diff --git a/llvm/lib/Target/AArch64/AArch64MIPeepholeOpt.cpp b/llvm/lib/Target/AArch64/AArch64MIPeepholeOpt.cpp
--- a/llvm/lib/Target/AArch64/AArch64MIPeepholeOpt.cpp
+++ b/llvm/lib/Target/AArch64/AArch64MIPeepholeOpt.cpp
@@ -11,12 +11,19 @@
 // 1. MOVi32imm + ANDWrr ==> ANDWri + ANDWri
 //    MOVi64imm + ANDXrr ==> ANDXri + ANDXri
 //
+// 2. MOVi32imm + ADDWrr ==> ADDWRi + ADDWRi
+//    MOVi64imm + ADDXrr ==> ANDXri + ANDXri
+//
+// 3. MOVi32imm + SUBWrr ==> SUBWRi + SUBWRi
+//    MOVi64imm + SUBXrr ==> SUBXri + SUBXri
+//
 //    The mov pseudo instruction could be expanded to multiple mov instructions
 //    later. In this case, we could try to split the constant  operand of mov
-//    instruction into two bitmask immediates. It makes two AND instructions
-//    intead of multiple `mov` + `and` instructions.
+//    instruction into two immediates which can be directly encoded into
+//    *Wri/*Xri instructions. It makes two AND/ADD/SUB instructions instead of
+//    multiple `mov` + `and/add/sub` instructions.
 //
-// 2. Remove redundant ORRWrs which is generated by zero-extend.
+// 4. Remove redundant ORRWrs which is generated by zero-extend.
 //
 //    %3:gpr32 = ORRWrs $wzr, %2, 0
 //    %4:gpr64 = SUBREG_TO_REG 0, %3, %subreg.sub_32
@@ -51,6 +58,12 @@
   MachineLoopInfo *MLI;
   MachineRegisterInfo *MRI;
 
+  bool checkMovImmInstr(MachineInstr &MI, MachineInstr *&MovMI,
+                        MachineInstr *&SubregToRegMI);
+
+  template <typename T>
+  bool visitADDSUB(MachineInstr &MI,
+                   SmallSetVector<MachineInstr *, 8> &ToBeRemoved, bool IsAdd);
   template <typename T>
   bool visitAND(MachineInstr &MI,
                 SmallSetVector<MachineInstr *, 8> &ToBeRemoved);
@@ -131,36 +144,9 @@
   assert((RegSize == 32 || RegSize == 64) &&
          "Invalid RegSize for AND bitmask peephole optimization");
 
-  // Check whether AND's MBB is in loop and the AND is loop invariant.
-  MachineBasicBlock *MBB = MI.getParent();
-  MachineLoop *L = MLI->getLoopFor(MBB);
-  if (L && !L->isLoopInvariant(MI))
-    return false;
-
-  // Check whether AND's operand is MOV with immediate.
-  MachineInstr *MovMI = MRI->getUniqueVRegDef(MI.getOperand(2).getReg());
-  if (!MovMI)
-    return false;
-
-  MachineInstr *SubregToRegMI = nullptr;
-  // If it is SUBREG_TO_REG, check its operand.
-  if (MovMI->getOpcode() == TargetOpcode::SUBREG_TO_REG) {
-    SubregToRegMI = MovMI;
-    MovMI = MRI->getUniqueVRegDef(MovMI->getOperand(2).getReg());
-    if (!MovMI)
-      return false;
-  }
-
-  if (MovMI->getOpcode() != AArch64::MOVi32imm &&
-      MovMI->getOpcode() != AArch64::MOVi64imm)
-    return false;
-
-  // If the MOV has multiple uses, do not split the immediate because it causes
-  // more instructions.
-  if (!MRI->hasOneUse(MovMI->getOperand(0).getReg()))
-    return false;
-
-  if (SubregToRegMI && !MRI->hasOneUse(SubregToRegMI->getOperand(0).getReg()))
+  // Perform several essential checks against current MI.
+  MachineInstr *MovMI = nullptr, *SubregToRegMI = nullptr;
+  if (!checkMovImmInstr(MI, MovMI, SubregToRegMI))
     return false;
 
   // Split the bitmask immediate into two.
@@ -177,6 +163,7 @@
 
   // Create new AND MIs.
