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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 :
17 : #include "llvm/Support/Compiler.h"
18 : #include "llvm/Support/SwapByteOrder.h"
19 : #include <cassert>
20 : #include <cstring>
21 : #include <type_traits>
22 :
23 : #ifdef _MSC_VER
24 : #include <intrin.h>
25 : #endif
26 :
27 : #ifdef __ANDROID_NDK__
28 : #include <android/api-level.h>
29 : #endif
30 :
31 : namespace llvm {
32 : /// \brief The behavior an operation has on an input of 0.
33 : enum ZeroBehavior {
34 : /// \brief The returned value is undefined.
35 : ZB_Undefined,
36 : /// \brief The returned value is numeric_limits<T>::max()
37 : ZB_Max,
38 : /// \brief The returned value is numeric_limits<T>::digits
39 : ZB_Width
40 : };
41 :
42 : namespace detail {
43 : template <typename T, std::size_t SizeOfT> struct TrailingZerosCounter {
44 : static std::size_t count(T Val, ZeroBehavior) {
45 : if (!Val)
46 : return std::numeric_limits<T>::digits;
47 : if (Val & 0x1)
48 : return 0;
49 :
50 : // Bisection method.
51 : std::size_t ZeroBits = 0;
52 : T Shift = std::numeric_limits<T>::digits >> 1;
53 : T Mask = std::numeric_limits<T>::max() >> Shift;
54 : while (Shift) {
55 : if ((Val & Mask) == 0) {
56 : Val >>= Shift;
57 : ZeroBits |= Shift;
58 : }
59 : Shift >>= 1;
60 : Mask >>= Shift;
61 : }
62 : return ZeroBits;
63 : }
64 : };
65 :
66 : #if __GNUC__ >= 4 || _MSC_VER
67 : template <typename T> struct TrailingZerosCounter<T, 4> {
68 : static std::size_t count(T Val, ZeroBehavior ZB) {
69 : if (ZB != ZB_Undefined && Val == 0)
70 : return 32;
71 :
72 : #if __has_builtin(__builtin_ctz) || LLVM_GNUC_PREREQ(4, 0, 0)
73 : return __builtin_ctz(Val);
74 : #elif _MSC_VER
75 : unsigned long Index;
76 : _BitScanForward(&Index, Val);
77 : return Index;
78 : #endif
79 : }
80 : };
81 :
82 : #if !defined(_MSC_VER) || defined(_M_X64)
83 : template <typename T> struct TrailingZerosCounter<T, 8> {
84 : static std::size_t count(T Val, ZeroBehavior ZB) {
85 : if (ZB != ZB_Undefined && Val == 0)
86 : return 64;
87 :
88 : #if __has_builtin(__builtin_ctzll) || LLVM_GNUC_PREREQ(4, 0, 0)
89 : return __builtin_ctzll(Val);
90 : #elif _MSC_VER
91 : unsigned long Index;
92 : _BitScanForward64(&Index, Val);
93 : return Index;
94 : #endif
95 : }
96 : };
97 : #endif
98 : #endif
99 : } // namespace detail
100 :
101 : /// \brief Count number of 0's from the least significant bit to the most
102 : /// stopping at the first 1.
103 : ///
104 : /// Only unsigned integral types are allowed.
105 : ///
106 : /// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
107 : /// valid arguments.
108 : template <typename T>
109 : std::size_t countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
110 : static_assert(std::numeric_limits<T>::is_integer &&
111 : !std::numeric_limits<T>::is_signed,
112 : "Only unsigned integral types are allowed.");
113 : return detail::TrailingZerosCounter<T, sizeof(T)>::count(Val, ZB);
114 : }
115 :
116 : namespace detail {
117 : template <typename T, std::size_t SizeOfT> struct LeadingZerosCounter {
118 : static std::size_t count(T Val, ZeroBehavior) {
119 : if (!Val)
120 : return std::numeric_limits<T>::digits;
121 :
122 : // Bisection method.
