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-rw-r--r--lib/CodeGen/SelectionDAG/DAGCombiner.cpp50
-rw-r--r--lib/CodeGen/SelectionDAG/TargetLowering.cpp43
-rw-r--r--lib/Target/X86/X86ISelLowering.cpp70
3 files changed, 127 insertions, 36 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 48e556b236..848051940f 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -102,6 +102,8 @@ namespace {
SDValue To[] = { Res0, Res1 };
return CombineTo(N, To, 2, AddTo);
}
+
+ void CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO);
private:
@@ -298,6 +300,10 @@ CombineTo(SDNode *N, SDValue Res0, SDValue Res1) {
return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1);
}
+void TargetLowering::DAGCombinerInfo::
+CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) {
+ return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO);
+}
//===----------------------------------------------------------------------===//
// Helper Functions
@@ -539,29 +545,14 @@ SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo,
return SDValue(N, 0);
}
-/// SimplifyDemandedBits - Check the specified integer node value to see if
-/// it can be simplified or if things it uses can be simplified by bit
-/// propagation. If so, return true.
-bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) {
- TargetLowering::TargetLoweringOpt TLO(DAG);
- APInt KnownZero, KnownOne;
- if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
- return false;
-
- // Revisit the node.
- AddToWorkList(Op.getNode());
-
- // Replace the old value with the new one.
- ++NodesCombined;
- DOUT << "\nReplacing.2 "; DEBUG(TLO.Old.getNode()->dump(&DAG));
- DOUT << "\nWith: "; DEBUG(TLO.New.getNode()->dump(&DAG));
- DOUT << '\n';
-
+void
+DAGCombiner::CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &
+ TLO) {
// Replace all uses. If any nodes become isomorphic to other nodes and
// are deleted, make sure to remove them from our worklist.
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, &DeadNodes);
-
+
// Push the new node and any (possibly new) users onto the worklist.
AddToWorkList(TLO.New.getNode());
AddUsersToWorkList(TLO.New.getNode());
@@ -580,6 +571,27 @@ bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) {
DAG.DeleteNode(TLO.Old.getNode());
}
+}
+
+/// SimplifyDemandedBits - Check the specified integer node value to see if
+/// it can be simplified or if things it uses can be simplified by bit
+/// propagation. If so, return true.
+bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) {
+ TargetLowering::TargetLoweringOpt TLO(DAG);
+ APInt KnownZero, KnownOne;
+ if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
+ return false;
+
+ // Revisit the node.
+ AddToWorkList(Op.getNode());
+
+ // Replace the old value with the new one.
+ ++NodesCombined;
+ DOUT << "\nReplacing.2 "; DEBUG(TLO.Old.getNode()->dump(&DAG));
+ DOUT << "\nWith: "; DEBUG(TLO.New.getNode()->dump(&DAG));
+ DOUT << '\n';
+
+ CommitTargetLoweringOpt(TLO);
return true;
}
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 7245244684..e479e05bdd 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -724,7 +724,7 @@ TargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
bool TargetLowering::TargetLoweringOpt::ShrinkDemandedConstant(SDValue Op,
const APInt &Demanded) {
// FIXME: ISD::SELECT, ISD::SELECT_CC
- switch(Op.getOpcode()) {
+ switch (Op.getOpcode()) {
default: break;
case ISD::AND:
case ISD::OR:
@@ -1054,6 +1054,14 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
}
break;
case ISD::SRA:
+ // If this is an arithmetic shift right and only the low-bit is set, we can
+ // always convert this into a logical shr, even if the shift amount is
+ // variable. The low bit of the shift cannot be an input sign bit unless
+ // the shift amount is >= the size of the datatype, which is undefined.
+ if (DemandedMask == 1)
+ return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, Op.getValueType(),
+ Op.getOperand(0), Op.getOperand(1)));
+
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
MVT VT = Op.getValueType();
unsigned ShAmt = SA->getZExtValue();
@@ -1332,6 +1340,21 @@ unsigned TargetLowering::ComputeNumSignBitsForTargetNode(SDValue Op,
return 1;
}
+static bool ValueHasAtMostOneBitSet(SDValue Val, const SelectionDAG &DAG) {
+ // Logical shift right or left won't ever introduce new set bits.
+ // We check for this case because we don't care which bits are
+ // set, but ComputeMaskedBits won't know anything unless it can
+ // determine which specific bits may be set.
