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llvm-project/llvm/lib/Target/AArch64/AArch64InstrInfo.h

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//===- AArch64InstrInfo.h - AArch64 Instruction Information -----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains the AArch64 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_AARCH64_AARCH64INSTRINFO_H
#define LLVM_LIB_TARGET_AARCH64_AARCH64INSTRINFO_H
#include "AArch64.h"
#include "AArch64RegisterInfo.h"
#include "llvm/ADT/Optional.h"
#include "llvm/CodeGen/MachineCombinerPattern.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#define GET_INSTRINFO_HEADER
#include "AArch64GenInstrInfo.inc"
namespace llvm {
class AArch64Subtarget;
class AArch64TargetMachine;
static const MachineMemOperand::Flags MOSuppressPair =
MachineMemOperand::MOTargetFlag1;
static const MachineMemOperand::Flags MOStridedAccess =
MachineMemOperand::MOTargetFlag2;
#define FALKOR_STRIDED_ACCESS_MD "falkor.strided.access"
class AArch64InstrInfo final : public AArch64GenInstrInfo {
const AArch64RegisterInfo RI;
const AArch64Subtarget &Subtarget;
public:
explicit AArch64InstrInfo(const AArch64Subtarget &STI);
/// getRegisterInfo - TargetInstrInfo is a superset of MRegister info. As
/// such, whenever a client has an instance of instruction info, it should
/// always be able to get register info as well (through this method).
const AArch64RegisterInfo &getRegisterInfo() const { return RI; }
unsigned getInstSizeInBytes(const MachineInstr &MI) const override;
bool isAsCheapAsAMove(const MachineInstr &MI) const override;
bool isCoalescableExtInstr(const MachineInstr &MI, unsigned &SrcReg,
unsigned &DstReg, unsigned &SubIdx) const override;
bool
areMemAccessesTriviallyDisjoint(MachineInstr &MIa, MachineInstr &MIb,
AliasAnalysis *AA = nullptr) const override;
unsigned isLoadFromStackSlot(const MachineInstr &MI,
int &FrameIndex) const override;
unsigned isStoreToStackSlot(const MachineInstr &MI,
int &FrameIndex) const override;
/// Does this instruction set its full destination register to zero?
static bool isGPRZero(const MachineInstr &MI);
/// Does this instruction rename a GPR without modifying bits?
static bool isGPRCopy(const MachineInstr &MI);
/// Does this instruction rename an FPR without modifying bits?
static bool isFPRCopy(const MachineInstr &MI);
/// Return true if pairing the given load or store is hinted to be
/// unprofitable.
static bool isLdStPairSuppressed(const MachineInstr &MI);
/// Return true if the given load or store is a strided memory access.
static bool isStridedAccess(const MachineInstr &MI);
/// Return true if this is an unscaled load/store.
static bool isUnscaledLdSt(unsigned Opc);
static bool isUnscaledLdSt(MachineInstr &MI) {
return isUnscaledLdSt(MI.getOpcode());
}
/// Returns the unscaled load/store for the scaled load/store opcode,
/// if there is a corresponding unscaled variant available.
static Optional<unsigned> getUnscaledLdSt(unsigned Opc);
/// Returns the index for the immediate for a given instruction.
static unsigned getLoadStoreImmIdx(unsigned Opc);
/// Return true if pairing the given load or store may be paired with another.
static bool isPairableLdStInst(const MachineInstr &MI);
/// Return the opcode that set flags when possible. The caller is
/// responsible for ensuring the opc has a flag setting equivalent.
static unsigned convertToFlagSettingOpc(unsigned Opc, bool &Is64Bit);
/// Return true if this is a load/store that can be potentially paired/merged.
bool isCandidateToMergeOrPair(MachineInstr &MI) const;
/// Hint that pairing the given load or store is unprofitable.
static void suppressLdStPair(MachineInstr &MI);
bool getMemOperandWithOffset(MachineInstr &MI, MachineOperand *&BaseOp,
int64_t &Offset,
const TargetRegisterInfo *TRI) const override;
bool getMemOperandWithOffsetWidth(MachineInstr &MI, MachineOperand *&BaseOp,
int64_t &Offset, unsigned &Width,
const TargetRegisterInfo *TRI) const;
/// Return the immediate offset of the base register in a load/store \p LdSt.