123 : std::size_t ZeroBits = 0;
124 : for (T Shift = std::numeric_limits<T>::digits >> 1; Shift; Shift >>= 1) {
125 : T Tmp = Val >> Shift;
126 : if (Tmp)
127 : Val = Tmp;
128 : else
129 : ZeroBits |= Shift;
130 : }
131 : return ZeroBits;
132 : }
133 : };
134 :
135 : #if __GNUC__ >= 4 || _MSC_VER
136 : template <typename T> struct LeadingZerosCounter<T, 4> {
137 : static std::size_t count(T Val, ZeroBehavior ZB) {
138 : if (ZB != ZB_Undefined && Val == 0)
139 : return 32;
140 :
141 : #if __has_builtin(__builtin_clz) || LLVM_GNUC_PREREQ(4, 0, 0)
142 : return __builtin_clz(Val);
143 : #elif _MSC_VER
144 : unsigned long Index;
145 : _BitScanReverse(&Index, Val);
146 : return Index ^ 31;
147 : #endif
148 : }
149 : };
150 :
151 : #if !defined(_MSC_VER) || defined(_M_X64)
152 : template <typename T> struct LeadingZerosCounter<T, 8> {
153 : static std::size_t count(T Val, ZeroBehavior ZB) {
154 : if (ZB != ZB_Undefined && Val == 0)
155 : return 64;
156 :
157 : #if __has_builtin(__builtin_clzll) || LLVM_GNUC_PREREQ(4, 0, 0)
158 : return __builtin_clzll(Val);
159 : #elif _MSC_VER
160 : unsigned long Index;
161 : _BitScanReverse64(&Index, Val);
162 : return Index ^ 63;
163 : #endif
164 : }
165 : };
166 : #endif
167 : #endif
168 : } // namespace detail
169 :
170 : /// \brief Count number of 0's from the most significant bit to the least
171 : /// stopping at the first 1.
172 : ///
173 : /// Only unsigned integral types are allowed.
174 : ///
175 : /// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
176 : /// valid arguments.
177 : template <typename T>
178 : std::size_t countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
179 : static_assert(std::numeric_limits<T>::is_integer &&
180 : !std::numeric_limits<T>::is_signed,
181 : "Only unsigned integral types are allowed.");
182 : return detail::LeadingZerosCounter<T, sizeof(T)>::count(Val, ZB);
183 : }
184 :
185 : /// \brief Get the index of the first set bit starting from the least
186 : /// significant bit.
187 : ///
188 : /// Only unsigned integral types are allowed.
189 : ///
190 : /// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are
191 : /// valid arguments.
192 : template <typename T> T findFirstSet(T Val, ZeroBehavior ZB = ZB_Max) {
193 : if (ZB == ZB_Max && Val == 0)
194 : return std::numeric_limits<T>::max();
195 :
196 : return countTrailingZeros(Val, ZB_Undefined);
197 : }
198 :
199 : /// \brief Get the index of the last set bit starting from the least
200 : /// significant bit.
201 : ///
202 : /// Only unsigned integral types are allowed.
203 : ///
204 : /// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are
205 : /// valid arguments.
206 : template <typename T> T findLastSet(T Val, ZeroBehavior ZB = ZB_Max) {
207 : if (ZB == ZB_Max && Val == 0)
208 : return std::numeric_limits<T>::max();
209 :
210 : // Use ^ instead of - because both gcc and llvm can remove the associated ^
211 : // in the __builtin_clz intrinsic on x86.
212 : return countLeadingZeros(Val, ZB_Undefined) ^
213 : (std::numeric_limits<T>::digits - 1);
214 : }
215 :
216 : /// \brief Macro compressed bit reversal table for 256 bits.
217 : ///
218 : /// http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable
219 : static const unsigned char BitReverseTable256[256] = {
220 : #define R2(n) n, n + 2 * 64, n + 1 * 64, n + 3 * 64
221 : #define R4(n) R2(n), R2(n + 2 * 16), R2(n + 1 * 16), R2(n + 3 * 16)
222 : #define R6(n) R4(n), R4(n + 2 * 4), R4(n + 1 * 4), R4(n + 3 * 4)
223 : R6(0), R6(2), R6(1), R6(3)
224 : #undef R2
225 : #undef R4
226 : #undef R6
227 : };
228 :
229 : /// \brief Reverse the bits in \p Val.
230 : template <typename T>
231 : T reverseBits(T Val) {
232 : unsigned char in[sizeof(Val)];
233 : unsigned char out[sizeof(Val)];
234 : std::memcpy(in, &Val, sizeof(Val));
235 : for (unsigned i = 0; i < sizeof(Val); ++i)
236 : out[(sizeof(Val) - i) - 1] = BitReverseTable256[in[i]];
237 : std::memcpy(&Val, out, sizeof(Val));
238 : return Val;
239 : }
240 :
241 : // NOTE: The following support functions use the _32/_64 extensions instead of
242 : // type overloading so that signed and unsigned integers can be used without
243 : // ambiguity.
