diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -10593,17 +10593,88 @@
   return BB;
 }
 
+static bool isSignExtended(MachineInstr &MI, const PPCInstrInfo *TII) {
+  switch(MI.getOpcode()) {
+  default:
+    return false;
+  case PPC::COPY:
+    return TII->isSignExtended(MI);
+  case PPC::LHA:
+  case PPC::LHA8:
+  case PPC::LHAU:
+  case PPC::LHAU8:
+  case PPC::LHAUX:
+  case PPC::LHAUX8:
+  case PPC::LHAX:
+  case PPC::LHAX8:
+  case PPC::LWA:
+  case PPC::LWAUX:
+  case PPC::LWAX:
+  case PPC::LWAX_32:
+  case PPC::LWA_32:
+  case PPC::PLHA:
+  case PPC::PLHA8:
+  case PPC::PLHA8pc:
+  case PPC::PLHApc:
+  case PPC::PLWA:
+  case PPC::PLWA8:
+  case PPC::PLWA8pc:
+  case PPC::PLWApc:
+  case PPC::EXTSB:
+  case PPC::EXTSB8:
+  case PPC::EXTSB8_32_64:
+  case PPC::EXTSB8_rec:
+  case PPC::EXTSB_rec:
+  case PPC::EXTSH:
+  case PPC::EXTSH8:
+  case PPC::EXTSH8_32_64:
+  case PPC::EXTSH8_rec:
+  case PPC::EXTSH_rec:
+  case PPC::EXTSW:
+  case PPC::EXTSWSLI:
+  case PPC::EXTSWSLI_32_64:
+  case PPC::EXTSWSLI_32_64_rec:
+  case PPC::EXTSWSLI_rec:
+  case PPC::EXTSW_32:
+  case PPC::EXTSW_32_64:
+  case PPC::EXTSW_32_64_rec:
+  case PPC::EXTSW_rec:
+  case PPC::SRAW:
+  case PPC::SRAWI:
+  case PPC::SRAWI_rec:
+  case PPC::SRAW_rec:
+    return true;
+  }
+  return false;
+}
+
 MachineBasicBlock *PPCTargetLowering::EmitPartwordAtomicBinary(
     MachineInstr &MI, MachineBasicBlock *BB,
     bool is8bit, // operation
     unsigned BinOpcode, unsigned CmpOpcode, unsigned CmpPred) const {
+  // This also handles ATOMIC_SWAP, indicated by BinOpcode==0.
+  const PPCInstrInfo *TII = Subtarget.getInstrInfo();
+
+  // If this is a signed comparison and the value being compared is not known
+  // to be sign extended, sign extend it here.
+  DebugLoc dl = MI.getDebugLoc();
+  MachineFunction *F = BB->getParent();
+  MachineRegisterInfo &RegInfo = F->getRegInfo();
+  Register incr = MI.getOperand(3).getReg();
+  bool IsSignExtended = Register::isVirtualRegister(incr) &&
+    isSignExtended(*RegInfo.getVRegDef(incr), TII);
+
+  if (CmpOpcode == PPC::CMPW && !IsSignExtended) {
+    Register ValueReg = RegInfo.createVirtualRegister(&PPC::GPRCRegClass);
+    BuildMI(*BB, MI, dl, TII->get(is8bit ? PPC::EXTSB : PPC::EXTSH), ValueReg)
+        .addReg(MI.getOperand(3).getReg());
+    MI.getOperand(3).setReg(ValueReg);
+  }
   // If we support part-word atomic mnemonics, just use them
   if (Subtarget.hasPartwordAtomics())
     return EmitAtomicBinary(MI, BB, is8bit ? 1 : 2, BinOpcode, CmpOpcode,
                             CmpPred);
 
-  // This also handles ATOMIC_SWAP, indicated by BinOpcode==0.
