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Expand ConstantFP to load from CP if float types are being expanded. 

llvm-svn: 32494
This commit is contained in:
Evan Cheng 2006-12-12 21:32:44 +00:00
parent 634885f71e
commit 47833a1d28
1 changed files with 44 additions and 27 deletions
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71
llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
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@ -488,6 +488,37 @@ void SelectionDAGLegalize::HandleOp(SDOperand Op) {
}
}
/// ExpandConstantFP - Expands the ConstantFP node by spilling the constant to
/// memory.
static SDOperand ExpandConstantFP(ConstantFPSDNode *CFP, SelectionDAG &DAG,
TargetLowering &TLI) {
bool Extend = false;
// If a FP immediate is precise when represented as a float and if the
// target can do an extending load from float to double, we put it into
// the constant pool as a float, even if it's is statically typed as a
// double.
MVT::ValueType VT = CFP->getValueType(0);
bool isDouble = VT == MVT::f64;
ConstantFP *LLVMC = ConstantFP::get(isDouble ? Type::DoubleTy :
Type::FloatTy, CFP->getValue());
if (isDouble && CFP->isExactlyValue((float)CFP->getValue()) &&
// Only do this if the target has a native EXTLOAD instruction from f32.
TLI.isLoadXLegal(ISD::EXTLOAD, MVT::f32)) {
LLVMC = cast<ConstantFP>(ConstantExpr::getFPTrunc(LLVMC,Type::FloatTy));
VT = MVT::f32;
Extend = true;
}
SDOperand CPIdx = DAG.getConstantPool(LLVMC, TLI.getPointerTy());
if (Extend) {
return DAG.getExtLoad(ISD::EXTLOAD, MVT::f64, DAG.getEntryNode(),
CPIdx, NULL, 0, MVT::f32);
} else {
return DAG.getLoad(VT, DAG.getEntryNode(), CPIdx, NULL, 0);
}
}
/// LegalizeOp - We know that the specified value has a legal type.
/// Recursively ensure that the operands have legal types, then return the
@ -775,33 +806,7 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
}
// FALLTHROUGH
case TargetLowering::Expand:
// Otherwise we need to spill the constant to memory.
bool Extend = false;
// If a FP immediate is precise when represented as a float and if the
// target can do an extending load from float to double, we put it into
// the constant pool as a float, even if it's is statically typed as a
// double.
MVT::ValueType VT = CFP->getValueType(0);
bool isDouble = VT == MVT::f64;
ConstantFP *LLVMC = ConstantFP::get(isDouble ? Type::DoubleTy :
Type::FloatTy, CFP->getValue());
if (isDouble && CFP->isExactlyValue((float)CFP->getValue()) &&
// Only do this if the target has a native EXTLOAD instruction from
// f32.
TLI.isLoadXLegal(ISD::EXTLOAD, MVT::f32)) {
LLVMC = cast<ConstantFP>(ConstantExpr::getFPTrunc(LLVMC,Type::FloatTy));
VT = MVT::f32;
Extend = true;
}
SDOperand CPIdx = DAG.getConstantPool(LLVMC, TLI.getPointerTy());
if (Extend) {
Result = DAG.getExtLoad(ISD::EXTLOAD, MVT::f64, DAG.getEntryNode(),
CPIdx, NULL, 0, MVT::f32);
} else {
Result = DAG.getLoad(VT, DAG.getEntryNode(), CPIdx, NULL, 0);
}
Result = ExpandConstantFP(CFP, DAG, TLI);
}
break;
}
@ -4398,6 +4403,12 @@ void SelectionDAGLegalize::ExpandOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi){
Hi = DAG.getConstant(Cst >> MVT::getSizeInBits(NVT), NVT);
break;
}
case ISD::ConstantFP: {
ConstantFPSDNode *CFP = cast<ConstantFPSDNode>(Node);
SDOperand Tmp = ExpandConstantFP(CFP, DAG, TLI);
ExpandOp(Tmp, Lo, Hi);
break;
}
case ISD::BUILD_PAIR:
// Return the operands.
Lo = Node->getOperand(0);
@ -4484,6 +4495,12 @@ void SelectionDAGLegalize::ExpandOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi){
if (ExtType == ISD::NON_EXTLOAD) {
Lo = DAG.getLoad(NVT, Ch, Ptr, LD->getSrcValue(), LD->getSrcValueOffset());
if (VT == MVT::f32 || VT == MVT::f64) {
// f32->i32 or f64->i64 one to one expansion.
// Remember that we legalized the chain.
AddLegalizedOperand(SDOperand(Node, 1), LegalizeOp(Lo.getValue(1)));
break;
}
// Increment the pointer to the other half.
unsigned IncrementSize = MVT::getSizeInBits(Lo.getValueType())/8;