diff --git a/llvm/include/llvm/CodeGen/TargetLowering.h b/llvm/include/llvm/CodeGen/TargetLowering.h
--- a/llvm/include/llvm/CodeGen/TargetLowering.h
+++ b/llvm/include/llvm/CodeGen/TargetLowering.h
@@ -106,6 +106,49 @@
 
 } // end namespace Sched
 
+// MemOp models a memory operation, either memset or memcpy/memmove.
+struct MemOp {
+  // Shared
+  uint64_t Size;
+  unsigned DstAlign; // Specified alignment of the memory operation or zero if
+                     // destination alignment can satisfy any constraint.
+  bool AllowOverlap;
+  // memset only
+  bool IsMemset;   // If setthis memory operation is a memset.
+  bool ZeroMemset; // If set clears out memory with zeros.
+  // memcpy only
+  bool MemcpyStrSrc; // Indicates whether the memcpy source is an in-register
+                     // constant so it does not need to be loaded.
+  unsigned SrcAlign; // Inferred alignment of the source or zero if the memory
+                     // operation does not need to load the value.
+
+  static MemOp Copy(uint64_t Size, bool DstAlignCanChange, unsigned DstAlign,
+                    unsigned SrcAlign, bool IsVolatile,
+                    bool MemcpyStrSrc = false) {
+    return {
+        /*.Size =*/Size,
+        /*.DstAlign =*/DstAlignCanChange ? 0 : DstAlign,
+        /*.AllowOverlap =*/!IsVolatile,
+        /*.IsMemset =*/false,
+        /*.ZeroMemset =*/false,
+        /*.MemcpyStrSrc =*/MemcpyStrSrc,
+        /*.SrcAlign =*/SrcAlign,
+    };
+  }
+  static MemOp Set(uint64_t Size, bool DstAlignCanChange, unsigned DstAlign,
+                   bool IsZeroMemset, bool IsVolatile) {
+    return {
+        /*.Size =*/Size,
+        /*.DstAlign =*/DstAlignCanChange ? 0 : DstAlign,
+        /*.AllowOverlap =*/!IsVolatile,
+        /*.IsMemset =*/true,
+        /*.ZeroMemset =*/IsZeroMemset,
+        /*.MemcpyStrSrc =*/false,
+        /*.SrcAlign =*/0,
+    };
+  }
+};
+
 /// This base class for TargetLowering contains the SelectionDAG-independent
 /// parts that can be used from the rest of CodeGen.
 class TargetLoweringBase {
@@ -1518,29 +1561,17 @@
 
   /// Returns the target specific optimal type for load and store operations as
   /// a result of memset, memcpy, and memmove lowering.
-  ///
-  /// If DstAlign is zero that means it's safe to destination alignment can
-  /// satisfy any constraint. Similarly if SrcAlign is zero it means there isn't
-  /// a need to check it against alignment requirement, probably because the
-  /// source does not need to be loaded. If 'IsMemset' is true, that means it's
-  /// expanding a memset. If 'ZeroMemset' is true, that means it's a memset of
-  /// zero. 'MemcpyStrSrc' indicates whether the memcpy source is constant so it
-  /// does not need to be loaded.  It returns EVT::Other if the type should be
-  /// determined using generic target-independent logic.
+  /// It returns EVT::Other if the type should be determined using generic
+  /// target-independent logic.
   virtual EVT
-  getOptimalMemOpType(uint64_t /*Size*/, unsigned /*DstAlign*/,
-                      unsigned /*SrcAlign*/, bool /*IsMemset*/,
-                      bool /*ZeroMemset*/, bool /*MemcpyStrSrc*/,
+  getOptimalMemOpType(const MemOp &Op,
                       const AttributeList & /*FuncAttributes*/) const {
     return MVT::Other;
   }
 
-
   /// LLT returning variant.
   virtual LLT
-  getOptimalMemOpLLT(uint64_t /*Size*/, unsigned /*DstAlign*/,
-                     unsigned /*SrcAlign*/, bool /*IsMemset*/,
-                     bool /*ZeroMemset*/, bool /*MemcpyStrSrc*/,
+  getOptimalMemOpLLT(const MemOp &Op,
                      const AttributeList & /*FuncAttributes*/) const {
     return LLT();
   }
@@ -3102,14 +3133,8 @@
   /// Return true if the number of memory ops is below the threshold (Limit).
   /// It returns the types of the sequence of memory ops to perform
   /// memset / memcpy by reference.
-  bool findOptimalMemOpLowering(std::vector<EVT> &MemOps,
-                                unsigned Limit, uint64_t Size,
-                                unsigned DstAlign, unsigned SrcAlign,
-                                bool IsMemset,
-                                bool ZeroMemset,
-                                bool MemcpyStrSrc,
-                                bool AllowOverlap,
-                                unsigned DstAS, unsigned SrcAS,
+  bool findOptimalMemOpLowering(std::vector<EVT> &MemOps, unsigned Limit,
+                                const MemOp &Op, unsigned DstAS, unsigned SrcAS,
                                 const AttributeList &FuncAttributes) const;
 
   /// Check to see if the specified operand of the specified instruction is a
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
@@ -855,37 +855,30 @@
 
