MathExtras.h revision 261991
1193323Sed//===-- llvm/Support/MathExtras.h - Useful math functions -------*- C++ -*-===// 2193323Sed// 3193323Sed// The LLVM Compiler Infrastructure 4193323Sed// 5193323Sed// This file is distributed under the University of Illinois Open Source 6193323Sed// License. See LICENSE.TXT for details. 7193323Sed// 8193323Sed//===----------------------------------------------------------------------===// 9193323Sed// 10193323Sed// This file contains some functions that are useful for math stuff. 11193323Sed// 12193323Sed//===----------------------------------------------------------------------===// 13193323Sed 14193323Sed#ifndef LLVM_SUPPORT_MATHEXTRAS_H 15193323Sed#define LLVM_SUPPORT_MATHEXTRAS_H 16193323Sed 17261991Sdim#include "llvm/Support/Compiler.h" 18218893Sdim#include "llvm/Support/SwapByteOrder.h" 19261991Sdim#include "llvm/Support/type_traits.h" 20193323Sed 21261991Sdim#include <cstring> 22261991Sdim 23249423Sdim#ifdef _MSC_VER 24261991Sdim#include <intrin.h> 25261991Sdim#include <limits> 26249423Sdim#endif 27249423Sdim 28193323Sednamespace llvm { 29261991Sdim/// \brief The behavior an operation has on an input of 0. 30261991Sdimenum ZeroBehavior { 31261991Sdim /// \brief The returned value is undefined. 32261991Sdim ZB_Undefined, 33261991Sdim /// \brief The returned value is numeric_limits<T>::max() 34261991Sdim ZB_Max, 35261991Sdim /// \brief The returned value is numeric_limits<T>::digits 36261991Sdim ZB_Width 37261991Sdim}; 38193323Sed 39261991Sdim/// \brief Count number of 0's from the least significant bit to the most 40261991Sdim/// stopping at the first 1. 41261991Sdim/// 42261991Sdim/// Only unsigned integral types are allowed. 43261991Sdim/// 44261991Sdim/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are 45261991Sdim/// valid arguments. 46261991Sdimtemplate <typename T> 47261991Sdimtypename enable_if_c<std::numeric_limits<T>::is_integer && 48261991Sdim !std::numeric_limits<T>::is_signed, std::size_t>::type 49261991SdimcountTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) { 50261991Sdim (void)ZB; 51261991Sdim 52261991Sdim if (!Val) 53261991Sdim return std::numeric_limits<T>::digits; 54261991Sdim if (Val & 0x1) 55261991Sdim return 0; 56261991Sdim 57261991Sdim // Bisection method. 58261991Sdim std::size_t ZeroBits = 0; 59261991Sdim T Shift = std::numeric_limits<T>::digits >> 1; 60261991Sdim T Mask = std::numeric_limits<T>::max() >> Shift; 61261991Sdim while (Shift) { 62261991Sdim if ((Val & Mask) == 0) { 63261991Sdim Val >>= Shift; 64261991Sdim ZeroBits |= Shift; 65261991Sdim } 66261991Sdim Shift >>= 1; 67261991Sdim Mask >>= Shift; 68261991Sdim } 69261991Sdim return ZeroBits; 70261991Sdim} 71261991Sdim 72261991Sdim// Disable signed. 73261991Sdimtemplate <typename T> 74261991Sdimtypename enable_if_c<std::numeric_limits<T>::is_integer && 75261991Sdim std::numeric_limits<T>::is_signed, std::size_t>::type 76261991SdimcountTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) LLVM_DELETED_FUNCTION; 77261991Sdim 78261991Sdim#if __GNUC__ >= 4 || _MSC_VER 79261991Sdimtemplate <> 80261991Sdiminline std::size_t countTrailingZeros<uint32_t>(uint32_t Val, ZeroBehavior ZB) { 81261991Sdim if (ZB != ZB_Undefined && Val == 0) 82261991Sdim return 32; 83261991Sdim 84261991Sdim#if __has_builtin(__builtin_ctz) || __GNUC_PREREQ(4, 0) 85261991Sdim return __builtin_ctz(Val); 86261991Sdim#elif _MSC_VER 87261991Sdim unsigned long Index; 88261991Sdim _BitScanForward(&Index, Val); 89261991Sdim return Index; 90261991Sdim#endif 91261991Sdim} 92261991Sdim 93261991Sdim#if !defined(_MSC_VER) || defined(_M_X64) 94261991Sdimtemplate <> 95261991Sdiminline std::size_t countTrailingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) { 96261991Sdim if (ZB != ZB_Undefined && Val == 0) 97261991Sdim return 64; 98261991Sdim 99261991Sdim#if __has_builtin(__builtin_ctzll) || __GNUC_PREREQ(4, 0) 100261991Sdim return __builtin_ctzll(Val); 101261991Sdim#elif _MSC_VER 102261991Sdim unsigned long Index; 103261991Sdim _BitScanForward64(&Index, Val); 104261991Sdim return Index; 105261991Sdim#endif 106261991Sdim} 107261991Sdim#endif 108261991Sdim#endif 109261991Sdim 110261991Sdim/// \brief Count number of 0's from the most significant bit to the least 111261991Sdim/// stopping at the first 1. 112261991Sdim/// 113261991Sdim/// Only unsigned integral types are allowed. 114261991Sdim/// 115261991Sdim/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are 116261991Sdim/// valid arguments. 117261991Sdimtemplate <typename T> 118261991Sdimtypename enable_if_c<std::numeric_limits<T>::is_integer && 119261991Sdim !std::numeric_limits<T>::is_signed, std::size_t>::type 120261991SdimcountLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) { 121261991Sdim (void)ZB; 122261991Sdim 123261991Sdim if (!Val) 124261991Sdim return std::numeric_limits<T>::digits; 125261991Sdim 126261991Sdim // Bisection method. 127261991Sdim std::size_t ZeroBits = 0; 128261991Sdim for (T Shift = std::numeric_limits<T>::digits >> 1; Shift; Shift >>= 1) { 129261991Sdim T Tmp = Val >> Shift; 130261991Sdim if (Tmp) 131261991Sdim Val = Tmp; 132261991Sdim else 133261991Sdim ZeroBits |= Shift; 134261991Sdim } 135261991Sdim return ZeroBits; 136261991Sdim} 137261991Sdim 138261991Sdim// Disable signed. 139261991Sdimtemplate <typename T> 140261991Sdimtypename enable_if_c<std::numeric_limits<T>::is_integer && 141261991Sdim std::numeric_limits<T>::is_signed, std::size_t>::type 142261991SdimcountLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) LLVM_DELETED_FUNCTION; 143261991Sdim 144261991Sdim#if __GNUC__ >= 4 || _MSC_VER 145261991Sdimtemplate <> 146261991Sdiminline std::size_t countLeadingZeros<uint32_t>(uint32_t Val, ZeroBehavior ZB) { 147261991Sdim if (ZB != ZB_Undefined && Val == 0) 148261991Sdim return 32; 149261991Sdim 150261991Sdim#if __has_builtin(__builtin_clz) || __GNUC_PREREQ(4, 0) 151261991Sdim return __builtin_clz(Val); 152261991Sdim#elif _MSC_VER 153261991Sdim unsigned long Index; 154261991Sdim _BitScanReverse(&Index, Val); 155261991Sdim return Index ^ 31; 156261991Sdim#endif 157261991Sdim} 158261991Sdim 159261991Sdim#if !defined(_MSC_VER) || defined(_M_X64) 160261991Sdimtemplate <> 161261991Sdiminline std::size_t countLeadingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) { 162261991Sdim if (ZB != ZB_Undefined && Val == 0) 163261991Sdim return 64; 164261991Sdim 165261991Sdim#if __has_builtin(__builtin_clzll) || __GNUC_PREREQ(4, 0) 166261991Sdim return __builtin_clzll(Val); 167261991Sdim#elif _MSC_VER 168261991Sdim unsigned long Index; 169261991Sdim _BitScanReverse64(&Index, Val); 170261991Sdim return Index ^ 63; 171261991Sdim#endif 172261991Sdim} 173261991Sdim#endif 174261991Sdim#endif 175261991Sdim 176261991Sdim/// \brief Get the index of the first set bit starting from the least 177261991Sdim/// significant bit. 178261991Sdim/// 179261991Sdim/// Only unsigned integral types are allowed. 