diff --git a/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h b/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
--- a/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
@@ -594,19 +594,6 @@
   bool tryEmitMemcpyInline(MachineInstr &MI);
 
 private:
-  // Memcpy family optimization helpers.
-  bool tryEmitMemcpyInline(MachineInstr &MI, Register Dst, Register Src,
-                           uint64_t KnownLen, Align DstAlign, Align SrcAlign,
-                           bool IsVolatile);
-  bool optimizeMemcpy(MachineInstr &MI, Register Dst, Register Src,
-                      uint64_t KnownLen, uint64_t Limit, Align DstAlign,
-                      Align SrcAlign, bool IsVolatile);
-  bool optimizeMemmove(MachineInstr &MI, Register Dst, Register Src,
-                       uint64_t KnownLen, Align DstAlign, Align SrcAlign,
-                       bool IsVolatile);
-  bool optimizeMemset(MachineInstr &MI, Register Dst, Register Val,
-                      uint64_t KnownLen, Align DstAlign, bool IsVolatile);
-
   /// Given a non-indexed load or store instruction \p MI, find an offset that
   /// can be usefully and legally folded into it as a post-indexing operation.
   ///
diff --git a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
--- a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
@@ -256,6 +256,20 @@
                                         LLT SrcTy, LLT NarrowTy,
                                         unsigned ScalarOpc);
 
+  // Memcpy family legalization helpers.
+  LegalizeResult lowerMemset(MachineInstr &MI, Register Dst, Register Val,
+                             uint64_t KnownLen, Align Alignment,
+                             bool IsVolatile);
+  LegalizeResult lowerMemcpyInline(MachineInstr &MI, Register Dst, Register Src,
+                                   uint64_t KnownLen, Align DstAlign,
+                                   Align SrcAlign, bool IsVolatile);
+  LegalizeResult lowerMemcpy(MachineInstr &MI, Register Dst, Register Src,
+                             uint64_t KnownLen, uint64_t Limit, Align DstAlign,
+                             Align SrcAlign, bool IsVolatile);
+  LegalizeResult lowerMemmove(MachineInstr &MI, Register Dst, Register Src,
+                              uint64_t KnownLen, Align DstAlign, Align SrcAlign,
+                              bool IsVolatile);
+
 public:
   /// Return the alignment to use for a stack temporary object with the given
   /// type.
@@ -403,6 +417,8 @@
   LegalizeResult lowerAbsToAddXor(MachineInstr &MI);
   LegalizeResult lowerAbsToMaxNeg(MachineInstr &MI);
   LegalizeResult lowerVectorReduction(MachineInstr &MI);
+  LegalizeResult lowerMemcpyInline(MachineInstr &MI);
+  LegalizeResult lowerMemCpyFamily(MachineInstr &MI, unsigned MaxLen = 0);
 };
 
 /// Helper function that creates a libcall to the given \p Name using the given
diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -12,6 +12,7 @@
 #include "llvm/CodeGen/GlobalISel/GISelChangeObserver.h"
 #include "llvm/CodeGen/GlobalISel/GISelKnownBits.h"
 #include "llvm/CodeGen/GlobalISel/GenericMachineInstrs.h"
+#include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
 #include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
@@ -28,7 +29,6 @@
 #include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/CodeGen/TargetOpcodes.h"
 #include "llvm/Support/MathExtras.h"
-#include "llvm/Target/TargetMachine.h"
 #include <tuple>
 
 #define DEBUG_TYPE "gi-combiner"
@@ -1111,81 +1111,6 @@
   Observer.changedInstr(*BrCond);
 }
 
-static bool shouldLowerMemFuncForSize(const MachineFunction &MF) {
-  // On Darwin, -Os means optimize for size without hurting performance, so
-  // only really optimize for size when -Oz (MinSize) is used.
-  if (MF.getTarget().getTargetTriple().isOSDarwin())
-    return MF.getFunction().hasMinSize();
-  return MF.getFunction().hasOptSize();
-}
-
-// Returns a list of types to use for memory op lowering in MemOps. A partial
-// port of findOptimalMemOpLowering in TargetLowering.
-static bool findGISelOptimalMemOpLowering(std::vector<LLT> &MemOps,
-                                          unsigned Limit, const MemOp &Op,
-                                          unsigned DstAS, unsigned SrcAS,
-                                          const AttributeList &FuncAttributes,
-                                          const TargetLowering &TLI) {
-  if (Op.isMemcpyWithFixedDstAlign() && Op.getSrcAlign() < Op.getDstAlign())
-    return false;
-
-  LLT Ty = TLI.getOptimalMemOpLLT(Op, FuncAttributes);
-
-  if (Ty == LLT()) {
-    // Use the largest scalar type whose alignment constraints are satisfied.
-    // We only need to check DstAlign here as SrcAlign is always greater or
-    // equal to DstAlign (or zero).
-    Ty = LLT::scalar(64);
-    if (Op.isFixedDstAlign())
-      while (Op.getDstAlign() < Ty.getSizeInBytes() &&
-             !TLI.allowsMisalignedMemoryAccesses(Ty, DstAS, Op.getDstAlign()))
-        Ty = LLT::scalar(Ty.getSizeInBytes());
-    assert(Ty.getSizeInBits() > 0 && "Could not find valid type");
-    // FIXME: check for the largest legal type we can load/store to.
-  }
-
-  unsigned NumMemOps = 0;
-  uint64_t Size = Op.size();
-  while (Size) {
-    unsigned TySize = Ty.getSizeInBytes();
-    while (TySize > Size) {
-      // For now, only use non-vector load / store's for the left-over pieces.
-      LLT NewTy = Ty;
-      // FIXME: check for mem op safety and legality of the types. Not all of
-      // SDAGisms map cleanly to GISel concepts.
-      if (NewTy.isVector())
-        NewTy = NewTy.getSizeInBits() > 64 ? LLT::scalar(64) : LLT::scalar(32);
-      NewTy = LLT::scalar(PowerOf2Floor(NewTy.getSizeInBits() - 1));
-      unsigned NewTySize = NewTy.getSizeInBytes();
-      assert(NewTySize > 0 && "Could not find appropriate type");
-
-      // If the new LLT cannot cover all of the remaining bits, then consider
-      // issuing a (or a pair of) unaligned and overlapping load / store.
-      bool Fast;
-      // Need to get a VT equivalent for allowMisalignedMemoryAccesses().
-      MVT VT = getMVTForLLT(Ty);
-      if (NumMemOps && Op.allowOverlap() && NewTySize < Size &&
-          TLI.allowsMisalignedMemoryAccesses(
-              VT, DstAS, Op.isFixedDstAlign() ? Op.getDstAlign() : Align(1),
-              MachineMemOperand::MONone, &Fast) &&
-          Fast)
-        TySize = Size;
-      else {
-        Ty = NewTy;
-        TySize = NewTySize;
-      }
-    }
-
-    if (++NumMemOps > Limit)
-      return false;
-
-    MemOps.push_back(Ty);
-    Size -= TySize;
-  }
-
-  return true;
-}
-
 static Type *getTypeForLLT(LLT Ty, LLVMContext &C) {
   if (Ty.isVector())
     return FixedVectorType::get(IntegerType::get(C, Ty.getScalarSizeInBits()),
@@ -1193,458 +1118,20 @@
   return IntegerType::get(C, Ty.getSizeInBits());
 }
 
-// Get a vectorized representation of the memset value operand, GISel edition.
-static Register getMemsetValue(Register Val, LLT Ty, MachineIRBuilder &MIB) {
-  MachineRegisterInfo &MRI = *MIB.getMRI();
-  unsigned NumBits = Ty.getScalarSizeInBits();
-  auto ValVRegAndVal = getConstantVRegValWithLookThrough(Val, MRI);
-  if (!Ty.isVector() && ValVRegAndVal) {
-    APInt Scalar = ValVRegAndVal->Value.truncOrSelf(8);
-    APInt SplatVal = APInt::getSplat(NumBits, Scalar);
-    return MIB.buildConstant(Ty, SplatVal).getReg(0);
-  }
-
-  // Extend the byte value to the larger type, and then multiply by a magic
-  // value 0x010101... in order to replicate it across every byte.
-  // Unless it's zero, in which case just emit a larger G_CONSTANT 0.
-  if (ValVRegAndVal && ValVRegAndVal->Value == 0) {
-    return MIB.buildConstant(Ty, 0).getReg(0);
-  }
-
-  LLT ExtType = Ty.getScalarType();
-  auto ZExt = MIB.buildZExtOrTrunc(ExtType, Val);
-  if (NumBits > 8) {
-    APInt Magic = APInt::getSplat(NumBits, APInt(8, 0x01));
-    auto MagicMI = MIB.buildConstant(ExtType, Magic);
-    Val = MIB.buildMul(ExtType, ZExt, MagicMI).getReg(0);
-  }
-
-  // For vector types create a G_BUILD_VECTOR.
-  if (Ty.isVector())
-    Val = MIB.buildSplatVector(Ty, Val).getReg(0);
-
-  return Val;
-}
-
-bool CombinerHelper::optimizeMemset(MachineInstr &MI, Register Dst,
-                                    Register Val, uint64_t KnownLen,
-                                    Align Alignment, bool IsVolatile) {
-  auto &MF = *MI.getParent()->getParent();
-  const auto &TLI = *MF.getSubtarget().getTargetLowering();
-  auto &DL = MF.getDataLayout();
-  LLVMContext &C = MF.getFunction().getContext();
-
-  assert(KnownLen != 0 && "Have a zero length memset length!");
-
-  bool DstAlignCanChange = false;
-  MachineFrameInfo &MFI = MF.getFrameInfo();
-  bool OptSize = shouldLowerMemFuncForSize(MF);
-
-  MachineInstr *FIDef = getOpcodeDef(TargetOpcode::G_FRAME_INDEX, Dst, MRI);
-  if (FIDef && !MFI.isFixedObjectIndex(FIDef->getOperand(1).getIndex()))
-    DstAlignCanChange = true;
-
-  unsigned Limit = TLI.getMaxStoresPerMemset(OptSize);
-  std::vector<LLT> MemOps;
-
-  const auto &DstMMO = **MI.memoperands_begin();
-  MachinePointerInfo DstPtrInfo = DstMMO.getPointerInfo();
-
-  auto ValVRegAndVal = getConstantVRegValWithLookThrough(Val, MRI);
-  bool IsZeroVal = ValVRegAndVal && ValVRegAndVal->Value == 0;
-
-  if (!findGISelOptimalMemOpLowering(MemOps, Limit,
-                                     MemOp::Set(KnownLen, DstAlignCanChange,
-                                                Alignment,
-                                                /*IsZeroMemset=*/IsZeroVal,
-                                                /*IsVolatile=*/IsVolatile),
-                                     DstPtrInfo.getAddrSpace(), ~0u,
-                                     MF.getFunction().getAttributes(), TLI))
-    return false;
-
-  if (DstAlignCanChange) {
-    // Get an estimate of the type from the LLT.
-    Type *IRTy = getTypeForLLT(MemOps[0], C);
-    Align NewAlign = DL.getABITypeAlign(IRTy);
-    if (NewAlign > Alignment) {
-      Alignment = NewAlign;
-      unsigned FI = FIDef->getOperand(1).getIndex();
-      // Give the stack frame object a larger alignment if needed.
