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[APFloat] Fix out of scope usage of a pointer to local variable

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This commit is contained in:
Ehud Katz 2020-01-07 11:24:11 +02:00
parent 756cc832bb
commit 9e236592f9
1 changed files with 7 additions and 3 deletions
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10
lib/Support/APFloat.cpp
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@ -1065,18 +1065,22 @@ lostFraction IEEEFloat::multiplySignificand(const IEEEFloat &rhs,
significand.parts = fullSignificand;
semantics = &extendedSemantics;
status = addend.convert(extendedSemantics, rmTowardZero, &ignored);
// Make a copy so we can convert it to the extended semantics.
// Note that we cannot convert the addend directly, as the extendedSemantics
// is a local variable (which we take a reference to).
IEEEFloat extendedAddend(addend);
status = extendedAddend.convert(extendedSemantics, rmTowardZero, &ignored);
assert(status == opOK);
(void)status;
// Shift the significand of the addend right by one bit. This guarantees
// that the high bit of the significand is zero (same as fullSignificand),
// so the addition will overflow (if it does overflow at all) into the top bit.
lost_fraction = addend.shiftSignificandRight(1);
lost_fraction = extendedAddend.shiftSignificandRight(1);
assert(lost_fraction == lfExactlyZero &&
"Lost precision while shifting addend for fused-multiply-add.");
lost_fraction = addOrSubtractSignificand(addend, false);
lost_fraction = addOrSubtractSignificand(extendedAddend, false);
/* Restore our state. */
if (newPartsCount == 1)