244 :
245 : /// Hi_32 - This function returns the high 32 bits of a 64 bit value.
246 : inline uint32_t Hi_32(uint64_t Value) {
247 : return static_cast<uint32_t>(Value >> 32);
248 : }
249 :
250 : /// Lo_32 - This function returns the low 32 bits of a 64 bit value.
251 : inline uint32_t Lo_32(uint64_t Value) {
252 : return static_cast<uint32_t>(Value);
253 : }
254 :
255 : /// Make_64 - This functions makes a 64-bit integer from a high / low pair of
256 : /// 32-bit integers.
257 : inline uint64_t Make_64(uint32_t High, uint32_t Low) {
258 : return ((uint64_t)High << 32) | (uint64_t)Low;
259 : }
260 :
261 : /// isInt - Checks if an integer fits into the given bit width.
262 : template<unsigned N>
263 : inline bool isInt(int64_t x) {
264 : return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1)));
265 : }
266 : // Template specializations to get better code for common cases.
267 : template<>
268 : inline bool isInt<8>(int64_t x) {
269 : return static_cast<int8_t>(x) == x;
270 : }
271 : template<>
272 : inline bool isInt<16>(int64_t x) {
273 : return static_cast<int16_t>(x) == x;
274 : }
275 : template<>
276 : inline bool isInt<32>(int64_t x) {
277 : return static_cast<int32_t>(x) == x;
278 : }
279 :
280 : /// isShiftedInt<N,S> - Checks if a signed integer is an N bit number shifted
281 : /// left by S.
282 : template<unsigned N, unsigned S>
283 : inline bool isShiftedInt(int64_t x) {
284 : return isInt<N+S>(x) && (x % (1<<S) == 0);
285 : }
286 :
287 : /// isUInt - Checks if an unsigned integer fits into the given bit width.
288 : template<unsigned N>
289 : inline bool isUInt(uint64_t x) {
290 : return N >= 64 || x < (UINT64_C(1)<<(N));
291 : }
292 : // Template specializations to get better code for common cases.
293 : template<>
294 : inline bool isUInt<8>(uint64_t x) {
295 : return static_cast<uint8_t>(x) == x;
296 : }
297 : template<>
298 : inline bool isUInt<16>(uint64_t x) {
299 : return static_cast<uint16_t>(x) == x;
300 : }
301 : template<>
302 : inline bool isUInt<32>(uint64_t x) {
303 : return static_cast<uint32_t>(x) == x;
304 : }
305 :
306 : /// isShiftedUInt<N,S> - Checks if a unsigned integer is an N bit number shifted
307 : /// left by S.
308 : template<unsigned N, unsigned S>
309 : inline bool isShiftedUInt(uint64_t x) {
310 : return isUInt<N+S>(x) && (x % (1<<S) == 0);
311 : }
312 :
313 : /// isUIntN - Checks if an unsigned integer fits into the given (dynamic)
314 : /// bit width.
315 : inline bool isUIntN(unsigned N, uint64_t x) {
316 : return x == (x & (~0ULL >> (64 - N)));
317 : }
318 :
319 : /// isIntN - Checks if an signed integer fits into the given (dynamic)
320 : /// bit width.
321 : inline bool isIntN(unsigned N, int64_t x) {
322 : return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1)));
323 : }
324 :
325 : /// isMask_32 - This function returns true if the argument is a non-empty
326 : /// sequence of ones starting at the least significant bit with the remainder
327 : /// zero (32 bit version). Ex. isMask_32(0x0000FFFFU) == true.
328 : inline bool isMask_32(uint32_t Value) {
329 : return Value && ((Value + 1) & Value) == 0;
330 : }
331 :
332 : /// isMask_64 - This function returns true if the argument is a non-empty
333 : /// sequence of ones starting at the least significant bit with the remainder
334 : /// zero (64 bit version).
335 : inline bool isMask_64(uint64_t Value) {
336 : return Value && ((Value + 1) & Value) == 0;
337 : }
338 :
339 : /// isShiftedMask_32 - This function returns true if the argument contains a
340 : /// non-empty sequence of ones with the remainder zero (32 bit version.)
341 : /// Ex. isShiftedMask_32(0x0000FF00U) == true.