-      if (MFI.getObjectAlign(FI) < Alignment)
-        MFI.setObjectAlignment(FI, Alignment);
-    }
-  }
-
-  MachineIRBuilder MIB(MI);
-  // Find the largest store and generate the bit pattern for it.
-  LLT LargestTy = MemOps[0];
-  for (unsigned i = 1; i < MemOps.size(); i++)
-    if (MemOps[i].getSizeInBits() > LargestTy.getSizeInBits())
-      LargestTy = MemOps[i];
-
-  // The memset stored value is always defined as an s8, so in order to make it
-  // work with larger store types we need to repeat the bit pattern across the
-  // wider type.
-  Register MemSetValue = getMemsetValue(Val, LargestTy, MIB);
-
-  if (!MemSetValue)
-    return false;
-
-  // Generate the stores. For each store type in the list, we generate the
-  // matching store of that type to the destination address.
-  LLT PtrTy = MRI.getType(Dst);
-  unsigned DstOff = 0;
-  unsigned Size = KnownLen;
-  for (unsigned I = 0; I < MemOps.size(); I++) {
-    LLT Ty = MemOps[I];
-    unsigned TySize = Ty.getSizeInBytes();
-    if (TySize > Size) {
-      // Issuing an unaligned load / store pair that overlaps with the previous
-      // pair. Adjust the offset accordingly.
-      assert(I == MemOps.size() - 1 && I != 0);
-      DstOff -= TySize - Size;
-    }
-
-    // If this store is smaller than the largest store see whether we can get
-    // the smaller value for free with a truncate.
-    Register Value = MemSetValue;
-    if (Ty.getSizeInBits() < LargestTy.getSizeInBits()) {
-      MVT VT = getMVTForLLT(Ty);
-      MVT LargestVT = getMVTForLLT(LargestTy);
-      if (!LargestTy.isVector() && !Ty.isVector() &&
-          TLI.isTruncateFree(LargestVT, VT))
-        Value = MIB.buildTrunc(Ty, MemSetValue).getReg(0);
-      else
-        Value = getMemsetValue(Val, Ty, MIB);
-      if (!Value)
-        return false;
-    }
-
-    auto *StoreMMO =
-        MF.getMachineMemOperand(&DstMMO, DstOff, Ty);
-
-    Register Ptr = Dst;
-    if (DstOff != 0) {
-      auto Offset =
-          MIB.buildConstant(LLT::scalar(PtrTy.getSizeInBits()), DstOff);
-      Ptr = MIB.buildPtrAdd(PtrTy, Dst, Offset).getReg(0);
-    }
-
-    MIB.buildStore(Value, Ptr, *StoreMMO);
-    DstOff += Ty.getSizeInBytes();
-    Size -= TySize;
-  }
-
-  MI.eraseFromParent();
-  return true;
-}
-
 bool CombinerHelper::tryEmitMemcpyInline(MachineInstr &MI) {
-  assert(MI.getOpcode() == TargetOpcode::G_MEMCPY_INLINE);
-
-  Register Dst = MI.getOperand(0).getReg();
-  Register Src = MI.getOperand(1).getReg();
-  Register Len = MI.getOperand(2).getReg();
-
-  const auto *MMOIt = MI.memoperands_begin();
-  const MachineMemOperand *MemOp = *MMOIt;
-  bool IsVolatile = MemOp->isVolatile();
-
-  // See if this is a constant length copy
-  auto LenVRegAndVal = getConstantVRegValWithLookThrough(Len, MRI);
-  // FIXME: support dynamically sized G_MEMCPY_INLINE
-  assert(LenVRegAndVal.hasValue() &&
-         "inline memcpy with dynamic size is not yet supported");
-  uint64_t KnownLen = LenVRegAndVal->Value.getZExtValue();
-  if (KnownLen == 0) {
-    MI.eraseFromParent();
-    return true;
-  }
-
-  const auto &DstMMO = **MI.memoperands_begin();
-  const auto &SrcMMO = **std::next(MI.memoperands_begin());
-  Align DstAlign = DstMMO.getBaseAlign();
-  Align SrcAlign = SrcMMO.getBaseAlign();
-
-  return tryEmitMemcpyInline(MI, Dst, Src, KnownLen, DstAlign, SrcAlign,
-                             IsVolatile);
-}
-
-bool CombinerHelper::tryEmitMemcpyInline(MachineInstr &MI, Register Dst,
-                                         Register Src, uint64_t KnownLen,
-                                         Align DstAlign, Align SrcAlign,
-                                         bool IsVolatile) {
-  assert(MI.getOpcode() == TargetOpcode::G_MEMCPY_INLINE);
-  return optimizeMemcpy(MI, Dst, Src, KnownLen,
-                        std::numeric_limits<uint64_t>::max(), DstAlign,
-                        SrcAlign, IsVolatile);
-}
-
-bool CombinerHelper::optimizeMemcpy(MachineInstr &MI, Register Dst,
-                                    Register Src, uint64_t KnownLen,
-                                    uint64_t Limit, Align DstAlign,
-                                    Align SrcAlign, bool IsVolatile) {
-  auto &MF = *MI.getParent()->getParent();
-  const auto &TLI = *MF.getSubtarget().getTargetLowering();
-  auto &DL = MF.getDataLayout();
-  LLVMContext &C = MF.getFunction().getContext();
-
-  assert(KnownLen != 0 && "Have a zero length memcpy length!");
-
-  bool DstAlignCanChange = false;
-  MachineFrameInfo &MFI = MF.getFrameInfo();
-  Align Alignment = commonAlignment(DstAlign, SrcAlign);
-
-  MachineInstr *FIDef = getOpcodeDef(TargetOpcode::G_FRAME_INDEX, Dst, MRI);
-  if (FIDef && !MFI.isFixedObjectIndex(FIDef->getOperand(1).getIndex()))
-    DstAlignCanChange = true;
-
-  // FIXME: infer better src pointer alignment like SelectionDAG does here.
-  // FIXME: also use the equivalent of isMemSrcFromConstant and alwaysinlining
-  // if the memcpy is in a tail call position.
-
-  std::vector<LLT> MemOps;
-
-  const auto &DstMMO = **MI.memoperands_begin();
-  const auto &SrcMMO = **std::next(MI.memoperands_begin());
-  MachinePointerInfo DstPtrInfo = DstMMO.getPointerInfo();
-  MachinePointerInfo SrcPtrInfo = SrcMMO.getPointerInfo();
-
-  if (!findGISelOptimalMemOpLowering(
-          MemOps, Limit,
-          MemOp::Copy(KnownLen, DstAlignCanChange, Alignment, SrcAlign,
-                      IsVolatile),
-          DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
-          MF.getFunction().getAttributes(), TLI))
-    return false;
-
-  if (DstAlignCanChange) {
-    // Get an estimate of the type from the LLT.
-    Type *IRTy = getTypeForLLT(MemOps[0], C);
-    Align NewAlign = DL.getABITypeAlign(IRTy);
-
-    // Don't promote to an alignment that would require dynamic stack
-    // realignment.
-    if (!TRI->hasStackRealignment(MF))
-      while (NewAlign > Alignment && DL.exceedsNaturalStackAlignment(NewAlign))
-        NewAlign = NewAlign / 2;
-
-    if (NewAlign > Alignment) {
-      Alignment = NewAlign;
-      unsigned FI = FIDef->getOperand(1).getIndex();
-      // Give the stack frame object a larger alignment if needed.
-      if (MFI.getObjectAlign(FI) < Alignment)
-        MFI.setObjectAlignment(FI, Alignment);
-    }
-  }
-
-  LLVM_DEBUG(dbgs() << "Inlining memcpy: " << MI << " into loads & stores\n");
-
-  MachineIRBuilder MIB(MI);
-  // Now we need to emit a pair of load and stores for each of the types we've
-  // collected. I.e. for each type, generate a load from the source pointer of
-  // that type width, and then generate a corresponding store to the dest buffer
-  // of that value loaded. This can result in a sequence of loads and stores
-  // mixed types, depending on what the target specifies as good types to use.
-  unsigned CurrOffset = 0;
-  LLT PtrTy = MRI.getType(Src);
-  unsigned Size = KnownLen;
-  for (auto CopyTy : MemOps) {
-    // Issuing an unaligned load / store pair  that overlaps with the previous
-    // pair. Adjust the offset accordingly.
-    if (CopyTy.getSizeInBytes() > Size)
-      CurrOffset -= CopyTy.getSizeInBytes() - Size;
-
-    // Construct MMOs for the accesses.
-    auto *LoadMMO =
-        MF.getMachineMemOperand(&SrcMMO, CurrOffset, CopyTy.getSizeInBytes());
-    auto *StoreMMO =
-        MF.getMachineMemOperand(&DstMMO, CurrOffset, CopyTy.getSizeInBytes());
-
-    // Create the load.
-    Register LoadPtr = Src;
-    Register Offset;
-    if (CurrOffset != 0) {
-      Offset = MIB.buildConstant(LLT::scalar(PtrTy.getSizeInBits()), CurrOffset)
-                   .getReg(0);
-      LoadPtr = MIB.buildPtrAdd(PtrTy, Src, Offset).getReg(0);
-    }
-    auto LdVal = MIB.buildLoad(CopyTy, LoadPtr, *LoadMMO);
-
-    // Create the store.
-    Register StorePtr =
-        CurrOffset == 0 ? Dst : MIB.buildPtrAdd(PtrTy, Dst, Offset).getReg(0);
-    MIB.buildStore(LdVal, StorePtr, *StoreMMO);
-    CurrOffset += CopyTy.getSizeInBytes();
-    Size -= CopyTy.getSizeInBytes();
-  }
-
-  MI.eraseFromParent();
-  return true;
-}
-
-bool CombinerHelper::optimizeMemmove(MachineInstr &MI, Register Dst,
-                                     Register Src, uint64_t KnownLen,
-                                     Align DstAlign, Align SrcAlign,
-                                     bool IsVolatile) {
-  auto &MF = *MI.getParent()->getParent();
-  const auto &TLI = *MF.getSubtarget().getTargetLowering();
-  auto &DL = MF.getDataLayout();
-  LLVMContext &C = MF.getFunction().getContext();
-
-  assert(KnownLen != 0 && "Have a zero length memmove length!");
-
-  bool DstAlignCanChange = false;
-  MachineFrameInfo &MFI = MF.getFrameInfo();
-  bool OptSize = shouldLowerMemFuncForSize(MF);
-  Align Alignment = commonAlignment(DstAlign, SrcAlign);
-
-  MachineInstr *FIDef = getOpcodeDef(TargetOpcode::G_FRAME_INDEX, Dst, MRI);
-  if (FIDef && !MFI.isFixedObjectIndex(FIDef->getOperand(1).getIndex()))
-    DstAlignCanChange = true;
-
-  unsigned Limit = TLI.getMaxStoresPerMemmove(OptSize);
-  std::vector<LLT> MemOps;
-
-  const auto &DstMMO = **MI.memoperands_begin();
-  const auto &SrcMMO = **std::next(MI.memoperands_begin());
-  MachinePointerInfo DstPtrInfo = DstMMO.getPointerInfo();
-  MachinePointerInfo SrcPtrInfo = SrcMMO.getPointerInfo();
-
-  // FIXME: SelectionDAG always passes false for 'AllowOverlap', apparently due
-  // to a bug in it's findOptimalMemOpLowering implementation. For now do the
-  // same thing here.
