Remove dead code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231883 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetRegisterInfo.h

@@ -686,14 +686,6 @@ public:
                                      const MachineFunction &MF,
                                      const VirtRegMap *VRM = nullptr) const;
 
-  /// avoidWriteAfterWrite - Return true if the register allocator should avoid
-  /// writing a register from RC in two consecutive instructions.
-  /// This can avoid pipeline stalls on certain architectures.
-  /// It does cause increased register pressure, though.
-  virtual bool avoidWriteAfterWrite(const TargetRegisterClass *RC) const {
-    return false;
-  }
-
   /// updateRegAllocHint - A callback to allow target a chance to update
   /// register allocation hints when a register is "changed" (e.g. coalesced)
   /// to another register. e.g. On ARM, some virtual registers should target

lib/Target/ARM/ARMBaseRegisterInfo.cpp

@@ -283,29 +283,6 @@ ARMBaseRegisterInfo::updateRegAllocHint(unsigned Reg, unsigned NewReg,
   }
 }
 
-bool
-ARMBaseRegisterInfo::avoidWriteAfterWrite(const TargetRegisterClass *RC) const {
-  // CortexA9 has a Write-after-write hazard for NEON registers.
-  if (!STI.isLikeA9())
-    return false;
-
-  switch (RC->getID()) {
-  case ARM::DPRRegClassID:
-  case ARM::DPR_8RegClassID:
-  case ARM::DPR_VFP2RegClassID:
-  case ARM::QPRRegClassID:
-  case ARM::QPR_8RegClassID:
-  case ARM::QPR_VFP2RegClassID:
-  case ARM::SPRRegClassID:
-  case ARM::SPR_8RegClassID:
-    // Avoid reusing S, D, and Q registers.
-    // Don't increase register pressure for QQ and QQQQ.
-    return true;
-  default:
-    return false;
-  }
-}
-
 bool ARMBaseRegisterInfo::hasBasePointer(const MachineFunction &MF) const {
   const MachineFrameInfo *MFI = MF.getFrameInfo();
   const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();

lib/Target/ARM/ARMBaseRegisterInfo.h

@@ -138,8 +138,6 @@ public:
   void updateRegAllocHint(unsigned Reg, unsigned NewReg,
                           MachineFunction &MF) const override;
 
-  bool avoidWriteAfterWrite(const TargetRegisterClass *RC) const override;
-
   bool hasBasePointer(const MachineFunction &MF) const;
 
   bool canRealignStack(const MachineFunction &MF) const;