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//===-- X86InstrInfo.h - X86 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 X86 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_X86_X86INSTRINFO_H
#define LLVM_LIB_TARGET_X86_X86INSTRINFO_H
#include "MCTargetDesc/X86BaseInfo.h"
#include "X86InstrFMA3Info.h"
#include "X86RegisterInfo.h"
#include "llvm/CodeGen/ISDOpcodes.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include <vector>
#define GET_INSTRINFO_HEADER
#include "X86GenInstrInfo.inc"
namespace llvm {
class X86Subtarget;
namespace X86 {
enum AsmComments {
// For instr that was compressed from EVEX to VEX.
AC_EVEX_2_VEX = MachineInstr::TAsmComments
};
/// Return a pair of condition code for the given predicate and whether
/// the instruction operands should be swaped to match the condition code.
std::pair<CondCode, bool> getX86ConditionCode(CmpInst::Predicate Predicate);
/// Return a setcc opcode based on whether it has a memory operand.
unsigned getSETOpc(bool HasMemoryOperand = false);
/// Return a cmov opcode for the given register size in bytes, and operand type.
unsigned getCMovOpcode(unsigned RegBytes, bool HasMemoryOperand = false);
// Turn jCC instruction into condition code.
CondCode getCondFromBranch(const MachineInstr &MI);
// Turn setCC instruction into condition code.
CondCode getCondFromSETCC(const MachineInstr &MI);
// Turn CMov instruction into condition code.
CondCode getCondFromCMov(const MachineInstr &MI);
/// GetOppositeBranchCondition - Return the inverse of the specified cond,
/// e.g. turning COND_E to COND_NE.
CondCode GetOppositeBranchCondition(CondCode CC);
/// Get the VPCMP immediate for the given condition.
unsigned getVPCMPImmForCond(ISD::CondCode CC);
/// Get the VPCMP immediate if the opcodes are swapped.
unsigned getSwappedVPCMPImm(unsigned Imm);
/// Get the VPCOM immediate if the opcodes are swapped.
unsigned getSwappedVPCOMImm(unsigned Imm);
/// Get the VCMP immediate if the opcodes are swapped.
unsigned getSwappedVCMPImm(unsigned Imm);
} // namespace X86
/// isGlobalStubReference - Return true if the specified TargetFlag operand is
/// a reference to a stub for a global, not the global itself.
inline static bool isGlobalStubReference(unsigned char TargetFlag) {
switch (TargetFlag) {
case X86II::MO_DLLIMPORT: // dllimport stub.
case X86II::MO_GOTPCREL: // rip-relative GOT reference.
case X86II::MO_GOT: // normal GOT reference.
case X86II::MO_DARWIN_NONLAZY_PIC_BASE: // Normal $non_lazy_ptr ref.
case X86II::MO_DARWIN_NONLAZY: // Normal $non_lazy_ptr ref.
case X86II::MO_COFFSTUB: // COFF .refptr stub.
return true;
default:
return false;
}
}
/// isGlobalRelativeToPICBase - Return true if the specified global value
/// reference is relative to a 32-bit PIC base (X86ISD::GlobalBaseReg). If this
/// is true, the addressing mode has the PIC base register added in (e.g. EBX).
inline static bool isGlobalRelativeToPICBase(unsigned char TargetFlag) {
switch (TargetFlag) {
case X86II::MO_GOTOFF: // isPICStyleGOT: local global.
case X86II::MO_GOT: // isPICStyleGOT: other global.
case X86II::MO_PIC_BASE_OFFSET: // Darwin local global.
case X86II::MO_DARWIN_NONLAZY_PIC_BASE: // Darwin/32 external global.
case X86II::MO_TLVP: // ??? Pretty sure..
