Drop ISD::MEMSET, ISD::MEMMOVE, and ISD::MEMCPY, which are not Legal

on any current target and aren't optimized in DAGCombiner. Instead
of using intermediate nodes, expand the operations, choosing between
simple loads/stores, target-specific code, and library calls,
immediately.

Previously, the code to emit optimized code for these operations
was only used at initial SelectionDAG construction time; now it is
used at all times. This fixes some cases where rep;movs was being
used for small copies where simple loads/stores would be better.

This also cleans up code that checks for alignments less than 4;
let the targets make that decision instead of doing it in
target-independent code. This allows x86 to use rep;movs in
low-alignment cases.

Also, this fixes a bug that resulted in the use of rep;stos for
memsets of 0 with non-constant memory size when the alignment was
at least 4. It's better to use the library in this case, which
can be significantly faster when the size is large.

This also preserves more SourceValue information when memory
intrinsics are lowered into simple loads/stores.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49572 91177308-0d34-0410-b5e6-96231b3b80d8

31 files changed, 687 insertions, 750 deletions

diff --git a/include/llvm/CodeGen/SelectionDAG.h b/include/llvm/CodeGen/SelectionDAG.h
index 2b8d678eb3..8ea14a5dfd 100644
--- a/include/llvm/CodeGen/SelectionDAG.h
+++ b/include/llvm/CodeGen/SelectionDAG.h
@@ -323,17 +323,20 @@ public:
   SDOperand getNode(unsigned Opcode, SDVTList VTs,
                     const SDOperand *Ops, unsigned NumOps);
 
-  SDOperand getMemcpy(SDOperand Chain, SDOperand Dest, SDOperand Src,
-                      SDOperand Size, SDOperand Align,
-                      SDOperand AlwaysInline);
-
-  SDOperand getMemmove(SDOperand Chain, SDOperand Dest, SDOperand Src,
-                      SDOperand Size, SDOperand Align,
-                      SDOperand AlwaysInline);
-
-  SDOperand getMemset(SDOperand Chain, SDOperand Dest, SDOperand Src,
-                      SDOperand Size, SDOperand Align,
-                      SDOperand AlwaysInline);
+  SDOperand getMemcpy(SDOperand Chain, SDOperand Dst, SDOperand Src,
+                      SDOperand Size, unsigned Align,
+                      bool AlwaysInline,
+                      Value *DstSV, uint64_t DstOff,
+                      Value *SrcSV, uint64_t SrcOff);
+
+  SDOperand getMemmove(SDOperand Chain, SDOperand Dst, SDOperand Src,
+                      SDOperand Size, unsigned Align,
+                      Value *DstSV, uint64_t DstOff,
+                      Value *SrcSV, uint64_t SrcOff);
+
+  SDOperand getMemset(SDOperand Chain, SDOperand Dst, SDOperand Src,
+                      SDOperand Size, unsigned Align,
+                      Value *DstSV, uint64_t DstOff);
 
   /// getSetCC - Helper function to make it easier to build SetCC's if you just
   /// have an ISD::CondCode instead of an SDOperand.
diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index 6b2b8572c3..deded1a36a 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -497,14 +497,6 @@ namespace ISD {
     // it returns an output chain.
     STACKRESTORE,
     
-    // MEMSET/MEMCPY/MEMMOVE - The first operand is the chain. The following
-    // correspond to the operands of the LLVM intrinsic functions and the last
-    // one is AlwaysInline.  The only result is a token chain.  The alignment
-    // argument is guaranteed to be a Constant node.
-    MEMSET,
-    MEMMOVE,
-    MEMCPY,
-
     // CALLSEQ_START/CALLSEQ_END - These operators mark the beginning and end of
     // a call sequence, and carry arbitrary information that target might want
     // to know.  The first operand is a chain, the rest are specified by the
diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index 719f719846..16f9ed63b3 100644
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -948,18 +948,61 @@ public:
               SDOperand Callee, ArgListTy &Args, SelectionDAG &DAG);
 