-  if (!findGISelOptimalMemOpLowering(
-          MemOps, Limit,
-          MemOp::Copy(KnownLen, DstAlignCanChange, Alignment, SrcAlign,
-                      /*IsVolatile*/ true),
-          DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
-          MF.getFunction().getAttributes(), TLI))
-    return false;
-
-  if (DstAlignCanChange) {
-    // Get an estimate of the type from the LLT.
-    Type *IRTy = getTypeForLLT(MemOps[0], C);
-    Align NewAlign = DL.getABITypeAlign(IRTy);
-
-    // Don't promote to an alignment that would require dynamic stack
-    // realignment.
-    if (!TRI->hasStackRealignment(MF))
-      while (NewAlign > Alignment && DL.exceedsNaturalStackAlignment(NewAlign))
-        NewAlign = NewAlign / 2;
-
-    if (NewAlign > Alignment) {
-      Alignment = NewAlign;
-      unsigned FI = FIDef->getOperand(1).getIndex();
-      // Give the stack frame object a larger alignment if needed.
-      if (MFI.getObjectAlign(FI) < Alignment)
-        MFI.setObjectAlignment(FI, Alignment);
-    }
-  }
-
-  LLVM_DEBUG(dbgs() << "Inlining memmove: " << MI << " into loads & stores\n");
-
-  MachineIRBuilder MIB(MI);
-  // Memmove requires that we perform the loads first before issuing the stores.
-  // Apart from that, this loop is pretty much doing the same thing as the
-  // memcpy codegen function.
-  unsigned CurrOffset = 0;
-  LLT PtrTy = MRI.getType(Src);
-  SmallVector<Register, 16> LoadVals;
-  for (auto CopyTy : MemOps) {
-    // Construct MMO for the load.
-    auto *LoadMMO =
-        MF.getMachineMemOperand(&SrcMMO, CurrOffset, CopyTy.getSizeInBytes());
-
-    // Create the load.
-    Register LoadPtr = Src;
-    if (CurrOffset != 0) {
-      auto Offset =
-          MIB.buildConstant(LLT::scalar(PtrTy.getSizeInBits()), CurrOffset);
-      LoadPtr = MIB.buildPtrAdd(PtrTy, Src, Offset).getReg(0);
-    }
-    LoadVals.push_back(MIB.buildLoad(CopyTy, LoadPtr, *LoadMMO).getReg(0));
-    CurrOffset += CopyTy.getSizeInBytes();
-  }
-
-  CurrOffset = 0;
-  for (unsigned I = 0; I < MemOps.size(); ++I) {
-    LLT CopyTy = MemOps[I];
-    // Now store the values loaded.
-    auto *StoreMMO =
-        MF.getMachineMemOperand(&DstMMO, CurrOffset, CopyTy.getSizeInBytes());
-
-    Register StorePtr = Dst;
-    if (CurrOffset != 0) {
-      auto Offset =
-          MIB.buildConstant(LLT::scalar(PtrTy.getSizeInBits()), CurrOffset);
-      StorePtr = MIB.buildPtrAdd(PtrTy, Dst, Offset).getReg(0);
-    }
-    MIB.buildStore(LoadVals[I], StorePtr, *StoreMMO);
-    CurrOffset += CopyTy.getSizeInBytes();
-  }
-  MI.eraseFromParent();
-  return true;
+  MachineIRBuilder HelperBuilder(MI);
+  GISelObserverWrapper DummyObserver;
+  LegalizerHelper Helper(HelperBuilder.getMF(), DummyObserver, HelperBuilder);
+  return Helper.lowerMemcpyInline(MI) ==
+         LegalizerHelper::LegalizeResult::Legalized;
 }
 
 bool CombinerHelper::tryCombineMemCpyFamily(MachineInstr &MI, unsigned MaxLen) {
-  const unsigned Opc = MI.getOpcode();
-  // This combine is fairly complex so it's not written with a separate
-  // matcher function.
-  assert((Opc == TargetOpcode::G_MEMCPY || Opc == TargetOpcode::G_MEMMOVE ||
-          Opc == TargetOpcode::G_MEMSET) && "Expected memcpy like instruction");
-
-  auto MMOIt = MI.memoperands_begin();
-  const MachineMemOperand *MemOp = *MMOIt;
-
-  Align DstAlign = MemOp->getBaseAlign();
-  Align SrcAlign;
-  Register Dst = MI.getOperand(0).getReg();
-  Register Src = MI.getOperand(1).getReg();
-  Register Len = MI.getOperand(2).getReg();
-
-  if (Opc != TargetOpcode::G_MEMSET) {
-    assert(MMOIt != MI.memoperands_end() && "Expected a second MMO on MI");
-    MemOp = *(++MMOIt);
-    SrcAlign = MemOp->getBaseAlign();
-  }
-
-  // See if this is a constant length copy
-  auto LenVRegAndVal = getConstantVRegValWithLookThrough(Len, MRI);
-  if (!LenVRegAndVal)
-    return false; // Leave it to the legalizer to lower it to a libcall.
-  uint64_t KnownLen = LenVRegAndVal->Value.getZExtValue();
-
-  if (KnownLen == 0) {
-    MI.eraseFromParent();
-    return true;
-  }
-
-  bool IsVolatile = MemOp->isVolatile();
-  if (Opc == TargetOpcode::G_MEMCPY_INLINE)
-    return tryEmitMemcpyInline(MI, Dst, Src, KnownLen, DstAlign, SrcAlign,
-                               IsVolatile);
-
-  // Don't try to optimize volatile.
-  if (IsVolatile)
-    return false;
-
-  if (MaxLen && KnownLen > MaxLen)
-    return false;
-
-  if (Opc == TargetOpcode::G_MEMCPY) {
-    auto &MF = *MI.getParent()->getParent();
-    const auto &TLI = *MF.getSubtarget().getTargetLowering();
-    bool OptSize = shouldLowerMemFuncForSize(MF);
-    uint64_t Limit = TLI.getMaxStoresPerMemcpy(OptSize);
-    return optimizeMemcpy(MI, Dst, Src, KnownLen, Limit, DstAlign, SrcAlign,
-                          IsVolatile);
-  }
-  if (Opc == TargetOpcode::G_MEMMOVE)
-    return optimizeMemmove(MI, Dst, Src, KnownLen, DstAlign, SrcAlign, IsVolatile);
-  if (Opc == TargetOpcode::G_MEMSET)
-    return optimizeMemset(MI, Dst, Src, KnownLen, DstAlign, IsVolatile);
-  return false;
+  MachineIRBuilder HelperBuilder(MI);
+  GISelObserverWrapper DummyObserver;
+  LegalizerHelper Helper(HelperBuilder.getMF(), DummyObserver, HelperBuilder);
+  return Helper.lowerMemCpyFamily(MI, MaxLen) ==
+         LegalizerHelper::LegalizeResult::Legalized;
 }
 
 static Optional<APFloat> constantFoldFpUnary(unsigned Opcode, LLT DstTy,
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
 
 #define DEBUG_TYPE "legalizer"
 
@@ -3486,6 +3487,12 @@
   case G_ROTL:
   case G_ROTR:
     return lowerRotate(MI);
+  case G_MEMSET:
+  case G_MEMCPY:
+  case G_MEMMOVE:
+    return lowerMemCpyFamily(MI);
+  case G_MEMCPY_INLINE:
+    return lowerMemcpyInline(MI);
   GISEL_VECREDUCE_CASES_NONSEQ
     return lowerVectorReduction(MI);
   }
@@ -7419,3 +7426,544 @@
   }
   return UnableToLegalize;;
 }
+
+static bool shouldLowerMemFuncForSize(const MachineFunction &MF) {
+  // On Darwin, -Os means optimize for size without hurting performance, so
+  // only really optimize for size when -Oz (MinSize) is used.
+  if (MF.getTarget().getTargetTriple().isOSDarwin())
+    return MF.getFunction().hasMinSize();
+  return MF.getFunction().hasOptSize();
+}
+
+// Returns a list of types to use for memory op lowering in MemOps. A partial
+// port of findOptimalMemOpLowering in TargetLowering.
+static bool findGISelOptimalMemOpLowering(std::vector<LLT> &MemOps,
+                                          unsigned Limit, const MemOp &Op,
+                                          unsigned DstAS, unsigned SrcAS,
+                                          const AttributeList &FuncAttributes,
+                                          const TargetLowering &TLI) {
+  if (Op.isMemcpyWithFixedDstAlign() && Op.getSrcAlign() < Op.getDstAlign())
+    return false;
+
+  LLT Ty = TLI.getOptimalMemOpLLT(Op, FuncAttributes);
+
+  if (Ty == LLT()) {
+    // Use the largest scalar type whose alignment constraints are satisfied.
+    // We only need to check DstAlign here as SrcAlign is always greater or
+    // equal to DstAlign (or zero).
+    Ty = LLT::scalar(64);
+    if (Op.isFixedDstAlign())
+      while (Op.getDstAlign() < Ty.getSizeInBytes() &&
+             !TLI.allowsMisalignedMemoryAccesses(Ty, DstAS, Op.getDstAlign()))
+        Ty = LLT::scalar(Ty.getSizeInBytes());
+    assert(Ty.getSizeInBits() > 0 && "Could not find valid type");
+    // FIXME: check for the largest legal type we can load/store to.
+  }
+
+  unsigned NumMemOps = 0;
+  uint64_t Size = Op.size();
+  while (Size) {
+    unsigned TySize = Ty.getSizeInBytes();
+    while (TySize > Size) {
+      // For now, only use non-vector load / store's for the left-over pieces.
+      LLT NewTy = Ty;
+      // FIXME: check for mem op safety and legality of the types. Not all of
+      // SDAGisms map cleanly to GISel concepts.
+      if (NewTy.isVector())
+        NewTy = NewTy.getSizeInBits() > 64 ? LLT::scalar(64) : LLT::scalar(32);
+      NewTy = LLT::scalar(PowerOf2Floor(NewTy.getSizeInBits() - 1));
+      unsigned NewTySize = NewTy.getSizeInBytes();
+      assert(NewTySize > 0 && "Could not find appropriate type");
+
+      // If the new LLT cannot cover all of the remaining bits, then consider
+      // issuing a (or a pair of) unaligned and overlapping load / store.
+      bool Fast;
+      // Need to get a VT equivalent for allowMisalignedMemoryAccesses().
+      MVT VT = getMVTForLLT(Ty);
+      if (NumMemOps && Op.allowOverlap() && NewTySize < Size &&
+          TLI.allowsMisalignedMemoryAccesses(
+              VT, DstAS, Op.isFixedDstAlign() ? Op.getDstAlign() : Align(1),
+              MachineMemOperand::MONone, &Fast) &&
+          Fast)
+        TySize = Size;
+      else {
+        Ty = NewTy;
+        TySize = NewTySize;
+      }
+    }
+
+    if (++NumMemOps > Limit)
+      return false;
+
+    MemOps.push_back(Ty);
+    Size -= TySize;
+  }
+
+  return true;
+}
+
+static Type *getTypeForLLT(LLT Ty, LLVMContext &C) {
+  if (Ty.isVector())
+    return FixedVectorType::get(IntegerType::get(C, Ty.getScalarSizeInBits()),
+                                Ty.getNumElements());
+  return IntegerType::get(C, Ty.getSizeInBits());
+}
+
+// Get a vectorized representation of the memset value operand, GISel edition.
