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Fix PR6522: implement copysign expansion for x86 long double

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(it seems that FreeBSD doesn't have copysignl).  Done by
removing a bunch of assumptions from the code.  This may also
help with sparc 128 bit floats.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98346 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan Sands 2010-03-12 11:45:06 +00:00
parent 0b6cb50738
commit 5d54b4112d
1 changed files with 38 additions and 22 deletions
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60
lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
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@ -1585,35 +1585,51 @@ SDValue SelectionDAGLegalize::ExpandFCOPYSIGN(SDNode* Node) {
DebugLoc dl = Node->getDebugLoc();
SDValue Tmp1 = Node->getOperand(0);
SDValue Tmp2 = Node->getOperand(1);
assert((Tmp2.getValueType() == MVT::f32 ||
Tmp2.getValueType() == MVT::f64) &&
"Ugly special-cased code!");
// Get the sign bit of the RHS.
// Get the sign bit of the RHS. First obtain a value that has the same
// sign as the sign bit, i.e. negative if and only if the sign bit is 1.
SDValue SignBit;
EVT IVT = Tmp2.getValueType() == MVT::f64 ? MVT::i64 : MVT::i32;
EVT FloatVT = Tmp2.getValueType();
EVT IVT = EVT::getIntegerVT(*DAG.getContext(), FloatVT.getSizeInBits());
if (isTypeLegal(IVT)) {
// Convert to an integer with the same sign bit.
SignBit = DAG.getNode(ISD::BIT_CONVERT, dl, IVT, Tmp2);
} else {
assert(isTypeLegal(TLI.getPointerTy()) &&
(TLI.getPointerTy() == MVT::i32 ||
TLI.getPointerTy() == MVT::i64) &&
"Legal type for load?!");
SDValue StackPtr = DAG.CreateStackTemporary(Tmp2.getValueType());
SDValue StorePtr = StackPtr, LoadPtr = StackPtr;
// Store the float to memory, then load the sign part out as an integer.
MVT LoadTy = TLI.getPointerTy();
// First create a temporary that is aligned for both the load and store.
SDValue StackPtr = DAG.CreateStackTemporary(FloatVT, LoadTy);
// Then store the float to it.
SDValue Ch =
DAG.getStore(DAG.getEntryNode(), dl, Tmp2, StorePtr, NULL, 0,
DAG.getStore(DAG.getEntryNode(), dl, Tmp2, StackPtr, NULL, 0,
false, false, 0);
if (Tmp2.getValueType() == MVT::f64 && TLI.isLittleEndian())
LoadPtr = DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(),
LoadPtr, DAG.getIntPtrConstant(4));
SignBit = DAG.getExtLoad(ISD::SEXTLOAD, dl, TLI.getPointerTy(),
Ch, LoadPtr, NULL, 0, MVT::i32,
false, false, 0);
if (TLI.isBigEndian()) {
assert(FloatVT.isByteSized() && "Unsupported floating point type!");
// Load out a legal integer with the same sign bit as the float.
SignBit = DAG.getLoad(LoadTy, dl, Ch, StackPtr, NULL, 0, false, false, 0);
} else { // Little endian
SDValue LoadPtr = StackPtr;
// The float may be wider than the integer we are going to load. Advance
// the pointer so that the loaded integer will contain the sign bit.
unsigned Strides = (FloatVT.getSizeInBits()-1)/LoadTy.getSizeInBits();
unsigned ByteOffset = (Strides * LoadTy.getSizeInBits()) / 8;
LoadPtr = DAG.getNode(ISD::ADD, dl, LoadPtr.getValueType(),
LoadPtr, DAG.getIntPtrConstant(ByteOffset));
// Load a legal integer containing the sign bit.
SignBit = DAG.getLoad(LoadTy, dl, Ch, LoadPtr, NULL, 0, false, false, 0);
// Move the sign bit to the top bit of the loaded integer.
unsigned BitShift = LoadTy.getSizeInBits() -
(FloatVT.getSizeInBits() - 8 * ByteOffset);
assert(BitShift < LoadTy.getSizeInBits() && "Pointer advanced wrong?");
if (BitShift)
SignBit = DAG.getNode(ISD::SHL, dl, LoadTy, SignBit,
DAG.getConstant(BitShift,TLI.getShiftAmountTy()));
}
}
SignBit =
DAG.getSetCC(dl, TLI.getSetCCResultType(SignBit.getValueType()),
SignBit, DAG.getConstant(0, SignBit.getValueType()),
ISD::SETLT);
// Now get the sign bit proper, by seeing whether the value is negative.
SignBit = DAG.getSetCC(dl, TLI.getSetCCResultType(SignBit.getValueType()),
SignBit, DAG.getConstant(0, SignBit.getValueType()),
ISD::SETLT);
// Get the absolute value of the result.
SDValue AbsVal = DAG.getNode(ISD::FABS, dl, Tmp1.getValueType(), Tmp1);
// Select between the nabs and abs value based on the sign bit of