 
-  virtual SDOperand LowerMEMCPY(SDOperand Op, SelectionDAG &DAG);
-  virtual SDOperand LowerMEMCPYCall(SDOperand Chain, SDOperand Dest,
-                                    SDOperand Source, SDOperand Count,
-                                    SelectionDAG &DAG);
-  virtual SDOperand LowerMEMCPYInline(SDOperand Chain, SDOperand Dest,
-                                      SDOperand Source, unsigned Size,
-                                      unsigned Align, SelectionDAG &DAG) {
-    assert(0 && "Not Implemented");
-    return SDOperand();   // this is here to silence compiler errors
+  /// EmitTargetCodeForMemcpy - Emit target-specific code that performs a
+  /// memcpy. This can be used by targets to provide code sequences for cases
+  /// that don't fit the target's parameters for simple loads/stores and can be
+  /// more efficient than using a library call. This function can return a null
+  /// SDOperand if the target declines to use inline code and a different
+  /// lowering strategy should be used.
+  /// 
+  /// If AlwaysInline is true, the size is constant and the target should not
+  /// emit any calls and is strongly encouraged to attempt to emit inline code
+  /// even if it is beyond the usual threshold because this intrinsic is being
+  /// expanded in a place where calls are not feasible (e.g. within the prologue
+  /// for another call). If the target chooses to decline an AlwaysInline
+  /// request here, legalize will resort to using simple loads and stores.
+  virtual SDOperand
+  EmitTargetCodeForMemcpy(SelectionDAG &DAG,
+                          SDOperand Chain,
+                          SDOperand Op1, SDOperand Op2,
+                          SDOperand Op3, unsigned Align,
+                          bool AlwaysInline,
+                          Value *DstSV, uint64_t DstOff,
+                          Value *SrcSV, uint64_t SrcOff) {
+    return SDOperand();
+  }
+
+  /// EmitTargetCodeForMemmove - Emit target-specific code that performs a
+  /// memmove. This can be used by targets to provide code sequences for cases
+  /// that don't fit the target's parameters for simple loads/stores and can be
+  /// more efficient than using a library call. This function can return a null
+  /// SDOperand if the target declines to use code and a different lowering
+  /// strategy should be used.
+  virtual SDOperand
+  EmitTargetCodeForMemmove(SelectionDAG &DAG,
+                           SDOperand Chain,
+                           SDOperand Op1, SDOperand Op2,
+                           SDOperand Op3, unsigned Align,
+                           Value *DstSV, uint64_t DstOff,
+                           Value *SrcSV, uint64_t SrcOff) {
+    return SDOperand();
+  }
+
+  /// EmitTargetCodeForMemset - Emit target-specific code that performs a
+  /// memset. This can be used by targets to provide code sequences for cases
+  /// that don't fit the target's parameters for simple stores and can be more
+  /// efficient than using a library call. This function can return a null
+  /// SDOperand if the target declines to use code and a different lowering
+  /// strategy should be used.
+  virtual SDOperand
+  EmitTargetCodeForMemset(SelectionDAG &DAG,
+                          SDOperand Chain,
+                          SDOperand Op1, SDOperand Op2,
+                          SDOperand Op3, unsigned Align,
+                          Value *DstSV, uint64_t DstOff) {
+    return SDOperand();
   }
 
-
   /// LowerOperation - This callback is invoked for operations that are 
   /// unsupported by the target, which are registered to use 'custom' lowering,
   /// and whose defined values are all legal.
diff --git a/include/llvm/Target/TargetSubtarget.h b/include/llvm/Target/TargetSubtarget.h
index 1096b1635c..fde8f44669 100644
--- a/include/llvm/Target/TargetSubtarget.h
+++ b/include/llvm/Target/TargetSubtarget.h
@@ -28,9 +28,6 @@ class TargetSubtarget {
 protected: // Can only create subclasses...
   TargetSubtarget();
 public:
-  /// getMaxInlineSizeThreshold - Returns the maximum memset / memcpy size
-  /// that still makes it profitable to inline the call.
-  virtual unsigned getMaxInlineSizeThreshold() const {return 0; }
   virtual ~TargetSubtarget();
 };
 