return true;
default:
return false;
}
}
inline static bool isScale(const MachineOperand &MO) {
return MO.isImm() && (MO.getImm() == 1 || MO.getImm() == 2 ||
MO.getImm() == 4 || MO.getImm() == 8);
}
inline static bool isLeaMem(const MachineInstr &MI, unsigned Op) {
if (MI.getOperand(Op).isFI())
return true;
return Op + X86::AddrSegmentReg <= MI.getNumOperands() &&
MI.getOperand(Op + X86::AddrBaseReg).isReg() &&
isScale(MI.getOperand(Op + X86::AddrScaleAmt)) &&
MI.getOperand(Op + X86::AddrIndexReg).isReg() &&
(MI.getOperand(Op + X86::AddrDisp).isImm() ||
MI.getOperand(Op + X86::AddrDisp).isGlobal() ||
MI.getOperand(Op + X86::AddrDisp).isCPI() ||
MI.getOperand(Op + X86::AddrDisp).isJTI());
}
inline static bool isMem(const MachineInstr &MI, unsigned Op) {
if (MI.getOperand(Op).isFI())
return true;
return Op + X86::AddrNumOperands <= MI.getNumOperands() &&
MI.getOperand(Op + X86::AddrSegmentReg).isReg() && isLeaMem(MI, Op);
}
class X86InstrInfo final : public X86GenInstrInfo {
X86Subtarget &Subtarget;
const X86RegisterInfo RI;
virtual void anchor();
bool AnalyzeBranchImpl(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
SmallVectorImpl<MachineInstr *> &CondBranches,
bool AllowModify) const;
public:
explicit X86InstrInfo(X86Subtarget &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 X86RegisterInfo &getRegisterInfo() const { return RI; }
/// Returns the stack pointer adjustment that happens inside the frame
/// setup..destroy sequence (e.g. by pushes, or inside the callee).
int64_t getFrameAdjustment(const MachineInstr &I) const {
assert(isFrameInstr(I));
if (isFrameSetup(I))
return I.getOperand(2).getImm();
return I.getOperand(1).getImm();
}
/// Sets the stack pointer adjustment made inside the frame made up by this
/// instruction.
void setFrameAdjustment(MachineInstr &I, int64_t V) const {
assert(isFrameInstr(I));
if (isFrameSetup(I))
I.getOperand(2).setImm(V);
else
I.getOperand(1).setImm(V);
}
/// getSPAdjust - This returns the stack pointer adjustment made by
/// this instruction. For x86, we need to handle more complex call
/// sequences involving PUSHes.
int getSPAdjust(const MachineInstr &MI) const override;
/// isCoalescableExtInstr - Return true if the instruction is a "coalescable"
/// extension instruction. That is, it's like a copy where it's legal for the
/// source to overlap the destination. e.g. X86::MOVSX64rr32. If this returns
/// true, then it's expected the pre-extension value is available as a subreg
/// of the result register. This also returns the sub-register index in
/// SubIdx.
bool isCoalescableExtInstr(const MachineInstr &MI, Register &SrcReg,
Register &DstReg, unsigned &SubIdx) const override;
/// Returns true if the instruction has no behavior (specified or otherwise)
/// that is based on the value of any of its register operands
///
/// Instructions are considered data invariant even if they set EFLAGS.
///
/// A classical example of something that is inherently not data invariant is
/// an indirect jump -- the destination is loaded into icache based on the
/// bits set in the jump destination register.
///
/// FIXME: This should become part of our instruction tables.
static bool isDataInvariant(MachineInstr &MI);
/// Returns true if the instruction has no behavior (specified or otherwise)
/// that is based on the value loaded from memory or the value of any
/// non-address register operands.
///
/// For example, if the latency of the instruction is dependent on the
/// particular bits set in any of the registers *or* any of the bits loaded
/// from memory.
///
/// Instructions are considered data invariant even if they set EFLAGS.
///
/// A classical example of something that is inherently not data invariant is
/// an indirect jump -- the destination is loaded into icache based on the
/// bits set in the jump destination register.
///
/// FIXME: This should become part of our instruction tables.
static bool isDataInvariantLoad(MachineInstr &MI);
unsigned isLoadFromStackSlot(const MachineInstr &MI,
int &FrameIndex) const override;
unsigned isLoadFromStackSlot(const MachineInstr &MI,
int &FrameIndex,
unsigned &MemBytes) const override;
/// isLoadFromStackSlotPostFE - Check for post-frame ptr elimination
/// stack locations as well. This uses a heuristic so it isn't
/// reliable for correctness.
unsigned isLoadFromStackSlotPostFE(const MachineInstr &MI,
int &FrameIndex) const override;
unsigned isStoreToStackSlot(const MachineInstr &MI,
int &FrameIndex) const override;
unsigned isStoreToStackSlot(const MachineInstr &MI,
int &FrameIndex,
unsigned &MemBytes) const override;
/// isStoreToStackSlotPostFE - Check for post-frame ptr elimination
/// stack locations as well. This uses a heuristic so it isn't
/// reliable for correctness.
