diff options
| -rw-r--r-- | include/llvm/ADT/APInt.h | 49 |
1 files changed, 40 insertions, 9 deletions
diff --git a/include/llvm/ADT/APInt.h b/include/llvm/ADT/APInt.h index d4fba2006c..b08da956ab 100644 --- a/include/llvm/ADT/APInt.h +++ b/include/llvm/ADT/APInt.h @@ -114,12 +114,22 @@ public: /// by the APInt. This is needed after the most significant word is assigned /// a value to ensure that those bits are zero'd out. /// @brief Clear high order bits - inline void clearUnusedBits() { + inline APInt& clearUnusedBits() { + // Compute how many bits are used in the final word + uint32_t wordBits = BitWidth % APINT_BITS_PER_WORD; + if (wordBits == 0) + // If all bits are used, we want to leave the value alone. This also + // avoids the undefined behavior of >> when the shfit is the same size as + // the word size (64). + return *this; + + // Mask out the hight bits. + uint64_t mask = ~uint64_t(0ULL) >> (APINT_BITS_PER_WORD - wordBits); if (isSingleWord()) - VAL &= ~uint64_t(0ULL) >> (APINT_BITS_PER_WORD - BitWidth); + VAL &= mask; else - pVal[getNumWords() - 1] &= ~uint64_t(0ULL) >> - (APINT_BITS_PER_WORD - (whichBit(BitWidth - 1) + 1)); + pVal[getNumWords() - 1] &= mask; + return *this; } /// @returns the corresponding word for the specified bit position. @@ -134,7 +144,9 @@ public: uint8_t radix); /// This is used by the toString method to divide by the radix. It simply - /// provides a more convenient form of divide for internal use. + /// provides a more convenient form of divide for internal use since KnuthDiv + /// has specific constraints on its inputs. If those constraints are not met + /// then it provides a simpler form of divide. /// @brief An internal division function for dividing APInts. static void divide(const APInt LHS, uint32_t lhsWords, const APInt &RHS, uint32_t rhsWords, @@ -481,15 +493,30 @@ public: /// @returns true if the argument APInt value is a power of two > 0. bool isPowerOf2() const; + /// countLeadingZeros - This function is an APInt version of the + /// countLeadingZeros_{32,64} functions in MathExtras.h. It counts the number + /// of zeros from the most significant bit to the first one bit. + /// @returns getNumWords() * APINT_BITS_PER_WORD if the value is zero. /// @returns the number of zeros from the most significant bit to the first /// one bits. + /// @brief Count the number of trailing one bits. uint32_t countLeadingZeros() const; + /// countTrailingZeros - This function is an APInt version of the + /// countTrailingZoers_{32,64} functions in MathExtras.h. It counts + /// the number of zeros from the least significant bit to the first one bit. + /// @returns getNumWords() * APINT_BITS_PER_WORD if the value is zero. /// @returns the number of zeros from the least significant bit to the first /// one bit. + /// @brief Count the number of trailing zero bits. uint32_t countTrailingZeros() const; + /// countPopulation - This function is an APInt version of the + /// countPopulation_{32,64} functions in MathExtras.h. It counts the number + /// of 1 bits in the APInt value. + /// @returns 0 if the value is zero. /// @returns the number of set bits. + /// @brief Count the number of bits set. uint32_t countPopulation() const; /// @returns the total number of bits. @@ -550,9 +577,11 @@ inline uint32_t logBase2(const APInt& APIVal) { return APIVal.logBase2(); } -/// @returns the greatest common divisor of the two values -/// using Euclid's algorithm. -APInt GreatestCommonDivisor(const APInt& API1, const APInt& API2); +/// GreatestCommonDivisor - This function returns the greatest common +/// divisor of the two APInt values using Enclid's algorithm. +/// @returns the greatest common divisor of Val1 and Val2 +/// @brief Compute GCD of two APInt values. +APInt GreatestCommonDivisor(const APInt& Val1, const APInt& Val2); /// @brief Converts the given APInt to a double value. inline double RoundAPIntToDouble(const APInt& APIVal, bool isSigned = false) { @@ -564,10 +593,12 @@ inline float RoundAPIntToFloat(const APInt& APIVal) { return float(RoundAPIntToDouble(APIVal)); } +/// RoundDoubleToAPInt - This function convert a double value to an APInt value. /// @brief Converts the given double value into a APInt. APInt RoundDoubleToAPInt(double Double); -/// @brief Converts the given float value into a APInt. +/// RoundFloatToAPInt - Converts a float value into an APInt value. +/// @brief Converts a float value into a APInt. inline APInt RoundFloatToAPInt(float Float) { return RoundDoubleToAPInt(double(Float)); } |