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 5cb13e3f44..2df363e5be 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -22,6 +22,7 @@
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
+#include "llvm/Target/TargetSubtarget.h"
 #include "llvm/CallingConv.h"
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
@@ -2842,123 +2843,6 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
       break;
     }
     break;
-  case ISD::MEMSET:
-  case ISD::MEMCPY:
-  case ISD::MEMMOVE: {
-    Tmp1 = LegalizeOp(Node->getOperand(0));      // Chain
-    Tmp2 = LegalizeOp(Node->getOperand(1));      // Pointer
-
-    if (Node->getOpcode() == ISD::MEMSET) {      // memset = ubyte
-      switch (getTypeAction(Node->getOperand(2).getValueType())) {
-      case Expand: assert(0 && "Cannot expand a byte!");
-      case Legal:
-        Tmp3 = LegalizeOp(Node->getOperand(2));
-        break;
-      case Promote:
-        Tmp3 = PromoteOp(Node->getOperand(2));
-        break;
-      }
-    } else {
-      Tmp3 = LegalizeOp(Node->getOperand(2));    // memcpy/move = pointer,
-    }
-
-    SDOperand Tmp4;
-    switch (getTypeAction(Node->getOperand(3).getValueType())) {
-    case Expand: {
-      // Length is too big, just take the lo-part of the length.
-      SDOperand HiPart;
-      ExpandOp(Node->getOperand(3), Tmp4, HiPart);
-      break;
-    }
-    case Legal:
-      Tmp4 = LegalizeOp(Node->getOperand(3));
-      break;
-    case Promote:
-      Tmp4 = PromoteOp(Node->getOperand(3));
-      break;
-    }
-
-    SDOperand Tmp5;
-    switch (getTypeAction(Node->getOperand(4).getValueType())) {  // uint
-    case Expand: assert(0 && "Cannot expand this yet!");
-    case Legal:
-      Tmp5 = LegalizeOp(Node->getOperand(4));
-      break;
-    case Promote:
-      Tmp5 = PromoteOp(Node->getOperand(4));
-      break;
-    }
-
-    SDOperand Tmp6;
-    switch (getTypeAction(Node->getOperand(5).getValueType())) {  // bool
-    case Expand: assert(0 && "Cannot expand this yet!");
-    case Legal:
-      Tmp6 = LegalizeOp(Node->getOperand(5));
-      break;
-    case Promote:
-      Tmp6 = PromoteOp(Node->getOperand(5));
-      break;
-    }
-
-    switch (TLI.getOperationAction(Node->getOpcode(), MVT::Other)) {
-    default: assert(0 && "This action not implemented for this operation!");
-    case TargetLowering::Custom:
-      isCustom = true;
-      // FALLTHROUGH
-    case TargetLowering::Legal: {
-      SDOperand Ops[] = { Tmp1, Tmp2, Tmp3, Tmp4, Tmp5, Tmp6 };
-      Result = DAG.UpdateNodeOperands(Result, Ops, 6);
-      if (isCustom) {
-        Tmp1 = TLI.LowerOperation(Result, DAG);
-        if (Tmp1.Val) Result = Tmp1;
-      }
-      break;
-    }
-    case TargetLowering::Expand: {
-      // Otherwise, the target does not support this operation.  Lower the
-      // operation to an explicit libcall as appropriate.
-      MVT::ValueType IntPtr = TLI.getPointerTy();
-      const Type *IntPtrTy = TLI.getTargetData()->getIntPtrType();
-      TargetLowering::ArgListTy Args;
-      TargetLowering::ArgListEntry Entry;
-
-      const char *FnName = 0;
-      if (Node->getOpcode() == ISD::MEMSET) {
-        Entry.Node = Tmp2; Entry.Ty = IntPtrTy;
-        Args.push_back(Entry);
-        // Extend the (previously legalized) ubyte argument to be an int value
-        // for the call.
-        if (Tmp3.getValueType() > MVT::i32)
-          Tmp3 = DAG.getNode(ISD::TRUNCATE, MVT::i32, Tmp3);
-        else
-          Tmp3 = DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Tmp3);
-        Entry.Node = Tmp3; Entry.Ty = Type::Int32Ty; Entry.isSExt = true;
-        Args.push_back(Entry);
-        Entry.Node = Tmp4; Entry.Ty = IntPtrTy; Entry.isSExt = false;
-        Args.push_back(Entry);
-
-        FnName = "memset";
-      } else if (Node->getOpcode() == ISD::MEMCPY ||
-                 Node->getOpcode() == ISD::MEMMOVE) {
-        Entry.Ty = IntPtrTy;
-        Entry.Node = Tmp2; Args.push_back(Entry);
-        Entry.Node = Tmp3; Args.push_back(Entry);
-        Entry.Node = Tmp4; Args.push_back(Entry);
-        FnName = Node->getOpcode() == ISD::MEMMOVE ? "memmove" : "memcpy";
-      } else {
-        assert(0 && "Unknown op!");
-      }
-
-      std::pair<SDOperand,SDOperand> CallResult =
-        TLI.LowerCallTo(Tmp1, Type::VoidTy,
-                        false, false, false, CallingConv::C, false,
-                        DAG.getExternalSymbol(FnName, IntPtr), Args, DAG);
-      Result = CallResult.second;
-      break;
-    }
-    }
-    break;
-  }
 
