Index: llvm/lib/Target/AArch64/AArch64InstrInfo.h
===================================================================
--- llvm/lib/Target/AArch64/AArch64InstrInfo.h
+++ llvm/lib/Target/AArch64/AArch64InstrInfo.h
@@ -79,10 +79,10 @@
   /// Return true if the given load or store is a strided memory access.
   static bool isStridedAccess(const MachineInstr &MI);
 
-  /// Return true if this is an unscaled load/store.
-  static bool isUnscaledLdSt(unsigned Opc);
-  static bool isUnscaledLdSt(MachineInstr &MI) {
-    return isUnscaledLdSt(MI.getOpcode());
+  /// Return true if it has an unscaled load/store offset.
+  static bool hasUnscaledLdStOffset(unsigned Opc);
+  static bool hasUnscaledLdStOffset(MachineInstr &MI) {
+    return hasUnscaledLdStOffset(MI.getOpcode());
   }
 
   /// Returns the unscaled load/store for the scaled load/store opcode,
@@ -95,6 +95,14 @@
     return getMemScale(MI.getOpcode());
   }
 
+  /// Returns whether the instruction is a pre-indexed load.
+  static bool isPreLd(const MachineInstr &MI);
+
+  /// Returns whether the instruction is a pre-indexed store.
+  static bool isPreSt(const MachineInstr &MI);
+
+  /// Returns whether the instruction is a pre-indexed load/store.
+  static bool isPreLdSt(const MachineInstr &MI);
 
   /// Returns the index for the immediate for a given instruction.
   static unsigned getLoadStoreImmIdx(unsigned Opc);
Index: llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -2118,22 +2118,32 @@
   });
 }
 
-bool AArch64InstrInfo::isUnscaledLdSt(unsigned Opc) {
+bool AArch64InstrInfo::hasUnscaledLdStOffset(unsigned Opc) {
   switch (Opc) {
   default:
     return false;
   case AArch64::STURSi:
+  case AArch64::STRSpre:
   case AArch64::STURDi:
+  case AArch64::STRDpre:
   case AArch64::STURQi:
+  case AArch64::STRQpre:
   case AArch64::STURBBi:
   case AArch64::STURHHi:
   case AArch64::STURWi:
+  case AArch64::STRWpre:
   case AArch64::STURXi:
+  case AArch64::STRXpre:
   case AArch64::LDURSi:
+  case AArch64::LDRSpre:
   case AArch64::LDURDi:
+  case AArch64::LDRDpre:
   case AArch64::LDURQi:
+  case AArch64::LDRQpre:
   case AArch64::LDURWi:
+  case AArch64::LDRWpre:
   case AArch64::LDURXi:
+  case AArch64::LDRXpre:
   case AArch64::LDURSWi:
   case AArch64::LDURHHi:
   case AArch64::LDURBBi:
@@ -2252,15 +2262,25 @@
   case AArch64::LDRSWui:
   // Unscaled instructions.
   case AArch64::STURSi:
+  case AArch64::STRSpre:
   case AArch64::STURDi:
+  case AArch64::STRDpre:
   case AArch64::STURQi:
+  case AArch64::STRQpre:
   case AArch64::STURWi:
+  case AArch64::STRWpre:
   case AArch64::STURXi:
+  case AArch64::STRXpre:
   case AArch64::LDURSi:
+  case AArch64::LDRSpre:
   case AArch64::LDURDi:
+  case AArch64::LDRDpre:
   case AArch64::LDURQi:
+  case AArch64::LDRQpre:
   case AArch64::LDURWi:
+  case AArch64::LDRWpre:
   case AArch64::LDURXi:
+  case AArch64::LDRXpre:
   case AArch64::LDURSWi:
     return true;
   }
@@ -2357,6 +2377,9 @@
 // Is this a candidate for ld/st merging or pairing?  For example, we don't
 // touch volatiles or load/stores that have a hint to avoid pair formation.
 bool AArch64InstrInfo::isCandidateToMergeOrPair(const MachineInstr &MI) const {
+
+  bool IsPreLdSt = isPreLdSt(MI);
+
   // If this is a volatile load/store, don't mess with it.
   if (MI.hasOrderedMemoryRef())
     return false;
@@ -2364,13 +2387,24 @@
   // Make sure this is a reg/fi+imm (as opposed to an address reloc).
   assert((MI.getOperand(1).isReg() || MI.getOperand(1).isFI()) &&
          "Expected a reg or frame index operand.");
-  if (!MI.getOperand(2).isImm())
+
+  // For Pre-indexed addressing quadword instructions, the third operand is the
+  // immediate value.
+  bool IsImmPreLdSt = IsPreLdSt && MI.getOperand(3).isImm();
+
+  if (!MI.getOperand(2).isImm() && !IsImmPreLdSt)
     return false;
 
   // Can't merge/pair if the instruction modifies the base register.
   // e.g., ldr x0, [x0]
   // This case will never occur with an FI base.
-  if (MI.getOperand(1).isReg()) {
+  // However, if the instruction is an LDR/STR<S,D,Q,W,X>pre, it can be merged.
+  // For example:
+  //   ldr q0, [x11, #32]!
+  //   ldr q1, [x11, #16]
+  //   to
+  //   ldp q0, q1, [x11, #32]!
+  if (MI.getOperand(1).isReg() && !IsPreLdSt) {
     Register BaseReg = MI.getOperand(1).getReg();
     const TargetRegisterInfo *TRI = &getRegisterInfo();
     if (MI.modifiesRegister(BaseReg, TRI))
@@ -2799,14 +2833,18 @@
     return 2;
   case AArch64::LDRSui:
   case AArch64::LDURSi:
+  case AArch64::LDRSpre:
   case AArch64::LDRSWui:
   case AArch64::LDURSWi:
+  case AArch64::LDRWpre:
   case AArch64::LDRWui:
   case AArch64::LDURWi:
   case AArch64::STRSui:
   case AArch64::STURSi:
+  case AArch64::STRSpre:
   case AArch64::STRWui:
   case AArch64::STURWi:
+  case AArch64::STRWpre:
   case AArch64::LDPSi:
   case AArch64::LDPSWi:
   case AArch64::LDPWi:
@@ -2815,12 +2853,16 @@
     return 4;
   case AArch64::LDRDui:
   case AArch64::LDURDi:
+  case AArch64::LDRDpre:
   case AArch64::LDRXui:
   case AArch64::LDURXi:
+  case AArch64::LDRXpre:
   case AArch64::STRDui:
   case AArch64::STURDi:
+  case AArch64::STRDpre:
   case AArch64::STRXui:
   case AArch64::STURXi:
+  case AArch64::STRXpre:
   case AArch64::LDPDi:
   case AArch64::LDPXi:
   case AArch64::STPDi:
@@ -2830,7 +2872,9 @@
   case AArch64::LDURQi:
   case AArch64::STRQui:
   case AArch64::STURQi:
+  case AArch64::STRQpre:
   case AArch64::LDPQi:
+  case AArch64::LDRQpre:
   case AArch64::STPQi:
   case AArch64::STGOffset:
   case AArch64::STZGOffset:
@@ -2841,6 +2885,36 @@
   }
 }
 
