diff options
Diffstat (limited to 'contrib/llvm/lib/Support/APFloat.cpp')
| -rw-r--r-- | contrib/llvm/lib/Support/APFloat.cpp | 696 |
1 files changed, 495 insertions, 201 deletions
diff --git a/contrib/llvm/lib/Support/APFloat.cpp b/contrib/llvm/lib/Support/APFloat.cpp index 6182e34..676e2d4 100644 --- a/contrib/llvm/lib/Support/APFloat.cpp +++ b/contrib/llvm/lib/Support/APFloat.cpp @@ -25,7 +25,13 @@ using namespace llvm; -#define convolve(lhs, rhs) ((lhs) * 4 + (rhs)) +/// A macro used to combine two fcCategory enums into one key which can be used +/// in a switch statement to classify how the interaction of two APFloat's +/// categories affects an operation. +/// +/// TODO: If clang source code is ever allowed to use constexpr in its own +/// codebase, change this into a static inline function. +#define PackCategoriesIntoKey(_lhs, _rhs) ((_lhs) * 4 + (_rhs)) /* Assumed in hexadecimal significand parsing, and conversion to hexadecimal strings. */ @@ -38,11 +44,11 @@ namespace llvm { struct fltSemantics { /* The largest E such that 2^E is representable; this matches the definition of IEEE 754. */ - exponent_t maxExponent; + APFloat::ExponentType maxExponent; /* The smallest E such that 2^E is a normalized number; this matches the definition of IEEE 754. */ - exponent_t minExponent; + APFloat::ExponentType minExponent; /* Number of bits in the significand. This includes the integer bit. */ @@ -288,9 +294,9 @@ interpretDecimal(StringRef::iterator begin, StringRef::iterator end, } /* Adjust the exponents for any decimal point. */ - D->exponent += static_cast<exponent_t>((dot - p) - (dot > p)); + D->exponent += static_cast<APFloat::ExponentType>((dot - p) - (dot > p)); D->normalizedExponent = (D->exponent + - static_cast<exponent_t>((p - D->firstSigDigit) + static_cast<APFloat::ExponentType>((p - D->firstSigDigit) - (dot > D->firstSigDigit && dot < p))); } @@ -313,8 +319,8 @@ trailingHexadecimalFraction(StringRef::iterator p, StringRef::iterator end, else if (digitValue < 8 && digitValue > 0) return lfLessThanHalf; - /* Otherwise we need to find the first non-zero digit. */ - while (*p == '0') + // Otherwise we need to find the first non-zero digit. + while (p != end && (*p == '0' || *p == '.')) p++; assert(p != end && "Invalid trailing hexadecimal fraction!"); @@ -580,7 +586,7 @@ APFloat::initialize(const fltSemantics *ourSemantics) void APFloat::freeSignificand() { - if (partCount() > 1) + if (needsCleanup()) delete [] significand.parts; } @@ -592,14 +598,14 @@ APFloat::assign(const APFloat &rhs) sign = rhs.sign; category = rhs.category; exponent = rhs.exponent; - if (category == fcNormal || category == fcNaN) + if (isFiniteNonZero() || category == fcNaN) copySignificand(rhs); } void APFloat::copySignificand(const APFloat &rhs) { - assert(category == fcNormal || category == fcNaN); + assert(isFiniteNonZero() || category == fcNaN); assert(rhs.partCount() >= partCount()); APInt::tcAssign(significandParts(), rhs.significandParts(), @@ -679,12 +685,73 @@ APFloat::operator=(const APFloat &rhs) bool APFloat::isDenormal() const { - return isNormal() && (exponent == semantics->minExponent) && + return isFiniteNonZero() && (exponent == semantics->minExponent) && (APInt::tcExtractBit(significandParts(), semantics->precision - 1) == 0); } bool +APFloat::isSmallest() const { + // The smallest number by magnitude in our format will be the smallest + // denormal, i.e. the floating point number with exponent being minimum + // exponent and significand bitwise equal to 1 (i.e. with MSB equal to 0). + return isFiniteNonZero() && exponent == semantics->minExponent && + significandMSB() == 0; +} + +bool APFloat::isSignificandAllOnes() const { + // Test if the significand excluding the integral bit is all ones. This allows + // us to test for binade boundaries. + const integerPart *Parts = significandParts(); + const unsigned PartCount = partCount(); + for (unsigned i = 0; i < PartCount - 1; i++) + if (~Parts[i]) + return false; + + // Set the unused high bits to all ones when we compare. + const unsigned NumHighBits = + PartCount*integerPartWidth - semantics->precision + 1; + assert(NumHighBits <= integerPartWidth && "Can not have more high bits to " + "fill than integerPartWidth"); + const integerPart HighBitFill = + ~integerPart(0) << (integerPartWidth - NumHighBits); + if (~(Parts[PartCount - 1] | HighBitFill)) + return false; + + return true; +} + +bool APFloat::isSignificandAllZeros() const { + // Test if the significand excluding the integral bit is all zeros. This + // allows us to test for binade boundaries. + const integerPart *Parts = significandParts(); + const unsigned PartCount = partCount(); + + for (unsigned i = 0; i < PartCount - 1; i++) + if (Parts[i]) + return false; + + const unsigned NumHighBits = + PartCount*integerPartWidth - semantics->precision + 1; + assert(NumHighBits <= integerPartWidth && "Can not have more high bits to " + "clear than integerPartWidth"); + const integerPart HighBitMask = ~integerPart(0) >> NumHighBits; + + if (Parts[PartCount - 1] & HighBitMask) + return false; + + return true; +} + +bool +APFloat::isLargest() const { + // The largest number by magnitude in our format will be the floating point + // number with maximum exponent and with significand that is all ones. + return isFiniteNonZero() && exponent == semantics->maxExponent + && isSignificandAllOnes(); +} + +bool APFloat::bitwiseIsEqual(const APFloat &rhs) const { if (this == &rhs) return true; @@ -694,7 +761,7 @@ APFloat::bitwiseIsEqual(const APFloat &rhs) const { return false; if (category==fcZero || category==fcInfinity) return true; - else if (category==fcNormal && exponent!