Make TargetInstrInfo::isCopyInstr return true for regular COPY-instructions

[aivchenk]

Summary

..Move all target-dependent checks into new isCopyInstrImpl method.

This change allows us to treat MoveReg-type instructions and generic
COPY instruction in the same way

[qcolombet]

LGTM.
Nitpicks on the comments.

include/llvm/CodeGen/TargetInstrInfo.h

866

The naming between the doxygen comment and the variable does not match (Source vs SourceOpNum).

lib/Target/ARM/ARMBaseInstrInfo.h

107

Ditto.

include/llvm/CodeGen/TargetInstrInfo.h

public:
   /// large registers. See for example the ARM target.
   virtual void copyPhysReg(MachineBasicBlock &MBB,
                            MachineBasicBlock::iterator MI, const DebugLoc &DL,
                            unsigned DestReg, unsigned SrcReg,
                            bool KillSrc) const {
     llvm_unreachable("Target didn't implement TargetInstrInfo::copyPhysReg!");
   }
 
+protected:
+  /// Target-dependent implemenation for IsCopyInstr.
   /// If the specific machine instruction is a instruction that moves/copies
   /// value from one register to another register return true along with
   /// @Source machine operand and @Destination machine operand.
-  virtual bool isCopyInstr(const MachineInstr &MI,
+  virtual bool isCopyInstrImpl(const MachineInstr &MI,
                                const MachineOperand *&SourceOpNum,
                                const MachineOperand *&Destination) const {
     return false;
   }
 
+public:
+  /// If the specific machine instruction is a instruction that moves/copies
+  /// value from one register to another register return true along with
+  /// @Source machine operand and @Destination machine operand.
+  /// For COPY-instruction the method naturally returns true, for all other
+  /// instructions the method calls target-dependent implementation.
+  bool isCopyInstr(const MachineInstr &MI, const MachineOperand *&SourceOpNum,
+                   const MachineOperand *&Destination) const {
+    if (MI.isCopy()) {
+      Destination = &MI.getOperand(0);
+      SourceOpNum = &MI.getOperand(1);
+      return true;
+    }
+    return isCopyInstrImpl(MI, SourceOpNum, Destination);
+  }
+
   /// Store the specified register of the given register class to the specified
   /// stack frame index. The store instruction is to be added to the given
   /// machine basic block before the specified machine instruction. If isKill
   /// is true, the register operand is the last use and must be marked kill.
   virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
                                    MachineBasicBlock::iterator MI,
                                    unsigned SrcReg, bool isKill, int FrameIndex,
                                    const TargetRegisterClass *RC,

lib/Target/ARM/ARMBaseInstrInfo.h

protected:
   /// Do not call this method for a non-commutable instruction or for
   /// non-commutable pair of operand indices OpIdx1 and OpIdx2.
   /// 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 OpIdx1,
                                        unsigned OpIdx2) const override;
 
+  /// If the specific machine instruction is a instruction that moves/copies
+  /// value from one register to another register return true along with
+  /// @Source machine operand and @Destination machine operand.
+  bool isCopyInstrImpl(const MachineInstr &MI, const MachineOperand *&Src,
+                       const MachineOperand *&Dest) const override;
+
 public:
   // Return whether the target has an explicit NOP encoding.
   bool hasNOP() const;
 
   // Return the non-pre/post incrementing version of 'Opc'. Return 0
   // if there is not such an opcode.
   virtual unsigned getUnindexedOpcode(unsigned Opc) const = 0;
 
public:
   void copyFromCPSR(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                     unsigned DestReg, bool KillSrc,
                     const ARMSubtarget &Subtarget) const;
 
   void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                    const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
                    bool KillSrc) const override;
 
-  bool isCopyInstr(const MachineInstr &MI, const MachineOperand *&Src,
-                   const MachineOperand *&Dest) 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,

lib/Target/ARM/ARMBaseInstrInfo.cpp

if (Opc == ARM::MOVr)
       Mov = Mov.add(condCodeOp());
   }
   // Add implicit super-register defs and kills to the last instruction.
   Mov->addRegisterDefined(DestReg, TRI);
   if (KillSrc)
     Mov->addRegisterKilled(SrcReg, TRI);
 }
 
