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[TargetLowering] Simplify the interface for expandCTPOP/expandCTLZ/expandCTTZ. 

There is no need to return a bool and have an SDValue output
parameter. Just return the SDValue and let the caller check if it
is null.

I have another patch to add more callers of these so I thought
I'd clean up the interface first.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D112267
This commit is contained in:
Craig Topper 2021-10-21 15:23:41 -07:00
parent 0bf230d422
commit 996123e5e8
4 changed files with 35 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
llvm/include/llvm/CodeGen/TargetLowering.h
View File

@ -4446,23 +4446,20 @@ public:
/// Expand CTPOP nodes. Expands vector/scalar CTPOP nodes,
/// vector nodes can only succeed if all operations are legal/custom.
/// \param N Node to expand
/// \param Result output after conversion
/// \returns True, if the expansion was successful, false otherwise
bool expandCTPOP(SDNode *N, SDValue &Result, SelectionDAG &DAG) const;
/// \returns The expansion result or SDValue() if it fails.
SDValue expandCTPOP(SDNode *N, SelectionDAG &DAG) const;
/// Expand CTLZ/CTLZ_ZERO_UNDEF nodes. Expands vector/scalar CTLZ nodes,
/// vector nodes can only succeed if all operations are legal/custom.
/// \param N Node to expand
/// \param Result output after conversion
/// \returns True, if the expansion was successful, false otherwise
bool expandCTLZ(SDNode *N, SDValue &Result, SelectionDAG &DAG) const;
/// \returns The expansion result or SDValue() if it fails.
SDValue expandCTLZ(SDNode *N, SelectionDAG &DAG) const;
/// Expand CTTZ/CTTZ_ZERO_UNDEF nodes. Expands vector/scalar CTTZ nodes,
/// vector nodes can only succeed if all operations are legal/custom.
/// \param N Node to expand
/// \param Result output after conversion
/// \returns True, if the expansion was successful, false otherwise
bool expandCTTZ(SDNode *N, SDValue &Result, SelectionDAG &DAG) const;
/// \returns The expansion result or SDValue() if it fails.
SDValue expandCTTZ(SDNode *N, SelectionDAG &DAG) const;
/// Expand ABS nodes. Expands vector/scalar ABS nodes,
/// vector nodes can only succeed if all operations are legal/custom.

6
llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
View File

@ -2688,17 +2688,17 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) {
Results.push_back(Tmp1);
break;
case ISD::CTPOP:
if (TLI.expandCTPOP(Node, Tmp1, DAG))
if ((Tmp1 = TLI.expandCTPOP(Node, DAG)))
Results.push_back(Tmp1);
break;
case ISD::CTLZ:
case ISD::CTLZ_ZERO_UNDEF:
if (TLI.expandCTLZ(Node, Tmp1, DAG))
if ((Tmp1 = TLI.expandCTLZ(Node, DAG)))
Results.push_back(Tmp1);
break;
case ISD::CTTZ:
case ISD::CTTZ_ZERO_UNDEF:
if (TLI.expandCTTZ(Node, Tmp1, DAG))
if ((Tmp1 = TLI.expandCTTZ(Node, DAG)))
Results.push_back(Tmp1);
break;
case ISD::BITREVERSE:

12
llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
View File

@ -783,22 +783,22 @@ void VectorLegalizer::Expand(SDNode *Node, SmallVectorImpl<SDValue> &Results) {
ExpandBITREVERSE(Node, Results);
return;
case ISD::CTPOP:
if (TLI.expandCTPOP(Node, Tmp, DAG)) {
Results.push_back(Tmp);
if (SDValue Expanded = TLI.expandCTPOP(Node, DAG)) {
Results.push_back(Expanded);
return;
}
break;
case ISD::CTLZ:
case ISD::CTLZ_ZERO_UNDEF:
if (TLI.expandCTLZ(Node, Tmp, DAG)) {
Results.push_back(Tmp);
if (SDValue Expanded = TLI.expandCTLZ(Node, DAG)) {
Results.push_back(Expanded);
return;
}
break;
case ISD::CTTZ:
case ISD::CTTZ_ZERO_UNDEF:
if (TLI.expandCTTZ(Node, Tmp, DAG)) {
Results.push_back(Tmp);
if (SDValue Expanded = TLI.expandCTTZ(Node, DAG)) {
Results.push_back(Expanded);
return;
}
break;