342 : inline bool isShiftedMask_32(uint32_t Value) {
343 : return Value && isMask_32((Value - 1) | Value);
344 : }
345 :
346 : /// isShiftedMask_64 - This function returns true if the argument contains a
347 : /// non-empty sequence of ones with the remainder zero (64 bit version.)
348 : inline bool isShiftedMask_64(uint64_t Value) {
349 : return Value && isMask_64((Value - 1) | Value);
350 : }
351 :
352 : /// isPowerOf2_32 - This function returns true if the argument is a power of
353 : /// two > 0. Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.)
354 : inline bool isPowerOf2_32(uint32_t Value) {
355 : return Value && !(Value & (Value - 1));
356 : }
357 :
358 : /// isPowerOf2_64 - This function returns true if the argument is a power of two
359 : /// > 0 (64 bit edition.)
360 : inline bool isPowerOf2_64(uint64_t Value) {
361 0 : return Value && !(Value & (Value - int64_t(1L)));
362 : }
363 :
364 : /// ByteSwap_16 - This function returns a byte-swapped representation of the
365 : /// 16-bit argument, Value.
366 : inline uint16_t ByteSwap_16(uint16_t Value) {
367 : return sys::SwapByteOrder_16(Value);
368 : }
369 :
370 : /// ByteSwap_32 - This function returns a byte-swapped representation of the
371 : /// 32-bit argument, Value.
372 : inline uint32_t ByteSwap_32(uint32_t Value) {
373 : return sys::SwapByteOrder_32(Value);
374 : }
375 :
376 : /// ByteSwap_64 - This function returns a byte-swapped representation of the
377 : /// 64-bit argument, Value.
378 : inline uint64_t ByteSwap_64(uint64_t Value) {
379 : return sys::SwapByteOrder_64(Value);
380 : }
381 :
382 : /// \brief Count the number of ones from the most significant bit to the first
383 : /// zero bit.
384 : ///
385 : /// Ex. CountLeadingOnes(0xFF0FFF00) == 8.
386 : /// Only unsigned integral types are allowed.
387 : ///
388 : /// \param ZB the behavior on an input of all ones. Only ZB_Width and
389 : /// ZB_Undefined are valid arguments.
390 : template <typename T>
391 : std::size_t countLeadingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
392 : static_assert(std::numeric_limits<T>::is_integer &&
393 : !std::numeric_limits<T>::is_signed,
394 : "Only unsigned integral types are allowed.");
395 : return countLeadingZeros(~Value, ZB);
396 : }
397 :
398 : /// \brief Count the number of ones from the least significant bit to the first
399 : /// zero bit.
400 : ///
401 : /// Ex. countTrailingOnes(0x00FF00FF) == 8.
402 : /// Only unsigned integral types are allowed.
403 : ///
404 : /// \param ZB the behavior on an input of all ones. Only ZB_Width and
405 : /// ZB_Undefined are valid arguments.
406 : template <typename T>
407 : std::size_t countTrailingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
408 : static_assert(std::numeric_limits<T>::is_integer &&
409 : !std::numeric_limits<T>::is_signed,
410 : "Only unsigned integral types are allowed.");
411 : return countTrailingZeros(~Value, ZB);
412 : }
413 :
414 : namespace detail {
415 : template <typename T, std::size_t SizeOfT> struct PopulationCounter {
416 : static unsigned count(T Value) {
417 : // Generic version, forward to 32 bits.
418 : static_assert(SizeOfT <= 4, "Not implemented!");
419 : #if __GNUC__ >= 4
420 : return __builtin_popcount(Value);
421 : #else
422 : uint32_t v = Value;
423 : v = v - ((v >> 1) & 0x55555555);
424 : v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
425 : return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24;
426 : #endif
427 : }
428 : };
429 :
430 : template <typename T> struct PopulationCounter<T, 8> {
431 : static unsigned count(T Value) {
432 : #if __GNUC__ >= 4
433 : return __builtin_popcountll(Value);
434 : #else
435 : uint64_t v = Value;
436 : v = v - ((v >> 1) & 0x5555555555555555ULL);
437 : v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL);
438 : v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL;
439 : return unsigned((uint64_t)(v * 0x0101010101010101ULL) >> 56);
440 : #endif
441 : }
442 : };
443 : } // namespace detail
444 :
445 : /// \brief Count the number of set bits in a value.
446 : /// Ex. countPopulation(0xF000F000) = 8
447 : /// Returns 0 if the word is zero.