 // 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, uint64_t Size, unsigned DstAlign,
-    unsigned SrcAlign, bool IsMemset, bool ZeroMemset, bool MemcpyStrSrc,
-    bool AllowOverlap, unsigned DstAS, unsigned SrcAS,
-    const AttributeList &FuncAttributes, const TargetLowering &TLI) {
-  // If 'SrcAlign' is zero, that means the memory operation does not need to
-  // load the value, i.e. memset or memcpy from constant string. Otherwise,
-  // it's the inferred alignment of the source. 'DstAlign', on the other hand,
-  // is the specified alignment of the memory operation. If it is zero, that
-  // means it's possible to change the alignment of the destination.
-  // 'MemcpyStrSrc' indicates whether the memcpy source is constant so it does
-  // not need to be loaded.
-  if (SrcAlign != 0 && SrcAlign < DstAlign)
+static bool findGISelOptimalMemOpLowering(std::vector<LLT> &MemOps,
+                                          unsigned Limit, const MemOp &Op,
+                                          unsigned DstAS, unsigned SrcAS,
+                                          const AttributeList &FuncAttributes,
+                                          const TargetLowering &TLI) {
+  if (Op.SrcAlign != 0 && Op.SrcAlign < Op.DstAlign)
     return false;
 
-  LLT Ty = TLI.getOptimalMemOpLLT(Size, DstAlign, SrcAlign, IsMemset,
-                                  ZeroMemset, MemcpyStrSrc, FuncAttributes);
+  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);
-    while (DstAlign && DstAlign < Ty.getSizeInBytes() &&
-           !TLI.allowsMisalignedMemoryAccesses(Ty, DstAS, DstAlign))
+    while (Op.DstAlign && Op.DstAlign < Ty.getSizeInBytes() &&
+           !TLI.allowsMisalignedMemoryAccesses(Ty, DstAS, Op.DstAlign))
       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;
+  auto Size = Op.Size;
   while (Size != 0) {
     unsigned TySize = Ty.getSizeInBytes();
     while (TySize > Size) {
@@ -904,9 +897,9 @@
       bool Fast;
       // Need to get a VT equivalent for allowMisalignedMemoryAccesses().
       MVT VT = getMVTForLLT(Ty);
-      if (NumMemOps && AllowOverlap && NewTySize < Size &&
+      if (NumMemOps && Op.AllowOverlap && NewTySize < Size &&
           TLI.allowsMisalignedMemoryAccesses(
-              VT, DstAS, DstAlign, MachineMemOperand::MONone, &Fast) &&
+              VT, DstAS, Op.DstAlign, MachineMemOperand::MONone, &Fast) &&
           Fast)
         TySize = Size;
       else {
@@ -988,12 +981,13 @@
   auto ValVRegAndVal = getConstantVRegValWithLookThrough(Val, MRI);
   bool IsZeroVal = ValVRegAndVal && ValVRegAndVal->Value == 0;
 
-  if (!findGISelOptimalMemOpLowering(
-          MemOps, Limit, KnownLen, (DstAlignCanChange ? 0 : Align), 0,
-          /*IsMemset=*/true,
-          /*ZeroMemset=*/IsZeroVal, /*MemcpyStrSrc=*/false,
-          /*AllowOverlap=*/!IsVolatile, DstPtrInfo.getAddrSpace(), ~0u,
-          MF.getFunction().getAttributes(), TLI))
+  if (!findGISelOptimalMemOpLowering(MemOps, Limit,
+                                     MemOp::Set(KnownLen, DstAlignCanChange,
+                                                Align,
+                                                /*IsZeroMemset=*/IsZeroVal,
+                                                /*IsVolatile=*/IsVolatile),
+                                     DstPtrInfo.getAddrSpace(), ~0u,
+                                     MF.getFunction().getAttributes(), TLI))
     return false;
 
   if (DstAlignCanChange) {
@@ -1107,12 +1101,11 @@
   MachinePointerInfo SrcPtrInfo = SrcMMO.getPointerInfo();
 
   if (!findGISelOptimalMemOpLowering(
-          MemOps, Limit, KnownLen, (DstAlignCanChange ? 0 : Alignment),
-          SrcAlign,
-          /*IsMemset=*/false,
-          /*ZeroMemset=*/false, /*MemcpyStrSrc=*/false,
-          /*AllowOverlap=*/!IsVolatile, DstPtrInfo.getAddrSpace(),
-          SrcPtrInfo.getAddrSpace(), MF.getFunction().getAttributes(), TLI))
+          MemOps, Limit,
+          MemOp::Copy(KnownLen, DstAlignCanChange, Alignment, SrcAlign,
+                      IsVolatile),
+          DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
+          MF.getFunction().getAttributes(), TLI))
     return false;
 