-  const TargetInstrInfo *TII = Subtarget.getInstrInfo();
   // In 64 bit mode we have to use 64 bits for addresses, even though the
   // lwarx/stwcx are 32 bits.  With the 32-bit atomics we can use address
   // registers without caring whether they're 32 or 64, but here we're
@@ -10613,14 +10684,11 @@
   unsigned ZeroReg = is64bit ? PPC::ZERO8 : PPC::ZERO;
 
   const BasicBlock *LLVM_BB = BB->getBasicBlock();
-  MachineFunction *F = BB->getParent();
   MachineFunction::iterator It = ++BB->getIterator();
 
   Register dest = MI.getOperand(0).getReg();
   Register ptrA = MI.getOperand(1).getReg();
   Register ptrB = MI.getOperand(2).getReg();
-  Register incr = MI.getOperand(3).getReg();
-  DebugLoc dl = MI.getDebugLoc();
 
   MachineBasicBlock *loopMBB = F->CreateMachineBasicBlock(LLVM_BB);
   MachineBasicBlock *loop2MBB =
@@ -10634,7 +10702,6 @@
                   std::next(MachineBasicBlock::iterator(MI)), BB->end());
   exitMBB->transferSuccessorsAndUpdatePHIs(BB);
 
-  MachineRegisterInfo &RegInfo = F->getRegInfo();
   const TargetRegisterClass *RC =
       is64bit ? &PPC::G8RCRegClass : &PPC::GPRCRegClass;
   const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
diff --git a/llvm/test/CodeGen/PowerPC/atomics-regression.ll b/llvm/test/CodeGen/PowerPC/atomics-regression.ll
--- a/llvm/test/CodeGen/PowerPC/atomics-regression.ll
+++ b/llvm/test/CodeGen/PowerPC/atomics-regression.ll
@@ -4352,16 +4352,17 @@
 define i8 @test260(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test260:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:  .LBB260_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB260_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB260_1
 ; PPC64LE-NEXT:  .LBB260_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val monotonic
   ret i8 %ret
@@ -4370,16 +4371,17 @@
 define i8 @test261(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test261:
 ; PPC64LE:       # %bb.0:
-; PPC64LE-NEXT:    mr 5, 3
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:  .LBB261_1:
-; PPC64LE-NEXT:    lbarx 3, 0, 5
-; PPC64LE-NEXT:    extsb 6, 3
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB261_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 5
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB261_1
 ; PPC64LE-NEXT:  .LBB261_3:
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val acquire
@@ -4389,17 +4391,18 @@
 define i8 @test262(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test262:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB262_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB262_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB262_1
 ; PPC64LE-NEXT:  .LBB262_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val release
   ret i8 %ret
@@ -4408,17 +4411,18 @@
 define i8 @test263(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test263:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB263_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB263_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB263_1
 ; PPC64LE-NEXT:  .LBB263_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val acq_rel
@@ -4428,17 +4432,18 @@
 define i8 @test264(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test264:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    sync
 ; PPC64LE-NEXT:  .LBB264_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB264_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB264_1
 ; PPC64LE-NEXT:  .LBB264_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val seq_cst
@@ -4448,16 +4453,17 @@
 define i16 @test265(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test265:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:  .LBB265_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB265_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB265_1
 ; PPC64LE-NEXT:  .LBB265_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val monotonic
   ret i16 %ret
@@ -4466,16 +4472,17 @@
 define i16 @test266(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test266:
 ; PPC64LE:       # %bb.0:
-; PPC64LE-NEXT:    mr 5, 3
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:  .LBB266_1:
-; PPC64LE-NEXT:    lharx 3, 0, 5
-; PPC64LE-NEXT:    extsh 6, 3
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB266_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 5
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB266_1
 ; PPC64LE-NEXT:  .LBB266_3:
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val acquire
@@ -4485,17 +4492,18 @@