180261991Sdim/// 181261991Sdim/// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are 182261991Sdim/// valid arguments. 183261991Sdimtemplate <typename T> 184261991Sdimtypename enable_if_c<std::numeric_limits<T>::is_integer && 185261991Sdim !std::numeric_limits<T>::is_signed, T>::type 186261991SdimfindFirstSet(T Val, ZeroBehavior ZB = ZB_Max) { 187261991Sdim if (ZB == ZB_Max && Val == 0) 188261991Sdim return std::numeric_limits<T>::max(); 189261991Sdim 190261991Sdim return countTrailingZeros(Val, ZB_Undefined); 191261991Sdim} 192261991Sdim 193261991Sdim// Disable signed. 194261991Sdimtemplate <typename T> 195261991Sdimtypename enable_if_c<std::numeric_limits<T>::is_integer && 196261991Sdim std::numeric_limits<T>::is_signed, T>::type 197261991SdimfindFirstSet(T Val, ZeroBehavior ZB = ZB_Max) LLVM_DELETED_FUNCTION; 198261991Sdim 199261991Sdim/// \brief Get the index of the last set bit starting from the least 200261991Sdim/// significant bit. 201261991Sdim/// 202261991Sdim/// Only unsigned integral types are allowed. 203261991Sdim/// 204261991Sdim/// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are 205261991Sdim/// valid arguments. 206261991Sdimtemplate <typename T> 207261991Sdimtypename enable_if_c<std::numeric_limits<T>::is_integer && 208261991Sdim !std::numeric_limits<T>::is_signed, T>::type 209261991SdimfindLastSet(T Val, ZeroBehavior ZB = ZB_Max) { 210261991Sdim if (ZB == ZB_Max && Val == 0) 211261991Sdim return std::numeric_limits<T>::max(); 212261991Sdim 213261991Sdim // Use ^ instead of - because both gcc and llvm can remove the associated ^ 214261991Sdim // in the __builtin_clz intrinsic on x86. 215261991Sdim return countLeadingZeros(Val, ZB_Undefined) ^ 216261991Sdim (std::numeric_limits<T>::digits - 1); 217261991Sdim} 218261991Sdim 219261991Sdim// Disable signed. 220261991Sdimtemplate <typename T> 221261991Sdimtypename enable_if_c<std::numeric_limits<T>::is_integer && 222261991Sdim std::numeric_limits<T>::is_signed, T>::type 223261991SdimfindLastSet(T Val, ZeroBehavior ZB = ZB_Max) LLVM_DELETED_FUNCTION; 224261991Sdim 225261991Sdim/// \brief Macro compressed bit reversal table for 256 bits. 226261991Sdim/// 227261991Sdim/// http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable 228261991Sdimstatic const unsigned char BitReverseTable256[256] = { 229261991Sdim#define R2(n) n, n + 2 * 64, n + 1 * 64, n + 3 * 64 230261991Sdim#define R4(n) R2(n), R2(n + 2 * 16), R2(n + 1 * 16), R2(n + 3 * 16) 231261991Sdim#define R6(n) R4(n), R4(n + 2 * 4), R4(n + 1 * 4), R4(n + 3 * 4) 232261991Sdim R6(0), R6(2), R6(1), R6(3) 233261991Sdim}; 234261991Sdim 235261991Sdim/// \brief Reverse the bits in \p Val. 236261991Sdimtemplate <typename T> 237261991SdimT reverseBits(T Val) { 238261991Sdim unsigned char in[sizeof(Val)]; 239261991Sdim unsigned char out[sizeof(Val)]; 240261991Sdim std::memcpy(in, &Val, sizeof(Val)); 241261991Sdim for (unsigned i = 0; i < sizeof(Val); ++i) 242261991Sdim out[(sizeof(Val) - i) - 1] = BitReverseTable256[in[i]]; 243261991Sdim std::memcpy(&Val, out, sizeof(Val)); 244261991Sdim return Val; 245261991Sdim} 246261991Sdim 247193323Sed// NOTE: The following support functions use the _32/_64 extensions instead of 248193323Sed// type overloading so that signed and unsigned integers can be used without 249193323Sed// ambiguity. 