   if (DstAlignCanChange) {
@@ -1214,12 +1207,11 @@
   // to a bug in it's findOptimalMemOpLowering implementation. For now do the
   // same thing here.
   if (!findGISelOptimalMemOpLowering(
-          MemOps, Limit, KnownLen, (DstAlignCanChange ? 0 : Alignment),
-          SrcAlign,
-          /*IsMemset=*/false,
-          /*ZeroMemset=*/false, /*MemcpyStrSrc=*/false,
-          /*AllowOverlap=*/false, DstPtrInfo.getAddrSpace(),
-          SrcPtrInfo.getAddrSpace(), MF.getFunction().getAttributes(), TLI))
+          MemOps, Limit,
+          MemOp::Copy(KnownLen, DstAlignCanChange, Alignment, SrcAlign,
+                      /*IsVolatile*/ true),
+          DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
+          MF.getFunction().getAttributes(), TLI))
     return false;
 
   if (DstAlignCanChange) {
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5908,13 +5908,12 @@
   bool CopyFromConstant = isMemSrcFromConstant(Src, Slice);
   bool isZeroConstant = CopyFromConstant && Slice.Array == nullptr;
   unsigned Limit = AlwaysInline ? ~0U : TLI.getMaxStoresPerMemcpy(OptSize);
-
   if (!TLI.findOptimalMemOpLowering(
-          MemOps, Limit, Size, (DstAlignCanChange ? 0 : Alignment),
-          (isZeroConstant ? 0 : SrcAlign), /*IsMemset=*/false,
-          /*ZeroMemset=*/false, /*MemcpyStrSrc=*/CopyFromConstant,
-          /*AllowOverlap=*/!isVol, DstPtrInfo.getAddrSpace(),
-          SrcPtrInfo.getAddrSpace(), MF.getFunction().getAttributes()))
+          MemOps, Limit,
+          MemOp::Copy(Size, DstAlignCanChange, Alignment,
+                      isZeroConstant ? 0 : SrcAlign, isVol, CopyFromConstant),
+          DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
+          MF.getFunction().getAttributes()))
     return SDValue();
 
   if (DstAlignCanChange) {
@@ -6088,14 +6087,11 @@
   if (Align > SrcAlign)
     SrcAlign = Align;
   unsigned Limit = AlwaysInline ? ~0U : TLI.getMaxStoresPerMemmove(OptSize);
-  // FIXME: `AllowOverlap` should really be `!isVol` but there is a bug in
-  // findOptimalMemOpLowering. Meanwhile, setting it to `false` produces the
-  // correct code.
-  bool AllowOverlap = false;
   if (!TLI.findOptimalMemOpLowering(
-          MemOps, Limit, Size, (DstAlignCanChange ? 0 : Align), SrcAlign,
-          /*IsMemset=*/false, /*ZeroMemset=*/false, /*MemcpyStrSrc=*/false,
-          AllowOverlap, DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
+          MemOps, Limit,
+          MemOp::Copy(Size, DstAlignCanChange, Align, SrcAlign,
+                      /*IsVolatile*/ true),
+          DstPtrInfo.getAddrSpace(), SrcPtrInfo.getAddrSpace(),
           MF.getFunction().getAttributes()))
     return SDValue();
 
@@ -6193,11 +6189,9 @@
   bool IsZeroVal =
     isa<ConstantSDNode>(Src) && cast<ConstantSDNode>(Src)->isNullValue();
   if (!TLI.findOptimalMemOpLowering(
-          MemOps, TLI.getMaxStoresPerMemset(OptSize), Size,
-          (DstAlignCanChange ? 0 : Align), 0, /*IsMemset=*/true,
-          /*ZeroMemset=*/IsZeroVal, /*MemcpyStrSrc=*/false,
-          /*AllowOverlap=*/!isVol, DstPtrInfo.getAddrSpace(), ~0u,
-          MF.getFunction().getAttributes()))
+          MemOps, TLI.getMaxStoresPerMemset(OptSize),
+          MemOp::Set(Size, DstAlignCanChange, Align, IsZeroVal, isVol),
+          DstPtrInfo.getAddrSpace(), ~0u, MF.getFunction().getAttributes()))
     return SDValue();
 
   if (DstAlignCanChange) {
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -176,16 +176,9 @@
   return LowerCallTo(CLI);
 }
 
-bool
-TargetLowering::findOptimalMemOpLowering(std::vector<EVT> &MemOps,
-                                         unsigned Limit, uint64_t Size,
-                                         unsigned DstAlign, unsigned SrcAlign,
-                                         bool IsMemset,
-                                         bool ZeroMemset,
-                                         bool MemcpyStrSrc,
-                                         bool AllowOverlap,
-                                         unsigned DstAS, unsigned SrcAS,
-                                         const AttributeList &FuncAttributes) const {
+bool TargetLowering::findOptimalMemOpLowering(
+    std::vector<EVT> &MemOps, unsigned Limit, const MemOp &Op, unsigned DstAS,
+    unsigned SrcAS, const AttributeList &FuncAttributes) const {
   // If 'SrcAlign' is zero, that means the memory operation does not need to
   // load the value, i.e. memset or memcpy from constant string. Otherwise,
   // it's the inferred alignment of the source. 'DstAlign', on the other hand,
@@ -193,20 +186,18 @@
   // means it's possible to change the alignment of the destination.
   // 'MemcpyStrSrc' indicates whether the memcpy source is constant so it does
   // not need to be loaded.
-  if (!(SrcAlign == 0 || SrcAlign >= DstAlign))
+  if (!(Op.SrcAlign == 0 || Op.SrcAlign >= Op.DstAlign))
     return false;
 