   case ISD::SHL_PARTS:
   case ISD::SRA_PARTS:
diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
index 6511cff1c6..380c42220c 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
@@ -439,51 +439,6 @@ SDOperand DAGTypeLegalizer::CreateStackStoreLoad(SDOperand Op,
   return DAG.getLoad(DestVT, Store, FIPtr, NULL, 0);
 }
 
-/// HandleMemIntrinsic - This handles memcpy/memset/memmove with invalid
-/// operands.  This promotes or expands the operands as required.
-SDOperand DAGTypeLegalizer::HandleMemIntrinsic(SDNode *N) {
-  // The chain and pointer [operands #0 and #1] are always valid types.
-  SDOperand Chain = N->getOperand(0);
-  SDOperand Ptr   = N->getOperand(1);
-  SDOperand Op2   = N->getOperand(2);
-  
-  // Op #2 is either a value (memset) or a pointer.  Promote it if required.
-  switch (getTypeAction(Op2.getValueType())) {
-  default: assert(0 && "Unknown action for pointer/value operand");
-  case Legal: break;
-  case Promote: Op2 = GetPromotedOp(Op2); break;
-  }
-
-  // The length could have any action required.
-  SDOperand Length = N->getOperand(3);
-  switch (getTypeAction(Length.getValueType())) {
-  default: assert(0 && "Unknown action for memop operand");
-  case Legal: break;
-  case Promote: Length = GetPromotedZExtOp(Length); break;
-  case Expand:
-    SDOperand Dummy;  // discard the high part.
-    GetExpandedOp(Length, Length, Dummy);
-    break;
-  }
-
-  SDOperand Align = N->getOperand(4);
-  switch (getTypeAction(Align.getValueType())) {
-  default: assert(0 && "Unknown action for memop operand");
-  case Legal: break;
-  case Promote: Align = GetPromotedZExtOp(Align); break;
-  }
-
-  SDOperand AlwaysInline = N->getOperand(5);
-  switch (getTypeAction(AlwaysInline.getValueType())) {
-  default: assert(0 && "Unknown action for memop operand");
-  case Legal: break;
-  case Promote: AlwaysInline = GetPromotedZExtOp(AlwaysInline); break;
-  }
-
-  SDOperand Ops[] = { Chain, Ptr, Op2, Length, Align, AlwaysInline };
-  return DAG.UpdateNodeOperands(SDOperand(N, 0), Ops, 6);
-}
-
 /// JoinIntegers - Build an integer with low bits Lo and high bits Hi.
 SDOperand DAGTypeLegalizer::JoinIntegers(SDOperand Lo, SDOperand Hi) {
   MVT::ValueType LVT = Lo.getValueType();
diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 7d245abed5..5b9879315f 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -165,7 +165,6 @@ private:
   // Common routines.
   SDOperand BitConvertToInteger(SDOperand Op);
   SDOperand CreateStackStoreLoad(SDOperand Op, MVT::ValueType DestVT);
-  SDOperand HandleMemIntrinsic(SDNode *N);
   SDOperand JoinIntegers(SDOperand Lo, SDOperand Hi);
   void SplitInteger(SDOperand Op, SDOperand &Lo, SDOperand &Hi);
   void SplitInteger(SDOperand Op, MVT::ValueType LoVT, MVT::ValueType HiVT,
diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypesExpand.cpp b/lib/CodeGen/SelectionDAG/LegalizeTypesExpand.cpp
index b872a44fec..fcde8f32d2 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypesExpand.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypesExpand.cpp
@@ -946,9 +946,6 @@ bool DAGTypeLegalizer::ExpandOperand(SDNode *N, unsigned OpNo) {
     case ISD::STORE:
       Res = ExpandOperand_STORE(cast<StoreSDNode>(N), OpNo);
       break;
-    case ISD::MEMSET:
-    case ISD::MEMCPY:
-    case ISD::MEMMOVE:     Res = HandleMemIntrinsic(N); break;
 