250193323Sed 251193323Sed/// Hi_32 - This function returns the high 32 bits of a 64 bit value. 252193323Sedinline uint32_t Hi_32(uint64_t Value) { 253193323Sed return static_cast<uint32_t>(Value >> 32); 254193323Sed} 255193323Sed 256193323Sed/// Lo_32 - This function returns the low 32 bits of a 64 bit value. 257193323Sedinline uint32_t Lo_32(uint64_t Value) { 258193323Sed return static_cast<uint32_t>(Value); 259193323Sed} 260193323Sed 261206083Srdivacky/// isInt - Checks if an integer fits into the given bit width. 262206083Srdivackytemplate<unsigned N> 263206083Srdivackyinline bool isInt(int64_t x) { 264206083Srdivacky return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1))); 265193323Sed} 266206083Srdivacky// Template specializations to get better code for common cases. 267206083Srdivackytemplate<> 268206083Srdivackyinline bool isInt<8>(int64_t x) { 269206083Srdivacky return static_cast<int8_t>(x) == x; 270193323Sed} 271206083Srdivackytemplate<> 272206083Srdivackyinline bool isInt<16>(int64_t x) { 273206083Srdivacky return static_cast<int16_t>(x) == x; 274193323Sed} 275206083Srdivackytemplate<> 276206083Srdivackyinline bool isInt<32>(int64_t x) { 277206083Srdivacky return static_cast<int32_t>(x) == x; 278193323Sed} 279193323Sed 280234353Sdim/// isShiftedInt<N,S> - Checks if a signed integer is an N bit number shifted 281234353Sdim/// left by S. 282234353Sdimtemplate<unsigned N, unsigned S> 283234353Sdiminline bool isShiftedInt(int64_t x) { 284234353Sdim return isInt<N+S>(x) && (x % (1<<S) == 0); 285234353Sdim} 286234353Sdim 287206083Srdivacky/// isUInt - Checks if an unsigned integer fits into the given bit width. 288198090Srdivackytemplate<unsigned N> 289206083Srdivackyinline bool isUInt(uint64_t x) { 290249423Sdim return N >= 64 || x < (UINT64_C(1)<<(N)); 291198090Srdivacky} 292206083Srdivacky// Template specializations to get better code for common cases. 293206083Srdivackytemplate<> 294206083Srdivackyinline bool isUInt<8>(uint64_t x) { 295206083Srdivacky return static_cast<uint8_t>(x) == x; 296206083Srdivacky} 297206083Srdivackytemplate<> 298206083Srdivackyinline bool isUInt<16>(uint64_t x) { 299206083Srdivacky return static_cast<uint16_t>(x) == x; 300206083Srdivacky} 301206083Srdivackytemplate<> 302206083Srdivackyinline bool isUInt<32>(uint64_t x) { 303206083Srdivacky return static_cast<uint32_t>(x) == x; 304206083Srdivacky} 305198090Srdivacky 306234353Sdim/// isShiftedUInt<N,S> - Checks if a unsigned integer is an N bit number shifted 307234353Sdim/// left by S. 308234353Sdimtemplate<unsigned N, unsigned S> 309234353Sdiminline bool isShiftedUInt(uint64_t x) { 310234353Sdim return isUInt<N+S>(x) && (x % (1<<S) == 0); 311234353Sdim} 312234353Sdim 313218893Sdim/// isUIntN - Checks if an unsigned integer fits into the given (dynamic) 314218893Sdim/// bit width. 315218893Sdiminline bool isUIntN(unsigned N, uint64_t x) { 316218893Sdim return x == (x & (~0ULL >> (64 - N))); 317218893Sdim} 318218893Sdim 319218893Sdim/// isIntN - Checks if an signed integer fits into the given (dynamic) 320218893Sdim/// bit width. 