+bool AArch64InstrInfo::isPreLd(const MachineInstr &MI) {
+  switch (MI.getOpcode()) {
+  default:
+    return false;
+  case AArch64::LDRWpre:
+  case AArch64::LDRXpre:
+  case AArch64::LDRSpre:
+  case AArch64::LDRDpre:
+  case AArch64::LDRQpre:
+    return true;
+  }
+}
+
+bool AArch64InstrInfo::isPreSt(const MachineInstr &MI) {
+  switch (MI.getOpcode()) {
+  default:
+    return false;
+  case AArch64::STRWpre:
+  case AArch64::STRXpre:
+  case AArch64::STRSpre:
+  case AArch64::STRDpre:
+  case AArch64::STRQpre:
+    return true;
+  }
+}
+
+bool AArch64InstrInfo::isPreLdSt(const MachineInstr &MI) {
+  return isPreLd(MI) || isPreSt(MI);
+}
+
 // Scale the unscaled offsets.  Returns false if the unscaled offset can't be
 // scaled.
 static bool scaleOffset(unsigned Opc, int64_t &Offset) {
@@ -2944,11 +3018,11 @@
 
   // isCandidateToMergeOrPair guarantees that operand 2 is an immediate.
   int64_t Offset1 = FirstLdSt.getOperand(2).getImm();
-  if (isUnscaledLdSt(FirstOpc) && !scaleOffset(FirstOpc, Offset1))
+  if (hasUnscaledLdStOffset(FirstOpc) && !scaleOffset(FirstOpc, Offset1))
     return false;
 
   int64_t Offset2 = SecondLdSt.getOperand(2).getImm();
-  if (isUnscaledLdSt(SecondOpc) && !scaleOffset(SecondOpc, Offset2))
+  if (hasUnscaledLdStOffset(SecondOpc) && !scaleOffset(SecondOpc, Offset2))
     return false;
 
   // Pairwise instructions have a 7-bit signed offset field.
Index: llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
+++ llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
@@ -248,28 +248,38 @@
     return std::numeric_limits<unsigned>::max();
   case AArch64::STRDui:
   case AArch64::STURDi:
+  case AArch64::STRDpre:
   case AArch64::STRQui:
   case AArch64::STURQi:
+  case AArch64::STRQpre:
   case AArch64::STRBBui:
   case AArch64::STURBBi:
   case AArch64::STRHHui:
   case AArch64::STURHHi:
   case AArch64::STRWui:
+  case AArch64::STRWpre:
   case AArch64::STURWi:
   case AArch64::STRXui:
+  case AArch64::STRXpre:
   case AArch64::STURXi:
   case AArch64::LDRDui:
   case AArch64::LDURDi:
+  case AArch64::LDRDpre:
   case AArch64::LDRQui:
   case AArch64::LDURQi:
+  case AArch64::LDRQpre:
   case AArch64::LDRWui:
   case AArch64::LDURWi:
+  case AArch64::LDRWpre:
   case AArch64::LDRXui:
   case AArch64::LDURXi:
+  case AArch64::LDRXpre:
   case AArch64::STRSui:
   case AArch64::STURSi:
+  case AArch64::STRSpre:
   case AArch64::LDRSui:
   case AArch64::LDURSi:
+  case AArch64::LDRSpre:
     return Opc;
   case AArch64::LDRSWui:
     return AArch64::LDRWui;
@@ -304,33 +314,53 @@
   case AArch64::STRSui:
   case AArch64::STURSi:
     return AArch64::STPSi;
+  case AArch64::STRSpre:
+    return AArch64::STPSpre;
   case AArch64::STRDui:
   case AArch64::STURDi:
     return AArch64::STPDi;
+  case AArch64::STRDpre:
+    return AArch64::STPDpre;
   case AArch64::STRQui:
   case AArch64::STURQi:
     return AArch64::STPQi;
+  case AArch64::STRQpre:
+    return AArch64::STPQpre;
   case AArch64::STRWui:
   case AArch64::STURWi:
     return AArch64::STPWi;
+  case AArch64::STRWpre:
+    return AArch64::STPWpre;
   case AArch64::STRXui:
   case AArch64::STURXi:
     return AArch64::STPXi;
+  case AArch64::STRXpre:
+    return AArch64::STPXpre;
   case AArch64::LDRSui:
   case AArch64::LDURSi:
     return AArch64::LDPSi;
+  case AArch64::LDRSpre:
+    return AArch64::LDPSpre;
   case AArch64::LDRDui:
   case AArch64::LDURDi:
     return AArch64::LDPDi;
+  case AArch64::LDRDpre:
+    return AArch64::LDPDpre;
   case AArch64::LDRQui:
   case AArch64::LDURQi:
     return AArch64::LDPQi;
+  case AArch64::LDRQpre:
+    return AArch64::LDPQpre;
   case AArch64::LDRWui:
   case AArch64::LDURWi:
     return AArch64::LDPWi;
+  case AArch64::LDRWpre:
+    return AArch64::LDPWpre;
   case AArch64::LDRXui:
   case AArch64::LDURXi:
     return AArch64::LDPXi;
+  case AArch64::LDRXpre:
+    return AArch64::LDPXpre;
   case AArch64::LDRSWui:
   case AArch64::LDURSWi:
     return AArch64::LDPSWi;
@@ -539,6 +569,37 @@
   }
 }
 