=rhs.exponent) + else if (isFiniteNonZero() && exponent!=rhs.exponent) return false; else { int i= partCount(); @@ -711,6 +778,7 @@ APFloat::bitwiseIsEqual(const APFloat &rhs) const { APFloat::APFloat(const fltSemantics &ourSemantics, integerPart value) { initialize(&ourSemantics); sign = 0; + category = fcNormal; zeroSignificand(); exponent = ourSemantics.precision - 1; significandParts()[0] = value; @@ -728,17 +796,6 @@ APFloat::APFloat(const fltSemantics &ourSemantics, uninitializedTag tag) { initialize(&ourSemantics); } -APFloat::APFloat(const fltSemantics &ourSemantics, - fltCategory ourCategory, bool negative) { - initialize(&ourSemantics); - category = ourCategory; - sign = negative; - if (category == fcNormal) - category = fcZero; - else if (ourCategory == fcNaN) - makeNaN(); -} - APFloat::APFloat(const fltSemantics &ourSemantics, StringRef text) { initialize(&ourSemantics); convertFromString(text, rmNearestTiesToEven); @@ -780,8 +837,6 @@ APFloat::significandParts() const integerPart * APFloat::significandParts() { - assert(category == fcNormal || category == fcNaN); - if (partCount() > 1) return significand.parts; else @@ -791,7 +846,6 @@ APFloat::significandParts() void APFloat::zeroSignificand() { - category = fcNormal; APInt::tcSet(significandParts(), 0, partCount()); } @@ -872,7 +926,21 @@ APFloat::multiplySignificand(const APFloat &rhs, const APFloat *addend) omsb = APInt::tcMSB(fullSignificand, newPartsCount) + 1; exponent += rhs.exponent; + // Assume the operands involved in the multiplication are single-precision + // FP, and the two multiplicants are: + // *this = a23 . a22 ... a0 * 2^e1 + // rhs = b23 . b22 ... b0 * 2^e2 + // the result of multiplication is: + // *this = c47 c46 . c45 ... c0 * 2^(e1+e2) + // Note that there are two significant bits at the left-hand side of the + // radix point. Move the radix point toward left by one bit, and adjust + // exponent accordingly. + exponent += 1; + if (addend) { + // The intermediate result of the multiplication has "2 * precision" + // signicant bit; adjust the addend to be consistent with mul result. + // Significand savedSignificand = significand; const fltSemantics *savedSemantics = semantics; fltSemantics extendedSemantics; @@ -880,8 +948,9 @@ APFloat::multiplySignificand(const APFloat &rhs, const APFloat *addend) unsigned int extendedPrecision; /* Normalize our MSB. */ - extendedPrecision = precision + precision - 1; + extendedPrecision = 2 * precision; if (omsb != extendedPrecision) { + assert(extendedPrecision > omsb); APInt::tcShiftLeft(fullSignificand, newPartsCount, extendedPrecision - omsb); exponent -= extendedPrecision - omsb; @@ -912,8 +981,18 @@ APFloat::multiplySignificand(const APFloat &rhs, const APFloat *addend) omsb = APInt::tcMSB(fullSignificand, newPartsCount) + 1; } - exponent -= (precision - 1); + // Convert the result having "2 * precision" significant-bits back to the one + // having "precision" significant-bits. First, move the radix point from + // poision "2*precision - 1" to "precision - 1". The exponent need to be + // adjusted by "2*precision - 1" - "precision - 1" = "precision". + exponent -= precision; + // In case MSB resides at the left-hand side of radix point, shift the + // mantissa right by some amount to make sure the MSB reside right before + // the radix point (i.e. "MSB . rest-significant-bits"). + // + // Note that the result is not normalized when "omsb < precision". So, the + // caller needs to call APFloat::normalize() if normalized value is expected. if (omsb > precision) { unsigned int bits, significantParts; lostFraction lf; @@ -1035,7 +1114,7 @@ lostFraction APFloat::shiftSignificandRight(unsigned int bits) { /* Our exponent should not overflow. */ - assert((exponent_t) (exponent + bits) >= exponent); + assert((ExponentType) (exponent + bits) >= exponent); exponent += bits; @@ -1064,8 +1143,8 @@ APFloat::compareAbsoluteValue(const APFloat &rhs) const int compare; assert(semantics == rhs.semantics); - assert(category == fcNormal); - assert(rhs.category == fcNormal); + assert(isFiniteNonZero()); + assert(rhs.isFiniteNonZero()); compare = exponent - rhs.exponent; @@ -1117,7 +1196,7 @@ APFloat::roundAwayFromZero(roundingMode rounding_mode, unsigned int bit) const { /* NaNs and infinities should not have lost fractions. */ - assert(category == fcNormal || category == fcZero); + assert(isFiniteNonZero() || category == fcZero); /* Current callers never pass this so we don't handle it. */ assert(lost_fraction != lfExactlyZero); @@ -1155,7 +1234,7 @@ APFloat::normalize(roundingMode rounding_mode, unsigned int omsb; /* One, not zero, based MSB. */ int exponentChange; - if (category != fcNormal) + if (!isFiniteNonZero()) return opOK; /* Before rounding normalize the exponent of fcNormal numbers. */ @@ -1259,42 +1338,43 @@ APFloat::normalize(roundingMode rounding_mode, APFloat::opStatus APFloat::addOrSubtractSpecials(const APFloat &rhs, bool subtract) { - switch (convolve(category, rhs.category)) { + switch (PackCategoriesIntoKey(category, rhs.category)) { default: llvm_unreachable(0); - case convolve(fcNaN, fcZero): - case convolve(fcNaN, fcNormal): - case convolve(fcNaN, fcInfinity): - case convolve(fcNaN, fcNaN): - case convolve(fcNormal, fcZero): - case convolve(fcInfinity, fcNormal): - case convolve(fcInfinity, fcZero): + case PackCategoriesIntoKey(fcNaN, fcZero): + case PackCategoriesIntoKey(fcNaN, fcNormal): + case PackCategoriesIntoKey(fcNaN, fcInfinity): + case PackCategoriesIntoKey(fcNaN, fcNaN): + case PackCategoriesIntoKey(fcNormal, fcZero): + case PackCategoriesIntoKey(fcInfinity, fcNormal): + case PackCategoriesIntoKey(fcInfinity, fcZero): return opOK; - case convolve(fcZero, fcNaN): - case convolve(fcNormal, fcNaN): - case convolve(fcInfinity, fcNaN): + case PackCategoriesIntoKey(fcZero, fcNaN): + case PackCategoriesIntoKey(fcNormal, fcNaN): + case PackCategoriesIntoKey(fcInfinity, fcNaN): + sign = false; category = fcNaN; copySignificand(rhs); return opOK; - case convolve(fcNormal, fcInfinity): - case convolve(fcZero, fcInfinity): + case PackCategoriesIntoKey(fcNormal, fcInfinity): + case PackCategoriesIntoKey(fcZero, fcInfinity): category = fcInfinity; sign = rhs.sign ^ subtract; return opOK; - case convolve(fcZero, fcNormal): + case PackCategoriesIntoKey(fcZero, fcNormal): assign(rhs); sign = rhs.sign ^ subtract; return opOK; - case convolve(fcZero, fcZero): + case PackCategoriesIntoKey(fcZero, fcZero): /* Sign depends on rounding mode; handled by caller. */ return opOK; - case convolve(fcInfinity, fcInfinity): + case PackCategoriesIntoKey(fcInfinity, fcInfinity): /* Differently signed infinities can only be validly subtracted. */ if (((sign ^ rhs.sign)!=0) != subtract) { @@ -1304,7 +1384,7 @@ APFloat::addOrSubtractSpecials(const APFloat &rhs, bool subtract) return opOK; - case convolve(fcNormal, fcNormal): + case PackCategoriesIntoKey(fcNormal, fcNormal): return opDivByZero; } } @@ -1385,41 +1465,43 @@ APFloat::addOrSubtractSignificand(const APFloat &rhs, bool subtract) APFloat::opStatus APFloat::multiplySpecials(const APFloat &rhs) { - switch (convolve(category, rhs.category)) { + switch (PackCategoriesIntoKey(category, rhs.category)) { default: llvm_unreachable(0); - case convolve(fcNaN, fcZero): - case convolve(fcNaN, fcNormal): - case convolve(fcNaN, fcInfinity): - case convolve(fcNaN, fcNaN): + case PackCategoriesIntoKey(fcNaN, fcZero): + case PackCategoriesIntoKey(fcNaN, fcNormal): + case PackCategoriesIntoKey(fcNaN, fcInfinity): + case PackCategoriesIntoKey(fcNaN, fcNaN): + sign = false; return opOK; - case convolve(fcZero, fcNaN): - case convolve(fcNormal, fcNaN): - case convolve(fcInfinity, fcNaN): + case PackCategoriesIntoKey(fcZero, fcNaN): + case PackCategoriesIntoKey(fcNormal, fcNaN): + case PackCategoriesIntoKey(fcInfinity, fcNaN): + sign = false; category = fcNaN; copySignificand(rhs); return opOK; - case convolve(fcNormal, fcInfinity): - case convolve(fcInfinity, fcNormal): - case convolve(fcInfinity, fcInfinity): + case PackCategoriesIntoKey(fcNormal, fcInfinity): + case PackCategoriesIntoKey(fcInfinity, fcNormal): + case PackCategoriesIntoKey(fcInfinity, fcInfinity): category = fcInfinity; return opOK; - case convolve(fcZero, fcNormal): - case convolve(fcNormal, fcZero): - case convolve(fcZero, fcZero): + case PackCategoriesIntoKey(fcZero, fcNormal): + case PackCategoriesIntoKey(fcNormal, fcZero): + case PackCategoriesIntoKey(fcZero, fcZero): category = fcZero; return opOK; - case convolve(fcZero, fcInfinity): - case convolve(fcInfinity, fcZero): + case PackCategoriesIntoKey(fcZero, fcInfinity): + case PackCategoriesIntoKey(fcInfinity, fcZero): makeNaN(); return opInvalidOp; - case convolve(fcNormal, fcNormal): + case PackCategoriesIntoKey(fcNormal, fcNormal): return opOK; } } @@ -1427,41 +1509,40 @@ APFloat::multiplySpecials(const APFloat &rhs) APFloat::opStatus APFloat::divideSpecials(const APFloat &rhs) { - switch (convolve(category, rhs.category)) { + switch (PackCategoriesIntoKey(category, rhs.category)) { default: llvm_unreachable(0); - case convolve(fcNaN, fcZero): - case convolve(fcNaN, fcNormal): - case convolve(fcNaN, fcInfinity): - case convolve(fcNaN, fcNaN): - case convolve(fcInfinity, fcZero): - case convolve(fcInfinity, fcNormal): - case convolve(fcZero, fcInfinity): - case convolve(fcZero, fcNormal): - return opOK; - - case convolve(fcZero, fcNaN): - case convolve(fcNormal, fcNaN): - case convolve(fcInfinity, fcNaN): + case PackCategoriesIntoKey(fcZero, fcNaN): + case PackCategoriesIntoKey(fcNormal, fcNaN): + case