unsigned isStoreToStackSlotPostFE(const MachineInstr &MI,
int &FrameIndex) const override;
bool isReallyTriviallyReMaterializable(const MachineInstr &MI,
AAResults *AA) const override;
void reMaterialize(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
Register DestReg, unsigned SubIdx,
const MachineInstr &Orig,
const TargetRegisterInfo &TRI) const override;
/// Given an operand within a MachineInstr, insert preceding code to put it
/// into the right format for a particular kind of LEA instruction. This may
/// involve using an appropriate super-register instead (with an implicit use
/// of the original) or creating a new virtual register and inserting COPY
/// instructions to get the data into the right class.
///
/// Reference parameters are set to indicate how caller should add this
/// operand to the LEA instruction.
bool classifyLEAReg(MachineInstr &MI, const MachineOperand &Src,
unsigned LEAOpcode, bool AllowSP, Register &NewSrc,
bool &isKill, MachineOperand &ImplicitOp,
LiveVariables *LV) const;
/// convertToThreeAddress - This method must be implemented by targets that
/// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
/// may be able to convert a two-address instruction into a true
/// three-address instruction on demand. This allows the X86 target (for
/// example) to convert ADD and SHL instructions into LEA instructions if they
/// would require register copies due to two-addressness.
///
/// This method returns a null pointer if the transformation cannot be
/// performed, otherwise it returns the new instruction.
///
MachineInstr *convertToThreeAddress(MachineFunction::iterator &MFI,
MachineInstr &MI,
LiveVariables *LV) const override;
/// Returns true iff the routine could find two commutable operands in the
/// given machine instruction.
/// The 'SrcOpIdx1' and 'SrcOpIdx2' are INPUT and OUTPUT arguments. Their
/// input values can be re-defined in this method only if the input values
/// are not pre-defined, which is designated by the special value
/// 'CommuteAnyOperandIndex' assigned to it.
/// If both of indices are pre-defined and refer to some operands, then the
/// method simply returns true if the corresponding operands are commutable
/// and returns false otherwise.
///
/// For example, calling this method this way:
/// unsigned Op1 = 1, Op2 = CommuteAnyOperandIndex;
/// findCommutedOpIndices(MI, Op1, Op2);
/// can be interpreted as a query asking to find an operand that would be
/// commutable with the operand#1.
bool findCommutedOpIndices(const MachineInstr &MI, unsigned &SrcOpIdx1,
unsigned &SrcOpIdx2) const override;
/// Returns true if we have preference on the operands order in MI, the
/// commute decision is returned in Commute.
bool hasCommutePreference(MachineInstr &MI, bool &Commute) const override;
/// Returns an adjusted FMA opcode that must be used in FMA instruction that
/// performs the same computations as the given \p MI but which has the
/// operands \p SrcOpIdx1 and \p SrcOpIdx2 commuted.
/// It may return 0 if it is unsafe to commute the operands.
/// Note that a machine instruction (instead of its opcode) is passed as the
/// first parameter to make it possible to analyze the instruction's uses and
/// commute the first operand of FMA even when it seems unsafe when you look
/// at the opcode. For example, it is Ok to commute the first operand of
/// VFMADD*SD_Int, if ONLY the lowest 64-bit element of the result is used.
///
/// The returned FMA opcode may differ from the opcode in the given \p MI.
/// For example, commuting the operands #1 and #3 in the following FMA
/// FMA213 #1, #2, #3
/// results into instruction with adjusted opcode:
/// FMA231 #3, #2, #1
unsigned
getFMA3OpcodeToCommuteOperands(const MachineInstr &MI, unsigned SrcOpIdx1,
unsigned SrcOpIdx2,
const X86InstrFMA3Group &FMA3Group) const;
// Branch analysis.