448 : template <typename T>
449 : inline unsigned countPopulation(T Value) {
450 : static_assert(std::numeric_limits<T>::is_integer &&
451 : !std::numeric_limits<T>::is_signed,
452 : "Only unsigned integral types are allowed.");
453 : return detail::PopulationCounter<T, sizeof(T)>::count(Value);
454 : }
455 :
456 : /// Log2 - This function returns the log base 2 of the specified value
457 : inline double Log2(double Value) {
458 : #if defined(__ANDROID_API__) && __ANDROID_API__ < 18
459 : return __builtin_log(Value) / __builtin_log(2.0);
460 : #else
461 : return log2(Value);
462 : #endif
463 : }
464 :
465 : /// Log2_32 - This function returns the floor log base 2 of the specified value,
466 : /// -1 if the value is zero. (32 bit edition.)
467 : /// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1, Log2_32(6) == 2
468 : inline unsigned Log2_32(uint32_t Value) {
469 : return 31 - countLeadingZeros(Value);
470 : }
471 :
472 : /// Log2_64 - This function returns the floor log base 2 of the specified value,
473 : /// -1 if the value is zero. (64 bit edition.)
474 : inline unsigned Log2_64(uint64_t Value) {
475 : return 63 - countLeadingZeros(Value);
476 : }
477 :
478 : /// Log2_32_Ceil - This function returns the ceil log base 2 of the specified
479 : /// value, 32 if the value is zero. (32 bit edition).
480 : /// Ex. Log2_32_Ceil(32) == 5, Log2_32_Ceil(1) == 0, Log2_32_Ceil(6) == 3
481 : inline unsigned Log2_32_Ceil(uint32_t Value) {
482 : return 32 - countLeadingZeros(Value - 1);
483 : }
484 :
485 : /// Log2_64_Ceil - This function returns the ceil log base 2 of the specified
486 : /// value, 64 if the value is zero. (64 bit edition.)
487 : inline unsigned Log2_64_Ceil(uint64_t Value) {
488 : return 64 - countLeadingZeros(Value - 1);
489 : }
490 :
491 : /// GreatestCommonDivisor64 - Return the greatest common divisor of the two
492 : /// values using Euclid's algorithm.
493 : inline uint64_t GreatestCommonDivisor64(uint64_t A, uint64_t B) {
494 : while (B) {
495 : uint64_t T = B;
496 : B = A % B;
497 : A = T;
498 : }
499 : return A;
500 : }
501 :
502 : /// BitsToDouble - This function takes a 64-bit integer and returns the bit
503 : /// equivalent double.
504 : inline double BitsToDouble(uint64_t Bits) {
505 : union {
506 : uint64_t L;
507 : double D;
508 : } T;
509 : T.L = Bits;
510 : return T.D;
511 : }
512 :
513 : /// BitsToFloat - This function takes a 32-bit integer and returns the bit
514 : /// equivalent float.
515 : inline float BitsToFloat(uint32_t Bits) {
516 : union {
517 : uint32_t I;
518 : float F;
519 : } T;
520 : T.I = Bits;
521 : return T.F;
522 : }
523 :
524 : /// DoubleToBits - This function takes a double and returns the bit
525 : /// equivalent 64-bit integer. Note that copying doubles around
526 : /// changes the bits of NaNs on some hosts, notably x86, so this
527 : /// routine cannot be used if these bits are needed.
528 : inline uint64_t DoubleToBits(double Double) {
529 : union {
530 : uint64_t L;
531 : double D;
532 : } T;
533 : T.D = Double;
534 : return T.L;
535 : }
536 :
537 : /// FloatToBits - This function takes a float and returns the bit
538 : /// equivalent 32-bit integer. Note that copying floats around
539 : /// changes the bits of NaNs on some hosts, notably x86, so this
540 : /// routine cannot be used if these bits are needed.
541 : inline uint32_t FloatToBits(float Float) {
542 : union {
543 : uint32_t I;
544 : float F;
545 : } T;
546 : T.F = Float;
547 : return T.I;
548 : }
549 :
550 : /// MinAlign - A and B are either alignments or offsets. Return the minimum
551 : /// alignment that may be assumed after adding the two together.
552 : inline uint64_t MinAlign(uint64_t A, uint64_t B) {
553 : // The largest power of 2 that divides both A and B.