+ if (Val.getOpcode() == ISD::SHL || Val.getOpcode() == ISD::SRL)
+ return ValueHasAtMostOneBitSet(Val.getOperand(0), DAG);
+
+ MVT OpVT = Val.getValueType();
+ unsigned BitWidth = OpVT.getSizeInBits();
+ APInt Mask = APInt::getAllOnesValue(BitWidth);
+ APInt KnownZero, KnownOne;
+ DAG.ComputeMaskedBits(Val, Mask, KnownZero, KnownOne);
+ return KnownZero.countPopulation() == BitWidth - 1;
+}
/// SimplifySetCC - Try to simplify a setcc built with the specified operands
/// and cc. If it is unable to simplify it, return a null SDValue.
@@ -1791,6 +1814,24 @@ TargetLowering::SimplifySetCC(MVT VT, SDValue N0, SDValue N1,
}
}
}
+
+ // Simpify x&y == y to x&y == 0 if y has exactly one bit set.
+ if (N0.getOpcode() == ISD::AND)
+ if (N0.getOperand(0) == N1 || N0.getOperand(1) == N1) {
+ if (ValueHasAtMostOneBitSet(N1, DAG)) {
+ Cond = ISD::getSetCCInverse(Cond, /*isInteger=*/true);
+ SDValue Zero = DAG.getConstant(0, N1.getValueType());
+ return DAG.getSetCC(VT, N0, Zero, Cond);
+ }
+ }
+ if (N1.getOpcode() == ISD::AND)
+ if (N1.getOperand(0) == N0 || N1.getOperand(1) == N0) {
+ if (ValueHasAtMostOneBitSet(N0, DAG)) {
+ Cond = ISD::getSetCCInverse(Cond, /*isInteger=*/true);
+ SDValue Zero = DAG.getConstant(0, N0.getValueType());
+ return DAG.getSetCC(VT, N1, Zero, Cond);
+ }
+ }
}
// Fold away ALL boolean setcc's.
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 6ec97e2db6..bf7c704b9b 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -5114,22 +5114,39 @@ SDValue X86TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) {
SDValue Op1 = Op.getOperand(1);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
- // Lower (X & (1 << N)) == 0 to BT.
- // Lower ((X >>u N) & 1) != 0 to BT.
- // Lower ((X >>s N) & 1) != 0 to BT.
+ // Lower (X & (1 << N)) == 0 to BT(X, N).
+ // Lower ((X >>u N) & 1) != 0 to BT(X, N).
+ // Lower ((X >>s N) & 1) != 0 to BT(X, N).
if (Op0.getOpcode() == ISD::AND &&
Op0.hasOneUse() &&
Op1.getOpcode() == ISD::Constant &&
- Op0.getOperand(1).getOpcode() == ISD::Constant &&
+ cast<ConstantSDNode>(Op1)->getZExtValue() == 0 &&
(CC == ISD::SETEQ || CC == ISD::SETNE)) {
- ConstantSDNode *AndRHS = cast<ConstantSDNode>(Op0.getOperand(1));
- ConstantSDNode *CmpRHS = cast<ConstantSDNode>(Op1);
- SDValue AndLHS = Op0.getOperand(0);
- if (CmpRHS->getZExtValue() == 0 && AndRHS->getZExtValue() == 1 &&
- AndLHS.getOpcode() == ISD::SRL) {
- SDValue LHS = AndLHS.getOperand(0);
- SDValue RHS = AndLHS.getOperand(1);
+ SDValue LHS, RHS;
+ if (Op0.getOperand(1).getOpcode() == ISD::SHL) {
+ if (ConstantSDNode *Op010C =
+ dyn_cast<ConstantSDNode>(Op0.getOperand(1).getOperand(0)))
+ if (Op010C->getZExtValue() == 1) {
+ LHS = Op0.getOperand(0);
+ RHS = Op0.getOperand(1).getOperand(1);
+ }
+ } else if (Op0.getOperand(0).getOpcode() == ISD::SHL) {
+ if (ConstantSDNode *Op000C =
+ dyn_cast<ConstantSDNode>(Op0.getOperand(0).getOperand(0)))
+ if (Op000C->getZExtValue() == 1) {
+ LHS = Op0.getOperand(1);
+ RHS = Op0.getOperand(0).getOperand(1);
+ }
+ } else if (Op0.getOperand(1).getOpcode() == ISD::Constant) {
+ ConstantSDNode *AndRHS = cast<ConstantSDNode>(Op0.getOperand(1));
+ SDValue AndLHS = Op0.getOperand(0);
+ if (AndRHS->getZExtValue() == 1 && AndLHS.getOpcode() == ISD::SRL) {
+ LHS = AndLHS.getOperand(0);
+ RHS = AndLHS.getOperand(1);
+ }
+ }
+ if (LHS.getNode()) {
// If LHS is i8, promote it to i16 with any_extend. There is no i8 BT
// instruction. Since the shift amount is in-range-or-undefined, we know
// that doing a bittest on the i16 value is ok. We extend to i32 because
@@ -5141,10 +5158,10 @@ SDValue X86TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) {
// BT ignores high bits (like shifts) we can use anyextend.