bool isUnconditionalTailCall(const MachineInstr &MI) const override;
bool canMakeTailCallConditional(SmallVectorImpl<MachineOperand> &Cond,
const MachineInstr &TailCall) const override;
void replaceBranchWithTailCall(MachineBasicBlock &MBB,
SmallVectorImpl<MachineOperand> &Cond,
const MachineInstr &TailCall) const override;
bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const override;
Optional<ExtAddrMode>
getAddrModeFromMemoryOp(const MachineInstr &MemI,
const TargetRegisterInfo *TRI) const override;
bool getConstValDefinedInReg(const MachineInstr &MI, const Register Reg,
int64_t &ImmVal) const override;
bool preservesZeroValueInReg(const MachineInstr *MI,
const Register NullValueReg,
const TargetRegisterInfo *TRI) const override;
bool getMemOperandsWithOffsetWidth(
const MachineInstr &LdSt,
SmallVectorImpl<const MachineOperand *> &BaseOps, int64_t &Offset,
bool &OffsetIsScalable, unsigned &Width,
const TargetRegisterInfo *TRI) const override;
bool analyzeBranchPredicate(MachineBasicBlock &MBB,
TargetInstrInfo::MachineBranchPredicate &MBP,
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 canInsertSelect(const MachineBasicBlock &, ArrayRef<MachineOperand> Cond,
Register, Register, Register, int &, int &,
int &) const override;
void insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
const DebugLoc &DL, Register DstReg,
ArrayRef<MachineOperand> Cond, Register TrueReg,
Register FalseReg) const override;
void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
const DebugLoc &DL, MCRegister DestReg, MCRegister SrcReg,
bool KillSrc) const override;
void storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI, Register SrcReg,
bool isKill, int FrameIndex,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const override;
void loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI, Register DestReg,
int FrameIndex, const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const override;
bool expandPostRAPseudo(MachineInstr &MI) const override;
/// Check whether the target can fold a load that feeds a subreg operand
/// (or a subreg operand that feeds a store).
bool isSubregFoldable() const override { return true; }
/// foldMemoryOperand - If this target supports it, fold a load or store of
/// the specified stack slot into the specified machine instruction for the
/// specified operand(s). If this is possible, the target should perform the
/// folding and return true, otherwise it should return false. If it folds
/// the instruction, it is likely that the MachineInstruction the iterator
/// references has been changed.
MachineInstr *
foldMemoryOperandImpl(MachineFunction &MF, MachineInstr &MI,
ArrayRef<unsigned> Ops,
MachineBasicBlock::iterator InsertPt, int FrameIndex,
LiveIntervals *LIS = nullptr,
VirtRegMap *VRM = nullptr) const override;
/// foldMemoryOperand - Same as the previous version except it allows folding
/// of any load and store from / to any address, not just from a specific
/// stack slot.
MachineInstr *foldMemoryOperandImpl(
MachineFunction &MF, MachineInstr &MI, ArrayRef<unsigned> Ops,
MachineBasicBlock::iterator InsertPt, MachineInstr &LoadMI,
LiveIntervals *LIS = nullptr) const override;
/// unfoldMemoryOperand - Separate a single instruction which folded a load or
/// a store or a load and a store into two or more instruction. If this is
/// possible, returns true as well as the new instructions by reference.
bool
unfoldMemoryOperand(MachineFunction &MF, MachineInstr &MI, unsigned Reg,
bool UnfoldLoad, bool UnfoldStore,
SmallVectorImpl<MachineInstr *> &NewMIs) const override;
bool unfoldMemoryOperand(SelectionDAG &DAG, SDNode *N,
SmallVectorImpl<SDNode *> &NewNodes) const override;
/// getOpcodeAfterMemoryUnfold - Returns the opcode of the would be new
/// instruction after load / store are unfolded from an instruction of the
/// specified opcode. It returns zero if the specified unfolding is not
/// possible. If LoadRegIndex is non-null, it is filled in with the operand
/// index of the operand which will hold the register holding the loaded
/// value.
unsigned
getOpcodeAfterMemoryUnfold(unsigned Opc, bool UnfoldLoad, bool UnfoldStore,
unsigned *LoadRegIndex = nullptr) const override;
/// areLoadsFromSameBasePtr - This is used by the pre-regalloc scheduler
/// to determine if two loads are loading from the same base address. It
/// should only return true if the base pointers are the same and the
/// only differences between the two addresses are the offset. It also returns
/// the offsets by reference.
bool areLoadsFromSameBasePtr(SDNode *Load1, SDNode *Load2, int64_t &Offset1,
int64_t &Offset2) const override;
/// isSchedulingBoundary - Overrides the isSchedulingBoundary from
/// Codegen/TargetInstrInfo.cpp to make it capable of identifying ENDBR
/// intructions and prevent it from being re-scheduled.