 define i16 @test267(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test267:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB267_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB267_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB267_1
 ; PPC64LE-NEXT:  .LBB267_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val release
   ret i16 %ret
@@ -4504,17 +4512,18 @@
 define i16 @test268(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test268:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB268_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB268_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB268_1
 ; PPC64LE-NEXT:  .LBB268_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val acq_rel
@@ -4524,17 +4533,18 @@
 define i16 @test269(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test269:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    sync
 ; PPC64LE-NEXT:  .LBB269_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB269_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB269_1
 ; PPC64LE-NEXT:  .LBB269_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val seq_cst
@@ -4726,16 +4736,17 @@
 define i8 @test280(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test280:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:  .LBB280_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB280_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB280_1
 ; PPC64LE-NEXT:  .LBB280_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val monotonic
   ret i8 %ret
@@ -4744,16 +4755,17 @@
 define i8 @test281(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test281:
 ; PPC64LE:       # %bb.0:
-; PPC64LE-NEXT:    mr 5, 3
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:  .LBB281_1:
-; PPC64LE-NEXT:    lbarx 3, 0, 5
-; PPC64LE-NEXT:    extsb 6, 3
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB281_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 5
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB281_1
 ; PPC64LE-NEXT:  .LBB281_3:
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val acquire
@@ -4763,17 +4775,18 @@
 define i8 @test282(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test282:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB282_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB282_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB282_1
 ; PPC64LE-NEXT:  .LBB282_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val release
   ret i8 %ret
@@ -4782,17 +4795,18 @@
 define i8 @test283(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test283:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB283_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB283_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB283_1
 ; PPC64LE-NEXT:  .LBB283_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val acq_rel
@@ -4802,17 +4816,18 @@
 define i8 @test284(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test284:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    sync
 ; PPC64LE-NEXT:  .LBB284_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB284_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB284_1
 ; PPC64LE-NEXT:  .LBB284_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val seq_cst
@@ -4822,16 +4837,17 @@
 define i16 @test285(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test285:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:  .LBB285_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB285_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB285_1
 ; PPC64LE-NEXT:  .LBB285_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val monotonic
   ret i16 %ret
@@ -4840,16 +4856,17 @@
 define i16 @test286(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test286:
 ; PPC64LE:       # %bb.0:
-; PPC64LE-NEXT:    mr 5, 3
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:  .LBB286_1:
-; PPC64LE-NEXT:    lharx 3, 0, 5
-; PPC64LE-NEXT:    extsh 6, 3
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB286_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 5
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB286_1
 ; PPC64LE-NEXT:  .LBB286_3:
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val acquire
@@ -4859,17 +4876,18 @@
 define i16 @test287(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test287:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB287_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB287_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB287_1
 ; PPC64LE-NEXT:  .LBB287_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val release
   ret i16 %ret