+static bool isPreLdStPairCandidate(MachineInstr &FirstMI, MachineInstr &MI) {
+
+  unsigned OpcA = FirstMI.getOpcode();
+  unsigned OpcB = MI.getOpcode();
+
+  switch (OpcA) {
+  default:
+    return false;
+  case AArch64::STRSpre:
+    return (OpcB == AArch64::STRSui) || (OpcB == AArch64::STURSi);
+  case AArch64::STRDpre:
+    return (OpcB == AArch64::STRDui) || (OpcB == AArch64::STURDi);
+  case AArch64::STRQpre:
+    return (OpcB == AArch64::STRQui) || (OpcB == AArch64::STURQi);
+  case AArch64::STRWpre:
+    return (OpcB == AArch64::STRWui) || (OpcB == AArch64::STURWi);
+  case AArch64::STRXpre:
+    return (OpcB == AArch64::STRXui) || (OpcB == AArch64::STURXi);
+  case AArch64::LDRSpre:
+    return (OpcB == AArch64::LDRSui) || (OpcB == AArch64::LDURSi);
+  case AArch64::LDRDpre:
+    return (OpcB == AArch64::LDRDui) || (OpcB == AArch64::LDURDi);
+  case AArch64::LDRQpre:
+    return (OpcB == AArch64::LDRQui) || (OpcB == AArch64::LDURQi);
+  case AArch64::LDRWpre:
+    return (OpcB == AArch64::LDRWui) || (OpcB == AArch64::LDURWi);
+  case AArch64::LDRXpre:
+    return (OpcB == AArch64::LDRXui) || (OpcB == AArch64::LDURXi);
+  }
+}
+
 // Returns the scale and offset range of pre/post indexed variants of MI.
 static void getPrePostIndexedMemOpInfo(const MachineInstr &MI, int &Scale,
                                        int &MinOffset, int &MaxOffset) {
@@ -561,17 +622,20 @@
 static MachineOperand &getLdStRegOp(MachineInstr &MI,
                                     unsigned PairedRegOp = 0) {
   assert(PairedRegOp < 2 && "Unexpected register operand idx.");
-  unsigned Idx = isPairedLdSt(MI) ? PairedRegOp : 0;
+  bool IsPreLdSt = AArch64InstrInfo::isPreLdSt(MI);
+  if (IsPreLdSt)
+    PairedRegOp += 1;
+  unsigned Idx = isPairedLdSt(MI) || IsPreLdSt ? PairedRegOp : 0;
   return MI.getOperand(Idx);
 }
 
 static const MachineOperand &getLdStBaseOp(const MachineInstr &MI) {
-  unsigned Idx = isPairedLdSt(MI) ? 2 : 1;
+  unsigned Idx = isPairedLdSt(MI) || AArch64InstrInfo::isPreLdSt(MI) ? 2 : 1;
   return MI.getOperand(Idx);
 }
 
 static const MachineOperand &getLdStOffsetOp(const MachineInstr &MI) {
-  unsigned Idx = isPairedLdSt(MI) ? 3 : 2;
+  unsigned Idx = isPairedLdSt(MI) || AArch64InstrInfo::isPreLdSt(MI) ? 3 : 2;
   return MI.getOperand(Idx);
 }
 
@@ -581,10 +645,10 @@
   assert(isMatchingStore(LoadInst, StoreInst) && "Expect only matched ld/st.");
   int LoadSize = TII->getMemScale(LoadInst);
   int StoreSize = TII->getMemScale(StoreInst);
-  int UnscaledStOffset = TII->isUnscaledLdSt(StoreInst)
+  int UnscaledStOffset = TII->hasUnscaledLdStOffset(StoreInst)
                              ? getLdStOffsetOp(StoreInst).getImm()
                              : getLdStOffsetOp(StoreInst).getImm() * StoreSize;
-  int UnscaledLdOffset = TII->isUnscaledLdSt(LoadInst)
+  int UnscaledLdOffset = TII->hasUnscaledLdStOffset(LoadInst)
                              ? getLdStOffsetOp(LoadInst).getImm()
                              : getLdStOffsetOp(LoadInst).getImm() * LoadSize;
   return (UnscaledStOffset <= UnscaledLdOffset) &&
@@ -689,7 +753,7 @@
     NextI = next_nodbg(NextI, E);
 
   unsigned Opc = I->getOpcode();
-  bool IsScaled = !TII->isUnscaledLdSt(Opc);
+  bool IsScaled = !TII->hasUnscaledLdStOffset(Opc);
   int OffsetStride = IsScaled ? 1 : TII->getMemScale(*I);
 
   bool MergeForward = Flags.getMergeForward();
@@ -795,7 +859,7 @@
   int SExtIdx = Flags.getSExtIdx();
   unsigned Opc =
       SExtIdx == -1 ? I->getOpcode() : getMatchingNonSExtOpcode(I->getOpcode());
-  bool IsUnscaled = TII->isUnscaledLdSt(Opc);
+  bool IsUnscaled = TII->hasUnscaledLdStOffset(Opc);
   int OffsetStride = IsUnscaled ? TII->getMemScale(*I) : 1;
 
   bool MergeForward = Flags.getMergeForward();
@@ -876,7 +940,7 @@
 
   int Offset = getLdStOffsetOp(*I).getImm();
   int PairedOffset = getLdStOffsetOp(*Paired).getImm();
-  bool PairedIsUnscaled = TII->isUnscaledLdSt(Paired->getOpcode());
+  bool PairedIsUnscaled = TII->hasUnscaledLdStOffset(Paired->getOpcode());
   if (IsUnscaled != PairedIsUnscaled) {
     // We're trying to pair instructions that differ in how they are scaled.  If
     // I is scaled then scale the offset of Paired accordingly.  Otherwise, do
@@ -894,8 +958,11 @@
   }
 
