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Diffstat (limited to 'include/llvm/Support/MathExtras.h')
| -rw-r--r-- | include/llvm/Support/MathExtras.h | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/include/llvm/Support/MathExtras.h b/include/llvm/Support/MathExtras.h new file mode 100644 index 0000000..85e19ac --- /dev/null +++ b/include/llvm/Support/MathExtras.h @@ -0,0 +1,437 @@ +//===-- llvm/Support/MathExtras.h - Useful math functions -------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains some functions that are useful for math stuff. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_SUPPORT_MATHEXTRAS_H +#define LLVM_SUPPORT_MATHEXTRAS_H + +#include "llvm/Support/DataTypes.h" + +namespace llvm { + +// NOTE: The following support functions use the _32/_64 extensions instead of +// type overloading so that signed and unsigned integers can be used without +// ambiguity. + +/// Hi_32 - This function returns the high 32 bits of a 64 bit value. +inline uint32_t Hi_32(uint64_t Value) { + return static_cast<uint32_t>(Value >> 32); +} + +/// Lo_32 - This function returns the low 32 bits of a 64 bit value. +inline uint32_t Lo_32(uint64_t Value) { + return static_cast<uint32_t>(Value); +} + +/// is?Type - these functions produce optimal testing for integer data types. +inline bool isInt8 (int64_t Value) { + return static_cast<int8_t>(Value) == Value; +} +inline bool isUInt8 (int64_t Value) { + return static_cast<uint8_t>(Value) == Value; +} +inline bool isInt16 (int64_t Value) { + return static_cast<int16_t>(Value) == Value; +} +inline bool isUInt16(int64_t Value) { + return static_cast<uint16_t>(Value) == Value; +} +inline bool isInt32 (int64_t Value) { + return static_cast<int32_t>(Value) == Value; +} +inline bool isUInt32(int64_t Value) { + return static_cast<uint32_t>(Value) == Value; +} + +/// isMask_32 - This function returns true if the argument is a sequence of ones +/// starting at the least significant bit with the remainder zero (32 bit +/// version). Ex. isMask_32(0x0000FFFFU) == true. +inline bool isMask_32(uint32_t Value) { + return Value && ((Value + 1) & Value) == 0; +} + +/// isMask_64 - This function returns true if the argument is a sequence of ones +/// starting at the least significant bit with the remainder zero (64 bit +/// version). +inline bool isMask_64(uint64_t Value) { + return Value && ((Value + 1) & Value) == 0; +} + +/// isShiftedMask_32 - This function returns true if the argument contains a +/// sequence of ones with the remainder zero (32 bit version.) +/// Ex. isShiftedMask_32(0x0000FF00U) == true. +inline bool isShiftedMask_32(uint32_t Value) { + return isMask_32((Value - 1) | Value); +} + +/// isShiftedMask_64 - This function returns true if the argument contains a +/// sequence of ones with the remainder zero (64 bit version.) +inline bool isShiftedMask_64(uint64_t Value) { + return isMask_64((Value - 1) | Value); +} + +/// isPowerOf2_32 - This function returns true if the argument is a power of +/// two > 0. Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.) +inline bool isPowerOf2_32(uint32_t Value) { + return Value && !(Value & (Value - 1)); +} + +/// isPowerOf2_64 - This function returns true if the argument is a power of two +/// > 0 (64 bit edition.) +inline bool isPowerOf2_64(uint64_t Value) { + return Value && !