554 : //
555 : // Replace "-Value" by "1+~Value" in the following commented code to avoid
556 : // MSVC warning C4146
557 : // return (A | B) & -(A | B);
558 : return (A | B) & (1 + ~(A | B));
559 : }
560 :
561 : /// \brief Aligns \c Addr to \c Alignment bytes, rounding up.
562 : ///
563 : /// Alignment should be a power of two. This method rounds up, so
564 : /// alignAddr(7, 4) == 8 and alignAddr(8, 4) == 8.
565 : inline uintptr_t alignAddr(const void *Addr, size_t Alignment) {
566 0 : assert(Alignment && isPowerOf2_64((uint64_t)Alignment) &&
567 : "Alignment is not a power of two!");
568 :
569 0 : assert((uintptr_t)Addr + Alignment - 1 >= (uintptr_t)Addr);
570 :
571 0 : return (((uintptr_t)Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1));
572 : }
573 :
574 : /// \brief Returns the necessary adjustment for aligning \c Ptr to \c Alignment
575 : /// bytes, rounding up.
576 : inline size_t alignmentAdjustment(const void *Ptr, size_t Alignment) {
577 0 : return alignAddr(Ptr, Alignment) - (uintptr_t)Ptr;
578 : }
579 :
580 : /// NextPowerOf2 - Returns the next power of two (in 64-bits)
581 : /// that is strictly greater than A. Returns zero on overflow.
582 : inline uint64_t NextPowerOf2(uint64_t A) {
583 : A |= (A >> 1);
584 : A |= (A >> 2);
585 : A |= (A >> 4);
586 : A |= (A >> 8);
587 : A |= (A >> 16);
588 : A |= (A >> 32);
589 : return A + 1;
590 : }
591 :
592 : /// Returns the power of two which is less than or equal to the given value.
593 : /// Essentially, it is a floor operation across the domain of powers of two.
594 : inline uint64_t PowerOf2Floor(uint64_t A) {
595 : if (!A) return 0;
596 : return 1ull << (63 - countLeadingZeros(A, ZB_Undefined));
597 : }
598 :
599 : /// Returns the next integer (mod 2**64) that is greater than or equal to
600 : /// \p Value and is a multiple of \p Align. \p Align must be non-zero.
601 : ///
602 : /// Examples:
603 : /// \code
604 : /// RoundUpToAlignment(5, 8) = 8
605 : /// RoundUpToAlignment(17, 8) = 24
606 : /// RoundUpToAlignment(~0LL, 8) = 0
607 : /// RoundUpToAlignment(321, 255) = 510
608 : /// \endcode
609 : inline uint64_t RoundUpToAlignment(uint64_t Value, uint64_t Align) {
610 63 : return (Value + Align - 1) / Align * Align;
611 : }
612 :
613 : /// Returns the offset to the next integer (mod 2**64) that is greater than
614 : /// or equal to \p Value and is a multiple of \p Align. \p Align must be
615 : /// non-zero.
616 : inline uint64_t OffsetToAlignment(uint64_t Value, uint64_t Align) {
617 : return RoundUpToAlignment(Value, Align) - Value;
618 : }
619 :
620 : /// SignExtend32 - Sign extend B-bit number x to 32-bit int.
621 : /// Usage int32_t r = SignExtend32<5>(x);
622 : template <unsigned B> inline int32_t SignExtend32(uint32_t x) {
623 : return int32_t(x << (32 - B)) >> (32 - B);
624 : }
625 :
626 : /// \brief Sign extend number in the bottom B bits of X to a 32-bit int.
627 : /// Requires 0 < B <= 32.
628 : inline int32_t SignExtend32(uint32_t X, unsigned B) {
629 : return int32_t(X << (32 - B)) >> (32 - B);
630 : }
631 :
632 : /// SignExtend64 - Sign extend B-bit number x to 64-bit int.
633 : /// Usage int64_t r = SignExtend64<5>(x);
634 : template <unsigned B> inline int64_t SignExtend64(uint64_t x) {
635 : return int64_t(x << (64 - B)) >> (64 - B);
636 : }
637 :
638 : /// \brief Sign extend number in the bottom B bits of X to a 64-bit int.
639 : /// Requires 0 < B <= 64.
640 : inline int64_t SignExtend64(uint64_t X, unsigned B) {
641 : return int64_t(X << (64 - B)) >> (64 - B);
642 : }
643 :
644 : extern const float huge_valf;
645 : } // End llvm namespace
646 :
647 : #endif
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