   // Which register is Rt and which is Rt2 depends on the offset order.
+  // However, for pre load/stores the Rt should be the one of the pre
+  // load/store.
   MachineInstr *RtMI, *Rt2MI;
-  if (Offset == PairedOffset + OffsetStride) {
+  if (Offset == PairedOffset + OffsetStride &&
+      !AArch64InstrInfo::isPreLdSt(*I)) {
     RtMI = &*Paired;
     Rt2MI = &*I;
     // Here we swapped the assumption made for SExtIdx.
@@ -909,7 +976,7 @@
   }
   int OffsetImm = getLdStOffsetOp(*RtMI).getImm();
   // Scale the immediate offset, if necessary.
-  if (TII->isUnscaledLdSt(RtMI->getOpcode())) {
+  if (TII->hasUnscaledLdStOffset(RtMI->getOpcode())) {
     assert(!(OffsetImm % TII->getMemScale(*RtMI)) &&
            "Unscaled offset cannot be scaled.");
     OffsetImm /= TII->getMemScale(*RtMI);
@@ -940,13 +1007,20 @@
         MI.clearRegisterKills(Reg, TRI);
     }
   }
-  MIB = BuildMI(*MBB, InsertionPoint, DL, TII->get(getMatchingPairOpcode(Opc)))
-            .add(RegOp0)
-            .add(RegOp1)
-            .add(BaseRegOp)
-            .addImm(OffsetImm)
-            .cloneMergedMemRefs({&*I, &*Paired})
-            .setMIFlags(I->mergeFlagsWith(*Paired));
+
+  unsigned int MatchPairOpcode = getMatchingPairOpcode(Opc);
+  MIB = BuildMI(*MBB, InsertionPoint, DL, TII->get(MatchPairOpcode));
+
+  // Adds the pre-index operand for pre-indexed ld/st pairs.
+  if (AArch64InstrInfo::isPreLdSt(*RtMI))
+    MIB.addReg(BaseRegOp.getReg(), RegState::Define);
+
+  MIB.add(RegOp0)
+      .add(RegOp1)
+      .add(BaseRegOp)
+      .addImm(OffsetImm)
+      .cloneMergedMemRefs({&*I, &*Paired})
+      .setMIFlags(I->mergeFlagsWith(*Paired));
 
   (void)MIB;
 
@@ -1054,8 +1128,8 @@
     // performance and correctness are verified only in little-endian.
     if (!Subtarget->isLittleEndian())
       return NextI;
-    bool IsUnscaled = TII->isUnscaledLdSt(*LoadI);
-    assert(IsUnscaled == TII->isUnscaledLdSt(*StoreI) &&
+    bool IsUnscaled = TII->hasUnscaledLdStOffset(*LoadI);
+    assert(IsUnscaled == TII->hasUnscaledLdStOffset(*StoreI) &&
            "Unsupported ld/st match");
     assert(LoadSize <= StoreSize && "Invalid load size");
     int UnscaledLdOffset = IsUnscaled
@@ -1232,9 +1306,10 @@
   unsigned OpcA = FirstMI.getOpcode();
   unsigned OpcB = MI.getOpcode();
 
-  // Opcodes match: nothing more to check.
+  // Opcodes match
   if (OpcA == OpcB)
-    return true;
+    // Same Pre Ld/St Opcodes are not candidates to merge/pair.
+    return !AArch64InstrInfo::isPreLdSt(FirstMI);
 
   // Try to match a sign-extended load/store with a zero-extended load/store.
   bool IsValidLdStrOpc, PairIsValidLdStrOpc;
@@ -1257,8 +1332,14 @@
   if (isNarrowStore(OpcA) || isNarrowStore(OpcB))
     return false;
 
+  // The STR<S,D,Q,W,X>pre - STR<S,D,Q,W,X>ui and
+  // LDR<S,D,Q,W,X>pre-LDR<S,D,Q,W,X>ui
+  // are candidate pairs that can be merged.
+  if (isPreLdStPairCandidate(FirstMI, MI))
+    return true;
+
   // Try to match an unscaled load/store with a scaled load/store.
-  return TII->isUnscaledLdSt(OpcA) != TII->isUnscaledLdSt(OpcB) &&
+  return TII->hasUnscaledLdStOffset(OpcA) != TII->hasUnscaledLdStOffset(OpcB) &&
          getMatchingPairOpcode(OpcA) == getMatchingPairOpcode(OpcB);
 
   // FIXME: Can we also match a mixed sext/zext unscaled/scaled pair?
@@ -1448,7 +1529,7 @@
   MBBI = next_nodbg(MBBI, E);
 
   bool MayLoad = FirstMI.mayLoad();
-  bool IsUnscaled = TII->isUnscaledLdSt(FirstMI);
+  bool IsUnscaled = TII->hasUnscaledLdStOffset(FirstMI);
   Register Reg = getLdStRegOp(FirstMI).getReg();
   Register BaseReg = getLdStBaseOp(FirstMI).getReg();
   int Offset = getLdStOffsetOp(FirstMI).getImm();
@@ -1496,7 +1577,7 @@
       // a relocation.
       Register MIBaseReg = getLdStBaseOp(MI).getReg();
       int MIOffset = getLdStOffsetOp(MI).getImm();
-      bool MIIsUnscaled = TII->isUnscaledLdSt(MI);
+      bool MIIsUnscaled = TII->hasUnscaledLdStOffset(MI);
       if (IsUnscaled != MIIsUnscaled) {
         // We're trying to pair instructions that differ in how they are scaled.
         // If FirstMI is scaled then scale the offset of MI accordingly.
@@ -1517,8 +1598,35 @@
         }
       }
 
-      if (BaseReg == MIBaseReg && ((Offset == MIOffset + OffsetStride) ||
-                                   (Offset + OffsetStride == MIOffset))) {
+      bool IsPreLdSt = isPreLdStPairCandidate(FirstMI, MI);
+
+      if (BaseReg == MIBaseReg) {
+        // If the offset of the second ld/st is not equal to the size of the
+        // destination register it can’t be paired with a pre-index ld/st
+        // pair. Additionally if the base reg is used or modified the operations
+        // can't be paired: bail and keep looking.
+        if (IsPreLdSt) {
+          bool IsOutOfBounds = MIOffset != TII->getMemScale(MI);
+          bool IsBaseRegUsed =
+              !UsedRegUnits.available(getLdStBaseOp(MI).getReg());
+          bool IsBaseRegModified =
+              !ModifiedRegUnits.available(getLdStBaseOp(MI).getReg());
+          if (IsOutOfBounds || IsBaseRegUsed || IsBaseRegModified) {
+            LiveRegUnits::accumulateUsedDefed(MI, ModifiedRegUnits,
+                                              UsedRegUnits, TRI);
+            MemInsns.push_back(&MI);
+            continue;
+          }
+        } else {
+          if ((Offset != MIOffset + OffsetStride) &&
+              (Offset + OffsetStride != MIOffset)) {
+            LiveRegUnits::accumulateUsedDefed(MI, ModifiedRegUnits,
+                                              UsedRegUnits, TRI);
+            MemInsns.push_back(&MI);
+            continue;
+          }
+        }
+
         int MinOffset = Offset < MIOffset ? Offset : MIOffset;
         if (FindNarrowMerge) {
           // If the alignment requirements of the scaled wide load/store
@@ -1985,7 +2093,7 @@
   // Early exit if the offset is not possible to match. (6 bits of positive
   // range, plus allow an extra one in case we find a later insn that matches
   // with Offset-1)
-  bool IsUnscaled = TII->isUnscaledLdSt(MI);
+  bool IsUnscaled = TII->hasUnscaledLdStOffset(MI);
   int Offset = getLdStOffsetOp(MI).getImm();
   int OffsetStride = IsUnscaled ? TII->getMemScale(MI) : 1;
   // Allow one more for offset.
@@ -2000,7 +2108,7 @@
       findMatchingInsn(MBBI, Flags, LdStLimit, /* FindNarrowMerge = */ false);
   if (Paired != E) {
     ++NumPairCreated;
-    if (TII->isUnscaledLdSt(MI))
+    if (TII->hasUnscaledLdStOffset(MI))
       ++NumUnscaledPairCreated;
     // Keeping the iterator straight is a pain, so we let the merge routine tell
     // us what the next instruction is after it's done mucking about.
@@ -2035,7 +2143,7 @@
   }
 