+static Register getMemsetValue(Register Val, LLT Ty, MachineIRBuilder &MIB) {
+  MachineRegisterInfo &MRI = *MIB.getMRI();
+  unsigned NumBits = Ty.getScalarSizeInBits();
+  auto ValVRegAndVal = getConstantVRegValWithLookThrough(Val, MRI);
+  if (!Ty.isVector() && ValVRegAndVal) {
+    APInt Scalar = ValVRegAndVal->Value.truncOrSelf(8);
+    APInt SplatVal = APInt::getSplat(NumBits, Scalar);
+    return MIB.buildConstant(Ty, SplatVal).getReg(0);
+  }
+
+  // Extend the byte value to the larger type, and then multiply by a magic
+  // value 0x010101... in order to replicate it across every byte.
+  // Unless it's zero, in which case just emit a larger G_CONSTANT 0.
+  if (ValVRegAndVal && ValVRegAndVal->Value == 0) {
+    return MIB.buildConstant(Ty, 0).getReg(0);
+  }
+
+  LLT ExtType = Ty.getScalarType();
+  auto ZExt = MIB.buildZExtOrTrunc(ExtType, Val);
+  if (NumBits > 8) {
+    APInt Magic = APInt::getSplat(NumBits, APInt(8, 0x01));
+    auto MagicMI = MIB.buildConstant(ExtType, Magic);
+    Val = MIB.buildMul(ExtType, ZExt, MagicMI).getReg(0);
+  }
+
+  // For vector types create a G_BUILD_VECTOR.
+  if (Ty.isVector())
+    Val = MIB.buildSplatVector(Ty, Val).getReg(0);
+
+  return Val;
+}
+
+LegalizerHelper::LegalizeResult
+LegalizerHelper::lowerMemset(MachineInstr &MI, Register Dst, Register Val,
+                             uint64_t KnownLen, Align Alignment,
+                             bool IsVolatile) {
+  auto &MF = *MI.getParent()->getParent();
+  const auto &TLI = *MF.getSubtarget().getTargetLowering();
+  auto &DL = MF.getDataLayout();
+  LLVMContext &C = MF.getFunction().getContext();
+
+  assert(KnownLen != 0 && "Have a zero length memset length!");
+
+  bool DstAlignCanChange = false;
+  MachineFrameInfo &MFI = MF.getFrameInfo();
+  bool OptSize = shouldLowerMemFuncForSize(MF);
+
+  MachineInstr *FIDef = getOpcodeDef(TargetOpcode::G_FRAME_INDEX, Dst, MRI);
+  if (FIDef && !MFI.isFixedObjectIndex(FIDef->getOperand(1).getIndex()))
+    DstAlignCanChange = true;
+
+  unsigned Limit = TLI.getMaxStoresPerMemset(OptSize);
+  std::vector<LLT> MemOps;
+
+  const auto &DstMMO = **MI.memoperands_begin();
+  MachinePointerInfo DstPtrInfo = DstMMO.getPointerInfo();
+
+  auto ValVRegAndVal = getConstantVRegValWithLookThrough(Val, MRI);
+  bool IsZeroVal = ValVRegAndVal && ValVRegAndVal->Value == 0;
+
+  if (!findGISelOptimalMemOpLowering(MemOps, Limit,
+                                     MemOp::Set(KnownLen, DstAlignCanChange,
+                                                Alignment,
+                                                /*IsZeroMemset=*/IsZeroVal,
+                                                /*IsVolatile=*/IsVolatile),
+                                     DstPtrInfo.getAddrSpace(), ~0u,
+                                     MF.getFunction().getAttributes(), TLI))
+    return UnableToLegalize;
+
+  if (DstAlignCanChange) {
+    // Get an estimate of the type from the LLT.
+    Type *IRTy = getTypeForLLT(MemOps[0], C);
+    Align NewAlign = DL.getABITypeAlign(IRTy);
+    if (NewAlign > Alignment) {
+      Alignment = NewAlign;
+      unsigned FI = FIDef->getOperand(1).getIndex();
+      // Give the stack frame object a larger alignment if needed.
+      if (MFI.getObjectAlign(FI) < Alignment)
+        MFI.setObjectAlignment(FI, Alignment);
+    }
+  }
+
+  MachineIRBuilder MIB(MI);
+  // Find the largest store and generate the bit pattern for it.
+  LLT LargestTy = MemOps[0];
+  for (unsigned i = 1; i < MemOps.size(); i++)
+    if (MemOps[i].getSizeInBits() > LargestTy.getSizeInBits())
+      LargestTy = MemOps[i];
+
+  // The memset stored value is always defined as an s8, so in order to make it
+  // work with larger store types we need to repeat the bit pattern across the
+  // wider type.
+  Register MemSetValue = getMemsetValue(Val, LargestTy, MIB);
+
+  if (!MemSetValue)
+    return UnableToLegalize;
+
+  // Generate the stores. For each store type in the list, we generate the
+  // matching store of that type to the destination address.
+  LLT PtrTy = MRI.getType(Dst);
+  unsigned DstOff = 0;
+  unsigned Size = KnownLen;
+  for (unsigned I = 0; I < MemOps.size(); I++) {
+    LLT Ty = MemOps[I];
+    unsigned TySize = Ty.getSizeInBytes();
+    if (TySize > Size) {
+      // Issuing an unaligned load / store pair that overlaps with the previous
+      // pair. Adjust the offset accordingly.
+      assert(I == MemOps.size() - 1 && I != 0);
+      DstOff -= TySize - Size;
+    }
+
+    // If this store is smaller than the largest store see whether we can get
+    // the smaller value for free with a truncate.
+    Register Value = MemSetValue;
+    if (Ty.getSizeInBits() < LargestTy.getSizeInBits()) {
+      MVT VT = getMVTForLLT(Ty);
+      MVT LargestVT = getMVTForLLT(LargestTy);
+      if (!LargestTy.isVector() && !Ty.isVector() &&
+          TLI.isTruncateFree(LargestVT, VT))
+        Value = MIB.buildTrunc(Ty, MemSetValue).getReg(0);
+      else
+        Value = getMemsetValue(Val, Ty, MIB);
+      if (!Value)
+        return UnableToLegalize;
+    }
+
+    auto *StoreMMO = MF.getMachineMemOperand(&DstMMO, DstOff, Ty);
+
+    Register Ptr = Dst;
+    if (DstOff != 0) {
+      auto Offset =
+          MIB.buildConstant(LLT::scalar(PtrTy.getSizeInBits()), DstOff);
+      Ptr = MIB.buildPtrAdd(PtrTy, Dst, Offset).getReg(0);
+    }
+
+    MIB.buildStore(Value, Ptr, *StoreMMO);
+    DstOff += Ty.getSizeInBytes();
+    Size -= TySize;
+  }
+
+  MI.eraseFromParent();
+  return Legalized;
+}
+
+LegalizerHelper::LegalizeResult
+LegalizerHelper::lowerMemcpyInline(MachineInstr &MI) {
+  assert(MI.getOpcode() == TargetOpcode::G_MEMCPY_INLINE);
+
+  Register Dst = MI.getOperand(0).getReg();
+  Register Src = MI.getOperand(1).getReg();
+  Register Len = MI.getOperand(2).getReg();
+
+  const auto *MMOIt = MI.memoperands_begin();
+  const MachineMemOperand *MemOp = *MMOIt;
+  bool IsVolatile = MemOp->isVolatile();
+
+  // See if this is a constant length copy
+  auto LenVRegAndVal = getConstantVRegValWithLookThrough(Len, MRI);
+  // FIXME: support dynamically sized G_MEMCPY_INLINE
+  assert(LenVRegAndVal.hasValue() &&
+         "inline memcpy with dynamic size is not yet supported");
+  uint64_t KnownLen = LenVRegAndVal->Value.getZExtValue();
+  if (KnownLen == 0) {
+    MI.eraseFromParent();
+    return Legalized;
+  }
+
+  const auto &DstMMO = **MI.memoperands_begin();
+  const auto &SrcMMO = **std::next(MI.memoperands_begin());
+  Align DstAlign = DstMMO.getBaseAlign();
+  Align SrcAlign = SrcMMO.getBaseAlign();
+
+  return lowerMemcpyInline(MI, Dst, Src, KnownLen, DstAlign, SrcAlign,
+                           IsVolatile);
+}
+
+LegalizerHelper::LegalizeResult
+LegalizerHelper::lowerMemcpyInline(MachineInstr &MI, Register Dst, Register Src,
+                                   uint64_t KnownLen, Align DstAlign,
+                                   Align SrcAlign, bool IsVolatile) {
+  assert(MI.getOpcode() == TargetOpcode::G_MEMCPY_INLINE);
+  return lowerMemcpy(MI, Dst, Src, KnownLen,
+                     std::numeric_limits<uint64_t>::max(), DstAlign, SrcAlign,
+                     IsVolatile);
+}
+
+LegalizerHelper::LegalizeResult
+LegalizerHelper::lowerMemcpy(MachineInstr &MI, Register Dst, Register Src,
+                             uint64_t KnownLen, uint64_t Limit, Align DstAlign,
+                             Align SrcAlign, bool IsVolatile) {
+  auto &MF = *MI.getParent()->getParent();
+  const auto &TLI = *MF.getSubtarget().getTargetLowering();
+  auto &DL = MF.getDataLayout();
+  LLVMContext &C = MF.getFunction().getContext();
+
+  assert(KnownLen != 0 && "Have a zero length memcpy length!");
+
+  bool DstAlignCanChange = false;
+  MachineFrameInfo &MFI = MF.getFrameInfo();
+  Align Alignment = commonAlignment(DstAlign, SrcAlign);
+
+  MachineInstr *FIDef = getOpcodeDef(TargetOpcode::G_FRAME_INDEX, Dst, MRI);
+  if (FIDef && !MFI.isFixedObjectIndex(FIDef->getOperand(1).getIndex()))
+    DstAlignCanChange = true;
+
+  // FIXME: infer better src pointer alignment like SelectionDAG does here.
+  // FIXME: also use the equivalent of isMemSrcFromConstant and alwaysinlining
+  // if the memcpy is in a tail call position.
+
+  std::vector<LLT> MemOps;
+
+  const auto &DstMMO = **MI.memoperands_begin();
+  const auto &SrcMMO = **std::next(MI.memoperands_begin());
+  MachinePointerInfo DstPtrInfo = DstMMO.getPointerInfo();
+  MachinePointerInfo SrcPtrInfo = SrcMMO.getPointerInfo();
+
+  if (!findGISelOptimalMemOpLowering(
+          MemOps, Limit,
+          MemOp::Copy(KnownLen, DstAlignCanChange, Alignment, SrcAlign,
+                      IsVolatile),
+          DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
+          MF.getFunction().getAttributes(), TLI))
+    return UnableToLegalize;
+
+  if (DstAlignCanChange) {
+    // Get an estimate of the type from the LLT.