     case ISD::BUILD_VECTOR: Res = ExpandOperand_BUILD_VECTOR(N); break;
     }
diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypesPromote.cpp b/lib/CodeGen/SelectionDAG/LegalizeTypesPromote.cpp
index b8118eb039..93c8c60584 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypesPromote.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypesPromote.cpp
@@ -447,9 +447,6 @@ bool DAGTypeLegalizer::PromoteOperand(SDNode *N, unsigned OpNo) {
 
   case ISD::STORE:       Res = PromoteOperand_STORE(cast<StoreSDNode>(N),
                                                     OpNo); break;
-  case ISD::MEMSET:
-  case ISD::MEMCPY:
-  case ISD::MEMMOVE:     Res = HandleMemIntrinsic(N); break;
 
   case ISD::BUILD_VECTOR: Res = PromoteOperand_BUILD_VECTOR(N); break;
   case ISD::INSERT_VECTOR_ELT:
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index f096c70a3e..327a8fe897 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Intrinsics.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Assembly/Writer.h"
+#include "llvm/CallingConv.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
@@ -2385,28 +2386,357 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
   return getNode(Opcode, VT, Ops, 5);
 }
 
-SDOperand SelectionDAG::getMemcpy(SDOperand Chain, SDOperand Dest,
-                                  SDOperand Src, SDOperand Size,
-                                  SDOperand Align,
-                                  SDOperand AlwaysInline) {
-  SDOperand Ops[] = { Chain, Dest, Src, Size, Align, AlwaysInline };
-  return getNode(ISD::MEMCPY, MVT::Other, Ops, 6);
+/// getMemsetValue - Vectorized representation of the memset value
+/// operand.
+static SDOperand getMemsetValue(SDOperand Value, MVT::ValueType VT,
+                                SelectionDAG &DAG) {
+  MVT::ValueType CurVT = VT;
+  if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Value)) {
+    uint64_t Val   = C->getValue() & 255;
+    unsigned Shift = 8;
+    while (CurVT != MVT::i8) {
+      Val = (Val << Shift) | Val;
+      Shift <<= 1;
+      CurVT = (MVT::ValueType)((unsigned)CurVT - 1);
+    }
+    return DAG.getConstant(Val, VT);
+  } else {
+    Value = DAG.getNode(ISD::ZERO_EXTEND, VT, Value);
+    unsigned Shift = 8;
+    while (CurVT != MVT::i8) {
+      Value =
+        DAG.getNode(ISD::OR, VT,
+                    DAG.getNode(ISD::SHL, VT, Value,
+                                DAG.getConstant(Shift, MVT::i8)), Value);
+      Shift <<= 1;
+      CurVT = (MVT::ValueType)((unsigned)CurVT - 1);
+    }
+
+    return Value;
+  }
 }
 