-bool ARMBaseInstrInfo::isCopyInstr(const MachineInstr &MI,
+bool ARMBaseInstrInfo::isCopyInstrImpl(const MachineInstr &MI,
                                        const MachineOperand *&Src,
                                        const MachineOperand *&Dest) const {
   // VMOVRRD is also a copy instruction but it requires
   // special way of handling. It is more complex copy version
   // and since that we are not considering it. For recognition
   // of such instruction isExtractSubregLike MI interface fuction
   // could be used.
   // VORRq is considered as a move only if two inputs are
   // the same register.
   if (!MI.isMoveReg() ||

lib/Target/Mips/Mips16InstrInfo.h

public:
   /// any side effects other than storing to the stack slot.
   unsigned isStoreToStackSlot(const MachineInstr &MI,
                               int &FrameIndex) const override;
 
   void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
                    const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
                    bool KillSrc) const override;
 
-  bool isCopyInstr(const MachineInstr &MI, const MachineOperand *&Src,
-                   const MachineOperand *&Dest) const override;
-
   void storeRegToStack(MachineBasicBlock &MBB,
                        MachineBasicBlock::iterator MBBI,
                        unsigned SrcReg, bool isKill, int FrameIndex,
                        const TargetRegisterClass *RC,
                        const TargetRegisterInfo *TRI,
                        int64_t Offset) const override;
 
   void loadRegFromStack(MachineBasicBlock &MBB,
public:
   }
 
   // build the proper one based on the Imm field
 
   const MCInstrDesc& AddiuSpImm(int64_t Imm) const;
 
   void BuildAddiuSpImm
     (MachineBasicBlock &MBB, MachineBasicBlock::iterator I, int64_t Imm) const;
+
+protected:
+  /// If the specific machine instruction is a instruction that moves/copies
+  /// value from one register to another register return true along with
+  /// @Source machine operand and @Destination machine operand.
+  bool isCopyInstrImpl(const MachineInstr &MI, const MachineOperand *&Src,
+                       const MachineOperand *&Dest) const override;
+
 private:
   unsigned getAnalyzableBrOpc(unsigned Opc) const override;
 
   void ExpandRetRA16(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                    unsigned Opc) const;
 
   // Adjust SP by Amount bytes where bytes can be up to 32bit number.
   void adjustStackPtrBig(unsigned SP, int64_t Amount, MachineBasicBlock &MBB,

lib/Target/Mips/Mips16InstrInfo.cpp

void Mips16InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
 
   if (DestReg)
     MIB.addReg(DestReg, RegState::Define);
 
   if (SrcReg)
     MIB.addReg(SrcReg, getKillRegState(KillSrc));
 }
 
-bool Mips16InstrInfo::isCopyInstr(const MachineInstr &MI,
+bool Mips16InstrInfo::isCopyInstrImpl(const MachineInstr &MI,
                                       const MachineOperand *&Src,
                                       const MachineOperand *&Dest) const {
   if (MI.isMoveReg()) {
     Dest = &MI.getOperand(0);
     Src = &MI.getOperand(1);
     return true;
   }
   return false;
 }
 

lib/Target/Mips/MipsSEInstrInfo.h

public:
   /// any side effects other than storing to the stack slot.
   unsigned isStoreToStackSlot(const MachineInstr &MI,
                               int &FrameIndex) const override;
 
   void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
                    const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
                    bool KillSrc) const override;
 
-  bool isCopyInstr(const MachineInstr &MI, const MachineOperand *&Src,
-                   const MachineOperand *&Dest) const override;
-
   void storeRegToStack(MachineBasicBlock &MBB,
                        MachineBasicBlock::iterator MI,
                        unsigned SrcReg, bool isKill, int FrameIndex,
                        const TargetRegisterClass *RC,
                        const TargetRegisterInfo *TRI,
                        int64_t Offset) const override;
 
   void loadRegFromStack(MachineBasicBlock &MBB,
public:
 