bool isSchedulingBoundary(const MachineInstr &MI,
const MachineBasicBlock *MBB,
const MachineFunction &MF) const override;
/// shouldScheduleLoadsNear - This is a used by the pre-regalloc scheduler to
/// determine (in conjunction with areLoadsFromSameBasePtr) if two loads
/// should be scheduled togther. On some targets if two loads are loading from
/// addresses in the same cache line, it's better if they are scheduled
/// together. This function takes two integers that represent the load offsets
/// from the common base address. It returns true if it decides it's desirable
/// to schedule the two loads together. "NumLoads" is the number of loads that
/// have already been scheduled after Load1.
bool shouldScheduleLoadsNear(SDNode *Load1, SDNode *Load2, int64_t Offset1,
int64_t Offset2,
unsigned NumLoads) const override;
MCInst getNop() const override;
bool
reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
/// isSafeToMoveRegClassDefs - Return true if it's safe to move a machine
/// instruction that defines the specified register class.
bool isSafeToMoveRegClassDefs(const TargetRegisterClass *RC) const override;
/// True if MI has a condition code def, e.g. EFLAGS, that is
/// not marked dead.
bool hasLiveCondCodeDef(MachineInstr &MI) const;
/// getGlobalBaseReg - Return a virtual register initialized with the
/// the global base register value. Output instructions required to
/// initialize the register in the function entry block, if necessary.
///
unsigned getGlobalBaseReg(MachineFunction *MF) const;
std::pair<uint16_t, uint16_t>
getExecutionDomain(const MachineInstr &MI) const override;
uint16_t getExecutionDomainCustom(const MachineInstr &MI) const;
void setExecutionDomain(MachineInstr &MI, unsigned Domain) const override;
bool setExecutionDomainCustom(MachineInstr &MI, unsigned Domain) const;
unsigned
getPartialRegUpdateClearance(const MachineInstr &MI, unsigned OpNum,
const TargetRegisterInfo *TRI) const override;
unsigned getUndefRegClearance(const MachineInstr &MI, unsigned OpNum,
const TargetRegisterInfo *TRI) const override;
void breakPartialRegDependency(MachineInstr &MI, unsigned OpNum,
const TargetRegisterInfo *TRI) const override;
MachineInstr *foldMemoryOperandImpl(MachineFunction &MF, MachineInstr &MI,
unsigned OpNum,
ArrayRef<MachineOperand> MOs,
MachineBasicBlock::iterator InsertPt,
unsigned Size, Align Alignment,
bool AllowCommute) const;
bool isHighLatencyDef(int opc) const override;
bool hasHighOperandLatency(const TargetSchedModel &SchedModel,
const MachineRegisterInfo *MRI,
const MachineInstr &DefMI, unsigned DefIdx,
const MachineInstr &UseMI,
unsigned UseIdx) const override;
bool useMachineCombiner() const override { return true; }
bool isAssociativeAndCommutative(const MachineInstr &Inst) const override;
bool hasReassociableOperands(const MachineInstr &Inst,
const MachineBasicBlock *MBB) const override;
void setSpecialOperandAttr(MachineInstr &OldMI1, MachineInstr &OldMI2,
MachineInstr &NewMI1,
MachineInstr &NewMI2) const override;
/// analyzeCompare - For a comparison instruction, return the source registers
/// in SrcReg and SrcReg2 if having two register operands, and the value it
/// compares against in CmpValue. Return true if the comparison instruction
/// can be analyzed.
bool analyzeCompare(const MachineInstr &MI, Register &SrcReg,
Register &SrcReg2, int &CmpMask,
int &CmpValue) const override;
/// optimizeCompareInstr - Check if there exists an earlier instruction that
/// operates on the same source operands and sets flags in the same way as
/// Compare; remove Compare if possible.
bool optimizeCompareInstr(MachineInstr &CmpInstr, Register SrcReg,
Register SrcReg2, int CmpMask, int CmpValue,
const MachineRegisterInfo *MRI) const override;
/// optimizeLoadInstr - Try to remove the load by folding it to a register
/// operand at the use. We fold the load instructions if and only if the
/// def and use are in the same BB. We only look at one load and see
/// whether it can be folded into MI. FoldAsLoadDefReg is the virtual register
/// defined by the load we are trying to fold. DefMI returns the machine
/// instruction that defines FoldAsLoadDefReg, and the function returns
/// the machine instruction generated due to folding.