+    Type *IRTy = getTypeForLLT(MemOps[0], C);
+    Align NewAlign = DL.getABITypeAlign(IRTy);
+
+    // Don't promote to an alignment that would require dynamic stack
+    // realignment.
+    const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
+    if (!TRI->hasStackRealignment(MF))
+      while (NewAlign > Alignment && DL.exceedsNaturalStackAlignment(NewAlign))
+        NewAlign = NewAlign / 2;
+
+    if (NewAlign > Alignment) {
+      Alignment = NewAlign;
+      unsigned FI = FIDef->getOperand(1).getIndex();
+      // Give the stack frame object a larger alignment if needed.
+      if (MFI.getObjectAlign(FI) < Alignment)
+        MFI.setObjectAlignment(FI, Alignment);
+    }
+  }
+
+  LLVM_DEBUG(dbgs() << "Inlining memcpy: " << MI << " into loads & stores\n");
+
+  MachineIRBuilder MIB(MI);
+  // Now we need to emit a pair of load and stores for each of the types we've
+  // collected. I.e. for each type, generate a load from the source pointer of
+  // that type width, and then generate a corresponding store to the dest buffer
+  // of that value loaded. This can result in a sequence of loads and stores
+  // mixed types, depending on what the target specifies as good types to use.
+  unsigned CurrOffset = 0;
+  LLT PtrTy = MRI.getType(Src);
+  unsigned Size = KnownLen;
+  for (auto CopyTy : MemOps) {
+    // Issuing an unaligned load / store pair  that overlaps with the previous
+    // pair. Adjust the offset accordingly.
+    if (CopyTy.getSizeInBytes() > Size)
+      CurrOffset -= CopyTy.getSizeInBytes() - Size;
+
+    // Construct MMOs for the accesses.
+    auto *LoadMMO =
+        MF.getMachineMemOperand(&SrcMMO, CurrOffset, CopyTy.getSizeInBytes());
+    auto *StoreMMO =
+        MF.getMachineMemOperand(&DstMMO, CurrOffset, CopyTy.getSizeInBytes());
+
+    // Create the load.
+    Register LoadPtr = Src;
+    Register Offset;
+    if (CurrOffset != 0) {
+      Offset = MIB.buildConstant(LLT::scalar(PtrTy.getSizeInBits()), CurrOffset)
+                   .getReg(0);
+      LoadPtr = MIB.buildPtrAdd(PtrTy, Src, Offset).getReg(0);
+    }
+    auto LdVal = MIB.buildLoad(CopyTy, LoadPtr, *LoadMMO);
+
+    // Create the store.
+    Register StorePtr =
+        CurrOffset == 0 ? Dst : MIB.buildPtrAdd(PtrTy, Dst, Offset).getReg(0);
+    MIB.buildStore(LdVal, StorePtr, *StoreMMO);
+    CurrOffset += CopyTy.getSizeInBytes();
+    Size -= CopyTy.getSizeInBytes();
+  }
+
+  MI.eraseFromParent();
+  return Legalized;
+}
+
+LegalizerHelper::LegalizeResult
+LegalizerHelper::lowerMemmove(MachineInstr &MI, Register Dst, Register Src,
+                              uint64_t KnownLen, Align DstAlign, Align SrcAlign,
+                              bool IsVolatile) {
+  auto &MF = *MI.getParent()->getParent();
+  const auto &TLI = *MF.getSubtarget().getTargetLowering();
+  auto &DL = MF.getDataLayout();
+  LLVMContext &C = MF.getFunction().getContext();
+
+  assert(KnownLen != 0 && "Have a zero length memmove length!");
+
+  bool DstAlignCanChange = false;
+  MachineFrameInfo &MFI = MF.getFrameInfo();
+  bool OptSize = shouldLowerMemFuncForSize(MF);
+  Align Alignment = commonAlignment(DstAlign, SrcAlign);
+
+  MachineInstr *FIDef = getOpcodeDef(TargetOpcode::G_FRAME_INDEX, Dst, MRI);
+  if (FIDef && !MFI.isFixedObjectIndex(FIDef->getOperand(1).getIndex()))
+    DstAlignCanChange = true;
+
+  unsigned Limit = TLI.getMaxStoresPerMemmove(OptSize);
+  std::vector<LLT> MemOps;
+
+  const auto &DstMMO = **MI.memoperands_begin();
+  const auto &SrcMMO = **std::next(MI.memoperands_begin());
+  MachinePointerInfo DstPtrInfo = DstMMO.getPointerInfo();
+  MachinePointerInfo SrcPtrInfo = SrcMMO.getPointerInfo();
+
+  // FIXME: SelectionDAG always passes false for 'AllowOverlap', apparently due
+  // to a bug in it's findOptimalMemOpLowering implementation. For now do the
+  // same thing here.
+  if (!findGISelOptimalMemOpLowering(
+          MemOps, Limit,
+          MemOp::Copy(KnownLen, DstAlignCanChange, Alignment, SrcAlign,
+                      /*IsVolatile*/ true),
+          DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
+          MF.getFunction().getAttributes(), TLI))
+    return UnableToLegalize;
+
+  if (DstAlignCanChange) {
+    // Get an estimate of the type from the LLT.
+    Type *IRTy = getTypeForLLT(MemOps[0], C);
+    Align NewAlign = DL.getABITypeAlign(IRTy);
+
+    // Don't promote to an alignment that would require dynamic stack
+    // realignment.
+    const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
+    if (!TRI->hasStackRealignment(MF))
+      while (NewAlign > Alignment && DL.exceedsNaturalStackAlignment(NewAlign))
+        NewAlign = NewAlign / 2;
+
+    if (NewAlign > Alignment) {
+      Alignment = NewAlign;
+      unsigned FI = FIDef->getOperand(1).getIndex();
+      // Give the stack frame object a larger alignment if needed.
+      if (MFI.getObjectAlign(FI) < Alignment)
+        MFI.setObjectAlignment(FI, Alignment);
+    }
+  }
+
+  LLVM_DEBUG(dbgs() << "Inlining memmove: " << MI << " into loads & stores\n");
+
+  MachineIRBuilder MIB(MI);
+  // Memmove requires that we perform the loads first before issuing the stores.
+  // Apart from that, this loop is pretty much doing the same thing as the
+  // memcpy codegen function.
+  unsigned CurrOffset = 0;
+  LLT PtrTy = MRI.getType(Src);
+  SmallVector<Register, 16> LoadVals;
+  for (auto CopyTy : MemOps) {
+    // Construct MMO for the load.
+    auto *LoadMMO =
+        MF.getMachineMemOperand(&SrcMMO, CurrOffset, CopyTy.getSizeInBytes());
+
+    // Create the load.
+    Register LoadPtr = Src;
+    if (CurrOffset != 0) {
+      auto Offset =
+          MIB.buildConstant(LLT::scalar(PtrTy.getSizeInBits()), CurrOffset);
+      LoadPtr = MIB.buildPtrAdd(PtrTy, Src, Offset).getReg(0);
+    }
+    LoadVals.push_back(MIB.buildLoad(CopyTy, LoadPtr, *LoadMMO).getReg(0));
+    CurrOffset += CopyTy.getSizeInBytes();
+  }
+
+  CurrOffset = 0;
+  for (unsigned I = 0; I < MemOps.size(); ++I) {
+    LLT CopyTy = MemOps[I];
+    // Now store the values loaded.
+    auto *StoreMMO =
+        MF.getMachineMemOperand(&DstMMO, CurrOffset, CopyTy.getSizeInBytes());
+
+    Register StorePtr = Dst;
+    if (CurrOffset != 0) {
+      auto Offset =
+          MIB.buildConstant(LLT::scalar(PtrTy.getSizeInBits()), CurrOffset);
+      StorePtr = MIB.buildPtrAdd(PtrTy, Dst, Offset).getReg(0);
+    }
+    MIB.buildStore(LoadVals[I], StorePtr, *StoreMMO);
+    CurrOffset += CopyTy.getSizeInBytes();
+  }
+  MI.eraseFromParent();
+  return Legalized;
+}
+
+LegalizerHelper::LegalizeResult
+LegalizerHelper::lowerMemCpyFamily(MachineInstr &MI, unsigned MaxLen) {
+  const unsigned Opc = MI.getOpcode();
+  // This combine is fairly complex so it's not written with a separate
+  // matcher function.
+  assert((Opc == TargetOpcode::G_MEMCPY || Opc == TargetOpcode::G_MEMMOVE ||
+          Opc == TargetOpcode::G_MEMSET) &&
+         "Expected memcpy like instruction");
+
+  auto MMOIt = MI.memoperands_begin();
+  const MachineMemOperand *MemOp = *MMOIt;
+
+  Align DstAlign = MemOp->getBaseAlign();
+  Align SrcAlign;
+  Register Dst = MI.getOperand(0).getReg();
+  Register Src = MI.getOperand(1).getReg();
+  Register Len = MI.getOperand(2).getReg();
+
+  if (Opc != TargetOpcode::G_MEMSET) {
+    assert(MMOIt != MI.memoperands_end() && "Expected a second MMO on MI");
+    MemOp = *(++MMOIt);
+    SrcAlign = MemOp->getBaseAlign();
+  }
+
+  // See if this is a constant length copy
+  auto LenVRegAndVal = getConstantVRegValWithLookThrough(Len, MRI);
+  if (!LenVRegAndVal)
+    return UnableToLegalize;
+  uint64_t KnownLen = LenVRegAndVal->Value.getZExtValue();
+
+  if (KnownLen == 0) {
+    MI.eraseFromParent();
+    return Legalized;
+  }
+
+  bool IsVolatile = MemOp->isVolatile();
+  if (Opc == TargetOpcode::G_MEMCPY_INLINE)
+    return lowerMemcpyInline(MI, Dst, Src, KnownLen, DstAlign, SrcAlign,
+                             IsVolatile);
+
+  // Don't try to optimize volatile.
