431 | return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; | |
432 | #endif | |
433 | } | |
434 | ||
435 | /// CountPopulation_64 - this function counts the number of set bits in a value, | |
436 | /// (64 bit edition.) | |
437 | inline unsigned CountPopulation_64(uint64_t Value) { | |
438 | #if __GNUC__ >= 4 | |
439 | return __builtin_popcountll(Value); | |
440 | #else | |
441 | uint64_t v = Value - ((Value >> 1) & 0x5555555555555555ULL); | |
442 | v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL); | |
443 | v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL; | |
444 | return unsigned((uint64_t)(v * 0x0101010101010101ULL) >> 56); | |
445 | #endif | |
446 | } | |
447 | ||
448 | /// Log2_32 - This function returns the floor log base 2 of the specified value, | |
449 | /// -1 if the value is zero. (32 bit edition.) | |
450 | /// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1, Log2_32(6) == 2 | |
451 | inline unsigned Log2_32(uint32_t Value) { | |
1a4d82fc | 452 | return 31 - countLeadingZeros(Value); |
223e47cc LB |
453 | } |
454 | ||
455 | /// Log2_64 - This function returns the floor log base 2 of the specified value, | |
456 | /// -1 if the value is zero. (64 bit edition.) | |
457 | inline unsigned Log2_64(uint64_t Value) { | |
1a4d82fc | 458 | return 63 - countLeadingZeros(Value); |
223e47cc LB |
459 | } |
460 | ||
461 | /// Log2_32_Ceil - This function returns the ceil log base 2 of the specified | |
462 | /// value, 32 if the value is zero. (32 bit edition). | |
463 | /// Ex. Log2_32_Ceil(32) == 5, Log2_32_Ceil(1) == 0, Log2_32_Ceil(6) == 3 | |
464 | inline unsigned Log2_32_Ceil(uint32_t Value) { | |
1a4d82fc | 465 | return 32 - countLeadingZeros(Value - 1); |
223e47cc LB |
466 | } |
467 | ||
468 | /// Log2_64_Ceil - This function returns the ceil log base 2 of the specified | |
469 | /// value, 64 if the value is zero. (64 bit edition.) | |
470 | inline unsigned Log2_64_Ceil(uint64_t Value) { | |
1a4d82fc | 471 | return 64 - countLeadingZeros(Value - 1); |
223e47cc LB |
472 | } |
473 | ||
474 | /// GreatestCommonDivisor64 - Return the greatest common divisor of the two | |
475 | /// values using Euclid's algorithm. | |
476 | inline uint64_t GreatestCommonDivisor64(uint64_t A, uint64_t B) { | |
477 | while (B) { | |
478 | uint64_t T = B; | |
479 | B = A % B; | |
480 | A = T; | |
481 | } | |
482 | return A; | |
483 | } | |
484 | ||
485 | /// BitsToDouble - This function takes a 64-bit integer and returns the bit | |
486 | /// equivalent double. | |
487 | inline double BitsToDouble(uint64_t Bits) { | |
488 | union { | |
489 | uint64_t L; | |
490 | double D; | |
491 | } T; | |
492 | T.L = Bits; | |
493 | return T.D; | |
494 | } | |
495 | ||
496 | /// BitsToFloat - This function takes a 32-bit integer and returns the bit | |
497 | /// equivalent float. | |
498 | inline float BitsToFloat(uint32_t Bits) { | |
499 | union { | |
500 | uint32_t I; | |
501 | float F; | |
502 | } T; | |
503 | T.I = Bits; | |
504 | return T.F; | |
505 | } | |
506 | ||
507 | /// DoubleToBits - This function takes a double and returns the bit | |
508 | /// equivalent 64-bit integer. Note that copying doubles around | |
509 | /// changes the bits of NaNs on some hosts, notably x86, so this | |
510 | /// routine cannot be used if these bits are needed. | |
511 | inline uint64_t DoubleToBits(double Double) { | |
512 | union { | |
513 | uint64_t L; | |
514 | double D; | |
515 | } T; | |
516 | T.D = Double; | |
517 | return T.L; | |
518 | } | |
519 | ||
520 | /// FloatToBits - This function takes a float and returns the bit | |
521 | /// equivalent 32-bit integer. Note that copying floats around | |
522 | /// changes the bits of NaNs on some hosts, notably x86, so this | |
523 | /// routine cannot be used if these bits are needed. | |
524 | inline uint32_t FloatToBits(float Float) { | |
525 | union { | |
526 | uint32_t I; | |
527 | float F; | |
528 | } T; | |
529 | T.F = Float; | |
530 | return T.I; | |
531 | } | |
532 | ||
533 | /// Platform-independent wrappers for the C99 isnan() function. | |
534 | int IsNAN(float f); | |
535 | int IsNAN(double d); | |
536 | ||
537 | /// Platform-independent wrappers for the C99 isinf() function. | |
538 | int IsInf(float f); | |
539 | int IsInf(double d); | |
540 | ||
541 | /// MinAlign - A and B are either alignments or offsets. Return the minimum | |
542 | /// alignment that may be assumed after adding the two together. | |