   DebugLoc DL = MI.getDebugLoc();
+  MachineBasicBlock *MBB = MI.getParent();
   const TargetRegisterClass *ANDImmRC =
       (RegSize == 32) ? &AArch64::GPR32spRegClass : &AArch64::GPR64spRegClass;
   Register DstReg = MI.getOperand(0).getReg();
@@ -251,6 +238,144 @@
   return true;
 }
 
+template <typename T>
+static bool splitAddSubImm(T Imm, unsigned RegSize, T &Imm0, T &Imm1) {
+  // The immediate must be in the form of ((imm0 << 12) + imm1), in which both
+  // imm0 and imm1 are non-zero 12-bit unsigned int.
+  if ((Imm & 0xfff000) == 0 || (Imm & 0xfff) == 0 ||
+      (Imm & ~static_cast<T>(0xffffff)) != 0)
+    return false;
+
+  // The immediate can not be composed via a single instruction.
+  SmallVector<AArch64_IMM::ImmInsnModel, 4> Insn;
+  AArch64_IMM::expandMOVImm(Imm, RegSize, Insn);
+  if (Insn.size() == 1)
+    return false;
+
+  // Split Imm into (Imm0 << 12) + Imm1;
+  Imm0 = (Imm >> 12) & 0xfff;
+  Imm1 = Imm & 0xfff;
+  return true;
+}
+
+template <typename T>
+bool AArch64MIPeepholeOpt::visitADDSUB(
+    MachineInstr &MI, SmallSetVector<MachineInstr *, 8> &ToBeRemoved,
+    bool IsAdd) {
+  // Try below transformation.
+  //
+  // MOVi32imm + ADDWrr ==> ADDWri + ADDWri
+  // MOVi64imm + ADDXrr ==> ADDXri + ADDXri
+  //
+  // MOVi32imm + SUBWrr ==> SUBWri + SUBWri
+  // MOVi64imm + SUBXrr ==> SUBXri + SUBXri
+  //
+  // The mov pseudo instruction could be expanded to multiple mov instructions
+  // later. Let's try to split the constant operand of mov instruction into two
+  // legal add/sub immediates. It makes only two ADD/SUB instructions intead of
+  // multiple `mov` + `and/sub` instructions.
+
+  unsigned RegSize = sizeof(T) * 8;
+  assert((RegSize == 32 || RegSize == 64) &&
+         "Invalid RegSize for legal add/sub immediate peephole optimization");
+
+  // Perform several essential checks against current MI.
+  MachineInstr *MovMI, *SubregToRegMI;
+  if (!checkMovImmInstr(MI, MovMI, SubregToRegMI))
+    return false;
+
+  // Split the immediate to Imm0 and Imm1, and calculate the Opcode.
+  T Imm = static_cast<T>(MovMI->getOperand(1).getImm()), Imm0, Imm1;
+  unsigned Opcode;
+  if (splitAddSubImm(Imm, RegSize, Imm0, Imm1)) {
+    if (IsAdd)
+      Opcode = RegSize == 32 ? AArch64::ADDWri : AArch64::ADDXri;
+    else
+      Opcode = RegSize == 32 ? AArch64::SUBWri : AArch64::SUBXri;
+  } else if (splitAddSubImm(-Imm, RegSize, Imm0, Imm1)) {
+    if (IsAdd)
+      Opcode = RegSize == 32 ? AArch64::SUBWri : AArch64::SUBXri;
+    else
+      Opcode = RegSize == 32 ? AArch64::ADDWri : AArch64::ADDXri;
+  } else {
+    return false;
+  }
+
+  // Create new ADD/SUB MIs.
+  DebugLoc DL = MI.getDebugLoc();
+  MachineBasicBlock *MBB = MI.getParent();
+  const TargetRegisterClass *RC =
+      (RegSize == 32) ? &AArch64::GPR32spRegClass : &AArch64::GPR64spRegClass;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
+  Register NewTmpReg = MRI->createVirtualRegister(RC);
+  Register NewDstReg = MRI->createVirtualRegister(RC);
+
+  MRI->constrainRegClass(SrcReg, RC);
+  BuildMI(*MBB, MI, DL, TII->get(Opcode), NewTmpReg)
+      .addReg(SrcReg)
+      .addImm(Imm0)
+      .addImm(12);
+
+  BuildMI(*MBB, MI, DL, TII->get(Opcode), NewDstReg)
+      .addReg(NewTmpReg)
+      .addImm(Imm1)
+      .addImm(0);
+
+  MRI->replaceRegWith(DstReg, NewDstReg);
+  // replaceRegWith changes MI's definition register. Keep it for SSA form until
+  // deleting MI.