+  if (IsVolatile)
+    return UnableToLegalize;
+
+  if (MaxLen && KnownLen > MaxLen)
+    return UnableToLegalize;
+
+  if (Opc == TargetOpcode::G_MEMCPY) {
+    auto &MF = *MI.getParent()->getParent();
+    const auto &TLI = *MF.getSubtarget().getTargetLowering();
+    bool OptSize = shouldLowerMemFuncForSize(MF);
+    uint64_t Limit = TLI.getMaxStoresPerMemcpy(OptSize);
+    return lowerMemcpy(MI, Dst, Src, KnownLen, Limit, DstAlign, SrcAlign,
+                       IsVolatile);
+  }
+  if (Opc == TargetOpcode::G_MEMMOVE)
+    return lowerMemmove(MI, Dst, Src, KnownLen, DstAlign, SrcAlign, IsVolatile);
+  if (Opc == TargetOpcode::G_MEMSET)
+    return lowerMemset(MI, Dst, Src, KnownLen, DstAlign, IsVolatile);
+  return UnableToLegalize;
+}
diff --git a/llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp b/llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
--- a/llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
@@ -1679,6 +1679,9 @@
        // TODO: Implement
       G_FMINIMUM, G_FMAXIMUM}).lower();
 
+  getActionDefinitionsBuilder({G_MEMCPY, G_MEMCPY_INLINE, G_MEMMOVE, G_MEMSET})
+      .lower();
+
   getActionDefinitionsBuilder({G_VASTART, G_VAARG, G_BRJT, G_JUMP_TABLE,
         G_INDEXED_LOAD, G_INDEXED_SEXTLOAD,
         G_INDEXED_ZEXTLOAD, G_INDEXED_STORE})
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUPreLegalizerCombiner.cpp b/llvm/lib/Target/AMDGPU/AMDGPUPreLegalizerCombiner.cpp
--- a/llvm/lib/Target/AMDGPU/AMDGPUPreLegalizerCombiner.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUPreLegalizerCombiner.cpp
@@ -205,8 +205,6 @@
     return true;
 
   switch (MI.getOpcode()) {
-  case TargetOpcode::G_MEMCPY_INLINE:
-    return Helper.tryEmitMemcpyInline(MI);
   case TargetOpcode::G_CONCAT_VECTORS:
     return Helper.tryCombineConcatVectors(MI);
   case TargetOpcode::G_SHUFFLE_VECTOR:
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memcpy.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memcpy.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memcpy.mir
@@ -0,0 +1,32 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-- -run-pass=legalizer -verify-machineinstrs -o - %s | FileCheck %s
+
+---
+name:            memcpy_test
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1, $vgpr2, $vgpr3
+
+    ; CHECK-LABEL: name: memcpy_test
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $vgpr1
+    ; CHECK: [[MV:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY]](s32), [[COPY1]](s32)
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $vgpr2
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY $vgpr3
+    ; CHECK: [[MV1:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY2]](s32), [[COPY3]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; CHECK: [[LOAD:%[0-9]+]]:_(s32) = G_LOAD [[MV1]](p0) :: (load (s8))
+    ; CHECK: G_STORE [[LOAD]](s32), [[MV]](p0) :: (store (s8))
+    ; CHECK: S_ENDPGM 0
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = COPY $vgpr1
+    %2:_(p0) = G_MERGE_VALUES %0:_(s32), %1:_(s32)
+    %3:_(s32) = COPY $vgpr2
+    %4:_(s32) = COPY $vgpr3
+    %5:_(p0) = G_MERGE_VALUES %3:_(s32), %4:_(s32)
+    %6:_(s32) = G_CONSTANT i32 1
+    %7:_(s64) = G_ZEXT %6:_(s32)
+    G_MEMCPY %2:_(p0), %5:_(p0), %7:_(s64), 0 :: (store (s8)), (load (s8))
+    S_ENDPGM 0
+
+...
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memcpyinline.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memcpyinline.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memcpyinline.mir
@@ -0,0 +1,32 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-- -run-pass=legalizer -verify-machineinstrs -o - %s | FileCheck %s
+
+---
+name:            memcpyinline_test
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1, $vgpr2, $vgpr3
+
+    ; CHECK-LABEL: name: memcpyinline_test
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $vgpr1
+    ; CHECK: [[MV:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY]](s32), [[COPY1]](s32)
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $vgpr2
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY $vgpr3
+    ; CHECK: [[MV1:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY2]](s32), [[COPY3]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; CHECK: [[LOAD:%[0-9]+]]:_(s32) = G_LOAD [[MV1]](p0) :: (load (s8))
+    ; CHECK: G_STORE [[LOAD]](s32), [[MV]](p0) :: (store (s8))
+    ; CHECK: S_ENDPGM 0
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = COPY $vgpr1
+    %2:_(p0) = G_MERGE_VALUES %0:_(s32), %1:_(s32)
+    %3:_(s32) = COPY $vgpr2
+    %4:_(s32) = COPY $vgpr3
+    %5:_(p0) = G_MERGE_VALUES %3:_(s32), %4:_(s32)
+    %6:_(s32) = G_CONSTANT i32 1
+    %7:_(s64) = G_ZEXT %6:_(s32)
+    G_MEMCPY_INLINE %2:_(p0), %5:_(p0), %7:_(s64) :: (store (s8)), (load (s8))
+    S_ENDPGM 0
+
+...
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memmove.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memmove.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memmove.mir
@@ -0,0 +1,32 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-- -run-pass=legalizer -verify-machineinstrs -o - %s | FileCheck %s
+
+---
+name:            memmove_test
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1, $vgpr2, $vgpr3
+
+    ; CHECK-LABEL: name: memmove_test
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $vgpr1
+    ; CHECK: [[MV:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY]](s32), [[COPY1]](s32)
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $vgpr2
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY $vgpr3
+    ; CHECK: [[MV1:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY2]](s32), [[COPY3]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; CHECK: [[LOAD:%[0-9]+]]:_(s32) = G_LOAD [[MV1]](p0) :: (load (s8))
+    ; CHECK: G_STORE [[LOAD]](s32), [[MV]](p0) :: (store (s8))
+    ; CHECK: S_ENDPGM 0
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = COPY $vgpr1
+    %2:_(p0) = G_MERGE_VALUES %0:_(s32), %1:_(s32)
+    %3:_(s32) = COPY $vgpr2
+    %4:_(s32) = COPY $vgpr3
+    %5:_(p0) = G_MERGE_VALUES %3:_(s32), %4:_(s32)
+    %6:_(s32) = G_CONSTANT i32 1
+    %7:_(s64) = G_ZEXT %6:_(s32)
+    G_MEMMOVE %2:_(p0), %5:_(p0), %7:_(s64), 0 :: (store (s8)), (load (s8))
+    S_ENDPGM 0
+
+...
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memset.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memset.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-memset.mir
@@ -0,0 +1,31 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-- -run-pass=legalizer -verify-machineinstrs -o - %s | FileCheck %s
+
+---
+name:            memset_test
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1, $vgpr2
+
+    ; CHECK-LABEL: name: memset_test
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $vgpr1
+    ; CHECK: [[MV:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY]](s32), [[COPY1]](s32)
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $vgpr2
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s8) = G_TRUNC [[COPY2]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s8) = COPY [[TRUNC]](s8)
+    ; CHECK: G_STORE [[COPY2]](s32), [[MV]](p0) :: (store (s8))
+    ; CHECK: S_ENDPGM 0
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = COPY $vgpr1
+    %2:_(p0) = G_MERGE_VALUES %0:_(s32), %1:_(s32)
+    %3:_(s32) = COPY $vgpr2
+    %4:_(s16) = G_TRUNC %3:_(s32)
+    %5:_(s8) = G_TRUNC %4:_(s16)
+    %6:_(s32) = G_CONSTANT i32 1
+    %7:_(s64) = G_ZEXT %6:_(s32)
+    G_MEMSET %2:_(p0), %5:_(s8), %7:_(s64), 0 :: (store (s8))
+    S_ENDPGM 0
+
+...
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memcpy.inline.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memcpy.inline.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memcpy.inline.ll
@@ -0,0 +1,30 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -global-isel -march=amdgcn -verify-machineinstrs -amdgpu-mem-intrinsic-expand-size=3 %s -o - | FileCheck -check-prefix=GCN %s
+; RUN: llc -global-isel -march=amdgcn -verify-machineinstrs -amdgpu-mem-intrinsic-expand-size=5 %s -o - | FileCheck -check-prefix=GCN %s
+
+declare void @llvm.memcpy.inline.p1i8.p1i8.i32(i8 addrspace(1)*, i8 addrspace(1)*, i32, i1 immarg)
+
+define amdgpu_cs void @test(i8 addrspace(1)* %dst, i8 addrspace(1)* %src) {
+; GCN-LABEL: test:
+; GCN:       ; %bb.0:
+; GCN-NEXT:    s_mov_b32 s2, 0
+; GCN-NEXT:    s_mov_b32 s3, 0xf000
+; GCN-NEXT:    s_mov_b64 s[0:1], 0
+; GCN-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64
+; GCN-NEXT:    s_waitcnt vmcnt(0)
+; GCN-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64
+; GCN-NEXT:    s_waitcnt expcnt(0)
+; GCN-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:1
+; GCN-NEXT:    s_waitcnt vmcnt(0)
+; GCN-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:1
+; GCN-NEXT:    s_waitcnt expcnt(0)
+; GCN-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:2
+; GCN-NEXT:    s_waitcnt vmcnt(0)
+; GCN-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:2
+; GCN-NEXT:    buffer_load_ubyte v2, v[2:3], s[0:3], 0 addr64 offset:3
+; GCN-NEXT:    s_waitcnt vmcnt(0)