@@ -4878,17 +4896,18 @@
 define i16 @test288(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test288:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB288_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB288_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB288_1
 ; PPC64LE-NEXT:  .LBB288_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val acq_rel
@@ -4898,17 +4917,18 @@
 define i16 @test289(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test289:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    sync
 ; PPC64LE-NEXT:  .LBB289_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB289_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB289_1
 ; PPC64LE-NEXT:  .LBB289_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val seq_cst
@@ -8076,16 +8096,17 @@
 define i8 @test480(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test480:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:  .LBB480_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB480_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB480_1
 ; PPC64LE-NEXT:  .LBB480_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val syncscope("singlethread") monotonic
   ret i8 %ret
@@ -8094,16 +8115,17 @@
 define i8 @test481(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test481:
 ; PPC64LE:       # %bb.0:
-; PPC64LE-NEXT:    mr 5, 3
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:  .LBB481_1:
-; PPC64LE-NEXT:    lbarx 3, 0, 5
-; PPC64LE-NEXT:    extsb 6, 3
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB481_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 5
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB481_1
 ; PPC64LE-NEXT:  .LBB481_3:
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val syncscope("singlethread") acquire
@@ -8113,17 +8135,18 @@
 define i8 @test482(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test482:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB482_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB482_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB482_1
 ; PPC64LE-NEXT:  .LBB482_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val syncscope("singlethread") release
   ret i8 %ret
@@ -8132,17 +8155,18 @@
 define i8 @test483(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test483:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB483_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB483_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB483_1
 ; PPC64LE-NEXT:  .LBB483_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val syncscope("singlethread") acq_rel
@@ -8152,17 +8176,18 @@
 define i8 @test484(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test484:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    sync
 ; PPC64LE-NEXT:  .LBB484_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB484_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB484_1
 ; PPC64LE-NEXT:  .LBB484_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i8* %ptr, i8 %val syncscope("singlethread") seq_cst
@@ -8172,16 +8197,17 @@
 define i16 @test485(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test485:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:  .LBB485_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB485_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB485_1
 ; PPC64LE-NEXT:  .LBB485_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val syncscope("singlethread") monotonic
   ret i16 %ret
@@ -8190,16 +8216,17 @@
 define i16 @test486(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test486:
 ; PPC64LE:       # %bb.0:
-; PPC64LE-NEXT:    mr 5, 3
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:  .LBB486_1:
-; PPC64LE-NEXT:    lharx 3, 0, 5
-; PPC64LE-NEXT:    extsh 6, 3
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB486_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 5
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB486_1
 ; PPC64LE-NEXT:  .LBB486_3:
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val syncscope("singlethread") acquire
@@ -8209,17 +8236,18 @@
 define i16 @test487(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test487:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB487_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB487_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB487_1
 ; PPC64LE-NEXT:  .LBB487_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val syncscope("singlethread") release
   ret i16 %ret
@@ -8228,17 +8256,18 @@