MachineOperand &getMemOpBaseRegImmOfsOffsetOperand(MachineInstr &LdSt) const;
/// Returns true if opcode \p Opc is a memory operation. If it is, set
/// \p Scale, \p Width, \p MinOffset, and \p MaxOffset accordingly.
///
/// For unscaled instructions, \p Scale is set to 1.
static bool getMemOpInfo(unsigned Opcode, unsigned &Scale, unsigned &Width,
int64_t &MinOffset, int64_t &MaxOffset);
bool shouldClusterMemOps(MachineOperand &BaseOp1, MachineOperand &BaseOp2,
unsigned NumLoads) const override;
void copyPhysRegTuple(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
bool KillSrc, unsigned Opcode,
llvm::ArrayRef<unsigned> Indices) const;
void copyGPRRegTuple(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
DebugLoc DL, unsigned DestReg, unsigned SrcReg,
bool KillSrc, unsigned Opcode, unsigned ZeroReg,
llvm::ArrayRef<unsigned> Indices) const;
void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
bool KillSrc) const override;
void storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, unsigned SrcReg,
bool isKill, int FrameIndex,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const override;
void loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, unsigned DestReg,
int FrameIndex, const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const override;
// This tells target independent code that it is okay to pass instructions
// with subreg operands to foldMemoryOperandImpl.
bool isSubregFoldable() const override { return true; }
using TargetInstrInfo::foldMemoryOperandImpl;
MachineInstr *
foldMemoryOperandImpl(MachineFunction &MF, MachineInstr &MI,
ArrayRef<unsigned> Ops,
MachineBasicBlock::iterator InsertPt, int FrameIndex,
LiveIntervals *LIS = nullptr) const override;
/// \returns true if a branch from an instruction with opcode \p BranchOpc
/// bytes is capable of jumping to a position \p BrOffset bytes away.
bool isBranchOffsetInRange(unsigned BranchOpc,
int64_t BrOffset) const override;
MachineBasicBlock *getBranchDestBlock(const MachineInstr &MI) const override;
bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify = false) const override;
unsigned removeBranch(MachineBasicBlock &MBB,
int *BytesRemoved = nullptr) const override;
unsigned insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB, ArrayRef<MachineOperand> Cond,
const DebugLoc &DL,
int *BytesAdded = nullptr) const override;
bool
reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
bool canInsertSelect(const MachineBasicBlock &, ArrayRef<MachineOperand> Cond,
unsigned, unsigned, int &, int &, int &) const override;
void insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
const DebugLoc &DL, unsigned DstReg,
ArrayRef<MachineOperand> Cond, unsigned TrueReg,
unsigned FalseReg) const override;
void getNoop(MCInst &NopInst) const override;
bool isSchedulingBoundary(const MachineInstr &MI,
const MachineBasicBlock *MBB,
const MachineFunction &MF) const override;
/// analyzeCompare - For a comparison instruction, return the source registers
/// in SrcReg and SrcReg2, and the value it compares against in CmpValue.
/// Return true if the comparison instruction can be analyzed.
bool analyzeCompare(const MachineInstr &MI, unsigned &SrcReg,
unsigned &SrcReg2, int &CmpMask,
int &CmpValue) const override;
/// optimizeCompareInstr - Convert the instruction supplying the argument to
/// the comparison into one that sets the zero bit in the flags register.
bool optimizeCompareInstr(MachineInstr &CmpInstr, unsigned SrcReg,
unsigned SrcReg2, int CmpMask, int CmpValue,
const MachineRegisterInfo *MRI) const override;
bool optimizeCondBranch(MachineInstr &MI) const override;
/// Return true when a code sequence can improve throughput. It
/// should be called only for instructions in loops.
