X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FMathExtras.h;h=00c6ad70d4350fb87c5e64975f85b04b70e88863;hb=280e5eef43ecf2279ab78f132922920ed7ce7952;hp=10911ea11c51ea96e8d4edf0a4b05e7b6a9c21f7;hpb=2dcc27367ccc0ce03a78336472b9476d708d351e;p=oota-llvm.git diff --git a/include/llvm/Support/MathExtras.h b/include/llvm/Support/MathExtras.h index 10911ea11c5..00c6ad70d43 100644 --- a/include/llvm/Support/MathExtras.h +++ b/include/llvm/Support/MathExtras.h @@ -14,9 +14,234 @@ #ifndef LLVM_SUPPORT_MATHEXTRAS_H #define LLVM_SUPPORT_MATHEXTRAS_H +#include "llvm/Support/Compiler.h" #include "llvm/Support/SwapByteOrder.h" +#include "llvm/Support/type_traits.h" + +#include + +#ifdef _MSC_VER +# include +#endif namespace llvm { +/// \brief The behavior an operation has on an input of 0. +enum ZeroBehavior { + /// \brief The returned value is undefined. + ZB_Undefined, + /// \brief The returned value is numeric_limits::max() + ZB_Max, + /// \brief The returned value is numeric_limits::digits + ZB_Width +}; + +/// \brief Count number of 0's from the least significant bit to the most +/// stopping at the first 1. +/// +/// Only unsigned integral types are allowed. +/// +/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are +/// valid arguments. +template +typename enable_if_c::is_integer && + !std::numeric_limits::is_signed, std::size_t>::type +countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) { + (void)ZB; + + if (!Val) + return std::numeric_limits::digits; + if (Val & 0x1) + return 0; + + // Bisection method. + std::size_t ZeroBits = 0; + T Shift = std::numeric_limits::digits >> 1; + T Mask = std::numeric_limits::max() >> Shift; + while (Shift) { + if ((Val & Mask) == 0) { + Val >>= Shift; + ZeroBits |= Shift; + } + Shift >>= 1; + Mask >>= Shift; + } + return ZeroBits; +} + +// Disable signed. +template +typename enable_if_c::is_integer && + std::numeric_limits::is_signed, std::size_t>::type +countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) LLVM_DELETED_FUNCTION; + +#if __GNUC__ >= 4 || _MSC_VER +template <> +inline std::size_t countTrailingZeros(uint32_t Val, ZeroBehavior ZB) { + if (ZB != ZB_Undefined && Val == 0) + return 32; + +#if __has_builtin(__builtin_ctz) || __GNUC_PREREQ(4, 0) + return __builtin_ctz(Val); +#elif _MSC_VER + unsigned long Index; + _BitScanForward(&Index, Val); + return Index; +#endif +} + +#if !defined(_MSC_VER) || defined(_M_X64) +template <> +inline std::size_t countTrailingZeros(uint64_t Val, ZeroBehavior ZB) { + if (ZB != ZB_Undefined && Val == 0) + return 64; + +#if __has_builtin(__builtin_ctzll) || __GNUC_PREREQ(4, 0) + return __builtin_ctzll(Val); +#elif _MSC_VER + unsigned long Index; + _BitScanForward64(&Index, Val); + return Index; +#endif +} +#endif +#endif + +/// \brief Count number of 0's from the most significant bit to the least +/// stopping at the first 1. +/// +/// Only unsigned integral types are allowed. +/// +/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are +/// valid arguments. +template +typename enable_if_c::is_integer && + !std::numeric_limits::is_signed, std::size_t>::type +countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) { + (void)ZB; + + if (!Val) + return std::numeric_limits::digits; + + // Bisection method. + std::size_t ZeroBits = 0; + for (T Shift = std::numeric_limits::digits >> 1; Shift; Shift >>= 1) { + T Tmp = Val >> Shift; + if (Tmp) + Val = Tmp; + else + ZeroBits |= Shift; + } + return ZeroBits; +} + +// Disable signed. +template +typename enable_if_c::is_integer && + std::numeric_limits::is_signed, std::size_t>::type +countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) LLVM_DELETED_FUNCTION; + +#if __GNUC__ >= 4 || _MSC_VER +template <> +inline std::size_t countLeadingZeros(uint32_t Val, ZeroBehavior ZB) { + if (ZB != ZB_Undefined && Val == 0) + return 32; + +#if __has_builtin(__builtin_clz) || __GNUC_PREREQ(4, 0) + return __builtin_clz(Val); +#elif _MSC_VER + unsigned long Index; + _BitScanReverse(&Index, Val); + return Index ^ 31; +#endif +} + +#if !defined(_MSC_VER) || defined(_M_X64) +template <> +inline std::size_t countLeadingZeros(uint64_t Val, ZeroBehavior ZB) { + if (ZB != ZB_Undefined && Val == 0) + return 64; + +#if __has_builtin(__builtin_clzll) || __GNUC_PREREQ(4, 0) + return __builtin_clzll(Val); +#elif _MSC_VER + unsigned long Index; + _BitScanReverse64(&Index, Val); + return Index ^ 63; +#endif +} +#endif +#endif + +/// \brief Get the index of the first set bit starting from the least +/// significant bit. +/// +/// Only unsigned integral types are allowed. +/// +/// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are +/// valid arguments. +template +typename enable_if_c::is_integer && + !std::numeric_limits::is_signed, T>::type +findFirstSet(T Val, ZeroBehavior ZB = ZB_Max) { + if (ZB == ZB_Max && Val == 0) + return std::numeric_limits::max(); + + return countTrailingZeros(Val, ZB_Undefined); +} + +// Disable signed. +template +typename enable_if_c::is_integer && + std::numeric_limits::is_signed, T>::type +findFirstSet(T Val, ZeroBehavior ZB = ZB_Max) LLVM_DELETED_FUNCTION; + +/// \brief Get the index of the last set bit starting from the least +/// significant bit. +/// +/// Only unsigned integral types are allowed. +/// +/// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are +/// valid arguments. +template +typename enable_if_c::is_integer && + !std::numeric_limits::is_signed, T>::type +findLastSet(T Val, ZeroBehavior ZB = ZB_Max) { + if (ZB == ZB_Max && Val == 0) + return std::numeric_limits::max(); + + // Use ^ instead of - because both gcc and llvm can remove the associated ^ + // in the __builtin_clz intrinsic on x86. + return countLeadingZeros(Val, ZB_Undefined) ^ + (std::numeric_limits::digits - 1); +} + +// Disable signed. +template +typename enable_if_c::is_integer && + std::numeric_limits::is_signed, T>::type +findLastSet(T Val, ZeroBehavior ZB = ZB_Max) LLVM_DELETED_FUNCTION; + +/// \brief Macro compressed bit reversal table for 256 bits. +/// +/// http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable +static const unsigned char BitReverseTable256[256] = { +#define R2(n) n, n + 2 * 64, n + 1 * 64, n + 3 * 64 +#define R4(n) R2(n), R2(n + 2 * 16), R2(n + 1 * 16), R2(n + 3 * 16) +#define R6(n) R4(n), R4(n + 2 * 4), R4(n + 1 * 4), R4(n + 3 * 4) + R6(0), R6(2), R6(1), R6(3) +}; + +/// \brief Reverse the bits in \p Val. +template +T reverseBits(T Val) { + unsigned char in[sizeof(Val)]; + unsigned char out[sizeof(Val)]; + std::memcpy(in, &Val, sizeof(Val)); + for (unsigned i = 0; i < sizeof(Val); ++i) + out[(sizeof(Val) - i) - 1] = BitReverseTable256[in[i]]; + std::memcpy(&Val, out, sizeof(Val)); + return Val; +} // NOTE: The following support functions use the _32/_64 extensions instead of // type overloading so that signed and unsigned integers can be used without @@ -61,7 +286,7 @@ inline bool isShiftedInt(int64_t x) { /// isUInt - Checks if an unsigned integer fits into the given bit width. template inline bool isUInt(uint64_t x) { - return N >= 64 || x < (UINT64_C(1)<= 64 || x < (UINT64_C(1)<<(N)); } // Template specializations to get better code for common cases. template<> @@ -153,84 +378,12 @@ inline uint64_t ByteSwap_64(uint64_t Value) { return sys::SwapByteOrder_64(Value); } -/// 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; - // bisection 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; - // bisection 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; + return countLeadingZeros(~Value); } /// CountLeadingOnes_64 - This function performs the operation @@ -238,24 +391,7 @@ inline unsigned CountLeadingZeros_64(uint64_t Value) { /// 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 + return countLeadingZeros(~Value); } /// CountTrailingOnes_32 - this function performs the operation of @@ -263,26 +399,7 @@ inline unsigned CountTrailingZeros_32(uint32_t Value) { /// 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 + return countTrailingZeros(~Value); } /// CountTrailingOnes_64 - This function performs the operation @@ -290,7 +407,7 @@ inline unsigned CountTrailingZeros_64(uint64_t Value) { /// zero bit (64 bit edition.) /// Returns 64 if the word is all ones. inline unsigned CountTrailingOnes_64(uint64_t Value) { - return CountTrailingZeros_64(~Value); + return countTrailingZeros(~Value); } /// CountPopulation_32 - this function counts the number of set bits in a value. @@ -299,8 +416,6 @@ inline unsigned CountTrailingOnes_64(uint64_t Value) { inline unsigned CountPopulation_32(uint32_t Value) { #if __GNUC__ >= 4 return __builtin_popcount(Value); -#elif _MSC_VER - return __popcnt(Value); #else uint32_t v = Value - ((Value >> 1) & 0x55555555); v = (v & 0x33333333) + ((v >> 2) & 0x33333333); @@ -313,8 +428,6 @@ inline unsigned CountPopulation_32(uint32_t Value) { inline unsigned CountPopulation_64(uint64_t Value) { #if __GNUC__ >= 4 return __builtin_popcountll(Value); -#elif _MSC_VER - return __popcnt64(Value); #else uint64_t v = Value - ((Value >> 1) & 0x5555555555555555ULL); v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL); @@ -327,26 +440,26 @@ inline unsigned CountPopulation_64(uint64_t 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); + return 31 - countLeadingZeros(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); + return 63 - countLeadingZeros(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); + return 32 - countLeadingZeros(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); + return 64 - countLeadingZeros(Value - 1); } /// GreatestCommonDivisor64 - Return the greatest common divisor of the two @@ -420,7 +533,11 @@ int IsInf(double d); /// alignment that may be assumed after adding the two together. 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); + // + // Replace "-Value" by "1+~Value" in the following commented code to avoid + // MSVC warning C4146 + // return (A | B) & -(A | B); + return (A | B) & (1 + ~(A | B)); } /// NextPowerOf2 - Returns the next power of two (in 64-bits)