diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp | 23 | ||||
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 28 |
2 files changed, 48 insertions, 3 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp index 0b7a3cbaa9f..23d88e55dc4 100644 --- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp @@ -861,7 +861,28 @@ void DAGTypeLegalizer::PromoteSetCCOperands(SDValue &NewLHS,SDValue &NewRHS, switch (CCCode) { default: llvm_unreachable("Unknown integer comparison!"); case ISD::SETEQ: - case ISD::SETNE: + case ISD::SETNE: { + SDValue OpL, OpR; + + OpL = GetPromotedInteger(NewLHS); + OpR = GetPromotedInteger(NewRHS); + + // We would prefer to promote the comparison operand with sign extension, + // if we find the operand is actually to truncate an AssertSext. With this + // optimization, we can avoid inserting real truncate instruction, which + // is redudant eventually. + if (OpL->getOpcode() == ISD::AssertSext && + cast<VTSDNode>(OpL->getOperand(1))->getVT() == NewLHS.getValueType() && + OpR->getOpcode() == ISD::AssertSext && + cast<VTSDNode>(OpR->getOperand(1))->getVT() == NewRHS.getValueType()) { + NewLHS = OpL; + NewRHS = OpR; + } else { + NewLHS = ZExtPromotedInteger(NewLHS); + NewRHS = ZExtPromotedInteger(NewRHS); + } + break; + } case ISD::SETUGE: case ISD::SETUGT: case ISD::SETULE: diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index e264cd9ae4a..1ca496bc3cf 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -757,6 +757,28 @@ SDValue RegsForValue::getCopyFromRegs(SelectionDAG &DAG, return DAG.getNode(ISD::MERGE_VALUES, dl, DAG.getVTList(ValueVTs), Values); } +static ISD::NodeType getPreferredExtendForValue(const Value *V) { + // For the users of the source value being used for compare instruction, if + // the number of signed predicate is greater than unsigned predicate, we + // prefer to use SIGN_EXTEND. + // + // With this optimization, we would be able to reduce some redundant sign or + // zero extension instruction, and eventually more machine CSE opportunities + // can be exposed. + ISD::NodeType ExtendKind = ISD::ANY_EXTEND; + unsigned int NumOfSigned = 0, NumOfUnsigned = 0; + for (const User *U : V->users()) { + if (const CmpInst *CI = dyn_cast<CmpInst>(U)) { + NumOfSigned += CI->isSigned(); + NumOfUnsigned += CI->isUnsigned(); + } + } + if (NumOfSigned > NumOfUnsigned) + ExtendKind = ISD::SIGN_EXTEND; + + return ExtendKind; +} + /// getCopyToRegs - Emit a series of CopyToReg nodes that copies the /// specified value into the registers specified by this object. This uses /// Chain/Flag as the input and updates them for the output Chain/Flag. @@ -765,6 +787,7 @@ void RegsForValue::getCopyToRegs(SDValue Val, SelectionDAG &DAG, SDLoc dl, SDValue &Chain, SDValue *Flag, const Value *V) const { const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + ISD::NodeType ExtendKind = getPreferredExtendForValue(V); // Get the list of the values's legal parts. unsigned NumRegs = Regs.size(); @@ -773,8 +796,9 @@ void RegsForValue::getCopyToRegs(SDValue Val, SelectionDAG &DAG, SDLoc dl, EVT ValueVT = ValueVTs[Value]; unsigned NumParts = TLI.getNumRegisters(*DAG.getContext(), ValueVT); MVT RegisterVT = RegVTs[Value]; - ISD::NodeType ExtendKind = - TLI.isZExtFree(Val, RegisterVT)? ISD::ZERO_EXTEND: ISD::ANY_EXTEND; + + if (ExtendKind == ISD::ANY_EXTEND && TLI.isZExtFree(Val, RegisterVT)) + ExtendKind = ISD::ZERO_EXTEND; getCopyToParts(DAG, dl, Val.getValue(Val.getResNo() + Value), &Parts[Part], NumParts, RegisterVT, V, ExtendKind); |