/// \param Pattern - combiner pattern
bool isThroughputPattern(MachineCombinerPattern Pattern) const override;
/// Return true when there is potentially a faster code sequence
/// for an instruction chain ending in ``Root``. All potential patterns are
/// listed in the ``Patterns`` array.
bool getMachineCombinerPatterns(
MachineInstr &Root,
SmallVectorImpl<MachineCombinerPattern> &Patterns) const override;
/// Return true when Inst is associative and commutative so that it can be
/// reassociated.
bool isAssociativeAndCommutative(const MachineInstr &Inst) const override;
/// When getMachineCombinerPatterns() finds patterns, this function generates
/// the instructions that could replace the original code sequence
void genAlternativeCodeSequence(
MachineInstr &Root, MachineCombinerPattern Pattern,
SmallVectorImpl<MachineInstr *> &InsInstrs,
SmallVectorImpl<MachineInstr *> &DelInstrs,
DenseMap<unsigned, unsigned> &InstrIdxForVirtReg) const override;
/// AArch64 supports MachineCombiner.
bool useMachineCombiner() const override;
bool expandPostRAPseudo(MachineInstr &MI) const override;
std::pair<unsigned, unsigned>
decomposeMachineOperandsTargetFlags(unsigned TF) const override;
ArrayRef<std::pair<unsigned, const char *>>
getSerializableDirectMachineOperandTargetFlags() const override;
ArrayRef<std::pair<unsigned, const char *>>
getSerializableBitmaskMachineOperandTargetFlags() const override;
ArrayRef<std::pair<MachineMemOperand::Flags, const char *>>
getSerializableMachineMemOperandTargetFlags() const override;
bool isFunctionSafeToOutlineFrom(MachineFunction &MF,
bool OutlineFromLinkOnceODRs) const override;
outliner::OutlinedFunction getOutliningCandidateInfo(
std::vector<outliner::Candidate> &RepeatedSequenceLocs) const override;
outliner::InstrType
getOutliningType(MachineBasicBlock::iterator &MIT, unsigned Flags) const override;
bool isMBBSafeToOutlineFrom(MachineBasicBlock &MBB,
unsigned &Flags) const override;
void buildOutlinedFrame(MachineBasicBlock &MBB, MachineFunction &MF,
const outliner::OutlinedFunction &OF) const override;
MachineBasicBlock::iterator
insertOutlinedCall(Module &M, MachineBasicBlock &MBB,
MachineBasicBlock::iterator &It, MachineFunction &MF,
const outliner::Candidate &C) const override;
bool shouldOutlineFromFunctionByDefault(MachineFunction &MF) const override;
/// Returns true if the instruction has a shift by immediate that can be
/// executed in one cycle less.
static bool isFalkorShiftExtFast(const MachineInstr &MI);
/// Return true if the instructions is a SEH instruciton used for unwinding
/// on Windows.
static bool isSEHInstruction(const MachineInstr &MI);
#define GET_INSTRINFO_HELPER_DECLS
#include "AArch64GenInstrInfo.inc"
private:
/// Sets the offsets on outlined instructions in \p MBB which use SP
/// so that they will be valid post-outlining.
///
/// \param MBB A \p MachineBasicBlock in an outlined function.
void fixupPostOutline(MachineBasicBlock &MBB) const;
void instantiateCondBranch(MachineBasicBlock &MBB, const DebugLoc &DL,
MachineBasicBlock *TBB,
ArrayRef<MachineOperand> Cond) const;
bool substituteCmpToZero(MachineInstr &CmpInstr, unsigned SrcReg,
const MachineRegisterInfo *MRI) const;
/// Returns an unused general-purpose register which can be used for
/// constructing an outlined call if one exists. Returns 0 otherwise.
unsigned findRegisterToSaveLRTo(const outliner::Candidate &C) const;
};
/// emitFrameOffset - Emit instructions as needed to set DestReg to SrcReg
/// plus Offset. This is intended to be used from within the prolog/epilog
/// insertion (PEI) pass, where a virtual scratch register may be allocated
/// if necessary, to be replaced by the scavenger at the end of PEI.