+; GCN-NEXT:    buffer_store_byte v2, v[0:1], s[0:3], 0 addr64 offset:3
+; GCN-NEXT:    s_endpgm
+  call void @llvm.memcpy.inline.p1i8.p1i8.i32(i8 addrspace(1)* %dst, i8 addrspace(1)* %src, i32 4, i1 false)
+  ret void
+}
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memcpy.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memcpy.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memcpy.ll
@@ -0,0 +1,181 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -global-isel -march=amdgcn -verify-machineinstrs -amdgpu-mem-intrinsic-expand-size=19 %s -o - | FileCheck -check-prefix=LOOP %s
+; RUN: llc -global-isel -march=amdgcn -verify-machineinstrs -amdgpu-mem-intrinsic-expand-size=21 %s -o - | FileCheck -check-prefix=UNROLL %s
+
+declare void @llvm.memcpy.p1i8.p1i8.i32(i8 addrspace(1)*, i8 addrspace(1)*, i32, i1 immarg)
+
+define amdgpu_cs void @memcpy_p1i8(i8 addrspace(1)* %dst, i8 addrspace(1)* %src) {
+; LOOP-LABEL: memcpy_p1i8:
+; LOOP:       ; %bb.0:
+; LOOP-NEXT:    s_mov_b32 s6, 0
+; LOOP-NEXT:    s_mov_b32 s7, 0xf000
+; LOOP-NEXT:    s_mov_b64 s[4:5], 0
+; LOOP-NEXT:    v_mov_b32_e32 v5, v3
+; LOOP-NEXT:    v_mov_b32_e32 v4, v2
+; LOOP-NEXT:    v_mov_b32_e32 v7, v1
+; LOOP-NEXT:    v_mov_b32_e32 v6, v0
+; LOOP-NEXT:    v_mov_b32_e32 v8, s6
+; LOOP-NEXT:  BB0_1: ; %load-store-loop
+; LOOP-NEXT:    ; =>This Inner Loop Header: Depth=1
+; LOOP-NEXT:    buffer_load_ubyte v9, v[4:5], s[4:7], 0 addr64
+; LOOP-NEXT:    buffer_load_ubyte v10, v[4:5], s[4:7], 0 addr64 offset:1
+; LOOP-NEXT:    buffer_load_ubyte v11, v[4:5], s[4:7], 0 addr64 offset:2
+; LOOP-NEXT:    buffer_load_ubyte v12, v[4:5], s[4:7], 0 addr64 offset:3
+; LOOP-NEXT:    buffer_load_ubyte v13, v[4:5], s[4:7], 0 addr64 offset:4
+; LOOP-NEXT:    buffer_load_ubyte v14, v[4:5], s[4:7], 0 addr64 offset:5
+; LOOP-NEXT:    buffer_load_ubyte v15, v[4:5], s[4:7], 0 addr64 offset:6
+; LOOP-NEXT:    buffer_load_ubyte v16, v[4:5], s[4:7], 0 addr64 offset:7
+; LOOP-NEXT:    buffer_load_ubyte v17, v[4:5], s[4:7], 0 addr64 offset:8
+; LOOP-NEXT:    s_waitcnt expcnt(6)
+; LOOP-NEXT:    buffer_load_ubyte v18, v[4:5], s[4:7], 0 addr64 offset:9
+; LOOP-NEXT:    s_waitcnt expcnt(5)
+; LOOP-NEXT:    buffer_load_ubyte v19, v[4:5], s[4:7], 0 addr64 offset:10
+; LOOP-NEXT:    s_waitcnt expcnt(4)
+; LOOP-NEXT:    buffer_load_ubyte v20, v[4:5], s[4:7], 0 addr64 offset:11
+; LOOP-NEXT:    s_waitcnt expcnt(3)
+; LOOP-NEXT:    buffer_load_ubyte v21, v[4:5], s[4:7], 0 addr64 offset:12
+; LOOP-NEXT:    s_waitcnt expcnt(2)
+; LOOP-NEXT:    buffer_load_ubyte v22, v[4:5], s[4:7], 0 addr64 offset:13
+; LOOP-NEXT:    s_waitcnt expcnt(1)
+; LOOP-NEXT:    buffer_load_ubyte v23, v[4:5], s[4:7], 0 addr64 offset:14
+; LOOP-NEXT:    s_waitcnt expcnt(0)
+; LOOP-NEXT:    buffer_load_ubyte v24, v[4:5], s[4:7], 0 addr64 offset:15
+; LOOP-NEXT:    v_add_i32_e32 v8, vcc, 1, v8
+; LOOP-NEXT:    s_xor_b64 s[0:1], vcc, -1
+; LOOP-NEXT:    s_xor_b64 s[0:1], s[0:1], -1
+; LOOP-NEXT:    s_and_b64 vcc, s[0:1], exec
+; LOOP-NEXT:    s_waitcnt vmcnt(14)
+; LOOP-NEXT:    buffer_store_byte v9, v[6:7], s[4:7], 0 addr64
+; LOOP-NEXT:    buffer_store_byte v10, v[6:7], s[4:7], 0 addr64 offset:1
+; LOOP-NEXT:    s_waitcnt vmcnt(14)
+; LOOP-NEXT:    buffer_store_byte v11, v[6:7], s[4:7], 0 addr64 offset:2
+; LOOP-NEXT:    buffer_store_byte v12, v[6:7], s[4:7], 0 addr64 offset:3
+; LOOP-NEXT:    s_waitcnt vmcnt(14)
+; LOOP-NEXT:    buffer_store_byte v13, v[6:7], s[4:7], 0 addr64 offset:4
+; LOOP-NEXT:    buffer_store_byte v14, v[6:7], s[4:7], 0 addr64 offset:5
+; LOOP-NEXT:    s_waitcnt vmcnt(14)
+; LOOP-NEXT:    buffer_store_byte v15, v[6:7], s[4:7], 0 addr64 offset:6
+; LOOP-NEXT:    buffer_store_byte v16, v[6:7], s[4:7], 0 addr64 offset:7
+; LOOP-NEXT:    s_waitcnt vmcnt(14)
+; LOOP-NEXT:    buffer_store_byte v17, v[6:7], s[4:7], 0 addr64 offset:8
+; LOOP-NEXT:    buffer_store_byte v18, v[6:7], s[4:7], 0 addr64 offset:9
+; LOOP-NEXT:    s_waitcnt vmcnt(14)
+; LOOP-NEXT:    buffer_store_byte v19, v[6:7], s[4:7], 0 addr64 offset:10
+; LOOP-NEXT:    buffer_store_byte v20, v[6:7], s[4:7], 0 addr64 offset:11
+; LOOP-NEXT:    s_waitcnt vmcnt(14)
+; LOOP-NEXT:    buffer_store_byte v21, v[6:7], s[4:7], 0 addr64 offset:12
+; LOOP-NEXT:    buffer_store_byte v22, v[6:7], s[4:7], 0 addr64 offset:13
+; LOOP-NEXT:    s_waitcnt vmcnt(14)
+; LOOP-NEXT:    buffer_store_byte v23, v[6:7], s[4:7], 0 addr64 offset:14
+; LOOP-NEXT:    buffer_store_byte v24, v[6:7], s[4:7], 0 addr64 offset:15
+; LOOP-NEXT:    v_add_i32_e64 v6, s[0:1], 16, v6
+; LOOP-NEXT:    v_addc_u32_e64 v7, s[0:1], 0, v7, s[0:1]
+; LOOP-NEXT:    v_add_i32_e64 v4, s[0:1], 16, v4
+; LOOP-NEXT:    v_addc_u32_e64 v5, s[0:1], 0, v5, s[0:1]
+; LOOP-NEXT:    s_cbranch_vccnz BB0_1
+; LOOP-NEXT:  ; %bb.2: ; %memcpy-split
+; LOOP-NEXT:    s_mov_b32 s2, 0
+; LOOP-NEXT:    s_mov_b32 s3, 0xf000
+; LOOP-NEXT:    s_mov_b64 s[0:1], 0
+; LOOP-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:16
+; LOOP-NEXT:    buffer_load_ubyte v5, v[2:3], s[0:3], 0 addr64 offset:17
+; LOOP-NEXT:    buffer_load_ubyte v6, v[2:3], s[0:3], 0 addr64 offset:18
+; LOOP-NEXT:    buffer_load_ubyte v2, v[2:3], s[0:3], 0 addr64 offset:19
+; LOOP-NEXT:    s_waitcnt vmcnt(3)
+; LOOP-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:16
+; LOOP-NEXT:    s_waitcnt vmcnt(3)
+; LOOP-NEXT:    buffer_store_byte v5, v[0:1], s[0:3], 0 addr64 offset:17
+; LOOP-NEXT:    s_waitcnt vmcnt(3)
+; LOOP-NEXT:    buffer_store_byte v6, v[0:1], s[0:3], 0 addr64 offset:18
+; LOOP-NEXT:    s_waitcnt vmcnt(3)
+; LOOP-NEXT:    buffer_store_byte v2, v[0:1], s[0:3], 0 addr64 offset:19
+; LOOP-NEXT:    s_endpgm
+;
+; UNROLL-LABEL: memcpy_p1i8:
+; UNROLL:       ; %bb.0:
+; UNROLL-NEXT:    s_mov_b32 s2, 0
+; UNROLL-NEXT:    s_mov_b32 s3, 0xf000
+; UNROLL-NEXT:    s_mov_b64 s[0:1], 0
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:1
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:1
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:2
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:2
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:3
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:3
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:4
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:4
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:5
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:5
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:6
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:6
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:7
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:7
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:8
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:8
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:9
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:9
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:10
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:10
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:11
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:11
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:12
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:12
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:13
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:13
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:14
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:14
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:15
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:15
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:16
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:16
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:17
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:17
+; UNROLL-NEXT:    s_waitcnt expcnt(0)
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64 offset:18
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64 offset:18
+; UNROLL-NEXT:    buffer_load_ubyte v2, v[2:3], s[0:3], 0 addr64 offset:19
+; UNROLL-NEXT:    s_waitcnt vmcnt(0)
+; UNROLL-NEXT:    buffer_store_byte v2, v[0:1], s[0:3], 0 addr64 offset:19
+; UNROLL-NEXT:    s_endpgm
+  call void @llvm.memcpy.p1i8.p1i8.i32(i8 addrspace(1)* %dst, i8 addrspace(1)* %src, i32 20, i1 false)
+  ret void
+}
+
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memmove.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memmove.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memmove.ll
@@ -0,0 +1,82 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -global-isel -march=amdgcn -verify-machineinstrs -amdgpu-mem-intrinsic-expand-size=3 %s -o - | FileCheck -check-prefix=LOOP %s
+; RUN: llc -global-isel -march=amdgcn -verify-machineinstrs -amdgpu-mem-intrinsic-expand-size=5 %s -o - | FileCheck -check-prefix=UNROLL %s
+
+declare void @llvm.memmove.p1i8.p1i8.i32(i8 addrspace(1)*, i8 addrspace(1)*, i32, i1)
+
+define amdgpu_cs void @memmove_p1i8(i8 addrspace(1)* %dst, i8 addrspace(1)* %src) {
+; LOOP-LABEL: memmove_p1i8:
+; LOOP:       ; %bb.0:
+; LOOP-NEXT:    v_cmp_ge_u64_e32 vcc, v[2:3], v[0:1]
+; LOOP-NEXT:    s_and_saveexec_b64 s[0:1], vcc