54
llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
View File

@ -6991,8 +6991,7 @@ static bool canExpandVectorCTPOP(const TargetLowering &TLI, EVT VT) {
TLI.isOperationLegalOrCustomOrPromote(ISD::AND, VT);
}
bool TargetLowering::expandCTPOP(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
SDValue TargetLowering::expandCTPOP(SDNode *Node, SelectionDAG &DAG) const {
SDLoc dl(Node);
EVT VT = Node->getValueType(0);
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
@ -7002,11 +7001,11 @@ bool TargetLowering::expandCTPOP(SDNode *Node, SDValue &Result,
// TODO: Add support for irregular type lengths.
if (!(Len <= 128 && Len % 8 == 0))
return false;
return SDValue();
// Only expand vector types if we have the appropriate vector bit operations.
if (VT.isVector() && !canExpandVectorCTPOP(*this, VT))
return false;
return SDValue();
// This is the "best" algorithm from
// http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
@ -7043,12 +7042,10 @@ bool TargetLowering::expandCTPOP(SDNode *Node, SDValue &Result,
DAG.getNode(ISD::SRL, dl, VT, DAG.getNode(ISD::MUL, dl, VT, Op, Mask01),
DAG.getConstant(Len - 8, dl, ShVT));
Result = Op;
return true;
return Op;
}
bool TargetLowering::expandCTLZ(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
SDValue TargetLowering::expandCTLZ(SDNode *Node, SelectionDAG &DAG) const {
SDLoc dl(Node);
EVT VT = Node->getValueType(0);
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
@ -7057,10 +7054,8 @@ bool TargetLowering::expandCTLZ(SDNode *Node, SDValue &Result,
// If the non-ZERO_UNDEF version is supported we can use that instead.
if (Node->getOpcode() == ISD::CTLZ_ZERO_UNDEF &&
isOperationLegalOrCustom(ISD::CTLZ, VT)) {
Result = DAG.getNode(ISD::CTLZ, dl, VT, Op);
return true;
}
isOperationLegalOrCustom(ISD::CTLZ, VT))
return DAG.getNode(ISD::CTLZ, dl, VT, Op);
// If the ZERO_UNDEF version is supported use that and handle the zero case.
if (isOperationLegalOrCustom(ISD::CTLZ_ZERO_UNDEF, VT)) {
@ -7069,9 +7064,8 @@ bool TargetLowering::expandCTLZ(SDNode *Node, SDValue &Result,
SDValue CTLZ = DAG.getNode(ISD::CTLZ_ZERO_UNDEF, dl, VT, Op);
SDValue Zero = DAG.getConstant(0, dl, VT);
SDValue SrcIsZero = DAG.getSetCC(dl, SetCCVT, Op, Zero, ISD::SETEQ);
Result = DAG.getNode(ISD::SELECT, dl, VT, SrcIsZero,
DAG.getConstant(NumBitsPerElt, dl, VT), CTLZ);
return true;
return DAG.getNode(ISD::SELECT, dl, VT, SrcIsZero,
DAG.getConstant(NumBitsPerElt, dl, VT), CTLZ);
}
// Only expand vector types if we have the appropriate vector bit operations.
@ -7081,7 +7075,7 @@ bool TargetLowering::expandCTLZ(SDNode *Node, SDValue &Result,
!canExpandVectorCTPOP(*this, VT)) ||
!isOperationLegalOrCustom(ISD::SRL, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::OR, VT)))
return false;
return SDValue();
// for now, we do this:
// x = x | (x >> 1);
@ -7098,12 +7092,10 @@ bool TargetLowering::expandCTLZ(SDNode *Node, SDValue &Result,
DAG.getNode(ISD::SRL, dl, VT, Op, Tmp));
}
Op = DAG.getNOT(dl, Op, VT);
Result = DAG.getNode(ISD::CTPOP, dl, VT, Op);
return true;
return DAG.getNode(ISD::CTPOP, dl, VT, Op);
}
bool TargetLowering::expandCTTZ(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
SDValue TargetLowering::expandCTTZ(SDNode *Node, SelectionDAG &DAG) const {
SDLoc dl(Node);
EVT VT = Node->getValueType(0);
SDValue Op = Node->getOperand(0);
@ -7111,10 +7103,8 @@ bool TargetLowering::expandCTTZ(SDNode *Node, SDValue &Result,
// If the non-ZERO_UNDEF version is supported we can use that instead.
if (Node->getOpcode() == ISD::CTTZ_ZERO_UNDEF &&
isOperationLegalOrCustom(ISD::CTTZ, VT)) {
Result = DAG.getNode(ISD::CTTZ, dl, VT, Op);
return true;
}
isOperationLegalOrCustom(ISD::CTTZ, VT))
return DAG.getNode(ISD::CTTZ, dl, VT, Op);
// If the ZERO_UNDEF version is supported use that and handle the zero case.
if (isOperationLegalOrCustom(ISD::CTTZ_ZERO_UNDEF, VT)) {
@ -7123,9 +7113,8 @@ bool TargetLowering::expandCTTZ(SDNode *Node, SDValue &Result,
SDValue CTTZ = DAG.getNode(ISD::CTTZ_ZERO_UNDEF, dl, VT, Op);
SDValue Zero = DAG.getConstant(0, dl, VT);
SDValue SrcIsZero = DAG.getSetCC(dl, SetCCVT, Op, Zero, ISD::SETEQ);
Result = DAG.getNode(ISD::SELECT, dl, VT, SrcIsZero,
DAG.getConstant(NumBitsPerElt, dl, VT), CTTZ);
return true;
return DAG.getNode(ISD::SELECT, dl, VT, SrcIsZero,
DAG.getConstant(NumBitsPerElt, dl, VT), CTTZ);
}
// Only expand vector types if we have the appropriate vector bit operations.
@ -7137,7 +7126,7 @@ bool TargetLowering::expandCTTZ(SDNode *Node, SDValue &Result,
!isOperationLegalOrCustom(ISD::SUB, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::AND, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::XOR, VT)))
return false;
return SDValue();
// for now, we use: { return popcount(~x & (x - 1)); }
// unless the target has ctlz but not ctpop, in which case we use:
@ -7149,14 +7138,11 @@ bool TargetLowering::expandCTTZ(SDNode *Node, SDValue &Result,
// If ISD::CTLZ is legal and CTPOP isn't, then do that instead.
if (isOperationLegal(ISD::CTLZ, VT) && !isOperationLegal(ISD::CTPOP, VT)) {
Result =
DAG.getNode(ISD::SUB, dl, VT, DAG.getConstant(NumBitsPerElt, dl, VT),
DAG.getNode(ISD::CTLZ, dl, VT, Tmp));
return true;
return DAG.getNode(ISD::SUB, dl, VT, DAG.getConstant(NumBitsPerElt, dl, VT),
DAG.getNode(ISD::CTLZ, dl, VT, Tmp));
}
Result = DAG.getNode(ISD::CTPOP, dl, VT, Tmp);
return true;
return DAG.getNode(ISD::CTPOP, dl, VT, Tmp);
}
bool TargetLowering::expandABS(SDNode *N, SDValue &Result,