PackCategoriesIntoKey(fcInfinity, fcNaN): category = fcNaN; copySignificand(rhs); + case PackCategoriesIntoKey(fcNaN, fcZero): + case PackCategoriesIntoKey(fcNaN, fcNormal): + case PackCategoriesIntoKey(fcNaN, fcInfinity): + case PackCategoriesIntoKey(fcNaN, fcNaN): + sign = false; + case PackCategoriesIntoKey(fcInfinity, fcZero): + case PackCategoriesIntoKey(fcInfinity, fcNormal): + case PackCategoriesIntoKey(fcZero, fcInfinity): + case PackCategoriesIntoKey(fcZero, fcNormal): return opOK; - case convolve(fcNormal, fcInfinity): + case PackCategoriesIntoKey(fcNormal, fcInfinity): category = fcZero; return opOK; - case convolve(fcNormal, fcZero): + case PackCategoriesIntoKey(fcNormal, fcZero): category = fcInfinity; return opDivByZero; - case convolve(fcInfinity, fcInfinity): - case convolve(fcZero, fcZero): + case PackCategoriesIntoKey(fcInfinity, fcInfinity): + case PackCategoriesIntoKey(fcZero, fcZero): makeNaN(); return opInvalidOp; - case convolve(fcNormal, fcNormal): + case PackCategoriesIntoKey(fcNormal, fcNormal): return opOK; } } @@ -1469,35 +1550,36 @@ APFloat::divideSpecials(const APFloat &rhs) APFloat::opStatus APFloat::modSpecials(const APFloat &rhs) { - switch (convolve(category, rhs.category)) { + switch (PackCategoriesIntoKey(category, rhs.category)) { default: llvm_unreachable(0); - case convolve(fcNaN, fcZero): - case convolve(fcNaN, fcNormal): - case convolve(fcNaN, fcInfinity): - case convolve(fcNaN, fcNaN): - case convolve(fcZero, fcInfinity): - case convolve(fcZero, fcNormal): - case convolve(fcNormal, fcInfinity): + case PackCategoriesIntoKey(fcNaN, fcZero): + case PackCategoriesIntoKey(fcNaN, fcNormal): + case PackCategoriesIntoKey(fcNaN, fcInfinity): + case PackCategoriesIntoKey(fcNaN, fcNaN): + case PackCategoriesIntoKey(fcZero, fcInfinity): + case PackCategoriesIntoKey(fcZero, fcNormal): + case PackCategoriesIntoKey(fcNormal, fcInfinity): return opOK; - case convolve(fcZero, fcNaN): - case convolve(fcNormal, fcNaN): - case convolve(fcInfinity, fcNaN): + case PackCategoriesIntoKey(fcZero, fcNaN): + case PackCategoriesIntoKey(fcNormal, fcNaN): + case PackCategoriesIntoKey(fcInfinity, fcNaN): + sign = false; category = fcNaN; copySignificand(rhs); return opOK; - case convolve(fcNormal, fcZero): - case convolve(fcInfinity, fcZero): - case convolve(fcInfinity, fcNormal): - case convolve(fcInfinity, fcInfinity): - case convolve(fcZero, fcZero): + case PackCategoriesIntoKey(fcNormal, fcZero): + case PackCategoriesIntoKey(fcInfinity, fcZero): + case PackCategoriesIntoKey(fcInfinity, fcNormal): + case PackCategoriesIntoKey(fcInfinity, fcInfinity): + case PackCategoriesIntoKey(fcZero, fcZero): makeNaN(); return opInvalidOp; - case convolve(fcNormal, fcNormal): + case PackCategoriesIntoKey(fcNormal, fcNormal): return opOK; } } @@ -1578,7 +1660,7 @@ APFloat::multiply(const APFloat &rhs, roundingMode rounding_mode) sign ^= rhs.sign; fs = multiplySpecials(rhs); - if (category == fcNormal) { + if (isFiniteNonZero()) { lostFraction lost_fraction = multiplySignificand(rhs, 0); fs = normalize(rounding_mode, lost_fraction); if (lost_fraction != lfExactlyZero) @@ -1597,7 +1679,7 @@ APFloat::divide(const APFloat &rhs, roundingMode rounding_mode) sign ^= rhs.sign; fs = divideSpecials(rhs); - if (category == fcNormal) { + if (isFiniteNonZero()) { lostFraction lost_fraction = divideSignificand(rhs); fs = normalize(rounding_mode, lost_fraction); if (lost_fraction != lfExactlyZero) @@ -1651,7 +1733,7 @@ APFloat::mod(const APFloat &rhs, roundingMode rounding_mode) opStatus fs; fs = modSpecials(rhs); - if (category == fcNormal && rhs.category == fcNormal) { + if (isFiniteNonZero() && rhs.isFiniteNonZero()) { APFloat V = *this; unsigned int origSign = sign; @@ -1697,9 +1779,9 @@ APFloat::fusedMultiplyAdd(const APFloat &multiplicand, /* If and only if all arguments are normal do we need to do an extended-precision calculation. */ - if (category == fcNormal && - multiplicand.category == fcNormal && - addend.category == fcNormal) { + if (isFiniteNonZero() && + multiplicand.isFiniteNonZero() && + addend.isFiniteNonZero()) { lostFraction lost_fraction; lost_fraction = multiplySignificand(multiplicand, &addend); @@ -1736,7 +1818,7 @@ APFloat::opStatus APFloat::roundToIntegral(roundingMode rounding_mode) { // If the exponent is large enough, we know that this value is already // integral, and the arithmetic below would potentially cause it to saturate // to +/-Inf. Bail out early instead. - if (category == fcNormal && exponent+1 >= (int)semanticsPrecision(*semantics)) + if (isFiniteNonZero() && exponent+1 >= (int)semanticsPrecision(*semantics)) return opOK; // The algorithm here is quite simple: we add 2^(p-1), where p is the @@ -1780,36 +1862,36 @@ APFloat::compare(const APFloat &rhs) const assert(semantics == rhs.semantics); - switch (convolve(category, rhs.category)) { + switch (PackCategoriesIntoKey(category, rhs.category)) { default: llvm_unreachable(0); - case convolve(fcNaN, fcZero): - case convolve(fcNaN, fcNormal): - case convolve(fcNaN, fcInfinity): - case convolve(fcNaN, fcNaN): - case convolve(fcZero, fcNaN): - case