+; LOOP-NEXT:    s_xor_b64 s[4:5], exec, s[0:1]
+; LOOP-NEXT:    s_cbranch_execz BB0_3
+; LOOP-NEXT:  ; %bb.1: ; %copy_forward
+; LOOP-NEXT:    s_mov_b64 s[0:1], 0
+; LOOP-NEXT:    s_mov_b32 s2, 0
+; LOOP-NEXT:    s_mov_b32 s3, 0xf000
+; LOOP-NEXT:    v_mov_b32_e32 v5, s1
+; LOOP-NEXT:    v_mov_b32_e32 v4, s0
+; LOOP-NEXT:  BB0_2: ; %copy_forward_loop
+; LOOP-NEXT:    ; =>This Inner Loop Header: Depth=1
+; LOOP-NEXT:    v_add_i32_e32 v6, vcc, v2, v4
+; LOOP-NEXT:    v_addc_u32_e32 v7, vcc, v3, v5, vcc
+; LOOP-NEXT:    s_waitcnt expcnt(0)
+; LOOP-NEXT:    buffer_load_ubyte v8, v[6:7], s[0:3], 0 addr64
+; LOOP-NEXT:    v_add_i32_e32 v6, vcc, v0, v4
+; LOOP-NEXT:    v_addc_u32_e32 v7, vcc, v1, v5, vcc
+; LOOP-NEXT:    v_add_i32_e32 v4, vcc, 1, v4
+; LOOP-NEXT:    v_addc_u32_e32 v5, vcc, 0, v5, vcc
+; LOOP-NEXT:    v_cmp_ne_u32_e32 vcc, 4, v4
+; LOOP-NEXT:    s_waitcnt vmcnt(0)
+; LOOP-NEXT:    buffer_store_byte v8, v[6:7], s[0:3], 0 addr64
+; LOOP-NEXT:    s_cbranch_vccnz BB0_2
+; LOOP-NEXT:  BB0_3: ; %Flow14
+; LOOP-NEXT:    s_or_saveexec_b64 s[0:1], s[4:5]
+; LOOP-NEXT:    s_xor_b64 exec, exec, s[0:1]
+; LOOP-NEXT:    s_cbranch_execz BB0_6
+; LOOP-NEXT:  ; %bb.4: ; %copy_backwards
+; LOOP-NEXT:    s_mov_b64 s[4:5], 3
+; LOOP-NEXT:    s_mov_b32 s2, 0
+; LOOP-NEXT:    s_mov_b32 s3, 0xf000
+; LOOP-NEXT:    s_mov_b64 s[0:1], 0
+; LOOP-NEXT:    v_mov_b32_e32 v4, s4
+; LOOP-NEXT:    v_mov_b32_e32 v5, s5
+; LOOP-NEXT:  BB0_5: ; %copy_backwards_loop
+; LOOP-NEXT:    ; =>This Inner Loop Header: Depth=1
+; LOOP-NEXT:    v_add_i32_e32 v6, vcc, v2, v4
+; LOOP-NEXT:    v_addc_u32_e32 v7, vcc, v3, v5, vcc
+; LOOP-NEXT:    s_waitcnt expcnt(0)
+; LOOP-NEXT:    buffer_load_ubyte v8, v[6:7], s[0:3], 0 addr64
+; LOOP-NEXT:    v_add_i32_e32 v6, vcc, v0, v4
+; LOOP-NEXT:    v_addc_u32_e32 v7, vcc, v1, v5, vcc
+; LOOP-NEXT:    v_add_i32_e32 v4, vcc, -1, v4
+; LOOP-NEXT:    v_addc_u32_e32 v5, vcc, -1, v5, vcc
+; LOOP-NEXT:    v_cmp_eq_u32_e32 vcc, -1, v4
+; LOOP-NEXT:    s_waitcnt vmcnt(0)
+; LOOP-NEXT:    buffer_store_byte v8, v[6:7], s[0:3], 0 addr64
+; LOOP-NEXT:    s_cbranch_vccz BB0_5
+; LOOP-NEXT:  BB0_6: ; %memmove_done
+; LOOP-NEXT:    s_endpgm
+;
+; UNROLL-LABEL: memmove_p1i8:
+; UNROLL:       ; %bb.0:
+; UNROLL-NEXT:    s_mov_b32 s2, 0
+; UNROLL-NEXT:    s_mov_b32 s3, 0xf000
+; UNROLL-NEXT:    s_mov_b64 s[0:1], 0
+; UNROLL-NEXT:    buffer_load_ubyte v4, v[2:3], s[0:3], 0 addr64
+; UNROLL-NEXT:    buffer_load_ubyte v5, v[2:3], s[0:3], 0 addr64 offset:1
+; UNROLL-NEXT:    buffer_load_ubyte v6, v[2:3], s[0:3], 0 addr64 offset:2
+; UNROLL-NEXT:    buffer_load_ubyte v2, v[2:3], s[0:3], 0 addr64 offset:3
+; UNROLL-NEXT:    s_waitcnt vmcnt(3)
+; UNROLL-NEXT:    buffer_store_byte v4, v[0:1], s[0:3], 0 addr64
+; UNROLL-NEXT:    s_waitcnt vmcnt(3)
+; UNROLL-NEXT:    buffer_store_byte v5, v[0:1], s[0:3], 0 addr64 offset:1
+; UNROLL-NEXT:    s_waitcnt vmcnt(3)
+; UNROLL-NEXT:    buffer_store_byte v6, v[0:1], s[0:3], 0 addr64 offset:2
+; UNROLL-NEXT:    s_waitcnt vmcnt(3)
+; UNROLL-NEXT:    buffer_store_byte v2, v[0:1], s[0:3], 0 addr64 offset:3
+; UNROLL-NEXT:    s_endpgm
+  call void @llvm.memmove.p1i8.p1i8.i32(i8 addrspace(1)* %dst, i8 addrspace(1)* %src, i32 4, i1 false)
+  ret void
+}
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memset.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memset.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.memset.ll
@@ -0,0 +1,39 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -global-isel -march=amdgcn -verify-machineinstrs -amdgpu-mem-intrinsic-expand-size=3 %s -o - | FileCheck -check-prefix=LOOP %s
+; RUN: llc -global-isel -march=amdgcn -verify-machineinstrs -amdgpu-mem-intrinsic-expand-size=5 %s -o - | FileCheck -check-prefix=UNROLL %s
+
+declare void @llvm.memset.p1i8.i32(i8 addrspace(1)*, i8, i32, i1)
+
+define amdgpu_cs void @memset_p1i8(i8 addrspace(1)* %dst, i8 %val) {
+; LOOP-LABEL: memset_p1i8:
+; LOOP:       ; %bb.0: ; %loadstoreloop.preheader
+; LOOP-NEXT:    s_mov_b64 s[0:1], 0
+; LOOP-NEXT:    s_mov_b32 s2, 0
+; LOOP-NEXT:    s_mov_b32 s3, 0xf000
+; LOOP-NEXT:    v_mov_b32_e32 v4, s1
+; LOOP-NEXT:    v_mov_b32_e32 v3, s0
+; LOOP-NEXT:  BB0_1: ; %loadstoreloop
+; LOOP-NEXT:    ; =>This Inner Loop Header: Depth=1
+; LOOP-NEXT:    v_add_i32_e32 v5, vcc, v0, v3
+; LOOP-NEXT:    v_addc_u32_e32 v6, vcc, v1, v4, vcc
+; LOOP-NEXT:    v_add_i32_e32 v3, vcc, 1, v3
+; LOOP-NEXT:    v_addc_u32_e32 v4, vcc, 0, v4, vcc
+; LOOP-NEXT:    v_cmp_gt_u32_e32 vcc, 4, v3
+; LOOP-NEXT:    buffer_store_byte v2, v[5:6], s[0:3], 0 addr64
+; LOOP-NEXT:    s_cbranch_vccnz BB0_1
+; LOOP-NEXT:  ; %bb.2: ; %split
+; LOOP-NEXT:    s_endpgm
+;
+; UNROLL-LABEL: memset_p1i8:
+; UNROLL:       ; %bb.0:
+; UNROLL-NEXT:    s_mov_b32 s2, 0
+; UNROLL-NEXT:    s_mov_b32 s3, 0xf000
+; UNROLL-NEXT:    s_mov_b64 s[0:1], 0
+; UNROLL-NEXT:    buffer_store_byte v2, v[0:1], s[0:3], 0 addr64
+; UNROLL-NEXT:    buffer_store_byte v2, v[0:1], s[0:3], 0 addr64 offset:1
+; UNROLL-NEXT:    buffer_store_byte v2, v[0:1], s[0:3], 0 addr64 offset:2
+; UNROLL-NEXT:    buffer_store_byte v2, v[0:1], s[0:3], 0 addr64 offset:3
+; UNROLL-NEXT:    s_endpgm
+  call void @llvm.memset.p1i8.i32(i8 addrspace(1)* %dst, i8 %val, i32 4, i1 false)
+  ret void
+}
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/prelegalizer-combiner-memcpy-inline.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/prelegalizer-combiner-memcpy-inline.mir
deleted file mode 100644
--- a/llvm/test/CodeGen/AMDGPU/GlobalISel/prelegalizer-combiner-memcpy-inline.mir
+++ /dev/null
@@ -1,81 +0,0 @@
-# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
-# RUN: llc -global-isel -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -run-pass=amdgpu-prelegalizer-combiner -verify-machineinstrs -o - %s | FileCheck %s
---- |
-  target datalayout = "e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-S32-A5-G1-ni:7"
-  target triple = "amdgcn-amd-amdhsa"
-
-  declare void @llvm.memcpy.inline.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64 immarg, i1 immarg) #0
-
-  define void @test_memcpy_inline(i32* nocapture %dst, i32* nocapture readonly %src) local_unnamed_addr #1 {
-  entry:
-    %0 = bitcast i32* %dst to i8*
-    %1 = bitcast i32* %src to i8*
-    tail call void @llvm.memcpy.inline.p0i8.p0i8.i64(i8* align 4 %0, i8* align 4 %1, i64 13, i1 false)
-    ret void
-  }
-
-  attributes #0 = { argmemonly nofree nounwind willreturn "target-cpu"="gfx900" }
-  attributes #1 = { "target-cpu"="gfx900" }
-
-...
----
-name:            test_memcpy_inline
-alignment:       1
-tracksRegLiveness: true
-registers:
-  - { id: 0, class: _ }
-  - { id: 1, class: _ }
-  - { id: 2, class: sgpr_64 }
-  - { id: 3, class: _ }
-  - { id: 4, class: _ }
-  - { id: 5, class: _ }
-  - { id: 6, class: _ }
-  - { id: 7, class: _ }
-  - { id: 8, class: ccr_sgpr_64 }
-liveins:
-  - { reg: '$sgpr30_sgpr31', virtual-reg: '%2' }
-frameInfo:
-  maxAlignment:    1
-machineFunctionInfo:
-  maxKernArgAlign: 1
-  scratchRSrcReg:  '$sgpr0_sgpr1_sgpr2_sgpr3'
-  frameOffsetReg:  '$sgpr33'
-  stackPtrOffsetReg: '$sgpr32'
-  argumentInfo:
-    privateSegmentBuffer: { reg: '$sgpr0_sgpr1_sgpr2_sgpr3' }
-  occupancy:       10
-body:             |
-  bb.1.entry:
-    liveins: $vgpr0, $vgpr1, $vgpr2, $vgpr3, $sgpr30_sgpr31
-
-    ; CHECK-LABEL: name: test_memcpy_inline
-    ; CHECK: liveins: $vgpr0, $vgpr1, $vgpr2, $vgpr3, $sgpr30_sgpr31
-    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
-    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $vgpr1
-    ; CHECK: [[MV:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY]](s32), [[COPY1]](s32)
-    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $vgpr2
-    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY $vgpr3
-    ; CHECK: [[MV1:%[0-9]+]]:_(p0) = G_MERGE_VALUES [[COPY2]](s32), [[COPY3]](s32)
-    ; CHECK: [[COPY4:%[0-9]+]]:sgpr_64 = COPY $sgpr30_sgpr31
-    ; CHECK: [[LOAD:%[0-9]+]]:_(s64) = G_LOAD [[MV1]](p0) :: (load (s64) from %ir.1, align 4)
-    ; CHECK: G_STORE [[LOAD]](s64), [[MV]](p0) :: (store (s64) into %ir.0, align 4)
-    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 5
-    ; CHECK: [[PTR_ADD:%[0-9]+]]:_(p0) = G_PTR_ADD [[MV1]], [[C]](s64)
-    ; CHECK: [[LOAD1:%[0-9]+]]:_(s64) = G_LOAD [[PTR_ADD]](p0) :: (load (s64) from %ir.1 + 5, align 1, basealign 4)
-    ; CHECK: [[PTR_ADD1:%[0-9]+]]:_(p0) = G_PTR_ADD [[MV]], [[C]](s64)
-    ; CHECK: G_STORE [[LOAD1]](s64), [[PTR_ADD1]](p0) :: (store (s64) into %ir.0 + 5, align 1, basealign 4)
-    ; CHECK: [[COPY5:%[0-9]+]]:ccr_sgpr_64 = COPY [[COPY4]]
-    ; CHECK: S_SETPC_B64_return [[COPY5]]
-    %3:_(s32) = COPY $vgpr0
-    %4:_(s32) = COPY $vgpr1
-    %0:_(p0) = G_MERGE_VALUES %3(s32), %4(s32)
-    %5:_(s32) = COPY $vgpr2
-    %6:_(s32) = COPY $vgpr3
-    %1:_(p0) = G_MERGE_VALUES %5(s32), %6(s32)
-    %2:sgpr_64 = COPY $sgpr30_sgpr31
-    %7:_(s64) = G_CONSTANT i64 13
-    G_MEMCPY_INLINE %0(p0), %1(p0), %7(s64) :: (store (s8) into %ir.0, align 4), (load (s8) from %ir.1, align 4)
-    %8:ccr_sgpr_64 = COPY %2
-    S_SETPC_B64_return %8
-
-...