+  MI.getOperand(0).setReg(DstReg);
+
+  // Record the MIs need to be removed.
+  ToBeRemoved.insert(&MI);
+  if (SubregToRegMI)
+    ToBeRemoved.insert(SubregToRegMI);
+  ToBeRemoved.insert(MovMI);
+
+  return true;
+}
+
+// Checks if the corresponding MOV immediate instruction is applicable for
+// this peephole optimization.
+bool AArch64MIPeepholeOpt::checkMovImmInstr(MachineInstr &MI,
+                                            MachineInstr *&MovMI,
+                                            MachineInstr *&SubregToRegMI) {
+  // Check whether current MBB is in loop and the AND is loop invariant.
+  MachineBasicBlock *MBB = MI.getParent();
+  MachineLoop *L = MLI->getLoopFor(MBB);
+  if (L && !L->isLoopInvariant(MI))
+    return false;
+
+  // Check whether current MI's operand is MOV with immediate.
+  MovMI = MRI->getUniqueVRegDef(MI.getOperand(2).getReg());
+  if (!MovMI)
+    return false;
+
+  // If it is SUBREG_TO_REG, check its operand.
+  SubregToRegMI = nullptr;
+  if (MovMI->getOpcode() == TargetOpcode::SUBREG_TO_REG) {
+    SubregToRegMI = MovMI;
+    MovMI = MRI->getUniqueVRegDef(MovMI->getOperand(2).getReg());
+    if (!MovMI)
+      return false;
+  }
+
+  if (MovMI->getOpcode() != AArch64::MOVi32imm &&
+      MovMI->getOpcode() != AArch64::MOVi64imm)
+    return false;
+
+  // If the MOV has multiple uses, do not split the immediate because it causes
+  // more instructions.
+  if (!MRI->hasOneUse(MovMI->getOperand(0).getReg()))
+    return false;
+  if (SubregToRegMI && !MRI->hasOneUse(SubregToRegMI->getOperand(0).getReg()))
+    return false;
+
+  // It is OK to perform this peephole optimization.
+  return true;
+}
+
 bool AArch64MIPeepholeOpt::runOnMachineFunction(MachineFunction &MF) {
   if (skipFunction(MF.getFunction()))
     return false;
@@ -278,6 +403,18 @@
       case AArch64::ORRWrs:
         Changed = visitORR(MI, ToBeRemoved);
         break;
+      case AArch64::ADDWrr:
+        Changed = visitADDSUB<uint32_t>(MI, ToBeRemoved, true);
+        break;
+      case AArch64::SUBWrr:
+        Changed = visitADDSUB<uint32_t>(MI, ToBeRemoved, false);
+        break;
+      case AArch64::ADDXrr:
+        Changed = visitADDSUB<uint64_t>(MI, ToBeRemoved, true);
+        break;
+      case AArch64::SUBXrr:
+        Changed = visitADDSUB<uint64_t>(MI, ToBeRemoved, false);
+        break;
       }
     }
   }
diff --git a/llvm/test/CodeGen/AArch64/addsub.ll b/llvm/test/CodeGen/AArch64/addsub.ll
--- a/llvm/test/CodeGen/AArch64/addsub.ll
+++ b/llvm/test/CodeGen/AArch64/addsub.ll
@@ -152,9 +152,8 @@
 define i64 @add_two_parts_imm_i64(i64 %a) {
 ; CHECK-LABEL: add_two_parts_imm_i64:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov w8, #42325
-; CHECK-NEXT:    movk w8, #170, lsl #16
-; CHECK-NEXT:    add x0, x0, x8
+; CHECK-NEXT:    add x8, x0, #2730, lsl #12 // =11182080
+; CHECK-NEXT:    add x0, x8, #1365
 ; CHECK-NEXT:    ret
   %b = add i64 %a, 11183445
   ret i64 %b
@@ -163,9 +162,8 @@
 define i32 @add_two_parts_imm_i32(i32 %a) {