convolve(fcNormal, fcNaN): - case convolve(fcInfinity, fcNaN): + case PackCategoriesIntoKey(fcNaN, fcZero): + case PackCategoriesIntoKey(fcNaN, fcNormal): + case PackCategoriesIntoKey(fcNaN, fcInfinity): + case PackCategoriesIntoKey(fcNaN, fcNaN): + case PackCategoriesIntoKey(fcZero, fcNaN): + case PackCategoriesIntoKey(fcNormal, fcNaN): + case PackCategoriesIntoKey(fcInfinity, fcNaN): return cmpUnordered; - case convolve(fcInfinity, fcNormal): - case convolve(fcInfinity, fcZero): - case convolve(fcNormal, fcZero): + case PackCategoriesIntoKey(fcInfinity, fcNormal): + case PackCategoriesIntoKey(fcInfinity, fcZero): + case PackCategoriesIntoKey(fcNormal, fcZero): if (sign) return cmpLessThan; else return cmpGreaterThan; - case convolve(fcNormal, fcInfinity): - case convolve(fcZero, fcInfinity): - case convolve(fcZero, fcNormal): + case PackCategoriesIntoKey(fcNormal, fcInfinity): + case PackCategoriesIntoKey(fcZero, fcInfinity): + case PackCategoriesIntoKey(fcZero, fcNormal): if (rhs.sign) return cmpGreaterThan; else return cmpLessThan; - case convolve(fcInfinity, fcInfinity): + case PackCategoriesIntoKey(fcInfinity, fcInfinity): if (sign == rhs.sign) return cmpEqual; else if (sign) @@ -1817,10 +1899,10 @@ APFloat::compare(const APFloat &rhs) const else return cmpGreaterThan; - case convolve(fcZero, fcZero): + case PackCategoriesIntoKey(fcZero, fcZero): return cmpEqual; - case convolve(fcNormal, fcNormal): + case PackCategoriesIntoKey(fcNormal, fcNormal): break; } @@ -1877,8 +1959,25 @@ APFloat::convert(const fltSemantics &toSemantics, X86SpecialNan = true; } + // If this is a truncation of a denormal number, and the target semantics + // has larger exponent range than the source semantics (this can happen + // when truncating from PowerPC double-double to double format), the + // right shift could lose result mantissa bits. Adjust exponent instead + // of performing excessive shift. + if (shift < 0 && isFiniteNonZero()) { + int exponentChange = significandMSB() + 1 - fromSemantics.precision; + if (exponent + exponentChange < toSemantics.minExponent) + exponentChange = toSemantics.minExponent - exponent; + if (exponentChange < shift) + exponentChange = shift; + if (exponentChange < 0) { + shift -= exponentChange; + exponent += exponentChange; + } + } + // If this is a truncation, perform the shift before we narrow the storage. - if (shift < 0 && (category==fcNormal || category==fcNaN)) + if (shift < 0 && (isFiniteNonZero() || category==fcNaN)) lostFraction = shiftRight(significandParts(), oldPartCount, -shift); // Fix the storage so it can hold to new value. @@ -1887,14 +1986,14 @@ APFloat::convert(const fltSemantics &toSemantics, integerPart *newParts; newParts = new integerPart[newPartCount]; APInt::tcSet(newParts, 0, newPartCount); - if (category==fcNormal || category==fcNaN) + if (isFiniteNonZero() || category==fcNaN) APInt::tcAssign(newParts, significandParts(), oldPartCount); freeSignificand(); significand.parts = newParts; } else if (newPartCount == 1 && oldPartCount != 1) { // Switch to built-in storage for a single part. integerPart newPart = 0; - if (category==fcNormal || category==fcNaN) + if (isFiniteNonZero() || category==fcNaN) newPart = significandParts()[0]; freeSignificand(); significand.part = newPart; @@ -1905,10 +2004,10 @@ APFloat::convert(const fltSemantics &toSemantics, // If this is an extension, perform the shift now that the storage is // available. - if (shift > 0 && (category==fcNormal || category==fcNaN)) + if (shift > 0 && (isFiniteNonZero() || category==fcNaN)) APInt::tcShiftLeft(significandParts(), newPartCount, shift); - if (category == fcNormal) { + if (isFiniteNonZero()) { fs = normalize(rounding_mode, lostFraction); *losesInfo = (fs != opOK); } else if (category == fcNaN) { @@ -2204,56 +2303,46 @@ APFloat::opStatus APFloat::convertFromHexadecimalString(StringRef s, roundingMode rounding_mode) { lostFraction lost_fraction = lfExactlyZero; - integerPart *significand; - unsigned int bitPos, partsCount; - StringRef::iterator dot, firstSignificantDigit; + category = fcNormal; zeroSignificand(); exponent = 0; - category = fcNormal; - significand = significandParts(); - partsCount = partCount(); - bitPos = partsCount * integerPartWidth; + integerPart *significand = significandParts(); + unsigned partsCount = partCount(); + unsigned bitPos = partsCount * integerPartWidth; + bool computedTrailingFraction = false; - /* Skip leading zeroes and any (hexa)decimal point. */ + // Skip leading zeroes and any (hexa)decimal point. StringRef::iterator begin = s.begin(); StringRef::iterator end = s.end(); + StringRef::iterator dot; StringRef::iterator p = skipLeadingZeroesAndAnyDot(begin, end, &dot); - firstSignificantDigit = p; + StringRef::iterator firstSignificantDigit = p; - for (; p != end;) { + while (p != end) { integerPart hex_value; if (*p == '.') { assert(dot == end && "String contains multiple dots"); dot = p++; - if (p == end) { - break; - } + continue; } hex_value = hexDigitValue(*p); - if (hex_value == -1U) { + if (hex_value == -1U) break; - } p++; - if (p == end) { - break; - } else { - /* Store the number whilst 4-bit nibbles remain. */ - if (bitPos) { - bitPos -= 4; - hex_value <<= bitPos % integerPartWidth; - significand[bitPos / integerPartWidth] |= hex_value; - } else { - lost_fraction = trailingHexadecimalFraction(p, end, hex_value); - while (p != end && hexDigitValue(*p) != -1U) - p++; - break; - } + // Store the number while we have space. + if (bitPos) { + bitPos -= 4; + hex_value <<= bitPos % integerPartWidth; + significand[bitPos / integerPartWidth] |= hex_value; + } else if (!computedTrailingFraction) { + lost_fraction = trailingHexadecimalFraction(p, end, hex_value); + computedTrailingFraction = true; } } @@ -2316,8 +2405,8 @@ APFloat::roundSignificandWithExponent(const integerPart *decSigParts, excessPrecision = calcSemantics.precision - semantics->precision; truncatedBits = excessPrecision; - APFloat decSig(calcSemantics, fcZero, sign); - APFloat pow5(calcSemantics, fcZero, false); + APFloat decSig = APFloat::getZero(calcSemantics, sign); + APFloat pow5(calcSemantics); sigStatus = decSig.convertFromUnsignedParts(decSigParts, sigPartCount, rmNearestTiesToEven); @@ -2402,7 +2491,14 @@ APFloat::convertFromDecimalString(StringRef str, roundingMode rounding_mode) 42039/12655 < L < 28738/8651 [ numerator <= 65536 ] */ - if (decDigitValue(*D.firstSigDigit) >= 10U) { + // Test if we have a zero number allowing for strings with no null terminators + // and zero decimals with non-zero exponents. + // + // We computed firstSigDigit by ignoring all zeros and dots. Thus if + // D->firstSigDigit equals str.end(), every digit must be a zero and there can + // be at most one dot. On the other hand, if we have a zero with a non-zero + // exponent, then we know that D.firstSigDigit will be non-numeric. + if (D.firstSigDigit == str.end() || decDigitValue(*D.firstSigDigit) >= 10U) { category = fcZero; fs = opOK; @@ -2419,6 +2515,7 @@ APFloat::convertFromDecimalString(StringRef str, roundingMode rounding_mode) (D.normalizedExponent + 1) * 28738 <= 8651 * (semantics->minExponent - (int) semantics->precision)) { /* Underflow to zero and round. */ + category = fcNormal; zeroSignificand(); fs = normalize(rounding_mode, lfLessThanHalf); @@ -2485,11 +2582,40 @@ APFloat::convertFromDecimalString(StringRef str, roundingMode rounding_mode) return fs; } +bool +APFloat::convertFromStringSpecials(StringRef str) { + if (str.equals("inf") || str.equals("INFINITY")) { + makeInf(false); + return true; + } + + if (str.equals("-inf") || str.equals("-INFINITY")) { + makeInf(true); + return true; + } + + if (str.equals("nan") || str.equals("NaN")) { + makeNaN(false, false); + return true; + } + + if (str.equals("-nan") || str.equals("-NaN")) { + makeNaN(false, true); + return true; + } + + return false; +} + APFloat::opStatus APFloat::convertFromString(StringRef str, roundingMode rounding_mode) { assert(!str.empty() && "Invalid string length"); + // Handle special cases. + if (convertFromStringSpecials(str)) + return opOK; + /* Handle a leading minus sign. */ StringRef::iterator p = str.begin(); size_t slen = str.size(); @@ -2686,7 +2812,7 @@ APFloat::convertNormalToHexString(char *dst, unsigned int hexDigits, } hash_code llvm::hash_value(const APFloat &Arg) { - if (Arg.category != APFloat::fcNormal) + if (!Arg.isFiniteNonZero()) return hash_combine((uint8_t)Arg.category, // NaN has no sign, fix it at zero. Arg.isNaN() ? (uint8_t)0 : (uint8_t)Arg.sign, @@ -2717,7 +2843,7 @@ APFloat::convertF80LongDoubleAPFloatToAPInt() const uint64_t myexponent, mysignificand; - if (category==fcNormal) { + if (isFiniteNonZero()) { myexponent = exponent+16383; //bias mysignificand = significandParts()[0]; if (myexponent==1 && !(mysignificand & 0x8000000000000000ULL)) @@ -2774,7 +2900,7 @@ APFloat::convertPPCDoubleDoubleAPFloatToAPInt() const // just set the second double to zero. Otherwise, re-convert back to // the extended format and compute the difference. This now should // convert exactly to double. - if (u.category == fcNormal && losesInfo) { + if (u.isFiniteNonZero() && losesInfo) { fs = u.convert(extendedSemantics, rmNearestTiesToEven, &losesInfo); assert(fs == opOK && !losesInfo); (void)fs; @@ -2800,7 +2926,7 @@ APFloat::convertQuadrupleAPFloatToAPInt() const uint64_t myexponent, mysignificand, mysignificand2; - if (category==fcNormal) { + if (isFiniteNonZero()) { myexponent = exponent+16383; //bias mysignificand = significandParts()[0]; mysignificand2 = significandParts()[1]; @@ -2836,7 +2962,7 @@ APFloat::convertDoubleAPFloatToAPInt() const uint64_t myexponent, mysignificand; - if (category==fcNormal) { + if (isFiniteNonZero()) { myexponent = exponent+1023; //bias mysignificand = *significandParts(); if (myexponent==1 && !(mysignificand & 0x10000000000000LL)) @@ -2866,7 +2992,7 @@ APFloat::convertFloatAPFloatToAPInt() const uint32_t myexponent, mysignificand; - if (category==fcNormal) { + if (isFiniteNonZero()) { myexponent = exponent+127; //bias mysignificand = (uint32_t)*significandParts(); if (myexponent == 1 && !