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Fix PR 1688. See comments there. 

llvm-svn: 42181
This commit is contained in:
Dale Johannesen 2007-09-20 23:47:58 +00:00
parent 83cc3f8f51
commit 146a0ea071
1 changed files with 25 additions and 13 deletions
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38
llvm/lib/Support/APFloat.cpp
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@ -47,7 +47,7 @@ namespace llvm {
const fltSemantics APFloat::IEEEdouble = { 1023, -1022, 53, true };
const fltSemantics APFloat::IEEEquad = { 16383, -16382, 113, true };
const fltSemantics APFloat::x87DoubleExtended = { 16383, -16382, 64, false };
const fltSemantics APFloat::Bogus = { 0, 0, 0, true };
const fltSemantics APFloat::Bogus = { 0, 0, 0, false };
}
/* Put a bunch of private, handy routines in an anonymous namespace. */
@ -339,8 +339,7 @@ APFloat::~APFloat()
unsigned int
APFloat::partCount() const
{
return partCountForBits(semantics->precision +
semantics->implicitIntegerBit ? 1 : 0);
return partCountForBits(semantics->precision + 1);
}
unsigned int
@ -1324,7 +1323,11 @@ APFloat::convert(const fltSemantics &toSemantics,
newPartCount = partCountForBits(toSemantics.precision + 1);
/* If our new form is wider, re-allocate our bit pattern into wider
storage. */
storage.
If we're narrowing from multiple words to 1 words, copy to the single
word. If we are losing information by doing this, we would have to
worry about rounding; right now the only case is f80 -> shorter
conversion, and we are keeping all 64 significant bits, so it's OK. */
if(newPartCount > partCount()) {
integerPart *newParts;
@ -1333,6 +1336,13 @@ APFloat::convert(const fltSemantics &toSemantics,
APInt::tcAssign(newParts, significandParts(), partCount());
freeSignificand();
significand.parts = newParts;
} else if (newPartCount==1 && newPartCount < partCount()) {
integerPart newPart;
APInt::tcSet(&newPart, 0, newPartCount);
APInt::tcAssign(&newPart, significandParts(), partCount());
freeSignificand();
significand.part = newPart;
}
if(category == fcNormal) {
@ -1588,22 +1598,22 @@ APFloat::getHashValue() const {
// Conversion from APFloat to/from host float/double. It may eventually be
// possible to eliminate these and have everybody deal with APFloats, but that
// will take a while. This approach will not easily extend to long double.
// Current implementation requires partCount()==1, which is correct at the
// moment but could be made more general.
// Current implementation requires integerPartWidth==64, which is correct at
// the moment but could be made more general.
// Denormals have exponent minExponent in APFloat, but minExponent-1 in
// the actual IEEE respresentation. We compensate for that here.
// the actual IEEE respresentations. We compensate for that here.
APInt
APFloat::convertF80LongDoubleAPFloatToAPInt() const {
assert(semantics == (const llvm::fltSemantics* const)&x87DoubleExtended);
assert (partCount()==1);
assert (partCount()==2);
uint64_t myexponent, mysignificand;
if (category==fcNormal) {
myexponent = exponent+16383; //bias
mysignificand = *significandParts();
mysignificand = significandParts()[0];
if (myexponent==1 && !(mysignificand & 0x8000000000000000ULL))
myexponent = 0; // denormal
} else if (category==fcZero) {
@ -1614,7 +1624,7 @@ APFloat::convertF80LongDoubleAPFloatToAPInt() const {
mysignificand = 0x8000000000000000ULL;
} else if (category==fcNaN) {
myexponent = 0x7fff;
mysignificand = *significandParts();
mysignificand = significandParts()[0];
} else
assert(0);
@ -1727,7 +1737,7 @@ APFloat::initFromF80LongDoubleAPInt(const APInt &api) {
(i2 & 0xffff);
initialize(&APFloat::x87DoubleExtended);
assert(partCount()==1);
assert(partCount()==2);
sign = i1>>63;
if (myexponent==0 && mysignificand==0) {
@ -1739,11 +1749,13 @@ APFloat::initFromF80LongDoubleAPInt(const APInt &api) {
} else if (myexponent==0x7fff && mysignificand!=0x8000000000000000ULL) {
// exponent meaningless
category = fcNaN;
*significandParts() = mysignificand;
significandParts()[0] = mysignificand;
significandParts()[1] = 0;
} else {
category = fcNormal;
exponent = myexponent - 16383;
*significandParts() = mysignificand;
significandParts()[0] = mysignificand;
significandParts()[1] = 0;
if (myexponent==0) // denormal
exponent = -16382;
}