-  EVT VT = getOptimalMemOpType(Size, DstAlign, SrcAlign,
-                               IsMemset, ZeroMemset, MemcpyStrSrc,
-                               FuncAttributes);
+  EVT VT = getOptimalMemOpType(Op, FuncAttributes);
 
   if (VT == MVT::Other) {
     // Use the largest integer type whose alignment constraints are satisfied.
     // We only need to check DstAlign here as SrcAlign is always greater or
     // equal to DstAlign (or zero).
     VT = MVT::i64;
-    while (DstAlign && DstAlign < VT.getSizeInBits() / 8 &&
-           !allowsMisalignedMemoryAccesses(VT, DstAS, DstAlign))
+    while (Op.DstAlign && Op.DstAlign < VT.getSizeInBits() / 8 &&
+           !allowsMisalignedMemoryAccesses(VT, DstAS, Op.DstAlign))
       VT = (MVT::SimpleValueType)(VT.getSimpleVT().SimpleTy - 1);
     assert(VT.isInteger());
 
@@ -223,6 +214,7 @@
   }
 
   unsigned NumMemOps = 0;
+  auto Size = Op.Size;
   while (Size != 0) {
     unsigned VTSize = VT.getSizeInBits() / 8;
     while (VTSize > Size) {
@@ -257,8 +249,8 @@
       // If the new VT cannot cover all of the remaining bits, then consider
       // issuing a (or a pair of) unaligned and overlapping load / store.
       bool Fast;
-      if (NumMemOps && AllowOverlap && NewVTSize < Size &&
-          allowsMisalignedMemoryAccesses(VT, DstAS, DstAlign,
+      if (NumMemOps && Op.AllowOverlap && NewVTSize < Size &&
+          allowsMisalignedMemoryAccesses(VT, DstAS, Op.DstAlign,
                                          MachineMemOperand::MONone, &Fast) &&
           Fast)
         VTSize = Size;
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.h b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.h
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
@@ -428,13 +428,11 @@
 
   bool shouldConsiderGEPOffsetSplit() const override;
 
-  EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign, unsigned SrcAlign,
-                          bool IsMemset, bool ZeroMemset, bool MemcpyStrSrc,
+  EVT getOptimalMemOpType(const MemOp &Op,
                           const AttributeList &FuncAttributes) const override;
 
-  LLT getOptimalMemOpLLT(uint64_t Size, unsigned DstAlign, unsigned SrcAlign,
-                          bool IsMemset, bool ZeroMemset, bool MemcpyStrSrc,
-                          const AttributeList &FuncAttributes) const override;
+  LLT getOptimalMemOpLLT(const MemOp &Op,
+                         const AttributeList &FuncAttributes) const override;
 
   /// Return true if the addressing mode represented by AM is legal for this
   /// target, for a load/store of the specified type.
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -9426,9 +9426,7 @@
 }
 
 EVT AArch64TargetLowering::getOptimalMemOpType(
-    uint64_t Size, unsigned DstAlign, unsigned SrcAlign, bool IsMemset,
-    bool ZeroMemset, bool MemcpyStrSrc,
-    const AttributeList &FuncAttributes) const {
+    const MemOp &Op, const AttributeList &FuncAttributes) const {
   bool CanImplicitFloat =
       !FuncAttributes.hasFnAttribute(Attribute::NoImplicitFloat);
   bool CanUseNEON = Subtarget->hasNEON() && CanImplicitFloat;
@@ -9436,9 +9434,9 @@
   // Only use AdvSIMD to implement memset of 32-byte and above. It would have
   // taken one instruction to materialize the v2i64 zero and one store (with
   // restrictive addressing mode). Just do i64 stores.
-  bool IsSmallMemset = IsMemset && Size < 32;
+  bool IsSmallMemset = Op.IsMemset && Op.Size < 32;
   auto AlignmentIsAcceptable = [&](EVT VT, unsigned AlignCheck) {
-    if (memOpAlign(SrcAlign, DstAlign, AlignCheck))
+    if (memOpAlign(Op.SrcAlign, Op.DstAlign, AlignCheck))
       return true;
     bool Fast;
     return allowsMisalignedMemoryAccesses(VT, 0, 1, MachineMemOperand::MONone,
@@ -9446,22 +9444,20 @@
            Fast;
   };
 
-  if (CanUseNEON && IsMemset && !IsSmallMemset &&
+  if (CanUseNEON && Op.IsMemset && !IsSmallMemset &&
       AlignmentIsAcceptable(MVT::v2i64, 16))
     return MVT::v2i64;
   if (CanUseFP && !IsSmallMemset && AlignmentIsAcceptable(MVT::f128, 16))
     return MVT::f128;
-  if (Size >= 8 && AlignmentIsAcceptable(MVT::i64, 8))
+  if (Op.Size >= 8 && AlignmentIsAcceptable(MVT::i64, 8))
     return MVT::i64;
-  if (Size >= 4 && AlignmentIsAcceptable(MVT::i32, 4))
+  if (Op.Size >= 4 && AlignmentIsAcceptable(MVT::i32, 4))
     return MVT::i32;
   return MVT::Other;
 }
 