(Value & (Value - int64_t(1L))); +} + +/// ByteSwap_16 - This function returns a byte-swapped representation of the +/// 16-bit argument, Value. +inline uint16_t ByteSwap_16(uint16_t Value) { +#if defined(_MSC_VER) && !defined(_DEBUG) + // The DLL version of the runtime lacks these functions (bug!?), but in a + // release build they're replaced with BSWAP instructions anyway. + return _byteswap_ushort(Value); +#else + uint16_t Hi = Value << 8; + uint16_t Lo = Value >> 8; + return Hi | Lo; +#endif +} + +/// ByteSwap_32 - This function returns a byte-swapped representation of the +/// 32-bit argument, Value. +inline uint32_t ByteSwap_32(uint32_t Value) { +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) + return __builtin_bswap32(Value); +#elif defined(_MSC_VER) && !defined(_DEBUG) + return _byteswap_ulong(Value); +#else + uint32_t Byte0 = Value & 0x000000FF; + uint32_t Byte1 = Value & 0x0000FF00; + uint32_t Byte2 = Value & 0x00FF0000; + uint32_t Byte3 = Value & 0xFF000000; + return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24); +#endif +} + +/// ByteSwap_64 - This function returns a byte-swapped representation of the +/// 64-bit argument, Value. +inline uint64_t ByteSwap_64(uint64_t Value) { +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) + return __builtin_bswap64(Value); +#elif defined(_MSC_VER) && !defined(_DEBUG) + return _byteswap_uint64(Value); +#else + uint64_t Hi = ByteSwap_32(uint32_t(Value)); + uint32_t Lo = ByteSwap_32(uint32_t(Value >> 32)); + return (Hi << 32) | Lo; +#endif +} + +/// CountLeadingZeros_32 - this function performs the platform optimal form of +/// counting the number of zeros from the most significant bit to the first one +/// bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8. +/// Returns 32 if the word is zero. +inline unsigned CountLeadingZeros_32(uint32_t Value) { + unsigned Count; // result +#if __GNUC__ >= 4 + // PowerPC is defined for __builtin_clz(0) +#if !defined(__ppc__) && !defined(__ppc64__) + if (!Value) return 32; +#endif + Count = __builtin_clz(Value); +#else + if (!Value) return 32; + Count = 0; + // bisecton method for count leading zeros + for (unsigned Shift = 32 >> 1; Shift; Shift >>= 1) { + uint32_t Tmp = Value >> Shift; + if (Tmp) { + Value = Tmp; + } else { + Count |= Shift; + } + } +#endif + return Count; +} + +/// CountLeadingOnes_32 - this function performs the operation of +/// counting the number of ones from the most significant bit to the first zero +/// bit. Ex. CountLeadingOnes_32(0xFF0FFF00) == 8. +/// Returns 32 if the word is all ones. +inline unsigned CountLeadingOnes_32(uint32_t Value) { + return CountLeadingZeros_32(~Value); +} + +/// CountLeadingZeros_64 - This function performs the platform optimal form +/// of counting the number of zeros from the most significant bit to the first +/// one bit (64 bit edition.) +/// Returns 64 if the word is zero. +inline unsigned CountLeadingZeros_64(uint64_t Value) { + unsigned Count; // result +#if __GNUC__ >= 4 + // PowerPC is defined for __builtin_clzll(0) +#if !defined(__ppc__) && !defined(__ppc64__) + if (!Value) return 64; +#endif + Count = __builtin_clzll(Value); +#else + if (sizeof(long) == sizeof(int64_t)) { + if (!Value) return 64; + Count = 0; + // bisecton method for count leading zeros + for (unsigned Shift = 64 >> 1; Shift; Shift >>= 1) { + uint64_t Tmp = Value >> Shift; + if (Tmp) { + Value = Tmp; + } else { + Count |= Shift; + } + } + } else { + // get hi portion + uint32_t Hi = Hi_32(Value); + + // if some bits in hi portion + if (Hi) { + // leading zeros in hi portion plus all bits in lo portion + Count = CountLeadingZeros_32(Hi); + } else { + // get lo portion + uint32_t Lo = Lo_32(Value); + // same as 32 bit value + Count = CountLeadingZeros_32(Lo)+32; + } + } +#endif + return Count; +} + +/// CountLeadingOnes_64 - This function performs the operation +/// of counting the number of ones