(mysignificand & 0x800000)) @@ -2895,7 +3021,7 @@ APFloat::convertHalfAPFloatToAPInt() const uint32_t myexponent, mysignificand; - if (category==fcNormal) { + if (isFiniteNonZero()) { myexponent = exponent+15; //bias mysignificand = (uint32_t)*significandParts(); if (myexponent == 1 && !(mysignificand & 0x400)) @@ -3018,7 +3144,7 @@ APFloat::initFromPPCDoubleDoubleAPInt(const APInt &api) (void)fs; // Unless we have a special case, add in second double. - if (category == fcNormal) { + if (isFiniteNonZero()) { APFloat v(IEEEdouble, APInt(64, i2)); fs = v.convert(PPCDoubleDouble, rmNearestTiesToEven, &losesInfo); assert(fs == opOK && !losesInfo); @@ -3211,55 +3337,75 @@ APFloat::getAllOnesValue(unsigned BitWidth, bool isIEEE) } } -APFloat APFloat::getLargest(const fltSemantics &Sem, bool Negative) { - APFloat Val(Sem, fcNormal, Negative); - +/// Make this number the largest magnitude normal number in the given +/// semantics. +void APFloat::makeLargest(bool Negative) { // We want (in interchange format): // sign = {Negative} // exponent = 1..10 // significand = 1..1 + category = fcNormal; + sign = Negative; + exponent = semantics->maxExponent; - Val.exponent = Sem.maxExponent; // unbiased + // Use memset to set all but the highest integerPart to all ones. + integerPart *significand = significandParts(); + unsigned PartCount = partCount(); + memset(significand, 0xFF, sizeof(integerPart)*(PartCount - 1)); - // 1-initialize all bits.... - Val.zeroSignificand(); - integerPart *significand = Val.significandParts(); - unsigned N = partCountForBits(Sem.precision); - for (unsigned i = 0; i != N; ++i) - significand[i] = ~((integerPart) 0); + // Set the high integerPart especially setting all unused top bits for + // internal consistency. + const unsigned NumUnusedHighBits = + PartCount*integerPartWidth - semantics->precision; + significand[PartCount - 1] = ~integerPart(0) >> NumUnusedHighBits; +} + +/// Make this number the smallest magnitude denormal number in the given +/// semantics. +void APFloat::makeSmallest(bool Negative) { + // We want (in interchange format): + // sign = {Negative} + // exponent = 0..0 + // significand = 0..01 + category = fcNormal; + sign = Negative; + exponent = semantics->minExponent; + APInt::tcSet(significandParts(), 1, partCount()); +} - // ...and then clear the top bits for internal consistency. - if (Sem.precision % integerPartWidth != 0) - significand[N-1] &= - (((integerPart) 1) << (Sem.precision % integerPartWidth)) - 1; +APFloat APFloat::getLargest(const fltSemantics &Sem, bool Negative) { + // We want (in interchange format): + // sign = {Negative} + // exponent = 1..10 + // significand = 1..1 + APFloat Val(Sem, uninitialized); + Val.makeLargest(Negative); return Val; } APFloat APFloat::getSmallest(const fltSemantics &Sem, bool Negative) { - APFloat Val(Sem, fcNormal, Negative); - // We want (in interchange format): // sign = {Negative} // exponent = 0..0 // significand = 0..01 - - Val.exponent = Sem.minExponent; // unbiased - Val.zeroSignificand(); - Val.significandParts()[0] = 1; + APFloat Val(Sem, uninitialized); + Val.makeSmallest(Negative); return Val; } APFloat APFloat::getSmallestNormalized(const fltSemantics &Sem, bool Negative) { - APFloat Val(Sem, fcNormal, Negative); + APFloat Val(Sem, uninitialized); // We want (in interchange format): // sign = {Negative} // exponent = 0..0 // significand = 10..0 - Val.exponent = Sem.minExponent; + Val.category = fcNormal; Val.zeroSignificand(); + Val.sign = Negative; + Val.exponent = Sem.minExponent; Val.significandParts()[partCountForBits(Sem.precision)-1] |= (((integerPart) 1) << ((Sem.precision - 1) % integerPartWidth)); @@ -3400,11 +3546,14 @@ void APFloat::toString(SmallVectorImpl<char> &Str, // Set FormatPrecision if zero. We want to do this before we // truncate trailing zeros, as those are part of the precision. if (!FormatPrecision) { - // It's an interesting question whether to use the nominal - // precision or the active precision here for denormals. + // We use enough digits so the number can be round-tripped back to an + // APFloat. The formula comes from "How to Print Floating-Point Numbers + // Accurately" by Steele and White. + // FIXME: Using a formula based purely on the precision is conservative; + // we can print fewer digits depending on the actual value being printed. - // FormatPrecision = ceil(significandBits / lg_2(10)) - FormatPrecision = (semantics->precision * 59 + 195) / 196; + // FormatPrecision = 2 + floor(significandBits / lg_2(10)) + FormatPrecision = 2 + semantics->precision * 59 / 196; } // Ignore trailing binary zeros. @@ -3564,7 +3713,7 @@ void APFloat::toString(SmallVectorImpl<char> &Str, bool APFloat::getExactInverse(APFloat *inv) const { // Special floats and denormals have no exact inverse. - if (category != fcNormal) + if (!isFiniteNonZero()) return false; // Check that the number is a power of two by making sure that only the @@ -3579,10 +3728,10 @@ bool APFloat::getExactInverse(APFloat *inv) const { // Avoid multiplication with a denormal, it is not safe on all platforms and // may be slower than a normal