   // Don't know how to handle unscaled pre/post-index versions below, so bail.
-  if (TII->isUnscaledLdSt(MI.getOpcode()))
+  if (TII->hasUnscaledLdStOffset(MI.getOpcode()))
     return false;
 
   // Look back to try to find a pre-index instruction. For example,
Index: llvm/test/CodeGen/AArch64/arm64-memset-inline.ll
===================================================================
--- llvm/test/CodeGen/AArch64/arm64-memset-inline.ll
+++ llvm/test/CodeGen/AArch64/arm64-memset-inline.ll
@@ -65,8 +65,8 @@
 
 define void @bzero_8_stack() {
 ; CHECK-LABEL: bzero_8_stack:
-; CHECK:       str xzr, [sp, #8]
-; CHECK-NEXT:  bl something
+; CHECK:       stp x30, xzr, [sp, #-16]!
+; CHECK:       bl something
   %buf = alloca [8 x i8], align 1
   %cast = bitcast [8 x i8]* %buf to i8*
   call void @llvm.memset.p0i8.i32(i8* %cast, i8 0, i32 8, i1 false)
@@ -232,8 +232,8 @@
 define void @memset_8_stack() {
 ; CHECK-LABEL: memset_8_stack:
 ; CHECK:       mov x8, #-6148914691236517206
-; CHECK-NEXT:  add x0, sp, #8
-; CHECK-NEXT:  str x8, [sp, #8]
+; CHECK-NEXT:  stp x30, x8, [sp, #-16]!
+; CHECK-NEXT:  add x0, sp, #8 // =8
 ; CHECK-NEXT:  bl something
   %buf = alloca [8 x i8], align 1
   %cast = bitcast [8 x i8]* %buf to i8*
Index: llvm/test/CodeGen/AArch64/ldrpre-ldr-merge.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/ldrpre-ldr-merge.mir
@@ -0,0 +1,654 @@
+# RUN: llc -o - %s -mtriple=aarch64-none-eabi -mcpu=cortex-a55 -lsr-preferred-addressing-mode=preindexed -stop-after=aarch64-ldst-opt | FileCheck %s
+
+---
+name:            1-ldrwpre-ldrwui-merge
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$w0' }
+  - { reg: '$w1' }
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $w0, $w1, $x1
+    ; CHECK-LABEL: name: 1-ldrwpre-ldrwui-merge
+    ; CHECK: liveins: $w0, $w1, $x1
+    ; CHECK: early-clobber $x1, renamable $w0, renamable $w1 = LDPWpre renamable $x1, 5 :: (load 4)
+    ; CHECK: STPWi renamable $w0, renamable $w1, renamable $x1, 0 :: (store 4)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $w0 = LDRWpre killed renamable $x1, 20 :: (load 4)
+    renamable $w1 = LDRWui renamable $x1, 1 :: (load 4)
+    STRWui killed renamable $w0, renamable $x1, 0 :: (store 4)
+    STRWui killed renamable $w1, renamable $x1, 1 :: (store 4)
+    RET undef $lr
+...
+
+
+---
+name:            2-ldrxpre-ldrxui-merge
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$x2' }
+  - { reg: '$x3' }
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $x2, $x3, $x1
+    ; CHECK-LABEL: name: 2-ldrxpre-ldrxui-merge
+    ; CHECK: liveins: $x1, $x2, $x3
+    ; CHECK: early-clobber $x1, renamable $x2, renamable $x3 = LDPXpre renamable $x1, 3 :: (load 8)
+    ; CHECK: STPXi renamable $x2, renamable $x3, renamable $x1, 0 :: (store 8)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $x2 = LDRXpre killed renamable $x1, 24 :: (load 8)
+    renamable $x3 = LDRXui renamable $x1, 1 :: (load 8)
+    STRXui killed renamable $x2, renamable $x1, 0 :: (store 8)
+    STRXui killed renamable $x3, renamable $x1, 1 :: (store 8)
+    RET undef $lr
+...
+
+
+---
+name:            3-ldrspre-ldrsui-merge
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $s0, $s1, $x1
+    ; CHECK-LABEL: name: 3-ldrspre-ldrsui-merge
+    ; CHECK: liveins: $s0, $s1, $x1
+    ; CHECK: early-clobber $x1, renamable $s0, renamable $s1 = LDPSpre renamable $x1, 3 :: (load 4)
+    ; CHECK: STRSui renamable $s0, renamable $x1, 0 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x1, 1 :: ("aarch64-suppress-pair" store 4)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $s0 = LDRSpre killed renamable $x1, 12 :: (load 4)
+    renamable $s1 = LDRSui renamable $x1, 1 :: (load 4)
+    STRSui killed renamable $s0, renamable $x1, 0 :: (store 4)
+    STRSui killed renamable $s1, renamable $x1, 1 :: (store 4)
+    RET undef $lr
+...
+
+
+---
+name:            4-ldrqdre-ldrdui-merge
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$d0' }
+  - { reg: '$d1' }
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $d0, $d1, $x1
+    ; CHECK-LABEL: name: 4-ldrqdre-ldrdui-merge
+    ; CHECK: liveins: $d0, $d1, $x1
+    ; CHECK: early-clobber $x1, renamable $d0, renamable $d1 = LDPDpre renamable $x1, 16 :: (load 8)
+    ; CHECK: STRDui renamable $d0, renamable $x1, 0 :: (store 8)
+    ; CHECK: STRDui renamable $d1, renamable $x1, 1 :: ("aarch64-suppress-pair" store 8)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $d0 = LDRDpre killed renamable $x1, 128 :: (load 8)
+    renamable $d1 = LDRDui renamable $x1, 1 :: (load 8)
+    STRDui killed renamable $d0, renamable $x1, 0 :: (store 8)
+    STRDui killed renamable $d1, renamable $x1, 1 :: (store 8)
+    RET undef $lr
+...
+
+
+---
+name:            5-ldrqpre-ldrqui-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 5-ldrqpre-ldrqui-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber $x1, renamable $q0, renamable $q1 = LDPQpre renamable $x1, 3 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 48 :: (load 16)
+    renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            6-ldrqui-ldrqpre-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 6-ldrqui-ldrqpre-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, 48, implicit $w1 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 48 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            7-ldrqpre-ldrqui-max-offset-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 7-ldrqpre-ldrqui-max-offset-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber $x1, renamable $q0, renamable $q1 = LDPQpre renamable $x1, 16 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 256 :: (load 16)
+    renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            8-ldrqpre-ldrqui-min-offset-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 8-ldrqpre-ldrqui-min-offset-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber $x1, renamable $q0, renamable $q1 = LDPQpre renamable $x1, -16 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, -256 :: (load 16)
+    renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            9-ldrqpre-ldrqui-after-max-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 9-ldrqpre-ldrqui-after-max-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, 257, implicit $w1 :: (load 16)
+    ; CHECK: renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 257 :: (load 16)
+    renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            10-ldrqpre-ldrqui-before-min-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 10-ldrqpre-ldrqui-before-min-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, -257, implicit $w1 :: (load 16)