 LLT AArch64TargetLowering::getOptimalMemOpLLT(
-    uint64_t Size, unsigned DstAlign, unsigned SrcAlign, bool IsMemset,
-    bool ZeroMemset, bool MemcpyStrSrc,
-    const AttributeList &FuncAttributes) const {
+    const MemOp &Op, const AttributeList &FuncAttributes) const {
   bool CanImplicitFloat =
       !FuncAttributes.hasFnAttribute(Attribute::NoImplicitFloat);
   bool CanUseNEON = Subtarget->hasNEON() && CanImplicitFloat;
@@ -9469,9 +9465,9 @@
   // Only use AdvSIMD to implement memset of 32-byte and above. It would have
   // taken one instruction to materialize the v2i64 zero and one store (with
   // restrictive addressing mode). Just do i64 stores.
-  bool IsSmallMemset = IsMemset && Size < 32;
+  bool IsSmallMemset = Op.IsMemset && Op.Size < 32;
   auto AlignmentIsAcceptable = [&](EVT VT, unsigned AlignCheck) {
-    if (memOpAlign(SrcAlign, DstAlign, AlignCheck))
+    if (memOpAlign(Op.SrcAlign, Op.DstAlign, AlignCheck))
       return true;
     bool Fast;
     return allowsMisalignedMemoryAccesses(VT, 0, 1, MachineMemOperand::MONone,
@@ -9479,14 +9475,14 @@
            Fast;
   };
 
-  if (CanUseNEON && IsMemset && !IsSmallMemset &&
+  if (CanUseNEON && Op.IsMemset && !IsSmallMemset &&
       AlignmentIsAcceptable(MVT::v2i64, 16))
     return LLT::vector(2, 64);
   if (CanUseFP && !IsSmallMemset && AlignmentIsAcceptable(MVT::f128, 16))
     return LLT::scalar(128);
-  if (Size >= 8 && AlignmentIsAcceptable(MVT::i64, 8))
+  if (Op.Size >= 8 && AlignmentIsAcceptable(MVT::i64, 8))
     return LLT::scalar(64);
-  if (Size >= 4 && AlignmentIsAcceptable(MVT::i32, 4))
+  if (Op.Size >= 4 && AlignmentIsAcceptable(MVT::i32, 4))
     return LLT::scalar(32);
   return LLT();
 }
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.h b/llvm/lib/Target/AMDGPU/SIISelLowering.h
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.h
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.h
@@ -257,10 +257,7 @@
       MachineMemOperand::Flags Flags = MachineMemOperand::MONone,
       bool *IsFast = nullptr) const override;
 
-  EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign,
-                          unsigned SrcAlign, bool IsMemset,
-                          bool ZeroMemset,
-                          bool MemcpyStrSrc,
+  EVT getOptimalMemOpType(const MemOp &Op,
                           const AttributeList &FuncAttributes) const override;
 
   bool isMemOpUniform(const SDNode *N) const;
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -1320,18 +1320,16 @@
 }
 
 EVT SITargetLowering::getOptimalMemOpType(
-    uint64_t Size, unsigned DstAlign, unsigned SrcAlign, bool IsMemset,
-    bool ZeroMemset, bool MemcpyStrSrc,
-    const AttributeList &FuncAttributes) const {
+    const MemOp &Op, const AttributeList &FuncAttributes) const {
   // FIXME: Should account for address space here.
 
   // The default fallback uses the private pointer size as a guess for a type to
   // use. Make sure we switch these to 64-bit accesses.
 
-  if (Size >= 16 && DstAlign >= 4) // XXX: Should only do for global
+  if (Op.Size >= 16 && Op.DstAlign >= 4) // XXX: Should only do for global
     return MVT::v4i32;
 
-  if (Size >= 8 && DstAlign >= 4)
+  if (Op.Size >= 8 && Op.DstAlign >= 4)
     return MVT::v2i32;
 
   // Use the default.
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.h b/llvm/lib/Target/ARM/ARMISelLowering.h
--- a/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -347,10 +347,7 @@
                                         MachineMemOperand::Flags Flags,
                                         bool *Fast) const override;
 
-    EVT getOptimalMemOpType(uint64_t Size,
-                            unsigned DstAlign, unsigned SrcAlign,
-                            bool IsMemset, bool ZeroMemset,
-                            bool MemcpyStrSrc,
+    EVT getOptimalMemOpType(const MemOp &Op,
                             const AttributeList &FuncAttributes) const override;
 
     bool isTruncateFree(Type *SrcTy, Type *DstTy) const override;
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -14961,21 +14961,19 @@
 }
 