 ; CHECK-LABEL: add_two_parts_imm_i32:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov w8, #42325
-; CHECK-NEXT:    movk w8, #170, lsl #16
-; CHECK-NEXT:    add w0, w0, w8
+; CHECK-NEXT:    add w8, w0, #2730, lsl #12 // =11182080
+; CHECK-NEXT:    add w0, w8, #1365
 ; CHECK-NEXT:    ret
   %b = add i32 %a, 11183445
   ret i32 %b
@@ -174,9 +172,8 @@
 define i64 @add_two_parts_imm_i64_neg(i64 %a) {
 ; CHECK-LABEL: add_two_parts_imm_i64_neg:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #-42325
-; CHECK-NEXT:    movk x8, #65365, lsl #16
-; CHECK-NEXT:    add x0, x0, x8
+; CHECK-NEXT:    sub x8, x0, #2730, lsl #12 // =11182080
+; CHECK-NEXT:    sub x0, x8, #1365
 ; CHECK-NEXT:    ret
   %b = add i64 %a, -11183445
   ret i64 %b
@@ -185,9 +182,8 @@
 define i32 @add_two_parts_imm_i32_neg(i32 %a) {
 ; CHECK-LABEL: add_two_parts_imm_i32_neg:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov w8, #23211
-; CHECK-NEXT:    movk w8, #65365, lsl #16
-; CHECK-NEXT:    add w0, w0, w8
+; CHECK-NEXT:    sub w8, w0, #2730, lsl #12 // =11182080
+; CHECK-NEXT:    sub w0, w8, #1365
 ; CHECK-NEXT:    ret
   %b = add i32 %a, -11183445
   ret i32 %b
@@ -196,9 +192,8 @@
 define i64 @sub_two_parts_imm_i64(i64 %a) {
 ; CHECK-LABEL: sub_two_parts_imm_i64:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #-42325
-; CHECK-NEXT:    movk x8, #65365, lsl #16
-; CHECK-NEXT:    add x0, x0, x8
+; CHECK-NEXT:    sub x8, x0, #2730, lsl #12 // =11182080
+; CHECK-NEXT:    sub x0, x8, #1365
 ; CHECK-NEXT:    ret
   %b = sub i64 %a, 11183445
   ret i64 %b
@@ -207,9 +202,8 @@
 define i32 @sub_two_parts_imm_i32(i32 %a) {
 ; CHECK-LABEL: sub_two_parts_imm_i32:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov w8, #23211
-; CHECK-NEXT:    movk w8, #65365, lsl #16
-; CHECK-NEXT:    add w0, w0, w8
+; CHECK-NEXT:    sub w8, w0, #2730, lsl #12 // =11182080
+; CHECK-NEXT:    sub w0, w8, #1365
 ; CHECK-NEXT:    ret
   %b = sub i32 %a, 11183445
   ret i32 %b
@@ -218,9 +212,8 @@
 define i64 @sub_two_parts_imm_i64_neg(i64 %a) {
 ; CHECK-LABEL: sub_two_parts_imm_i64_neg:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov w8, #42325
-; CHECK-NEXT:    movk w8, #170, lsl #16
-; CHECK-NEXT:    add x0, x0, x8
+; CHECK-NEXT:    add x8, x0, #2730, lsl #12 // =11182080
+; CHECK-NEXT:    add x0, x8, #1365
 ; CHECK-NEXT:    ret
   %b = sub i64 %a, -11183445
   ret i64 %b
@@ -229,14 +222,57 @@
 define i32 @sub_two_parts_imm_i32_neg(i32 %a) {
 ; CHECK-LABEL: sub_two_parts_imm_i32_neg:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov w8, #42325
-; CHECK-NEXT:    movk w8, #170, lsl #16
-; CHECK-NEXT:    add w0, w0, w8
+; CHECK-NEXT:    add w8, w0, #2730, lsl #12 // =11182080
+; CHECK-NEXT:    add w0, w8, #1365
 ; CHECK-NEXT:    ret
   %b = sub i32 %a, -11183445
   ret i32 %b
 }
 
+define i32 @add_27962026(i32 %a) {
+; CHECK-LABEL: add_27962026:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #43690
+; CHECK-NEXT:    movk w8, #426, lsl #16
+; CHECK-NEXT:    add w0, w0, w8
+; CHECK-NEXT:    ret
+  %b = add i32 %a, 27962026