 define i16 @test488(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test488:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB488_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB488_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB488_1
 ; PPC64LE-NEXT:  .LBB488_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val syncscope("singlethread") acq_rel
@@ -8248,17 +8277,18 @@
 define i16 @test489(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test489:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    sync
 ; PPC64LE-NEXT:  .LBB489_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    ble 0, .LBB489_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB489_1
 ; PPC64LE-NEXT:  .LBB489_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw max i16* %ptr, i16 %val syncscope("singlethread") seq_cst
@@ -8450,16 +8480,17 @@
 define i8 @test500(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test500:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:  .LBB500_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB500_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB500_1
 ; PPC64LE-NEXT:  .LBB500_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val syncscope("singlethread") monotonic
   ret i8 %ret
@@ -8468,16 +8499,17 @@
 define i8 @test501(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test501:
 ; PPC64LE:       # %bb.0:
-; PPC64LE-NEXT:    mr 5, 3
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:  .LBB501_1:
-; PPC64LE-NEXT:    lbarx 3, 0, 5
-; PPC64LE-NEXT:    extsb 6, 3
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB501_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 5
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB501_1
 ; PPC64LE-NEXT:  .LBB501_3:
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val syncscope("singlethread") acquire
@@ -8487,17 +8519,18 @@
 define i8 @test502(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test502:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB502_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB502_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB502_1
 ; PPC64LE-NEXT:  .LBB502_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val syncscope("singlethread") release
   ret i8 %ret
@@ -8506,17 +8539,18 @@
 define i8 @test503(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test503:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB503_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB503_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB503_1
 ; PPC64LE-NEXT:  .LBB503_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val syncscope("singlethread") acq_rel
@@ -8526,17 +8560,18 @@
 define i8 @test504(i8* %ptr, i8 %val) {
 ; PPC64LE-LABEL: test504:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsb 5, 4
 ; PPC64LE-NEXT:    sync
 ; PPC64LE-NEXT:  .LBB504_1:
-; PPC64LE-NEXT:    lbarx 5, 0, 3
-; PPC64LE-NEXT:    extsb 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lbarx 4, 0, 3
+; PPC64LE-NEXT:    extsb 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB504_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    stbcx. 4, 0, 3
+; PPC64LE-NEXT:    stbcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB504_1
 ; PPC64LE-NEXT:  .LBB504_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i8* %ptr, i8 %val syncscope("singlethread") seq_cst
@@ -8546,16 +8581,17 @@
 define i16 @test505(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test505:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:  .LBB505_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB505_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB505_1
 ; PPC64LE-NEXT:  .LBB505_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val syncscope("singlethread") monotonic
   ret i16 %ret
@@ -8564,16 +8600,17 @@
 define i16 @test506(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test506:
 ; PPC64LE:       # %bb.0:
-; PPC64LE-NEXT:    mr 5, 3
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:  .LBB506_1:
-; PPC64LE-NEXT:    lharx 3, 0, 5
-; PPC64LE-NEXT:    extsh 6, 3
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB506_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 5
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB506_1
 ; PPC64LE-NEXT:  .LBB506_3:
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val syncscope("singlethread") acquire
@@ -8583,17 +8620,18 @@
 define i16 @test507(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test507:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB507_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB507_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB507_1