543 | inline uint64_t MinAlign(uint64_t A, uint64_t B) { | |
544 | // The largest power of 2 that divides both A and B. | |
970d7e83 LB |
545 | // |
546 | // Replace "-Value" by "1+~Value" in the following commented code to avoid | |
547 | // MSVC warning C4146 | |
548 | // return (A | B) & -(A | B); | |
549 | return (A | B) & (1 + ~(A | B)); | |
223e47cc LB |
550 | } |
551 | ||
1a4d82fc JJ |
552 | /// \brief Aligns \c Addr to \c Alignment bytes, rounding up. |
553 | /// | |
554 | /// Alignment should be a power of two. This method rounds up, so | |
555 | /// alignAddr(7, 4) == 8 and alignAddr(8, 4) == 8. | |
556 | inline uintptr_t alignAddr(void *Addr, size_t Alignment) { | |
557 | assert(Alignment && isPowerOf2_64((uint64_t)Alignment) && | |
558 | "Alignment is not a power of two!"); | |
559 | ||
560 | assert((uintptr_t)Addr + Alignment - 1 >= (uintptr_t)Addr); | |
561 | ||
562 | return (((uintptr_t)Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1)); | |
563 | } | |
564 | ||
565 | /// \brief Returns the necessary adjustment for aligning \c Ptr to \c Alignment | |
566 | /// bytes, rounding up. | |
567 | inline size_t alignmentAdjustment(void *Ptr, size_t Alignment) { | |
568 | return alignAddr(Ptr, Alignment) - (uintptr_t)Ptr; | |
569 | } | |
570 | ||
223e47cc LB |
571 | /// NextPowerOf2 - Returns the next power of two (in 64-bits) |
572 | /// that is strictly greater than A. Returns zero on overflow. | |
573 | inline uint64_t NextPowerOf2(uint64_t A) { | |
574 | A |= (A >> 1); | |
575 | A |= (A >> 2); | |
576 | A |= (A >> 4); | |
577 | A |= (A >> 8); | |
578 | A |= (A >> 16); | |
579 | A |= (A >> 32); | |
580 | return A + 1; | |
581 | } | |
582 | ||
1a4d82fc JJ |
583 | /// Returns the power of two which is less than or equal to the given value. |
584 | /// Essentially, it is a floor operation across the domain of powers of two. | |
585 | inline uint64_t PowerOf2Floor(uint64_t A) { | |
586 | if (!A) return 0; | |
587 | return 1ull << (63 - countLeadingZeros(A, ZB_Undefined)); | |
588 | } | |
589 | ||
223e47cc LB |
590 | /// Returns the next integer (mod 2**64) that is greater than or equal to |
591 | /// \p Value and is a multiple of \p Align. \p Align must be non-zero. | |
592 | /// | |
593 | /// Examples: | |
594 | /// \code | |
595 | /// RoundUpToAlignment(5, 8) = 8 | |
596 | /// RoundUpToAlignment(17, 8) = 24 | |
597 | /// RoundUpToAlignment(~0LL, 8) = 0 | |
598 | /// \endcode | |
599 | inline uint64_t RoundUpToAlignment(uint64_t Value, uint64_t Align) { | |
600 | return ((Value + Align - 1) / Align) * Align; | |
601 | } | |
602 | ||
603 | /// Returns the offset to the next integer (mod 2**64) that is greater than | |
604 | /// or equal to \p Value and is a multiple of \p Align. \p Align must be | |
605 | /// non-zero. | |
606 | inline uint64_t OffsetToAlignment(uint64_t Value, uint64_t Align) { | |
607 | return RoundUpToAlignment(Value, Align) - Value; | |
608 | } | |
609 | ||
610 | /// abs64 - absolute value of a 64-bit int. Not all environments support | |
611 | /// "abs" on whatever their name for the 64-bit int type is. The absolute | |
612 | /// value of the largest negative number is undefined, as with "abs". | |
613 | inline int64_t abs64(int64_t x) { | |
614 | return (x < 0) ? -x : x; | |
615 | } | |
616 | ||
617 | /// SignExtend32 - Sign extend B-bit number x to 32-bit int. | |
618 | /// Usage int32_t r = SignExtend32<5>(x); | |
619 | template <unsigned B> inline int32_t SignExtend32(uint32_t x) { | |
620 | return int32_t(x << (32 - B)) >> (32 - B); | |
621 | } | |
622 | ||
623 | /// \brief Sign extend number in the bottom B bits of X to a 32-bit int. | |
624 | /// Requires 0 < B <= 32. | |
625 | inline int32_t SignExtend32(uint32_t X, unsigned B) { | |
626 | return int32_t(X << (32 - B)) >> (32 - B); | |
627 | } | |
628 | ||
629 | /// SignExtend64 - Sign extend B-bit number x to 64-bit int. | |
630 | /// Usage int64_t r = SignExtend64<5>(x); | |
631 | template <unsigned B> inline int64_t SignExtend64(uint64_t x) { | |
632 | return int64_t(x << (64 - B)) >> (64 - B); | |
633 | } | |
634 | ||
635 | /// \brief Sign extend number in the bottom B bits of X to a 64-bit int. | |
636 | /// Requires 0 < B <= 64. | |
637 | inline int64_t SignExtend64(uint64_t X, unsigned B) { | |
638 | return int64_t(X << (64 - B)) >> (64 - B); | |
639 | } | |
640 | ||
1a4d82fc | 641 | extern const float huge_valf; |
223e47cc LB |
642 | } // End llvm namespace |
643 | ||
644 | #endif |