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Properly clear all the extra bits in a significand when making a NaN from an
APInt. Be certain to set the integer bit in an x87 extended-precision significand so that we don't accidentally make a pseudo-NaN. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97382 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -631,25 +631,45 @@ void APFloat::makeNaN(bool SNaN, bool Negative, const APInt *fill)
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category = fcNaN;
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sign = Negative;
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integerPart *significand = significandParts();
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unsigned numParts = partCount();
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// Set the significand bits to the fill.
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if (!fill || fill->getNumWords() < partCount())
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APInt::tcSet(significandParts(), 0, partCount());
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if (fill)
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APInt::tcAssign(significandParts(), fill->getRawData(), partCount());
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if (!fill || fill->getNumWords() < numParts)
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APInt::tcSet(significand, 0, numParts);
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if (fill) {
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APInt::tcAssign(significand, fill->getRawData(), partCount());
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// Zero out the excess bits of the significand.
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unsigned bitsToPreserve = semantics->precision - 1;
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unsigned part = bitsToPreserve / 64;
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bitsToPreserve %= 64;
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significand[part] &= ((1ULL << bitsToPreserve) - 1);
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for (part++; part != numParts; ++part)
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significand[part] = 0;
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}
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unsigned QNaNBit = semantics->precision - 2;
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if (SNaN) {
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// We always have to clear the QNaN bit to make it an SNaN.
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APInt::tcClearBit(significandParts(), semantics->precision - 2);
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APInt::tcClearBit(significand, QNaNBit);
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// If there are no bits set in the payload, we have to set
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// *something* to make it a NaN instead of an infinity;
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// conventionally, this is the next bit down from the QNaN bit.
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if (APInt::tcIsZero(significandParts(), partCount()))
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APInt::tcSetBit(significandParts(), semantics->precision - 3);
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if (APInt::tcIsZero(significand, numParts))
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APInt::tcSetBit(significand, QNaNBit - 1);
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} else {
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// We always have to set the QNaN bit to make it a QNaN.
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APInt::tcSetBit(significandParts(), semantics->precision - 2);
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APInt::tcSetBit(significand, QNaNBit);
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}
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// For x87 extended precision, we want to make a NaN, not a
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// pseudo-NaN. Maybe we should expose the ability to make
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// pseudo-NaNs?
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if (semantics == &APFloat::x87DoubleExtended)
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APInt::tcSetBit(significand, QNaNBit + 1);
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}
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APFloat APFloat::makeNaN(const fltSemantics &Sem, bool SNaN, bool Negative,
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