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Teach DAG combiner to constant fold FABS of a BUILD_VECTOR of ConstantFPs. Factor similar code out of FNEG DAG combiner. 

llvm-svn: 163587
This commit is contained in:
Craig Topper 2012-09-11 01:45:21 +00:00
parent 13453d32ff
commit 8238461211
1 changed files with 47 additions and 22 deletions
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69
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -194,6 +194,7 @@ namespace {
SDValue visitOR(SDNode *N);
SDValue visitXOR(SDNode *N);
SDValue SimplifyVBinOp(SDNode *N);
SDValue SimplifyVUnaryOp(SDNode *N);
SDValue visitSHL(SDNode *N);
SDValue visitSRA(SDNode *N);
SDValue visitSRL(SDNode *N);
@ -6409,28 +6410,9 @@ SDValue DAGCombiner::visitFNEG(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
if (VT.isVector() && !LegalOperations) {
// If operand is a BUILD_VECTOR node, see if we can constant fold it.
if (N0.getOpcode() == ISD::BUILD_VECTOR) {
SmallVector<SDValue, 8> Ops;
for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) {
SDValue Op = N0.getOperand(i);
if (Op.getOpcode() != ISD::UNDEF &&
Op.getOpcode() != ISD::ConstantFP)
break;
EVT EltVT = Op.getValueType();
SDValue FoldOp = DAG.getNode(ISD::FNEG, N0.getDebugLoc(), EltVT, Op);
if (FoldOp.getOpcode() != ISD::UNDEF &&
FoldOp.getOpcode() != ISD::ConstantFP)
break;
Ops.push_back(FoldOp);
AddToWorkList(FoldOp.getNode());
}
if (Ops.size() == N0.getNumOperands())
return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
VT, &Ops[0], Ops.size());
}
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVUnaryOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
if (isNegatibleForFree(N0, LegalOperations, DAG.getTargetLoweringInfo(),
@ -6509,6 +6491,11 @@ SDValue DAGCombiner::visitFABS(SDNode *N) {
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
EVT VT = N->getValueType(0);
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVUnaryOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (fabs c1) -> fabs(c1)
if (N0CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0);
@ -8491,6 +8478,44 @@ SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) {
return SDValue();
}
/// SimplifyVUnaryOp - Visit a binary vector operation, like FABS/FNEG.
SDValue DAGCombiner::SimplifyVUnaryOp(SDNode *N) {
// After legalize, the target may be depending on adds and other
// binary ops to provide legal ways to construct constants or other
// things. Simplifying them may result in a loss of legality.
if (LegalOperations) return SDValue();
assert(N->getValueType(0).isVector() &&
"SimplifyVUnaryOp only works on vectors!");
SDValue N0 = N->getOperand(0);
if (N0.getOpcode() != ISD::BUILD_VECTOR)
return SDValue();
// Operand is a BUILD_VECTOR node, see if we can constant fold it.
SmallVector<SDValue, 8> Ops;
for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) {
SDValue Op = N0.getOperand(i);
if (Op.getOpcode() != ISD::UNDEF &&
Op.getOpcode() != ISD::ConstantFP)
break;
EVT EltVT = Op.getValueType();
SDValue FoldOp = DAG.getNode(N->getOpcode(), N0.getDebugLoc(), EltVT, Op);
if (FoldOp.getOpcode() != ISD::UNDEF &&
FoldOp.getOpcode() != ISD::ConstantFP)
break;
Ops.push_back(FoldOp);
AddToWorkList(FoldOp.getNode());
}
if (Ops.size() != N0.getNumOperands())
return SDValue();
return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
N0.getValueType(), &Ops[0], Ops.size());
}
SDValue DAGCombiner::SimplifySelect(DebugLoc DL, SDValue N0,
SDValue N1, SDValue N2){
assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");