321218893Sdiminline bool isIntN(unsigned N, int64_t x) { 322218893Sdim return N >= 64 || (-(INT64_C(1)<<(N-1)) <= x && x < (INT64_C(1)<<(N-1))); 323218893Sdim} 324218893Sdim 325193323Sed/// isMask_32 - This function returns true if the argument is a sequence of ones 326193323Sed/// starting at the least significant bit with the remainder zero (32 bit 327193323Sed/// version). Ex. isMask_32(0x0000FFFFU) == true. 328193323Sedinline bool isMask_32(uint32_t Value) { 329193323Sed return Value && ((Value + 1) & Value) == 0; 330193323Sed} 331193323Sed 332193323Sed/// isMask_64 - This function returns true if the argument is a sequence of ones 333193323Sed/// starting at the least significant bit with the remainder zero (64 bit 334193323Sed/// version). 335193323Sedinline bool isMask_64(uint64_t Value) { 336193323Sed return Value && ((Value + 1) & Value) == 0; 337193323Sed} 338193323Sed 339193323Sed/// isShiftedMask_32 - This function returns true if the argument contains a 340193323Sed/// sequence of ones with the remainder zero (32 bit version.) 341193323Sed/// Ex. isShiftedMask_32(0x0000FF00U) == true. 342193323Sedinline bool isShiftedMask_32(uint32_t Value) { 343193323Sed return isMask_32((Value - 1) | Value); 344193323Sed} 345193323Sed 346193323Sed/// isShiftedMask_64 - This function returns true if the argument contains a 347193323Sed/// sequence of ones with the remainder zero (64 bit version.) 348193323Sedinline bool isShiftedMask_64(uint64_t Value) { 349193323Sed return isMask_64((Value - 1) | Value); 350193323Sed} 351193323Sed 352193323Sed/// isPowerOf2_32 - This function returns true if the argument is a power of 353193323Sed/// two > 0. Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.) 354193323Sedinline bool isPowerOf2_32(uint32_t Value) { 355193323Sed return Value && !(Value & (Value - 1)); 356193323Sed} 357193323Sed 358193323Sed/// isPowerOf2_64 - This function returns true if the argument is a power of two 359193323Sed/// > 0 (64 bit edition.) 360193323Sedinline bool isPowerOf2_64(uint64_t Value) { 361193323Sed return Value && !(Value & (Value - int64_t(1L))); 362193323Sed} 363193323Sed 364193323Sed/// ByteSwap_16 - This function returns a byte-swapped representation of the 365193323Sed/// 16-bit argument, Value. 366193323Sedinline uint16_t ByteSwap_16(uint16_t Value) { 367218893Sdim return sys::SwapByteOrder_16(Value); 368193323Sed} 369193323Sed 370193323Sed/// ByteSwap_32 - This function returns a byte-swapped representation of the 371193323Sed/// 32-bit argument, Value. 372193323Sedinline uint32_t ByteSwap_32(uint32_t Value) { 373218893Sdim return sys::SwapByteOrder_32(Value); 374193323Sed} 375193323Sed 376193323Sed/// ByteSwap_64 - This function returns a byte-swapped representation of the 377193323Sed/// 64-bit argument, Value. 378193323Sedinline uint64_t ByteSwap_64(uint64_t Value) { 379218893Sdim return sys::SwapByteOrder_64(Value); 380193323Sed} 381193323Sed 382193323Sed/// CountLeadingOnes_32 - this function performs the operation of 383193323Sed/// counting the number of ones from the most significant bit to the first zero 384193323Sed/// bit. Ex. CountLeadingOnes_32(0xFF0FFF00) == 8. 385193323Sed/// Returns 32 if the word is all ones. 386193323Sedinline unsigned CountLeadingOnes_32(uint32_t Value) { 387261991Sdim return countLeadingZeros(~Value); 388193323Sed} 389193323Sed 390193323Sed/// CountLeadingOnes_64 - This function performs the operation 391193323Sed/// of counting the number of ones from the most significant bit to the first 392193323Sed/// zero bit (64 bit edition.) 