 EVT ARMTargetLowering::getOptimalMemOpType(
-    uint64_t Size, unsigned DstAlign, unsigned SrcAlign, bool IsMemset,
-    bool ZeroMemset, bool MemcpyStrSrc,
-    const AttributeList &FuncAttributes) const {
+    const MemOp &Op, const AttributeList &FuncAttributes) const {
   // See if we can use NEON instructions for this...
-  if ((!IsMemset || ZeroMemset) && Subtarget->hasNEON() &&
+  if ((!Op.IsMemset || Op.ZeroMemset) && Subtarget->hasNEON() &&
       !FuncAttributes.hasFnAttribute(Attribute::NoImplicitFloat)) {
     bool Fast;
-    if (Size >= 16 &&
-        (memOpAlign(SrcAlign, DstAlign, 16) ||
+    if (Op.Size >= 16 &&
+        (memOpAlign(Op.SrcAlign, Op.DstAlign, 16) ||
          (allowsMisalignedMemoryAccesses(MVT::v2f64, 0, 1,
                                          MachineMemOperand::MONone, &Fast) &&
           Fast))) {
       return MVT::v2f64;
-    } else if (Size >= 8 &&
-               (memOpAlign(SrcAlign, DstAlign, 8) ||
+    } else if (Op.Size >= 8 &&
+               (memOpAlign(Op.SrcAlign, Op.DstAlign, 8) ||
                 (allowsMisalignedMemoryAccesses(
                      MVT::f64, 0, 1, MachineMemOperand::MONone, &Fast) &&
                  Fast))) {
diff --git a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
--- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
@@ -576,8 +576,9 @@
   // loaded and stored. That's why we multiply the number of elements by 2 to
   // get the cost for this memcpy.
   if (getTLI()->findOptimalMemOpLowering(
-          MemOps, Limit, Size, DstAlign, SrcAlign, false /*IsMemset*/,
-          false /*ZeroMemset*/, false /*MemcpyStrSrc*/, false /*AllowOverlap*/,
+          MemOps, Limit,
+          MemOp::Copy(Size, /*DstAlignCanChange*/ false, DstAlign, SrcAlign,
+                      /*IsVolatile*/ true),
           MI->getDestAddressSpace(), MI->getSourceAddressSpace(),
           F->getAttributes()))
     return MemOps.size() * 2;
diff --git a/llvm/lib/Target/BPF/BPFISelLowering.h b/llvm/lib/Target/BPF/BPFISelLowering.h
--- a/llvm/lib/Target/BPF/BPFISelLowering.h
+++ b/llvm/lib/Target/BPF/BPFISelLowering.h
@@ -99,10 +99,9 @@
                       const SmallVectorImpl<SDValue> &OutVals, const SDLoc &DL,
                       SelectionDAG &DAG) const override;
 
-  EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign, unsigned SrcAlign,
-                          bool IsMemset, bool ZeroMemset, bool MemcpyStrSrc,
+  EVT getOptimalMemOpType(const MemOp &Op,
                           const AttributeList &FuncAttributes) const override {
-    return Size >= 8 ? MVT::i64 : MVT::i32;
+    return Op.Size >= 8 ? MVT::i64 : MVT::i32;
   }
 
   bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
diff --git a/llvm/lib/Target/Hexagon/HexagonISelLowering.h b/llvm/lib/Target/Hexagon/HexagonISelLowering.h
--- a/llvm/lib/Target/Hexagon/HexagonISelLowering.h
+++ b/llvm/lib/Target/Hexagon/HexagonISelLowering.h
@@ -302,9 +302,8 @@
     /// the immediate into a register.
     bool isLegalICmpImmediate(int64_t Imm) const override;
 
-    EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign,
-        unsigned SrcAlign, bool IsMemset, bool ZeroMemset, bool MemcpyStrSrc,
-        const AttributeList &FuncAttributes) const override;
+    EVT getOptimalMemOpType(const MemOp &Op,
+                            const AttributeList &FuncAttributes) const override;
 
     bool allowsMisalignedMemoryAccesses(EVT VT, unsigned AddrSpace,
         unsigned Align, MachineMemOperand::Flags Flags, bool *Fast)
diff --git a/llvm/lib/Target/Hexagon/HexagonISelLowering.cpp b/llvm/lib/Target/Hexagon/HexagonISelLowering.cpp
--- a/llvm/lib/Target/Hexagon/HexagonISelLowering.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonISelLowering.cpp
@@ -3379,19 +3379,21 @@
 /// zero. 'MemcpyStrSrc' indicates whether the memcpy source is constant so it
 /// does not need to be loaded.  It returns EVT::Other if the type should be
 /// determined using generic target-independent logic.
-EVT HexagonTargetLowering::getOptimalMemOpType(uint64_t Size,
-      unsigned DstAlign, unsigned SrcAlign, bool IsMemset, bool ZeroMemset,
-      bool MemcpyStrSrc, const AttributeList &FuncAttributes) const {
+EVT HexagonTargetLowering::getOptimalMemOpType(
+    const MemOp &Op, const AttributeList &FuncAttributes) const {
 
   auto Aligned = [](unsigned GivenA, unsigned MinA) -> bool {
     return (GivenA % MinA) == 0;
   };
 