+    ; CHECK: renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, -257 :: (load 16)
+    renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            11-ldrspre-ldrsui-mod-base-reg-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$x1' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $s0, $s1, $x0, $x1
+    ; CHECK-LABEL: name: 11-ldrspre-ldrsui-mod-base-reg-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0, $x1
+    ; CHECK: dead early-clobber renamable $x1, renamable $s0 = LDRSpre renamable $x1, 12, implicit $w1 :: (load 4)
+    ; CHECK: renamable $x1 = LDRXui renamable $x0, 1 :: (load 8)
+    ; CHECK: renamable $s1 = LDRSui renamable $x1, 1 :: (load 4)
+    ; CHECK: STPSi renamable $s0, renamable $s1, renamable $x1, 0 :: (store 4)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $s0 = LDRSpre killed renamable $x1, 12 :: (load 4)
+    renamable $x1 = LDRXui renamable $x0, 1 :: (load 8)
+    renamable $s1 = LDRSui renamable $x1, 1 :: (load 4)
+    STRSui killed renamable $s0, renamable $x1, 0 :: (store 4)
+    STRSui killed renamable $s1, renamable $x1, 1 :: (store 4)
+    RET undef $lr
+...
+
+
+---
+name:            12-ldrspre-ldrsui-used-base-reg-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$x1' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $s0, $s1, $x0, $x1
+    ; CHECK-LABEL: name: 12-ldrspre-ldrsui-used-base-reg-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $s0 = LDRSpre renamable $x1, 12, implicit $w1 :: (load 4)
+    ; CHECK: renamable $x0 = LDRXui renamable $x1, 1 :: (load 8)
+    ; CHECK: STRXui renamable $x0, renamable $x0, 1 :: (store 8)
+    ; CHECK: renamable $s1 = LDRSui renamable $x1, 1 :: (load 4)
+    ; CHECK: STRSui renamable $s0, renamable $x1, 0 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x1, 1 :: ("aarch64-suppress-pair" store 4)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $s0 = LDRSpre killed renamable $x1, 12 :: (load 4)
+    renamable $x0 = LDRXui renamable $x1, 1 :: (load 8)
+    STRXui killed renamable $x0, renamable $x0, 1 :: (store 8)
+    renamable $s1 = LDRSui renamable $x1, 1 :: (load 4)
+    STRSui killed renamable $s0, renamable $x1, 0 :: (store 4)
+    STRSui killed renamable $s1, renamable $x1, 1 :: (store 4)
+    RET undef $lr
+...
+
+
+---
+name:            13-ldrqpre-ldrqpre-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 13-ldrqpre-ldrqpre-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber renamable $x1, dead renamable $q0 = LDRQpre renamable $x1, 48, implicit $w1 :: (load 16)
+    ; CHECK: early-clobber renamable $x1, dead renamable $q1 = LDRQpre renamable $x1, 1, implicit $w1 :: (load 16)
+    ; CHECK: early-clobber renamable $x1, dead renamable $q0 = LDRQpre renamable $x1, 16, implicit $w1 :: (load 16)
+    ; CHECK: early-clobber renamable $x1, dead renamable $q1 = LDRQpre renamable $x1, 12, implicit $w1 :: (load 16)
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, 16, implicit $w1 :: (load 16)
+    ; CHECK: early-clobber renamable $x1, renamable $q1 = LDRQpre renamable $x1, 16, implicit $w1 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 48 :: (load 16)
+    early-clobber renamable $x1, renamable $q1 = LDRQpre killed renamable $x1, 1  :: (load 16)
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 16 :: (load 16)
+    early-clobber renamable $x1, renamable $q1 = LDRQpre killed renamable $x1, 12  :: (load 16)
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 16 :: (load 16)
+    early-clobber renamable $x1, renamable $q1 = LDRQpre killed renamable $x1, 16  :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            14-ldrspre-ldrsui-no-merge
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $s0, $s1, $x1
+
+    ; The offset of the second load is not equal to the
+    ; size of the destination register,  and hence can’t be merged.
+
+    ; CHECK-LABEL: name: 14-ldrspre-ldrsui-no-merge
+    ; CHECK: liveins: $s0, $s1, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $s0 = LDRSpre renamable $x1, 12, implicit $w1 :: (load 4)
+    ; CHECK: renamable $s1 = LDRSui renamable $x1, 2 :: (load 4)
+    ; CHECK: STRSui renamable $s0, renamable $x1, 0 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x1, 1 :: ("aarch64-suppress-pair" store 4)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $s0 = LDRSpre killed renamable $x1, 12 :: (load 4)
+    renamable $s1 = LDRSui renamable $x1, 2 :: (load 4)
+    STRSui killed renamable $s0, renamable $x1, 0 :: (store 4)
+    STRSui killed renamable $s1, renamable $x1, 1 :: (store 4)
+    RET undef $lr
+...
+
+
+---
+name:            15-ldrqpre-ldrdui-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$d1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $d1, $x1
+    ; CHECK-LABEL: name: 15-ldrqpre-ldrdui-no-merge
+    ; CHECK: liveins: $d1, $q0, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, 32, implicit $w1 :: (load 16)
+    ; CHECK: renamable $d1 = LDRDui renamable $x1, 1 :: (load 8)
+    ; CHECK: STRQui renamable $q0, renamable $x1, 0 :: (store 16)
+    ; CHECK: STRDui renamable $d1, renamable $x1, 1 :: (store 4)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 32 :: (load 16)
+    renamable $d1 = LDRDui renamable $x1, 1 :: (load 8)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRDui killed renamable $d1, renamable $x1, 1 :: (store 4)
+    RET undef $lr
+...
+
+
+---
+name:            16-ldrqpre-strqui-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 16-ldrqpre-strqui-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, 32, implicit $w1 :: (load 16)
+    ; CHECK: STRQui renamable $q0, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 32 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            17-ldrqpre-ldrqui-same-dst-reg-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $x1
+    ; CHECK-LABEL: name: 17-ldrqpre-ldrqui-same-dst-reg-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber renamable $x1, dead renamable $q0 = LDRQpre renamable $x1, 32, implicit $w1 :: (load 16)
+    ; CHECK: renamable $q0 = LDRQui renamable $x1, 1 :: (load 16)
+    ; CHECK: STRQui renamable $q0, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 32 :: (load 16)
+    renamable $q0 = LDRQui renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            18-ldrqpre-ldrqui-diff-base-reg-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$x2' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1, $x2
+    ; CHECK-LABEL: name: 18-ldrqpre-ldrqui-diff-base-reg-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1, $x2