from the most significant bit to the first +/// zero bit (64 bit edition.) +/// Returns 64 if the word is all ones. +inline unsigned CountLeadingOnes_64(uint64_t Value) { + return CountLeadingZeros_64(~Value); +} + +/// CountTrailingZeros_32 - this function performs the platform optimal form of +/// counting the number of zeros from the least significant bit to the first one +/// bit. Ex. CountTrailingZeros_32(0xFF00FF00) == 8. +/// Returns 32 if the word is zero. +inline unsigned CountTrailingZeros_32(uint32_t Value) { +#if __GNUC__ >= 4 + return Value ? __builtin_ctz(Value) : 32; +#else + static const unsigned Mod37BitPosition[] = { + 32, 0, 1, 26, 2, 23, 27, 0, 3, 16, 24, 30, 28, 11, 0, 13, + 4, 7, 17, 0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9, + 5, 20, 8, 19, 18 + }; + return Mod37BitPosition[(-Value & Value) % 37]; +#endif +} + +/// CountTrailingOnes_32 - this function performs the operation of +/// counting the number of ones from the least significant bit to the first zero +/// bit. Ex. CountTrailingOnes_32(0x00FF00FF) == 8. +/// Returns 32 if the word is all ones. +inline unsigned CountTrailingOnes_32(uint32_t Value) { + return CountTrailingZeros_32(~Value); +} + +/// CountTrailingZeros_64 - This function performs the platform optimal form +/// of counting the number of zeros from the least significant bit to the first +/// one bit (64 bit edition.) +/// Returns 64 if the word is zero. +inline unsigned CountTrailingZeros_64(uint64_t Value) { +#if __GNUC__ >= 4 + return Value ? __builtin_ctzll(Value) : 64; +#else + static const unsigned Mod67Position[] = { + 64, 0, 1, 39, 2, 15, 40, 23, 3, 12, 16, 59, 41, 19, 24, 54, + 4, 64, 13, 10, 17, 62, 60, 28, 42, 30, 20, 51, 25, 44, 55, + 47, 5, 32, 65, 38, 14, 22, 11, 58, 18, 53, 63, 9, 61, 27, + 29, 50, 43, 46, 31, 37, 21, 57, 52, 8, 26, 49, 45, 36, 56, + 7, 48, 35, 6, 34, 33, 0 + }; + return Mod67Position[(-Value & Value) % 67]; +#endif +} + +/// CountTrailingOnes_64 - This function performs the operation +/// of counting the number of ones from the least significant bit to the first +/// zero bit (64 bit edition.) +/// Returns 64 if the word is all ones. +inline unsigned CountTrailingOnes_64(uint64_t Value) { + return CountTrailingZeros_64(~Value); +} + +/// CountPopulation_32 - this function counts the number of set bits in a value. +/// Ex. CountPopulation(0xF000F000) = 8 +/// Returns 0 if the word is zero. +inline unsigned CountPopulation_32(uint32_t Value) { +#if __GNUC__ >= 4 + return __builtin_popcount(Value); +#else + uint32_t v = Value - ((Value >> 1) & 0x55555555); + v = (v & 0x33333333) + ((v >> 2) & 0x33333333); + return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; +#endif +} + +/// CountPopulation_64 - this function counts the number of set bits in a value, +/// (64 bit edition.) +inline unsigned CountPopulation_64(uint64_t Value) { +#if __GNUC__ >= 4 + return __builtin_popcountll(Value); +#else + uint64_t v = Value - ((Value >> 1) & 0x5555555555555555ULL); + v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL); + v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL; + return unsigned((uint64_t)(v * 0x0101010101010101ULL) >> 56); +#endif +} + +/// Log2_32 - This function returns the floor log base 2 of the specified value, +/// -1 if the value is zero. (32 bit edition.) +/// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1, Log2_32(6) == 2 +inline unsigned Log2_32(uint32_t Value) { + return 31 - CountLeadingZeros_32(Value); +} + +/// Log2_64 - This function returns the floor log base 2 of the specified value, +/// -1 if the value is zero. (64 bit edition.) +inline