393193323Sed/// Returns 64 if the word is all ones. 394193323Sedinline unsigned CountLeadingOnes_64(uint64_t Value) { 395261991Sdim return countLeadingZeros(~Value); 396193323Sed} 397193323Sed 398193323Sed/// CountTrailingOnes_32 - this function performs the operation of 399193323Sed/// counting the number of ones from the least significant bit to the first zero 400193323Sed/// bit. Ex. CountTrailingOnes_32(0x00FF00FF) == 8. 401193323Sed/// Returns 32 if the word is all ones. 402193323Sedinline unsigned CountTrailingOnes_32(uint32_t Value) { 403261991Sdim return countTrailingZeros(~Value); 404193323Sed} 405193323Sed 406193323Sed/// CountTrailingOnes_64 - This function performs the operation 407193323Sed/// of counting the number of ones from the least significant bit to the first 408193323Sed/// zero bit (64 bit edition.) 409193323Sed/// Returns 64 if the word is all ones. 410193323Sedinline unsigned CountTrailingOnes_64(uint64_t Value) { 411261991Sdim return countTrailingZeros(~Value); 412193323Sed} 413193323Sed 414193323Sed/// CountPopulation_32 - this function counts the number of set bits in a value. 415193323Sed/// Ex. CountPopulation(0xF000F000) = 8 416193323Sed/// Returns 0 if the word is zero. 417193323Sedinline unsigned CountPopulation_32(uint32_t Value) { 418193323Sed#if __GNUC__ >= 4 419193323Sed return __builtin_popcount(Value); 420193323Sed#else 421193323Sed uint32_t v = Value - ((Value >> 1) & 0x55555555); 422193323Sed v = (v & 0x33333333) + ((v >> 2) & 0x33333333); 423193323Sed return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; 424193323Sed#endif 425193323Sed} 426193323Sed 427193323Sed/// CountPopulation_64 - this function counts the number of set bits in a value, 428193323Sed/// (64 bit edition.) 429193323Sedinline unsigned CountPopulation_64(uint64_t Value) { 430193323Sed#if __GNUC__ >= 4 431193323Sed return __builtin_popcountll(Value); 432193323Sed#else 433193323Sed uint64_t v = Value - ((Value >> 1) & 0x5555555555555555ULL); 434193323Sed v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL); 435193323Sed v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL; 436193323Sed return unsigned((uint64_t)(v * 0x0101010101010101ULL) >> 56); 437193323Sed#endif 438193323Sed} 439193323Sed 440193323Sed/// Log2_32 - This function returns the floor log base 2 of the specified value, 441193323Sed/// -1 if the value is zero. (32 bit edition.) 442193323Sed/// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1, Log2_32(6) == 2 443193323Sedinline unsigned Log2_32(uint32_t Value) { 444261991Sdim return 31 - countLeadingZeros(Value); 445193323Sed} 446193323Sed 447193323Sed/// Log2_64 - This function returns the floor log base 2 of the specified value, 448193323Sed/// -1 if the value is zero. (64 bit edition.) 449193323Sedinline unsigned Log2_64(uint64_t Value) { 450261991Sdim return 63 - countLeadingZeros(Value); 451193323Sed} 452193323Sed 453193323Sed/// Log2_32_Ceil - This function returns the ceil log base 2 of the specified 454193323Sed/// value, 32 if the value is zero. (32 bit edition). 