-  if (Size >= 8 && Aligned(DstAlign, 8) && (IsMemset || Aligned(SrcAlign, 8)))
+  if (Op.Size >= 8 && Aligned(Op.DstAlign, 8) &&
+      (Op.IsMemset || Aligned(Op.SrcAlign, 8)))
     return MVT::i64;
-  if (Size >= 4 && Aligned(DstAlign, 4) && (IsMemset || Aligned(SrcAlign, 4)))
+  if (Op.Size >= 4 && Aligned(Op.DstAlign, 4) &&
+      (Op.IsMemset || Aligned(Op.SrcAlign, 4)))
     return MVT::i32;
-  if (Size >= 2 && Aligned(DstAlign, 2) && (IsMemset || Aligned(SrcAlign, 2)))
+  if (Op.Size >= 2 && Aligned(Op.DstAlign, 2) &&
+      (Op.IsMemset || Aligned(Op.SrcAlign, 2)))
     return MVT::i16;
 
   return MVT::Other;
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.h b/llvm/lib/Target/Mips/MipsISelLowering.h
--- a/llvm/lib/Target/Mips/MipsISelLowering.h
+++ b/llvm/lib/Target/Mips/MipsISelLowering.h
@@ -669,10 +669,7 @@
 
     bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const override;
 
-    EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign,
-                            unsigned SrcAlign,
-                            bool IsMemset, bool ZeroMemset,
-                            bool MemcpyStrSrc,
+    EVT getOptimalMemOpType(const MemOp &Op,
                             const AttributeList &FuncAttributes) const override;
 
     /// isFPImmLegal - Returns true if the target can instruction select the
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -4269,9 +4269,7 @@
 }
 
 EVT MipsTargetLowering::getOptimalMemOpType(
-    uint64_t Size, unsigned DstAlign, unsigned SrcAlign, bool IsMemset,
-    bool ZeroMemset, bool MemcpyStrSrc,
-    const AttributeList &FuncAttributes) const {
+    const MemOp &Op, const AttributeList &FuncAttributes) const {
   if (Subtarget.hasMips64())
     return MVT::i64;
 
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -892,21 +892,10 @@
                             MachineFunction &MF,
                             unsigned Intrinsic) const override;
 
-    /// getOptimalMemOpType - Returns the target specific optimal type for load
-    /// and store operations as a result of memset, memcpy, and memmove
-    /// lowering. If DstAlign is zero that means it's safe to destination
-    /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
-    /// means there isn't a need to check it against alignment requirement,
-    /// probably because the source does not need to be loaded. If 'IsMemset' is
-    /// true, that means it's expanding a memset. If 'ZeroMemset' is true, that
-    /// means it's a memset of zero. 'MemcpyStrSrc' indicates whether the memcpy
-    /// source is constant so it does not need to be loaded.
     /// It returns EVT::Other if the type should be determined using generic
     /// target-independent logic.
-    EVT
-    getOptimalMemOpType(uint64_t Size, unsigned DstAlign, unsigned SrcAlign,
-                        bool IsMemset, bool ZeroMemset, bool MemcpyStrSrc,
-                        const AttributeList &FuncAttributes) const override;
+    EVT getOptimalMemOpType(const MemOp &Op,
+                            const AttributeList &FuncAttributes) const override;
 
     /// Is unaligned memory access allowed for the given type, and is it fast
     /// relative to software emulation.
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
@@ -15069,35 +15069,27 @@
   return false;
 }
 
-/// getOptimalMemOpType - Returns the target specific optimal type for load
-/// and store operations as a result of memset, memcpy, and memmove
-/// lowering. If DstAlign is zero that means it's safe to destination
-/// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
-/// means there isn't a need to check it against alignment requirement,
-/// probably because the source does not need to be loaded. If 'IsMemset' is
-/// true, that means it's expanding a memset. If 'ZeroMemset' is true, that
-/// means it's a memset of zero. 'MemcpyStrSrc' indicates whether the memcpy
-/// source is constant so it does not need to be loaded.
 /// It returns EVT::Other if the type should be determined using generic
 /// target-independent logic.
 EVT PPCTargetLowering::getOptimalMemOpType(
-    uint64_t Size, unsigned DstAlign, unsigned SrcAlign, bool IsMemset,
-    bool ZeroMemset, bool MemcpyStrSrc,
-    const AttributeList &FuncAttributes) const {
+    const MemOp &Op, const AttributeList &FuncAttributes) const {
   if (getTargetMachine().getOptLevel() != CodeGenOpt::None) {
     // When expanding a memset, require at least two QPX instructions to cover
     // the cost of loading the value to be stored from the constant pool.
-    if (Subtarget.hasQPX() && Size >= 32 && (!IsMemset || Size >= 64) &&
-       (!SrcAlign || SrcAlign >= 32) && (!DstAlign || DstAlign >= 32) &&
+    if (Subtarget.hasQPX() && Op.Size >= 32 &&
+        (!Op.IsMemset || Op.Size >= 64) &&
+        (!Op.SrcAlign || Op.SrcAlign >= 32) &&
+        (!Op.DstAlign || Op.DstAlign >= 32) &&
         !FuncAttributes.hasFnAttribute(Attribute::NoImplicitFloat)) {
       return MVT::v4f64;
     }
 
     // We should use Altivec/VSX loads and stores when available. For unaligned
     // addresses, unaligned VSX loads are only fast starting with the P8.
-    if (Subtarget.hasAltivec() && Size >= 16 &&
-        (((!SrcAlign || SrcAlign >= 16) && (!DstAlign || DstAlign >= 16)) ||
-         ((IsMemset && Subtarget.hasVSX()) || Subtarget.hasP8Vector())))
+    if (Subtarget.hasAltivec() && Op.Size >= 16 &&
+        (((!Op.SrcAlign || Op.SrcAlign >= 16) &&
+          (!Op.DstAlign || Op.DstAlign >= 16)) ||
+         ((Op.IsMemset && Subtarget.hasVSX()) || Subtarget.hasP8Vector())))
       return MVT::v4i32;
   }
 