if (LHS.getValueType() != RHS.getValueType())
RHS = DAG.getNode(ISD::ANY_EXTEND, LHS.getValueType(), RHS);
-
+
SDValue BT = DAG.getNode(X86ISD::BT, MVT::i32, LHS, RHS);
unsigned Cond = CC == ISD::SETEQ ? X86::COND_AE : X86::COND_B;
- return DAG.getNode(X86ISD::SETCC, MVT::i8,
+ return DAG.getNode(X86ISD::SETCC, MVT::i8,
DAG.getConstant(Cond, MVT::i8), BT);
}
}
@@ -5295,7 +5312,7 @@ SDValue X86TargetLowering::LowerSELECT(SDValue Op, SelectionDAG &DAG) {
!isScalarFPTypeInSSEReg(VT)) // FPStack?
IllegalFPCMov = !hasFPCMov(cast<ConstantSDNode>(CC)->getSExtValue());
- if (isX86LogicalCmp(Opc) && !IllegalFPCMov) {
+ if ((isX86LogicalCmp(Opc) && !IllegalFPCMov) || Opc == X86ISD::BT) { // FIXME
Cond = Cmp;
addTest = false;
}
@@ -7547,6 +7564,7 @@ static SDValue PerformShuffleCombine(SDNode *N, SelectionDAG &DAG,
/// PerformBuildVectorCombine - build_vector 0,(load i64 / f64) -> movq / movsd.
static SDValue PerformBuildVectorCombine(SDNode *N, SelectionDAG &DAG,
+ TargetLowering::DAGCombinerInfo &DCI,
const X86Subtarget *Subtarget,
const TargetLowering &TLI) {
unsigned NumOps = N->getNumOperands();
@@ -7587,7 +7605,9 @@ static SDValue PerformBuildVectorCombine(SDNode *N, SelectionDAG &DAG,
SDVTList Tys = DAG.getVTList(VT, MVT::Other);
SDValue Ops[] = { LD->getChain(), LD->getBasePtr() };
SDValue ResNode = DAG.getNode(X86ISD::VZEXT_LOAD, Tys, Ops, 2);
- DAG.ReplaceAllUsesOfValueWith(SDValue(Base, 1), ResNode.getValue(1));
+ TargetLowering::TargetLoweringOpt TLO(DAG);
+ TLO.CombineTo(SDValue(Base, 1), ResNode.getValue(1));
+ DCI.CommitTargetLoweringOpt(TLO);
return ResNode;
}
@@ -7875,6 +7895,23 @@ static SDValue PerformFANDCombine(SDNode *N, SelectionDAG &DAG) {
return SDValue();
}
+static SDValue PerformBTCombine(SDNode *N,
+ SelectionDAG &DAG,
+ TargetLowering::DAGCombinerInfo &DCI) {
+ // BT ignores high bits in the bit index operand.
+ SDValue Op1 = N->getOperand(1);
+ if (Op1.hasOneUse()) {
+ unsigned BitWidth = Op1.getValueSizeInBits();
+ APInt DemandedMask = APInt::getLowBitsSet(BitWidth, Log2_32(BitWidth));
+ APInt KnownZero, KnownOne;
+ TargetLowering::TargetLoweringOpt TLO(DAG);
+ TargetLowering &TLI = DAG.getTargetLoweringInfo();
+ if (TLO.ShrinkDemandedConstant(Op1, DemandedMask) ||
+ TLI.SimplifyDemandedBits(Op1, DemandedMask, KnownZero, KnownOne, TLO))
+ DCI.CommitTargetLoweringOpt(TLO);
+ }
+ return SDValue();
+}
SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
@@ -7883,7 +7920,7 @@ SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
default: break;
case ISD::VECTOR_SHUFFLE: return PerformShuffleCombine(N, DAG, *this);
case ISD::BUILD_VECTOR:
- return PerformBuildVectorCombine(N, DAG, Subtarget, *this);
+ return PerformBuildVectorCombine(N, DAG, DCI, Subtarget, *this);
case ISD::SELECT: return PerformSELECTCombine(N, DAG, Subtarget);
case ISD::SHL:
case ISD::SRA:
@@ -7892,6 +7929,7 @@ SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
case X86ISD::FXOR:
case X86ISD::FOR: return PerformFORCombine(N, DAG);
case X86ISD::FAND: return PerformFANDCombine(N, DAG);
+ case X86ISD::BT: return PerformBTCombine(N, DAG, DCI);
}
return SDValue();
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-23 22:49:09 +0000