455193323Sed/// Ex. Log2_32_Ceil(32) == 5, Log2_32_Ceil(1) == 0, Log2_32_Ceil(6) == 3 456193323Sedinline unsigned Log2_32_Ceil(uint32_t Value) { 457261991Sdim return 32 - countLeadingZeros(Value - 1); 458193323Sed} 459193323Sed 460193323Sed/// Log2_64_Ceil - This function returns the ceil log base 2 of the specified 461193323Sed/// value, 64 if the value is zero. (64 bit edition.) 462193323Sedinline unsigned Log2_64_Ceil(uint64_t Value) { 463261991Sdim return 64 - countLeadingZeros(Value - 1); 464193323Sed} 465193323Sed 466193323Sed/// GreatestCommonDivisor64 - Return the greatest common divisor of the two 467193323Sed/// values using Euclid's algorithm. 468193323Sedinline uint64_t GreatestCommonDivisor64(uint64_t A, uint64_t B) { 469193323Sed while (B) { 470193323Sed uint64_t T = B; 471193323Sed B = A % B; 472193323Sed A = T; 473193323Sed } 474193323Sed return A; 475193323Sed} 476193323Sed 477193323Sed/// BitsToDouble - This function takes a 64-bit integer and returns the bit 478193323Sed/// equivalent double. 479193323Sedinline double BitsToDouble(uint64_t Bits) { 480193323Sed union { 481193323Sed uint64_t L; 482193323Sed double D; 483193323Sed } T; 484193323Sed T.L = Bits; 485193323Sed return T.D; 486193323Sed} 487193323Sed 488193323Sed/// BitsToFloat - This function takes a 32-bit integer and returns the bit 489193323Sed/// equivalent float. 490193323Sedinline float BitsToFloat(uint32_t Bits) { 491193323Sed union { 492193323Sed uint32_t I; 493193323Sed float F; 494193323Sed } T; 495193323Sed T.I = Bits; 496193323Sed return T.F; 497193323Sed} 498193323Sed 499193323Sed/// DoubleToBits - This function takes a double and returns the bit 500193323Sed/// equivalent 64-bit integer. Note that copying doubles around 501193323Sed/// changes the bits of NaNs on some hosts, notably x86, so this 502193323Sed/// routine cannot be used if these bits are needed. 503193323Sedinline uint64_t DoubleToBits(double Double) { 504193323Sed union { 505193323Sed uint64_t L; 506193323Sed double D; 507193323Sed } T; 508193323Sed T.D = Double; 509193323Sed return T.L; 510193323Sed} 511193323Sed 512193323Sed/// FloatToBits - This function takes a float and returns the bit 513193323Sed/// equivalent 32-bit integer. Note that copying floats around 514193323Sed/// changes the bits of NaNs on some hosts, notably x86, so this 515193323Sed/// routine cannot be used if these bits are needed. 516193323Sedinline uint32_t FloatToBits(float Float) { 517193323Sed union { 518193323Sed uint32_t I; 519193323Sed float F; 520193323Sed } T; 521193323Sed T.F = Float; 522193323Sed return T.I; 523193323Sed} 524193323Sed 525193323Sed/// Platform-independent wrappers for the C99 isnan() function. 526193323Sedint IsNAN(float f); 527193323Sedint IsNAN(double d); 528193323Sed 529193323Sed/// Platform-independent wrappers for the C99 isinf() function. 530193323Sedint IsInf(float f); 531193323Sedint IsInf(double d); 532193323Sed 533193323Sed/// MinAlign - A and B are either alignments or offsets. Return the minimum 534193323Sed/// alignment that may be assumed after adding the two together. 535239462Sdiminline uint64_t MinAlign(uint64_t A, uint64_t B) { 536193323Sed // The largest power of 2 that divides both A and B. 537249423Sdim // 538249423Sdim // Replace "-Value" by "1+~Value" in the following commented code to avoid 539249423Sdim // MSVC warning C4146 540249423Sdim // return (A | B) & -(A | B); 541249423Sdim return (A | B) & (1 + ~(A | B)); 542193323Sed} 543193323Sed 544193323Sed/// NextPowerOf2 - Returns the next power of two (in 64-bits) 545193323Sed/// that is strictly greater than A. Returns zero on overflow. 