+  ret i32 %b
+}
+
+define i32 @add_65534(i32 %a) {
+; CHECK-LABEL: add_65534:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #65534
+; CHECK-NEXT:    add w0, w0, w8
+; CHECK-NEXT:    ret
+  %b = add i32 %a, 65534
+  ret i32 %b
+}
+
+declare i32 @foox(i32)
+
+define void @add_in_loop(i32 %0) {
+; CHECK-LABEL: add_in_loop:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    stp x30, x19, [sp, #-16]! // 16-byte Folded Spill
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset w19, -8
+; CHECK-NEXT:    .cfi_offset w30, -16
+; CHECK-NEXT:    mov w19, #43690
+; CHECK-NEXT:    movk w19, #170, lsl #16
+; CHECK-NEXT:  .LBB15_1: // =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    add w0, w0, w19
+; CHECK-NEXT:    bl foox
+; CHECK-NEXT:    b .LBB15_1
+  br label %2
+2:
+  %3 = phi i32 [ %0, %1 ], [ %5, %2 ]
+  %4 = add nsw i32 %3, 11184810
+  %5 = tail call i32 @foox(i32 %4) #2
+  br label %2
+}
+
 define void @testing() {
 ; CHECK-LABEL: testing:
 ; CHECK:       // %bb.0:
@@ -244,7 +280,7 @@
 ; CHECK-NEXT:    ldr x8, [x8, :got_lo12:var_i32]
 ; CHECK-NEXT:    ldr w9, [x8]
 ; CHECK-NEXT:    cmp w9, #4095
-; CHECK-NEXT:    b.ne .LBB13_6
+; CHECK-NEXT:    b.ne .LBB16_6
 ; CHECK-NEXT:  // %bb.1: // %test2
 ; CHECK-NEXT:    adrp x10, :got:var2_i32
 ; CHECK-NEXT:    add w11, w9, #1
@@ -252,26 +288,26 @@
 ; CHECK-NEXT:    str w11, [x8]
 ; CHECK-NEXT:    ldr w10, [x10]
 ; CHECK-NEXT:    cmp w10, #3567, lsl #12 // =14610432
-; CHECK-NEXT:    b.lo .LBB13_6
+; CHECK-NEXT:    b.lo .LBB16_6
 ; CHECK-NEXT:  // %bb.2: // %test3
 ; CHECK-NEXT:    add w11, w9, #2
 ; CHECK-NEXT:    cmp w9, #123
 ; CHECK-NEXT:    str w11, [x8]
-; CHECK-NEXT:    b.lt .LBB13_6
+; CHECK-NEXT:    b.lt .LBB16_6
 ; CHECK-NEXT:  // %bb.3: // %test4
 ; CHECK-NEXT:    add w11, w9, #3
 ; CHECK-NEXT:    cmp w10, #321
 ; CHECK-NEXT:    str w11, [x8]
-; CHECK-NEXT:    b.gt .LBB13_6
+; CHECK-NEXT:    b.gt .LBB16_6
 ; CHECK-NEXT:  // %bb.4: // %test5
 ; CHECK-NEXT:    add w11, w9, #4
 ; CHECK-NEXT:    cmn w10, #443
 ; CHECK-NEXT:    str w11, [x8]
-; CHECK-NEXT:    b.ge .LBB13_6
+; CHECK-NEXT:    b.ge .LBB16_6
 ; CHECK-NEXT:  // %bb.5: // %test6
 ; CHECK-NEXT:    add w9, w9, #5
 ; CHECK-NEXT:    str w9, [x8]
-; CHECK-NEXT:  .LBB13_6: // %common.ret
+; CHECK-NEXT:  .LBB16_6: // %common.ret
 ; CHECK-NEXT:    ret
   %val = load i32, i32* @var_i32
   %val2 = load i32, i32* @var2_i32
diff --git a/llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll b/llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll
--- a/llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll
@@ -214,10 +214,9 @@
 ; CHECK-LABEL: test5:
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:    ldr x9, [x0]
-; CHECK-NEXT:    mov w10, #14464
-; CHECK-NEXT:    movk w10, #1, lsl #16
 ; CHECK-NEXT:    mov w8, wzr
-; CHECK-NEXT:    add x9, x9, x10
+; CHECK-NEXT:    add x9, x9, #19, lsl #12 // =77824
+; CHECK-NEXT:    add x9, x9, #2176
 ; CHECK-NEXT:    cmp w8, w1
 ; CHECK-NEXT:    b.ge .LBB4_2
 ; CHECK-NEXT:  .LBB4_1: // %while_body