 ; PPC64LE-NEXT:  .LBB507_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val syncscope("singlethread") release
   ret i16 %ret
@@ -8602,17 +8640,18 @@
 define i16 @test508(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test508:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:  .LBB508_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB508_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB508_1
 ; PPC64LE-NEXT:  .LBB508_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val syncscope("singlethread") acq_rel
@@ -8622,17 +8661,18 @@
 define i16 @test509(i16* %ptr, i16 %val) {
 ; PPC64LE-LABEL: test509:
 ; PPC64LE:       # %bb.0:
+; PPC64LE-NEXT:    extsh 5, 4
 ; PPC64LE-NEXT:    sync
 ; PPC64LE-NEXT:  .LBB509_1:
-; PPC64LE-NEXT:    lharx 5, 0, 3
-; PPC64LE-NEXT:    extsh 6, 5
-; PPC64LE-NEXT:    cmpw 4, 6
+; PPC64LE-NEXT:    lharx 4, 0, 3
+; PPC64LE-NEXT:    extsh 6, 4
+; PPC64LE-NEXT:    cmpw 5, 6
 ; PPC64LE-NEXT:    bge 0, .LBB509_3
 ; PPC64LE-NEXT:  # %bb.2:
-; PPC64LE-NEXT:    sthcx. 4, 0, 3
+; PPC64LE-NEXT:    sthcx. 5, 0, 3
 ; PPC64LE-NEXT:    bne 0, .LBB509_1
 ; PPC64LE-NEXT:  .LBB509_3:
-; PPC64LE-NEXT:    mr 3, 5
+; PPC64LE-NEXT:    mr 3, 4
 ; PPC64LE-NEXT:    lwsync
 ; PPC64LE-NEXT:    blr
   %ret = atomicrmw min i16* %ptr, i16 %val syncscope("singlethread") seq_cst
diff --git a/llvm/test/CodeGen/PowerPC/sign-ext-atomics.ll b/llvm/test/CodeGen/PowerPC/sign-ext-atomics.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/sign-ext-atomics.ll
@@ -0,0 +1,105 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=powerpc64le-linux-gnu < %s | FileCheck %s
+define i16 @SEXTParam(i16 signext %0) #0 {
+; CHECK-LABEL: SEXTParam:
+; CHECK:       # %bb.0: # %top
+; CHECK-NEXT:    li 4, 0
+; CHECK-NEXT:    sth 4, -4(1)
+; CHECK-NEXT:    addi 4, 1, -4
+; CHECK-NEXT:    lwsync
+; CHECK-NEXT:  .LBB0_1: # %top
+; CHECK-NEXT:    #
+; CHECK-NEXT:    lharx 5, 0, 4
+; CHECK-NEXT:    extsh 5, 5
+; CHECK-NEXT:    cmpw 3, 5
+; CHECK-NEXT:    bge 0, .LBB0_3
+; CHECK-NEXT:  # %bb.2: # %top
+; CHECK-NEXT:    #
+; CHECK-NEXT:    sthcx. 3, 0, 4
+; CHECK-NEXT:    bne 0, .LBB0_1
+; CHECK-NEXT:  .LBB0_3: # %top
+; CHECK-NEXT:    lwsync
+; CHECK-NEXT:    lhz 3, -4(1)
+; CHECK-NEXT:    cmpd 7, 3, 3
+; CHECK-NEXT:    bne- 7, .+4
+; CHECK-NEXT:    isync
+; CHECK-NEXT:    blr
+top:
+  %1 = alloca i16, align 4
+  %2 = bitcast i16* %1 to i8*
+  store i16 0, i16* %1, align 4
+  %rv.i = atomicrmw min i16* %1, i16 %0 acq_rel
+  %rv.i2 = load atomic i16, i16* %1 acquire, align 16
+  ret i16 %rv.i2
+}
+
+define i16 @noSEXTParam(i16 %0) #0 {
+; CHECK-LABEL: noSEXTParam:
+; CHECK:       # %bb.0: # %top
+; CHECK-NEXT:    li 4, 0
+; CHECK-NEXT:    extsh 3, 3
+; CHECK-NEXT:    sth 4, -4(1)
+; CHECK-NEXT:    addi 4, 1, -4
+; CHECK-NEXT:    lwsync
+; CHECK-NEXT:  .LBB1_1: # %top
+; CHECK-NEXT:    #
+; CHECK-NEXT:    lharx 5, 0, 4
+; CHECK-NEXT:    extsh 5, 5
+; CHECK-NEXT:    cmpw 3, 5
+; CHECK-NEXT:    bge 0, .LBB1_3
+; CHECK-NEXT:  # %bb.2: # %top
+; CHECK-NEXT:    #
+; CHECK-NEXT:    sthcx. 3, 0, 4
+; CHECK-NEXT:    bne 0, .LBB1_1
+; CHECK-NEXT:  .LBB1_3: # %top
+; CHECK-NEXT:    lwsync
+; CHECK-NEXT:    lhz 3, -4(1)
+; CHECK-NEXT:    cmpd 7, 3, 3
+; CHECK-NEXT:    bne- 7, .+4
+; CHECK-NEXT:    isync
+; CHECK-NEXT:    blr
+top:
+  %1 = alloca i16, align 4
+  %2 = bitcast i16* %1 to i8*
+  store i16 0, i16* %1, align 4
+  %rv.i = atomicrmw min i16* %1, i16 %0 acq_rel
+  %rv.i2 = load atomic i16, i16* %1 acquire, align 16
+  ret i16 %rv.i2
+}
+
+define i16 @noSEXTLoad(i16 *%p) #0 {
+; CHECK-LABEL: noSEXTLoad:
+; CHECK:       # %bb.0: # %top
+; CHECK-NEXT:    lhz 5, 0(3)
+; CHECK-NEXT:    li 4, 0
+; CHECK-NEXT:    addi 3, 1, -4
+; CHECK-NEXT:    sth 4, -4(1)
+; CHECK-NEXT:    extsh 4, 5
+; CHECK-NEXT:    lwsync
+; CHECK-NEXT:  .LBB2_1: # %top
+; CHECK-NEXT:    #
+; CHECK-NEXT:    lharx 5, 0, 3
+; CHECK-NEXT:    extsh 5, 5
+; CHECK-NEXT:    cmpw 4, 5
+; CHECK-NEXT:    bge 0, .LBB2_3
+; CHECK-NEXT:  # %bb.2: # %top
+; CHECK-NEXT:    #
+; CHECK-NEXT:    sthcx. 4, 0, 3
+; CHECK-NEXT:    bne 0, .LBB2_1
+; CHECK-NEXT:  .LBB2_3: # %top
+; CHECK-NEXT:    lwsync
+; CHECK-NEXT:    lhz 3, -4(1)
+; CHECK-NEXT:    cmpd 7, 3, 3
+; CHECK-NEXT:    bne- 7, .+4
+; CHECK-NEXT:    isync
+; CHECK-NEXT:    blr
+top:
+  %0 = load i16, i16* %p, align 2
+  %1 = alloca i16, align 4
+  %2 = bitcast i16* %1 to i8*
+  store i16 0, i16* %1, align 4
+  %rv.i = atomicrmw min i16* %1, i16 %0 acq_rel
+  %rv.i2 = load atomic i16, i16* %1 acquire, align 16
+  ret i16 %rv.i2
+}
+attributes #0 = { nounwind }