diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index 68b5b0e9a18b..0230bfe5fe79 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -991,8 +991,6 @@ void SIInstrInfo::insertVectorSelect(MachineBasicBlock &MBB,
                                      Register TrueReg,
                                      Register FalseReg) const {
   MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
-  MachineFunction *MF = MBB.getParent();
-  const GCNSubtarget &ST = MF->getSubtarget<GCNSubtarget>();
   const TargetRegisterClass *BoolXExecRC =
     RI.getRegClass(AMDGPU::SReg_1_XEXECRegClassID);
   assert(MRI.getRegClass(DstReg) == &AMDGPU::VGPR_32RegClass &&
@@ -1496,7 +1494,6 @@ unsigned SIInstrInfo::calculateLDSSpillAddress(
     unsigned FrameOffset, unsigned Size) const {
   MachineFunction *MF = MBB.getParent();
   SIMachineFunctionInfo *MFI = MF->getInfo<SIMachineFunctionInfo>();
-  const GCNSubtarget &ST = MF->getSubtarget<GCNSubtarget>();
   const DebugLoc &DL = MBB.findDebugLoc(MI);
   unsigned WorkGroupSize = MFI->getMaxFlatWorkGroupSize();
   unsigned WavefrontSize = ST.getWavefrontSize();
@@ -3312,9 +3309,6 @@ bool SIInstrInfo::isImmOperandLegal(const MachineInstr &MI, unsigned OpNo,
   if (OpInfo.RegClass < 0)
     return false;
 
-  const MachineFunction *MF = MI.getParent()->getParent();
-  const GCNSubtarget &ST = MF->getSubtarget<GCNSubtarget>();
-
   if (MO.isImm() && isInlineConstant(MO, OpInfo)) {
     if (isMAI(MI) && ST.hasMFMAInlineLiteralBug() &&
         OpNo ==(unsigned)AMDGPU::getNamedOperandIdx(MI.getOpcode(),
@@ -3849,7 +3843,6 @@ bool SIInstrInfo::verifyInstruction(const MachineInstr &MI,
         }
       }
     }
-    const GCNSubtarget &ST = MF->getSubtarget<GCNSubtarget>();
     // v_writelane_b32 is an exception from constant bus restriction:
     // vsrc0 can be sgpr, const or m0 and lane select sgpr, m0 or inline-const
     if (ConstantBusCount > ST.getConstantBusLimit(Opcode) &&
@@ -4017,7 +4010,7 @@ bool SIInstrInfo::verifyInstruction(const MachineInstr &MI,
     }
   }
 
-  if (isFLAT(MI) && !MF->getSubtarget<GCNSubtarget>().hasFlatInstOffsets()) {
+  if (isFLAT(MI) && !ST.hasFlatInstOffsets()) {
     const MachineOperand *Offset = getNamedOperand(MI, AMDGPU::OpName::offset);
     if (Offset->getImm() != 0) {
       ErrInfo = "subtarget does not support offsets in flat instructions";
@@ -4236,11 +4229,9 @@ void SIInstrInfo::legalizeOpWithMove(MachineInstr &MI, unsigned OpIdx) const {
   MachineBasicBlock *MBB = MI.getParent();
   MachineOperand &MO = MI.getOperand(OpIdx);
   MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
-  const SIRegisterInfo *TRI =
-      static_cast<const SIRegisterInfo*>(MRI.getTargetRegisterInfo());
   unsigned RCID = get(MI.getOpcode()).OpInfo[OpIdx].RegClass;
   const TargetRegisterClass *RC = RI.getRegClass(RCID);
-  unsigned Size = TRI->getRegSizeInBits(*RC);
+  unsigned Size = RI.getRegSizeInBits(*RC);
   unsigned Opcode = (Size == 64) ? AMDGPU::V_MOV_B64_PSEUDO : AMDGPU::V_MOV_B32_e32;
   if (MO.isReg())
     Opcode = AMDGPU::COPY;
@@ -4361,7 +4352,6 @@ bool SIInstrInfo::isOperandLegal(const MachineInstr &MI, unsigned OpIdx,
   const MachineRegisterInfo &MRI = MF.getRegInfo();
   const MCInstrDesc &InstDesc = MI.getDesc();
   const MCOperandInfo &OpInfo = InstDesc.OpInfo[OpIdx];
-  const GCNSubtarget &ST = MF.getSubtarget<GCNSubtarget>();
   const TargetRegisterClass *DefinedRC =
       OpInfo.RegClass != -1 ? RI.getRegClass(OpInfo.RegClass) : nullptr;
   if (!MO)
@@ -5181,8 +5171,7 @@ void SIInstrInfo::legalizeOperands(MachineInstr &MI,
     } else if (!VAddr && ST.hasAddr64()) {
       // This instructions is the _OFFSET variant, so we need to convert it to
       // ADDR64.
-      assert(MBB.getParent()->getSubtarget<GCNSubtarget>().getGeneration()
-             < AMDGPUSubtarget::VOLCANIC_ISLANDS &&
+      assert(ST.getGeneration() < AMDGPUSubtarget::VOLCANIC_ISLANDS &&
              "FIXME: Need to emit flat atomics here");
 
       unsigned RsrcPtr, NewSRsrc;
@@ -6663,8 +6652,7 @@ unsigned SIInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
   case TargetOpcode::INLINEASM_BR: {
     const MachineFunction *MF = MI.getParent()->getParent();
     const char *AsmStr = MI.getOperand(0).getSymbolName();
-    return getInlineAsmLength(AsmStr, *MF->getTarget().getMCAsmInfo(),
-                              &MF->getSubtarget());
+    return getInlineAsmLength(AsmStr, *MF->getTarget().getMCAsmInfo(), &ST);
   }
   default:
     return DescSize;