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, 32, implicit $w1 :: (load 16)
+    ; CHECK: renamable $q1 = LDRQui renamable $x2, 1 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 32 :: (load 16)
+    renamable $q1 = LDRQui renamable $x2, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            19-ldrqpre-ldurqi-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 19-ldrqpre-ldurqi-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber $x1, renamable $q0, renamable $q1 = LDPQpre renamable $x1, 2 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 32 :: (load 16)
+    renamable $q1 = LDURQi renamable $x1, 16 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            20-ldrqpre-ldurqi-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 20-ldrqpre-ldurqi-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, 32, implicit $w1 :: (load 16)
+    ; CHECK: renamable $q1 = LDURQi renamable $x1, 1 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 32 :: (load 16)
+    renamable $q1 = LDURQi renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            21-ldrqpre-ldrqui-after-max-aligned-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 21-ldrqpre-ldrqui-after-max-aligned-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, 260, implicit $w1 :: (load 16)
+    ; CHECK: renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, 260 :: (load 16)
+    renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
+
+
+---
+name:            22-ldrqpre-ldrqui-before-min-aligned-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x1' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x1
+    ; CHECK-LABEL: name: 22-ldrqpre-ldrqui-before-min-aligned-no-merge
+    ; CHECK: liveins: $q0, $q1, $x1
+    ; CHECK: early-clobber renamable $x1, renamable $q0 = LDRQpre renamable $x1, -260, implicit $w1 :: (load 16)
+    ; CHECK: renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    ; CHECK: STPQi renamable $q0, renamable $q1, renamable $x1, 0 :: (store 16)
+    ; CHECK: RET undef $lr
+    early-clobber renamable $x1, renamable $q0 = LDRQpre killed renamable $x1, -260 :: (load 16)
+    renamable $q1 = LDRQui renamable $x1, 1 :: (load 16)
+    STRQui killed renamable $q0, renamable $x1, 0 :: (store 16)
+    STRQui killed renamable $q1, renamable $x1, 1 :: (store 16)
+    RET undef $lr
+...
Index: llvm/test/CodeGen/AArch64/strpre-str-merge.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/strpre-str-merge.mir
@@ -0,0 +1,508 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -o - %s -mtriple=aarch64-none-eabi -mcpu=cortex-a55 -lsr-preferred-addressing-mode=preindexed -stop-after=aarch64-ldst-opt | FileCheck %s
+
+---
+name:            1-strwpre-strwui-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$w1' }
+  - { reg: '$w2' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $w1, $w2, $x0
+    ; CHECK-LABEL: name: 1-strwpre-strwui-merge
+    ; CHECK: liveins: $w1, $w2, $x0
+    ; CHECK: early-clobber $x0 = STPWpre renamable $w1, renamable $w2, renamable $x0, 5 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRWpre killed renamable $w1, killed renamable $x0, 20 :: (store 4)
+    STRWui killed renamable $w2, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+
+...
+
+
+---
+name:            2-strxpre-strxui-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$x1' }
+  - { reg: '$x2' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $x0, $x1, $x2
+
+    ; CHECK-LABEL: name: 2-strxpre-strxui-merge
+    ; CHECK: liveins: $x0, $x1, $x2
+    ; CHECK: early-clobber $x0 = STPXpre renamable $x1, renamable $x2, renamable $x0, 3 :: (store 8)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRXpre killed renamable $x1, killed renamable $x0, 24 :: (store 8)
+    STRXui killed renamable $x2, renamable $x0, 1 :: (store 8)
+    RET undef $lr, implicit $x0
+
+...
+
+
+---
+name:            3-strspre-strsui-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 3-strspre-strsui-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber $x0 = STPSpre renamable $s0, renamable $s1, renamable $x0, 3 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, 12 :: (store 4)
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            4-strdpre-strdui-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$d0' }
+  - { reg: '$d1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $d0, $d1, $x0
+
+    ; CHECK-LABEL: name: 4-strdpre-strdui-merge
+    ; CHECK: liveins: $d0, $d1, $x0
+    ; CHECK: early-clobber $x0 = STPDpre renamable $d0, renamable $d1, renamable $x0, 16 :: (store 8)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRDpre killed renamable $d0, killed renamable $x0, 128 :: (store 8)
+    STRDui killed renamable $d1, renamable $x0, 1 :: (store 8)
+    RET undef $lr, implicit $x0
+
+...
+
+
+---
+name:            5-strqpre-strqui-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $q0, $q1, $x0
+
+    ; CHECK-LABEL: name: 5-strqpre-strqui-merge
+    ; CHECK: liveins: $q0, $q1, $x0
+    ; CHECK: early-clobber $x0 = STPQpre renamable $q0, renamable $q1, renamable $x0, 3 :: (store 16)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRQpre killed renamable $q0, killed renamable $x0, 48 :: (store 16)
+    STRQui killed renamable $q1, renamable $x0, 1 :: (store 16)
+    RET undef $lr, implicit $x0
+
+...
+
+
+---
+name:            6-strqui-strqpre-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $q0, $q1, $x0
+    ; CHECK-LABEL: name: 6-strqui-strqpre-no-merge
+    ; CHECK: liveins: $q0, $q1, $x0
+    ; CHECK: STRQui renamable $q1, renamable $x0, 1 :: (store 16)
+    ; CHECK: early-clobber renamable $x0 = STRQpre renamable $q0, renamable $x0, 48, implicit $w0 :: (store 16)
+    ; CHECK: RET undef $lr, implicit $x0
+    STRQui killed renamable $q1, renamable $x0, 1 :: (store 16)
+    early-clobber renamable $x0 = STRQpre killed renamable $q0, killed renamable $x0, 48 :: (store 16)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            7-strspre-strsui-max-offset-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 7-strspre-strsui-max-offset-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber $x0 = STPSpre renamable $s0, renamable $s1, renamable $x0, 64 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, 256 :: (store 4)
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            8-strspre-strsui-min-offset-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 8-strspre-strsui-min-offset-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber $x0 = STPSpre renamable $s0, renamable $s1, renamable $x0, -64 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, -256 :: (store 4)