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -758,19 +758,7 @@
     unsigned getByValTypeAlignment(Type *Ty,
                                    const DataLayout &DL) const override;
 
-    /// Returns the target specific optimal type for load
-    /// and store operations as a result of memset, memcpy, and memmove
-    /// lowering. If DstAlign is zero that means it's safe to destination
-    /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
-    /// means there isn't a need to check it against alignment requirement,
-    /// probably because the source does not need to be loaded. If 'IsMemset' is
-    /// true, that means it's expanding a memset. If 'ZeroMemset' is true, that
-    /// means it's a memset of zero. 'MemcpyStrSrc' indicates whether the memcpy
-    /// source is constant so it does not need to be loaded.
-    /// It returns EVT::Other if the type should be determined using generic
-    /// target-independent logic.
-    EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign, unsigned SrcAlign,
-                            bool IsMemset, bool ZeroMemset, bool MemcpyStrSrc,
+    EVT getOptimalMemOpType(const MemOp &Op,
                             const AttributeList &FuncAttributes) const override;
 
     /// Returns true if it's safe to use load / store of the
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -2245,34 +2245,23 @@
   return Align;
 }
 
-/// Returns the target specific optimal type for load
-/// and store operations as a result of memset, memcpy, and memmove
-/// lowering. If DstAlign is zero that means it's safe to destination
-/// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
-/// means there isn't a need to check it against alignment requirement,
-/// probably because the source does not need to be loaded. If 'IsMemset' is
-/// true, that means it's expanding a memset. If 'ZeroMemset' is true, that
-/// means it's a memset of zero. 'MemcpyStrSrc' indicates whether the memcpy
-/// source is constant so it does not need to be loaded.
 /// It returns EVT::Other if the type should be determined using generic
 /// target-independent logic.
 /// For vector ops we check that the overall size isn't larger than our
 /// preferred vector width.
 EVT X86TargetLowering::getOptimalMemOpType(
-    uint64_t Size, unsigned DstAlign, unsigned SrcAlign, bool IsMemset,
-    bool ZeroMemset, bool MemcpyStrSrc,
-    const AttributeList &FuncAttributes) const {
+    const MemOp &Op, const AttributeList &FuncAttributes) const {
   if (!FuncAttributes.hasFnAttribute(Attribute::NoImplicitFloat)) {
-    if (Size >= 16 && (!Subtarget.isUnalignedMem16Slow() ||
-                       ((DstAlign == 0 || DstAlign >= 16) &&
-                        (SrcAlign == 0 || SrcAlign >= 16)))) {
+    if (Op.Size >= 16 && (!Subtarget.isUnalignedMem16Slow() ||
+                          ((Op.DstAlign == 0 || Op.DstAlign >= 16) &&
+                           (Op.SrcAlign == 0 || Op.SrcAlign >= 16)))) {
       // FIXME: Check if unaligned 64-byte accesses are slow.
-      if (Size >= 64 && Subtarget.hasAVX512() &&
+      if (Op.Size >= 64 && Subtarget.hasAVX512() &&
           (Subtarget.getPreferVectorWidth() >= 512)) {
         return Subtarget.hasBWI() ? MVT::v64i8 : MVT::v16i32;
       }
       // FIXME: Check if unaligned 32-byte accesses are slow.
-      if (Size >= 32 && Subtarget.hasAVX() &&
+      if (Op.Size >= 32 && Subtarget.hasAVX() &&
           (Subtarget.getPreferVectorWidth() >= 256)) {
         // Although this isn't a well-supported type for AVX1, we'll let
         // legalization and shuffle lowering produce the optimal codegen. If we
@@ -2288,8 +2277,8 @@
       if (Subtarget.hasSSE1() && (Subtarget.is64Bit() || Subtarget.hasX87()) &&
           (Subtarget.getPreferVectorWidth() >= 128))
         return MVT::v4f32;
-    } else if ((!IsMemset || ZeroMemset) && !MemcpyStrSrc && Size >= 8 &&
-               !Subtarget.is64Bit() && Subtarget.hasSSE2()) {
+    } else if ((!Op.IsMemset || Op.ZeroMemset) && !Op.MemcpyStrSrc &&
+               Op.Size >= 8 && !Subtarget.is64Bit() && Subtarget.hasSSE2()) {
       // Do not use f64 to lower memcpy if source is string constant. It's
       // better to use i32 to avoid the loads.
       // Also, do not use f64 to lower memset unless this is a memset of zeros.
@@ -2302,7 +2291,7 @@
   // This is a compromise. If we reach here, unaligned accesses may be slow on
   // this target. However, creating smaller, aligned accesses could be even
   // slower and would certainly be a lot more code.
-  if (Subtarget.is64Bit() && Size >= 8)
+  if (Subtarget.is64Bit() && Op.Size >= 8)
     return MVT::i64;
   return MVT::i32;
 }