MachineInstr *optimizeLoadInstr(MachineInstr &MI,
const MachineRegisterInfo *MRI,
Register &FoldAsLoadDefReg,
MachineInstr *&DefMI) const override;
std::pair<unsigned, unsigned>
decomposeMachineOperandsTargetFlags(unsigned TF) const override;
ArrayRef<std::pair<unsigned, const char *>>
getSerializableDirectMachineOperandTargetFlags() const override;
virtual outliner::OutlinedFunction getOutliningCandidateInfo(
std::vector<outliner::Candidate> &RepeatedSequenceLocs) const override;
bool isFunctionSafeToOutlineFrom(MachineFunction &MF,
bool OutlineFromLinkOnceODRs) const override;
outliner::InstrType
getOutliningType(MachineBasicBlock::iterator &MIT, 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;
#define GET_INSTRINFO_HELPER_DECLS
#include "X86GenInstrInfo.inc"
static bool hasLockPrefix(const MachineInstr &MI) {
return MI.getDesc().TSFlags & X86II::LOCK;
}
Optional<ParamLoadedValue> describeLoadedValue(const MachineInstr &MI,
Register Reg) const override;
protected:
/// Commutes the operands in the given instruction by changing the operands
/// order and/or changing the instruction's opcode and/or the immediate value
/// operand.
///
/// The arguments 'CommuteOpIdx1' and 'CommuteOpIdx2' specify the operands
/// to be commuted.
///
/// Do not call this method for a non-commutable instruction or
/// non-commutable operands.
/// Even though the instruction is commutable, the method may still
/// fail to commute the operands, null pointer is returned in such cases.
MachineInstr *commuteInstructionImpl(MachineInstr &MI, bool NewMI,
unsigned CommuteOpIdx1,
unsigned CommuteOpIdx2) const override;
/// If the specific machine instruction is a instruction that moves/copies
/// value from one register to another register return destination and source
/// registers as machine operands.
Optional<DestSourcePair>
isCopyInstrImpl(const MachineInstr &MI) const override;
private:
/// This is a helper for convertToThreeAddress for 8 and 16-bit instructions.
/// We use 32-bit LEA to form 3-address code by promoting to a 32-bit
/// super-register and then truncating back down to a 8/16-bit sub-register.
MachineInstr *convertToThreeAddressWithLEA(unsigned MIOpc,
MachineFunction::iterator &MFI,
MachineInstr &MI,
LiveVariables *LV,
bool Is8BitOp) const;
/// Handles memory folding for special case instructions, for instance those
/// requiring custom manipulation of the address.
MachineInstr *foldMemoryOperandCustom(MachineFunction &MF, MachineInstr &MI,
unsigned OpNum,
ArrayRef<MachineOperand> MOs,
MachineBasicBlock::iterator InsertPt,
unsigned Size, Align Alignment) const;
/// isFrameOperand - Return true and the FrameIndex if the specified
/// operand and follow operands form a reference to the stack frame.
bool isFrameOperand(const MachineInstr &MI, unsigned int Op,
int &FrameIndex) const;
/// Returns true iff the routine could find two commutable operands in the
/// given machine instruction with 3 vector inputs.
/// The 'SrcOpIdx1' and 'SrcOpIdx2' are INPUT and OUTPUT arguments. Their
/// input values can be re-defined in this method only if the input values
/// are not pre-defined, which is designated by the special value
/// 'CommuteAnyOperandIndex' assigned to it.
/// If both of indices are pre-defined and refer to some operands, then the
/// method simply returns true if the corresponding operands are commutable
/// and returns false otherwise.
///
/// For example, calling this method this way:
/// unsigned Op1 = 1, Op2 = CommuteAnyOperandIndex;
/// findThreeSrcCommutedOpIndices(MI, Op1, Op2);
/// can be interpreted as a query asking to find an operand that would be
/// commutable with the operand#1.
///
/// If IsIntrinsic is set, operand 1 will be ignored for commuting.
bool findThreeSrcCommutedOpIndices(const MachineInstr &MI,
unsigned &SrcOpIdx1,
unsigned &SrcOpIdx2,
bool IsIntrinsic = false) const;
};
} // namespace llvm
#endif