-SDOperand SelectionDAG::getMemmove(SDOperand Chain, SDOperand Dest,
-                                  SDOperand Src, SDOperand Size,
-                                  SDOperand Align,
-                                  SDOperand AlwaysInline) {
-  SDOperand Ops[] = { Chain, Dest, Src, Size, Align, AlwaysInline };
-  return getNode(ISD::MEMMOVE, MVT::Other, Ops, 6);
+/// getMemsetStringVal - Similar to getMemsetValue. Except this is only
+/// used when a memcpy is turned into a memset when the source is a constant
+/// string ptr.
+static SDOperand getMemsetStringVal(MVT::ValueType VT,
+                                    SelectionDAG &DAG,
+                                    const TargetLowering &TLI,
+                                    std::string &Str, unsigned Offset) {
+  uint64_t Val = 0;
+  unsigned MSB = MVT::getSizeInBits(VT) / 8;
+  if (TLI.isLittleEndian())
+    Offset = Offset + MSB - 1;
+  for (unsigned i = 0; i != MSB; ++i) {
+    Val = (Val << 8) | (unsigned char)Str[Offset];
+    Offset += TLI.isLittleEndian() ? -1 : 1;
+  }
+  return DAG.getConstant(Val, VT);
+}
+
+/// getMemBasePlusOffset - Returns base and offset node for the 
+static SDOperand getMemBasePlusOffset(SDOperand Base, unsigned Offset,
+                                      SelectionDAG &DAG) {
+  MVT::ValueType VT = Base.getValueType();
+  return DAG.getNode(ISD::ADD, VT, Base, DAG.getConstant(Offset, VT));
 }
 