void emitFrameOffset(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
int Offset, const TargetInstrInfo *TII,
MachineInstr::MIFlag = MachineInstr::NoFlags,
bool SetNZCV = false, bool NeedsWinCFI = false);
/// rewriteAArch64FrameIndex - Rewrite MI to access 'Offset' bytes from the
/// FP. Return false if the offset could not be handled directly in MI, and
/// return the left-over portion by reference.
bool rewriteAArch64FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const AArch64InstrInfo *TII);
/// Use to report the frame offset status in isAArch64FrameOffsetLegal.
enum AArch64FrameOffsetStatus {
AArch64FrameOffsetCannotUpdate = 0x0, ///< Offset cannot apply.
AArch64FrameOffsetIsLegal = 0x1, ///< Offset is legal.
AArch64FrameOffsetCanUpdate = 0x2 ///< Offset can apply, at least partly.
};
/// Check if the @p Offset is a valid frame offset for @p MI.
/// The returned value reports the validity of the frame offset for @p MI.
/// It uses the values defined by AArch64FrameOffsetStatus for that.
/// If result == AArch64FrameOffsetCannotUpdate, @p MI cannot be updated to
/// use an offset.eq
/// If result & AArch64FrameOffsetIsLegal, @p Offset can completely be
/// rewritten in @p MI.
/// If result & AArch64FrameOffsetCanUpdate, @p Offset contains the
/// amount that is off the limit of the legal offset.
/// If set, @p OutUseUnscaledOp will contain the whether @p MI should be
/// turned into an unscaled operator, which opcode is in @p OutUnscaledOp.
/// If set, @p EmittableOffset contains the amount that can be set in @p MI
/// (possibly with @p OutUnscaledOp if OutUseUnscaledOp is true) and that
/// is a legal offset.
int isAArch64FrameOffsetLegal(const MachineInstr &MI, int &Offset,
bool *OutUseUnscaledOp = nullptr,
unsigned *OutUnscaledOp = nullptr,
int *EmittableOffset = nullptr);
static inline bool isUncondBranchOpcode(int Opc) { return Opc == AArch64::B; }
static inline bool isCondBranchOpcode(int Opc) {
switch (Opc) {
case AArch64::Bcc:
case AArch64::CBZW:
case AArch64::CBZX:
case AArch64::CBNZW:
case AArch64::CBNZX:
case AArch64::TBZW:
case AArch64::TBZX:
case AArch64::TBNZW:
case AArch64::TBNZX:
return true;
default:
return false;
}
}
static inline bool isIndirectBranchOpcode(int Opc) {
return Opc == AArch64::BR;
}
// struct TSFlags {
#define TSFLAG_ELEMENT_SIZE_TYPE(X) (X) // 3-bits
#define TSFLAG_DESTRUCTIVE_INST_TYPE(X) ((X) << 3) // 1-bit
// }
namespace AArch64 {
enum ElementSizeType {
ElementSizeMask = TSFLAG_ELEMENT_SIZE_TYPE(0x7),
ElementSizeNone = TSFLAG_ELEMENT_SIZE_TYPE(0x0),
ElementSizeB = TSFLAG_ELEMENT_SIZE_TYPE(0x1),
ElementSizeH = TSFLAG_ELEMENT_SIZE_TYPE(0x2),
ElementSizeS = TSFLAG_ELEMENT_SIZE_TYPE(0x3),
ElementSizeD = TSFLAG_ELEMENT_SIZE_TYPE(0x4),
};
enum DestructiveInstType {
DestructiveInstTypeMask = TSFLAG_DESTRUCTIVE_INST_TYPE(0x1),
NotDestructive = TSFLAG_DESTRUCTIVE_INST_TYPE(0x0),
Destructive = TSFLAG_DESTRUCTIVE_INST_TYPE(0x1),
};
#undef TSFLAG_ELEMENT_SIZE_TYPE
#undef TSFLAG_DESTRUCTIVE_INST_TYPE
}
} // end namespace llvm
#endif
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