   /// Emit a series of instructions to load an immediate. If NewImm is a
   /// non-NULL parameter, the last instruction is not emitted, but instead
   /// its immediate operand is returned in NewImm.
   unsigned loadImmediate(int64_t Imm, MachineBasicBlock &MBB,
                          MachineBasicBlock::iterator II, const DebugLoc &DL,
                          unsigned *NewImm) const;
 
+protected:
+  /// If the specific machine instruction is a instruction that moves/copies
+  /// value from one register to another register return true along with
+  /// @Source machine operand and @Destination machine operand.
+  bool isCopyInstrImpl(const MachineInstr &MI, const MachineOperand *&Src,
+                       const MachineOperand *&Dest) const override;
+
 private:
   unsigned getAnalyzableBrOpc(unsigned Opc) const override;
 
   void expandRetRA(MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const;
 
   void expandERet(MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const;
 
   std::pair<bool, bool> compareOpndSize(unsigned Opc,

lib/Target/Mips/MipsSEInstrInfo.cpp

case Mips::RDDSP_MM:
     break;
   }
   return true;
 }
 
 /// We check for the common case of 'or', as it's MIPS' preferred instruction
 /// for GPRs but we have to check the operands to ensure that is the case.
 /// Other move instructions for MIPS are directly identifiable.
-bool MipsSEInstrInfo::isCopyInstr(const MachineInstr &MI,
+bool MipsSEInstrInfo::isCopyInstrImpl(const MachineInstr &MI,
                                       const MachineOperand *&Src,
                                       const MachineOperand *&Dest) const {
   bool isDSPControlWrite = false;
   // Condition is made to match the creation of WRDSP/RDDSP copy instruction
   // from copyPhysReg function.
   if (isReadOrWriteToDSPReg(MI, isDSPControlWrite)) {
     if (!MI.getOperand(1).isImm() || MI.getOperand(1).getImm() != (1<<4))
       return false;
     else if (isDSPControlWrite) {
       Src = &MI.getOperand(0);

lib/Target/X86/X86InstrInfo.h

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 copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
                    const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
                    bool KillSrc) const override;
-  bool isCopyInstr(const MachineInstr &MI, const MachineOperand *&Src,
-                   const MachineOperand *&Dest) const override;
   void storeRegToStackSlot(MachineBasicBlock &MBB,
                            MachineBasicBlock::iterator MI, unsigned SrcReg,
                            bool isKill, int FrameIndex,
                            const TargetRegisterClass *RC,
                            const TargetRegisterInfo *TRI) const override;
 
   void storeRegToAddr(MachineFunction &MF, unsigned SrcReg, bool isKill,
                       SmallVectorImpl<MachineOperand> &Addr,
protected:
   /// 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 true along with
+  /// @Source machine operand and @Destination machine operand.
+  bool isCopyInstrImpl(const MachineInstr &MI, const MachineOperand *&Src,
+                       const MachineOperand *&Dest) const override;
+
 private:
   MachineInstr *convertToThreeAddressWithLEA(unsigned MIOpc,
                                              MachineFunction::iterator &MFI,
                                              MachineInstr &MI,
                                              LiveVariables *LV) const;
 
   /// Handles memory folding for special case instructions, for instance those
   /// requiring custom manipulation of the address.

lib/Target/X86/X86InstrInfo.cpp

if (SrcReg == X86::EFLAGS || DestReg == X86::EFLAGS) {
     report_fatal_error("Unable to copy EFLAGS physical register!");
   }
 
   LLVM_DEBUG(dbgs() << "Cannot copy " << RI.getName(SrcReg) << " to "
                     << RI.getName(DestReg) << '\n');
   llvm_unreachable("Cannot emit physreg copy instruction");
 }
 
-bool X86InstrInfo::isCopyInstr(const MachineInstr &MI,
+bool X86InstrInfo::isCopyInstrImpl(const MachineInstr &MI,
                                    const MachineOperand *&Src,
                                    const MachineOperand *&Dest) const {
   if (MI.isMoveReg()) {
     Dest = &MI.getOperand(0);
     Src = &MI.getOperand(1);
     return true;
   }
   return false;
 }