division. - if (reciprocal.significandMSB() + 1 < reciprocal.semantics->precision) + if (reciprocal.isDenormal()) return false; - assert(reciprocal.category == fcNormal && + assert(reciprocal.isFiniteNonZero() && reciprocal.significandLSB() == reciprocal.semantics->precision - 1); if (inv) @@ -3590,3 +3739,148 @@ bool APFloat::getExactInverse(APFloat *inv) const { return true; } + +bool APFloat::isSignaling() const { + if (!isNaN()) + return false; + + // IEEE-754R 2008 6.2.1: A signaling NaN bit string should be encoded with the + // first bit of the trailing significand being 0. + return !APInt::tcExtractBit(significandParts(), semantics->precision - 2); +} + +/// IEEE-754R 2008 5.3.1: nextUp/nextDown. +/// +/// *NOTE* since nextDown(x) = -nextUp(-x), we only implement nextUp with +/// appropriate sign switching before/after the computation. +APFloat::opStatus APFloat::next(bool nextDown) { + // If we are performing nextDown, swap sign so we have -x. + if (nextDown) + changeSign(); + + // Compute nextUp(x) + opStatus result = opOK; + + // Handle each float category separately. + switch (category) { + case fcInfinity: + // nextUp(+inf) = +inf + if (!isNegative()) + break; + // nextUp(-inf) = -getLargest() + makeLargest(true); + break; + case fcNaN: + // IEEE-754R 2008 6.2 Par 2: nextUp(sNaN) = qNaN. Set Invalid flag. + // IEEE-754R 2008 6.2: nextUp(qNaN) = qNaN. Must be identity so we do not + // change the payload. + if (isSignaling()) { + result = opInvalidOp; + // For consistency, propogate the sign of the sNaN to the qNaN. + makeNaN(false, isNegative(), 0); + } + break; + case fcZero: + // nextUp(pm 0) = +getSmallest() + makeSmallest(false); + break; + case fcNormal: + // nextUp(-getSmallest()) = -0 + if (isSmallest() && isNegative()) { + APInt::tcSet(significandParts(), 0, partCount()); + category = fcZero; + exponent = 0; + break; + } + + // nextUp(getLargest()) == INFINITY + if (isLargest() && !isNegative()) { + APInt::tcSet(significandParts(), 0, partCount()); + category = fcInfinity; + exponent = semantics->maxExponent + 1; + break; + } + + // nextUp(normal) == normal + inc. + if (isNegative()) { + // If we are negative, we need to decrement the significand. + + // We only cross a binade boundary that requires adjusting the exponent + // if: + // 1. exponent != semantics->minExponent. This implies we are not in the + // smallest binade or are dealing with denormals. + // 2. Our significand excluding the integral bit is all zeros. + bool WillCrossBinadeBoundary = + exponent != semantics->minExponent && isSignificandAllZeros(); + + // Decrement the significand. + // + // We always do this since: + // 1. If we are dealing with a non binade decrement, by definition we + // just decrement the significand. + // 2. If we are dealing with a normal -> normal binade decrement, since + // we have an explicit integral bit the fact that all bits but the + // integral bit are zero implies that subtracting one will yield a + // significand with 0 integral bit and 1 in all other spots. Thus we + // must just adjust the exponent and set the integral bit to 1. + // 3. If we are dealing with a normal -> denormal binade decrement, + // since we set the integral bit to 0 when we represent denormals, we + // just decrement the significand. + integerPart *Parts = significandParts(); + APInt::tcDecrement(Parts, partCount()); + + if (WillCrossBinadeBoundary) { + // Our result is a normal number. Do the following: + // 1. Set the integral bit to 1. + // 2. Decrement the exponent. + APInt::tcSetBit(Parts, semantics->precision - 1); + exponent--; + } + } else { + // If we are positive, we need to increment the significand. + + // We only cross a binade boundary that requires adjusting the exponent if + // the input is not a denormal and all of said input's significand bits + // are set. If all of said conditions are true: clear the significand, set + // the integral bit to 1, and increment the exponent. If we have a + // denormal always increment since moving denormals and the numbers in the + // smallest normal binade have the same exponent in our representation. + bool WillCrossBinadeBoundary = !isDenormal() && isSignificandAllOnes(); + + if (WillCrossBinadeBoundary) { + integerPart *Parts = significandParts(); + APInt::tcSet(Parts, 0, partCount()); + APInt::tcSetBit(Parts, semantics->precision - 1); + assert(exponent != semantics->maxExponent && + "We can not increment an exponent beyond the maxExponent allowed" + " by the given floating point semantics."); + exponent++; + } else { + incrementSignificand(); + } + } + break; + } + + // If we are performing nextDown, swap sign so we have -nextUp(-x) + if (nextDown) + changeSign(); + + return result; +} + +void +APFloat::makeInf(bool Negative) { + category = fcInfinity; + sign = Negative; + exponent = semantics->maxExponent + 1; + APInt::tcSet(significandParts(), 0, partCount()); +} + +void +APFloat::makeZero(bool Negative) { + category = fcZero; + sign = Negative; + exponent = semantics->minExponent-1; + APInt::tcSet(significandParts(), 0, partCount()); +} |
