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//===-- RISCVISelLowering.h - RISCV DAG Lowering Interface ------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file defines the interfaces that RISCV uses to lower LLVM code into a
// selection DAG.
#include "RISCV.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/TargetLowering.h"
namespace llvm {
class RISCVSubtarget;
namespace RISCVISD {
enum NodeType : unsigned {
// RV64I shifts, directly matching the semantics of the named RISC-V
// instructions.
// 32-bit operations from RV64M that can't be simply matched with a pattern
// at instruction selection time.
// FPR32<->GPR transfer operations for RV64. Needed as an i32<->f32 bitcast
// is not legal on RV64. FMV_W_X_RV64 matches the semantics of the FMV.W.X.
// FMV_X_ANYEXTW_RV64 is similar to FMV.X.W but has an any-extended result.
// This is a more convenient semantic for producing dagcombines that remove
// unnecessary GPR->FPR->GPR moves.
// READ_CYCLE_WIDE - A read of the 64-bit cycle CSR on a 32-bit target
// (returns (Lo, Hi)). It takes a chain operand.
class RISCVTargetLowering : public TargetLowering {
const RISCVSubtarget &Subtarget;
explicit RISCVTargetLowering(const TargetMachine &TM,
const RISCVSubtarget &STI);
bool getTgtMemIntrinsic(IntrinsicInfo &Info, const CallInst &I,
MachineFunction &MF,
unsigned Intrinsic) const override;
bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM, Type *Ty,
unsigned AS,
Instruction *I = nullptr) const override;
bool isLegalICmpImmediate(int64_t Imm) const override;
bool isLegalAddImmediate(int64_t Imm) const override;
bool isTruncateFree(Type *SrcTy, Type *DstTy) const override;
bool isTruncateFree(EVT SrcVT, EVT DstVT) const override;
bool isZExtFree(SDValue Val, EVT VT2) const override;
bool isSExtCheaperThanZExt(EVT SrcVT, EVT DstVT) const override;
bool hasBitPreservingFPLogic(EVT VT) const override;
// Provide custom lowering hooks for some operations.
SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results,
SelectionDAG &DAG) const override;
SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
unsigned ComputeNumSignBitsForTargetNode(SDValue Op,
const APInt &DemandedElts,
const SelectionDAG &DAG,
unsigned Depth) const override;
// This method returns the name of a target specific DAG node.
const char *getTargetNodeName(unsigned Opcode) const override;
ConstraintType getConstraintType(StringRef Constraint) const override;
unsigned getInlineAsmMemConstraint(StringRef ConstraintCode) const override;
std::pair<unsigned, const TargetRegisterClass *>
getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
StringRef Constraint, MVT VT) const override;
void LowerAsmOperandForConstraint(SDValue Op, std::string &Constraint,
std::vector<SDValue> &Ops,
SelectionDAG &DAG) const override;
MachineBasicBlock *
EmitInstrWithCustomInserter(MachineInstr &MI,
MachineBasicBlock *BB) const override;
EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
EVT VT) const override;
bool convertSetCCLogicToBitwiseLogic(EVT VT) const override {
return VT.isScalarInteger();
bool shouldInsertFencesForAtomic(const Instruction *I) const override {
return isa<LoadInst>(I) || isa<StoreInst>(I);
Instruction *emitLeadingFence(IRBuilder<> &Builder, Instruction *Inst,
AtomicOrdering Ord) const override;
Instruction *emitTrailingFence(IRBuilder<> &Builder, Instruction *Inst,
AtomicOrdering Ord) const override;
ISD::NodeType getExtendForAtomicOps() const override {
bool shouldExpandShift(SelectionDAG &DAG, SDNode *N) const override {
if (DAG.getMachineFunction().getFunction().hasMinSize())
return false;
return true;
bool isDesirableToCommuteWithShift(const SDNode *N,
CombineLevel Level) const override;
/// If a physical register, this returns the register that receives the
/// exception address on entry to an EH pad.
getExceptionPointerRegister(const Constant *PersonalityFn) const override;
/// If a physical register, this returns the register that receives the
/// exception typeid on entry to a landing pad.
getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
bool shouldExtendTypeInLibCall(EVT Type) const override;
void analyzeInputArgs(MachineFunction &MF, CCState &CCInfo,
const SmallVectorImpl<ISD::InputArg> &Ins,
bool IsRet) const;
void analyzeOutputArgs(MachineFunction &MF, CCState &CCInfo,
const SmallVectorImpl<ISD::OutputArg> &Outs,
bool IsRet, CallLoweringInfo *CLI) const;
// Lower incoming arguments, copy physregs into vregs
SDValue LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv,
bool IsVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
const SDLoc &DL, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const override;
bool CanLowerReturn(CallingConv::ID CallConv, MachineFunction &MF,
bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
LLVMContext &Context) const override;
SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals, const SDLoc &DL,
SelectionDAG &DAG) const override;
SDValue LowerCall(TargetLowering::CallLoweringInfo &CLI,
SmallVectorImpl<SDValue> &InVals) const override;
bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
Type *Ty) const override {
return true;
template <class NodeTy>
SDValue getAddr(NodeTy *N, SelectionDAG &DAG, bool IsLocal = true) const;
SDValue getStaticTLSAddr(GlobalAddressSDNode *N, SelectionDAG &DAG,
bool UseGOT) const;
SDValue getDynamicTLSAddr(GlobalAddressSDNode *N, SelectionDAG &DAG) const;
bool shouldConsiderGEPOffsetSplit() const override { return true; }
SDValue lowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerConstantPool(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerSELECT(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerVASTART(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerShiftLeftParts(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerShiftRightParts(SDValue Op, SelectionDAG &DAG, bool IsSRA) const;
bool isEligibleForTailCallOptimization(
CCState &CCInfo, CallLoweringInfo &CLI, MachineFunction &MF,
const SmallVector<CCValAssign, 16> &ArgLocs) const;
shouldExpandAtomicRMWInIR(AtomicRMWInst *AI) const override;
virtual Value *emitMaskedAtomicRMWIntrinsic(
IRBuilder<> &Builder, AtomicRMWInst *AI, Value *AlignedAddr, Value *Incr,
Value *Mask, Value *ShiftAmt, AtomicOrdering Ord) const override;
shouldExpandAtomicCmpXchgInIR(AtomicCmpXchgInst *CI) const override;
virtual Value *
emitMaskedAtomicCmpXchgIntrinsic(IRBuilder<> &Builder, AtomicCmpXchgInst *CI,
Value *AlignedAddr, Value *CmpVal,
Value *NewVal, Value *Mask,
AtomicOrdering Ord) const override;