546239462Sdiminline uint64_t NextPowerOf2(uint64_t A) { 547193323Sed A |= (A >> 1); 548193323Sed A |= (A >> 2); 549193323Sed A |= (A >> 4); 550193323Sed A |= (A >> 8); 551193323Sed A |= (A >> 16); 552193323Sed A |= (A >> 32); 553193323Sed return A + 1; 554193323Sed} 555193323Sed 556243830Sdim/// Returns the next integer (mod 2**64) that is greater than or equal to 557243830Sdim/// \p Value and is a multiple of \p Align. \p Align must be non-zero. 558193323Sed/// 559193323Sed/// Examples: 560243830Sdim/// \code 561243830Sdim/// RoundUpToAlignment(5, 8) = 8 562243830Sdim/// RoundUpToAlignment(17, 8) = 24 563243830Sdim/// RoundUpToAlignment(~0LL, 8) = 0 564243830Sdim/// \endcode 565193323Sedinline uint64_t RoundUpToAlignment(uint64_t Value, uint64_t Align) { 566193323Sed return ((Value + Align - 1) / Align) * Align; 567193323Sed} 568193323Sed 569243830Sdim/// Returns the offset to the next integer (mod 2**64) that is greater than 570243830Sdim/// or equal to \p Value and is a multiple of \p Align. \p Align must be 571243830Sdim/// non-zero. 572198090Srdivackyinline uint64_t OffsetToAlignment(uint64_t Value, uint64_t Align) { 573198090Srdivacky return RoundUpToAlignment(Value, Align) - Value; 574198090Srdivacky} 575198090Srdivacky 576193323Sed/// abs64 - absolute value of a 64-bit int. Not all environments support 577193323Sed/// "abs" on whatever their name for the 64-bit int type is. The absolute 578193323Sed/// value of the largest negative number is undefined, as with "abs". 579193323Sedinline int64_t abs64(int64_t x) { 580193323Sed return (x < 0) ? -x : x; 581193323Sed} 582193323Sed 583206124Srdivacky/// SignExtend32 - Sign extend B-bit number x to 32-bit int. 584206124Srdivacky/// Usage int32_t r = SignExtend32<5>(x); 585206274Srdivackytemplate <unsigned B> inline int32_t SignExtend32(uint32_t x) { 586206274Srdivacky return int32_t(x << (32 - B)) >> (32 - B); 587206124Srdivacky} 588206124Srdivacky 589243830Sdim/// \brief Sign extend number in the bottom B bits of X to a 32-bit int. 590243830Sdim/// Requires 0 < B <= 32. 591243830Sdiminline int32_t SignExtend32(uint32_t X, unsigned B) { 592243830Sdim return int32_t(X << (32 - B)) >> (32 - B); 593243830Sdim} 594243830Sdim 595206124Srdivacky/// SignExtend64 - Sign extend B-bit number x to 64-bit int. 596206124Srdivacky/// Usage int64_t r = SignExtend64<5>(x); 597206274Srdivackytemplate <unsigned B> inline int64_t SignExtend64(uint64_t x) { 598206274Srdivacky return int64_t(x << (64 - B)) >> (64 - B); 599206124Srdivacky} 600206124Srdivacky 601243830Sdim/// \brief Sign extend number in the bottom B bits of X to a 64-bit int. 602243830Sdim/// Requires 0 < B <= 64. 603243830Sdiminline int64_t SignExtend64(uint64_t X, unsigned B) { 604243830Sdim return int64_t(X << (64 - B)) >> (64 - B); 605243830Sdim} 606243830Sdim 607261991Sdim#if defined(_MSC_VER) 608261991Sdim // Visual Studio defines the HUGE_VAL class of macros using purposeful 609261991Sdim // constant arithmetic overflow, which it then warns on when encountered. 610261991Sdim const float huge_valf = std::numeric_limits<float>::infinity(); 611261991Sdim#else 612261991Sdim const float huge_valf = HUGE_VALF; 613261991Sdim#endif 614193323Sed} // End llvm namespace 615193323Sed 616193323Sed#endif 617