unsigned Log2_64(uint64_t Value) { + return 63 - CountLeadingZeros_64(Value); +} + +/// Log2_32_Ceil - This function returns the ceil log base 2 of the specified +/// value, 32 if the value is zero. (32 bit edition). +/// Ex. Log2_32_Ceil(32) == 5, Log2_32_Ceil(1) == 0, Log2_32_Ceil(6) == 3 +inline unsigned Log2_32_Ceil(uint32_t Value) { + return 32-CountLeadingZeros_32(Value-1); +} + +/// Log2_64_Ceil - This function returns the ceil log base 2 of the specified +/// value, 64 if the value is zero. (64 bit edition.) +inline unsigned Log2_64_Ceil(uint64_t Value) { + return 64-CountLeadingZeros_64(Value-1); +} + +/// GreatestCommonDivisor64 - Return the greatest common divisor of the two +/// values using Euclid's algorithm. +inline uint64_t GreatestCommonDivisor64(uint64_t A, uint64_t B) { + while (B) { + uint64_t T = B; + B = A % B; + A = T; + } + return A; +} + +/// BitsToDouble - This function takes a 64-bit integer and returns the bit +/// equivalent double. +inline double BitsToDouble(uint64_t Bits) { + union { + uint64_t L; + double D; + } T; + T.L = Bits; + return T.D; +} + +/// BitsToFloat - This function takes a 32-bit integer and returns the bit +/// equivalent float. +inline float BitsToFloat(uint32_t Bits) { + union { + uint32_t I; + float F; + } T; + T.I = Bits; + return T.F; +} + +/// DoubleToBits - This function takes a double and returns the bit +/// equivalent 64-bit integer. Note that copying doubles around +/// changes the bits of NaNs on some hosts, notably x86, so this +/// routine cannot be used if these bits are needed. +inline uint64_t DoubleToBits(double Double) { + union { + uint64_t L; + double D; + } T; + T.D = Double; + return T.L; +} + +/// FloatToBits - This function takes a float and returns the bit +/// equivalent 32-bit integer. Note that copying floats around +/// changes the bits of NaNs on some hosts, notably x86, so this +/// routine cannot be used if these bits are needed. +inline uint32_t FloatToBits(float Float) { + union { + uint32_t I; + float F; + } T; + T.F = Float; + return T.I; +} + +/// Platform-independent wrappers for the C99 isnan() function. +int IsNAN(float f); +int IsNAN(double d); + +/// Platform-independent wrappers for the C99 isinf() function. +int IsInf(float f); +int IsInf(double d); + +/// MinAlign - A and B are either alignments or offsets. Return the minimum +/// alignment that may be assumed after adding the two together. +static inline uint64_t MinAlign(uint64_t A, uint64_t B) { + // The largest power of 2 that divides both A and B. + return (A | B) & -(A | B); +} + +/// NextPowerOf2 - Returns the next power of two (in 64-bits) +/// that is strictly greater than A. Returns zero on overflow. +static inline uint64_t NextPowerOf2(uint64_t A) { + A |= (A >> 1); + A |= (A >> 2); + A |= (A >> 4); + A |= (A >> 8); + A |= (A >> 16); + A |= (A >> 32); + return A + 1; +} + +/// RoundUpToAlignment - Returns the next integer (mod 2**64) that is +/// greater than or equal to \arg Value and is a multiple of \arg +/// Align. Align must be non-zero. +/// +/// Examples: +/// RoundUpToAlignment(5, 8) = 8 +/// RoundUpToAlignment(17, 8) = 24 +/// RoundUpToAlignment(~0LL, 8) = 0 +inline uint64_t RoundUpToAlignment(uint64_t Value, uint64_t Align) { + return ((Value + Align - 1) / Align) * Align; +} + +/// abs64 - absolute value of a 64-bit int. Not all environments support +/// "abs" on whatever their name for the 64-bit int type is. The absolute +/// value of the largest negative number is undefined, as with "abs". +inline int64_t abs64(int64_t x) { + return (x < 0) ? -x : x; +} + +} // End llvm namespace + +#endif |