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            9-strspre-strsui-out-of-bounds-after-max-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 9-strspre-strsui-out-of-bounds-after-max-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, 257, implicit $w0 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x0, 1 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, 257 :: (store 4)
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            10-strspre-strsui-out-of-bounds-before-min-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 10-strspre-strsui-out-of-bounds-before-min-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, -257, implicit $w0 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x0, 1 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, -257 :: (store 4)
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            11-strspre-strsui-mod-base-reg-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$x1' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0, $x1
+    ; CHECK-LABEL: name: 11-strspre-strsui-mod-base-reg-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0, $x1
+    ; CHECK: dead early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, 12, implicit $w0 :: (store 4)
+    ; CHECK: renamable $x0 = LDRXui renamable $x1, 1 :: (load 8)
+    ; CHECK: STRSui renamable $s1, renamable $x0, 1 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, 12 :: (store 4)
+    renamable $x0 = LDRXui renamable $x1, 1 :: (load 8)
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            12-strspre-strsui-used-base-reg-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$x1' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0, $x1
+    ; CHECK-LABEL: name: 12-strspre-strsui-used-base-reg-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0, $x1
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, 12, implicit $w0 :: (store 4)
+    ; CHECK: STRXui renamable $x1, renamable $x1, 1 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x0, 1 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, 12 :: (store 4)
+
+    STRXui killed renamable $x1, renamable $x1, 1 :: (store 4)
+
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            13-strspre-strspre-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 13-strspre-strspre-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, 12, implicit $w0 :: (store 4)
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s1, renamable $x0, 16, implicit $w0 :: (store 4)
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, 4, implicit $w0 :: (store 4)
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s1, renamable $x0, 12, implicit $w0 :: (store 4)
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, 4, implicit $w0 :: (store 4)
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s1, renamable $x0, 4, implicit $w0 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre renamable $s0, killed renamable $x0, 12 :: (store 4)
+    early-clobber renamable $x0 = STRSpre renamable $s1, killed renamable $x0, 16 :: (store 4)
+    early-clobber renamable $x0 = STRSpre renamable $s0, killed renamable $x0, 4 :: (store 4)
+    early-clobber renamable $x0 = STRSpre renamable $s1, killed renamable $x0, 12 :: (store 4)
+    early-clobber renamable $x0 = STRSpre renamable $s0, killed renamable $x0, 4 :: (store 4)
+    early-clobber renamable $x0 = STRSpre renamable $s1, killed renamable $x0, 4 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            14-strspre-strsui-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+
+    ; The offset of the second st is not equal to the
+    ; size of the destination register,  and hence can’t be merged.
+
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 14-strspre-strsui-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, 12, implicit $w0 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x0, 2 :: (store 8)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, 12 :: (store 4)
+    STRSui killed renamable $s1, renamable $x0, 2 :: (store 8)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            15-strqpre-sturqi-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $q0, $q1, $x0
+
+    ; CHECK-LABEL: name: 15-strqpre-sturqi-merge
+    ; CHECK: liveins: $q0, $q1, $x0
+    ; CHECK: early-clobber $x0 = STPQpre renamable $q0, renamable $q1, renamable $x0, 3 :: (store 16)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRQpre killed renamable $q0, killed renamable $x0, 48 :: (store 16)
+    STURQi killed renamable $q1, renamable $x0, 16 :: (store 16)
+    RET undef $lr, implicit $x0
+
+...
+
+
+---
+name:            16-strqpre-sturqi-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$q0' }
+  - { reg: '$q1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $q0, $q1, $x0
+    ; CHECK-LABEL: name: 16-strqpre-sturqi-no-merge
+    ; CHECK: liveins: $q0, $q1, $x0
+    ; CHECK: early-clobber renamable $x0 = STRQpre renamable $q0, renamable $x0, 48, implicit $w0 :: (store 16)
+    ; CHECK: STURQi renamable $q1, renamable $x0, 1 :: (store 16)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRQpre killed renamable $q0, killed renamable $x0, 48 :: (store 16)
+    STURQi killed renamable $q1, renamable $x0, 1 :: (store 16)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            17-strspre-strsui-out-of-bounds-after-max-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 17-strspre-strsui-out-of-bounds-after-max-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, 260, implicit $w0 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x0, 1 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, 260 :: (store 4)
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...
+
+
+---
+name:            18-strspre-strsui-out-of-bounds-aligned-before-min-no-merge
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$s0' }
+  - { reg: '$s1' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  bb.0.entry:
+    liveins: $s0, $s1, $x0
+    ; CHECK-LABEL: name: 18-strspre-strsui-out-of-bounds-aligned-before-min-no-merge
+    ; CHECK: liveins: $s0, $s1, $x0
+    ; CHECK: early-clobber renamable $x0 = STRSpre renamable $s0, renamable $x0, -260, implicit $w0 :: (store 4)
+    ; CHECK: STRSui renamable $s1, renamable $x0, 1 :: (store 4)
+    ; CHECK: RET undef $lr, implicit $x0
+    early-clobber renamable $x0 = STRSpre killed renamable $s0, killed renamable $x0, -260 :: (store 4)
+    STRSui killed renamable $s1, renamable $x0, 1 :: (store 4)
+    RET undef $lr, implicit $x0
+...