-SDOperand SelectionDAG::getMemset(SDOperand Chain, SDOperand Dest,
+/// MeetsMaxMemopRequirement - Determines if the number of memory ops required
+/// to replace the memset / memcpy is below the threshold. It also returns the
+/// types of the sequence of memory ops to perform memset / memcpy.
+static bool MeetsMaxMemopRequirement(std::vector<MVT::ValueType> &MemOps,
+                                     unsigned Limit, uint64_t Size,
+                                     unsigned Align,
+                                     const TargetLowering &TLI) {
+  MVT::ValueType VT;
+
+  if (TLI.allowsUnalignedMemoryAccesses()) {
+    VT = MVT::i64;
+  } else {
+    switch (Align & 7) {
+    case 0:
+      VT = MVT::i64;
+      break;
+    case 4:
+      VT = MVT::i32;
+      break;
+    case 2:
+      VT = MVT::i16;
+      break;
+    default:
+      VT = MVT::i8;
+      break;
+    }
+  }
+
+  MVT::ValueType LVT = MVT::i64;
+  while (!TLI.isTypeLegal(LVT))
+    LVT = (MVT::ValueType)((unsigned)LVT - 1);
+  assert(MVT::isInteger(LVT));
+
+  if (VT > LVT)
+    VT = LVT;
+
+  unsigned NumMemOps = 0;
+  while (Size != 0) {
+    unsigned VTSize = MVT::getSizeInBits(VT) / 8;
+    while (VTSize > Size) {
+      VT = (MVT::ValueType)((unsigned)VT - 1);
+      VTSize >>= 1;
+    }
+    assert(MVT::isInteger(VT));
+
+    if (++NumMemOps > Limit)
+      return false;
+    MemOps.push_back(VT);
+    Size -= VTSize;
+  }
+
+  return true;
+}
+
+static SDOperand getMemcpyLoadsAndStores(SelectionDAG &DAG,
+                                         SDOperand Chain, SDOperand Dst,
+                                         SDOperand Src, uint64_t Size,
+                                         unsigned Align,
+                                         bool AlwaysInline,
+                                         Value *DstSV, uint64_t DstOff,
+                                         Value *SrcSV, uint64_t SrcOff) {
+  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+
+  // Expand memcpy to a series of store ops if the size operand falls below
+  // a certain threshold.
+  std::vector<MVT::ValueType> MemOps;
+  uint64_t Limit = -1;
+  if (!AlwaysInline)
+    Limit = TLI.getMaxStoresPerMemcpy();
+  if (!MeetsMaxMemopRequirement(MemOps, Limit, Size, Align, TLI))
+    return SDOperand();
+
+  SmallVector<SDOperand, 8> OutChains;
+
+  unsigned NumMemOps = MemOps.size();
+  unsigned SrcDelta = 0;
+  GlobalAddressSDNode *G = NULL;
+  std::string Str;
+  bool CopyFromStr = false;
+
+  if (Src.getOpcode() == ISD::GlobalAddress)
+    G = cast<GlobalAddressSDNode>(Src);
+  else if (Src.getOpcode() == ISD::ADD &&
+           Src.getOperand(0).getOpcode() == ISD::GlobalAddress &&
+           Src.getOperand(1).getOpcode() == ISD::Constant) {
+    G = cast<GlobalAddressSDNode>(Src.getOperand(0));
+    SrcDelta = cast<ConstantSDNode>(Src.getOperand(1))->getValue();
+  }
+  if (G) {
+    GlobalVariable *GV = dyn_cast<GlobalVariable>(G->getGlobal());
+    if (GV && GV->isConstant()) {
+      Str = GV->getStringValue(false);
+      if (!Str.empty()) {
+        CopyFromStr = true;
+        SrcOff += SrcDelta;
+      }
+    }
+  }
+
+  for (unsigned i = 0; i < NumMemOps; i++) {
+    MVT::ValueType VT = MemOps[i];
+    unsigned VTSize = MVT::getSizeInBits(VT) / 8;
+    SDOperand Value, Store;
+
+    if (CopyFromStr) {
+      Value = getMemsetStringVal(VT, DAG, TLI, Str, SrcOff);
+      Store =
+        DAG.getStore(Chain, Value,
+                     getMemBasePlusOffset(Dst, DstOff, DAG),
+                     DstSV, DstOff);
+    } else {
+      Value = DAG.getLoad(VT, Chain,
+                          getMemBasePlusOffset(Src, SrcOff, DAG),
+                          SrcSV, SrcOff, false, Align);
+      Store =
+        DAG.getStore(Chain, Value,
+                     getMemBasePlusOffset(Dst, DstOff, DAG),
+                     DstSV, DstOff, false, Align);
+    }
+    OutChains.push_back(Store);
+    SrcOff += VTSize;
+    DstOff += VTSize;
+  }
+
+  return DAG.getNode(ISD::TokenFactor, MVT::Other,
+                     &OutChains[0], OutChains.size());
+}
+
+static SDOperand getMemsetStores(SelectionDAG &DAG,
+                                 SDOperand Chain, SDOperand Dst,
+                                 SDOperand Src, uint64_t Size,
+                                 unsigned Align,
+                                 Value *DstSV, uint64_t DstOff) {
+  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+
+  // Expand memset to a series of load/store ops if the size operand
+  // falls below a certain threshold.
+  std::vector<MVT::ValueType> MemOps;
+  if (!MeetsMaxMemopRequirement(MemOps, TLI.getMaxStoresPerMemset(),
+                                Size, Align, TLI))
+    return SDOperand();
+
+  SmallVector<SDOperand, 8> OutChains;
+
+  unsigned NumMemOps = MemOps.size();
+  for (unsigned i = 0; i < NumMemOps; i++) {
+    MVT::ValueType VT = MemOps[i];
+    unsigned VTSize = MVT::getSizeInBits(VT) / 8;
+    SDOperand Value = getMemsetValue(Src, VT, DAG);
+    SDOperand Store = DAG.getStore(Chain, Value,
+                                   getMemBasePlusOffset(Dst, DstOff, DAG),
+                                   DstSV, DstOff);
+    OutChains.push_back(Store);
+    DstOff += VTSize;
+  }
+
+  return DAG.getNode(ISD::TokenFactor, MVT::Other,
+                     &OutChains[0], OutChains.size());
+}
+
+SDOperand SelectionDAG::getMemcpy(SDOperand Chain, SDOperand Dst,
+                                  SDOperand Src, SDOperand Size,
+                                  unsigned Align, bool AlwaysInline,
+                                  Value *DstSV, uint64_t DstOff,
+                                  Value *SrcSV, uint64_t SrcOff) {
+
+  // Check to see if we should lower the memcpy to loads and stores first.
+  // For cases within the target-specified limits, this is the best choice.
+  ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
+  if (ConstantSize) {
+    // Memcpy with size zero? Just return the original chain.
+    if (ConstantSize->isNullValue())
+      return Chain;
+
+    SDOperand Result =
+      getMemcpyLoadsAndStores(*this, Chain, Dst, Src, ConstantSize->getValue(),
+                              Align, false, DstSV, DstOff, SrcSV, SrcOff);
+    if (Result.Val)
+      return Result;
+  }
+
+  // Then check to see if we should lower the memcpy with target-specific
+  // code. If the target chooses to do this, this is the next best.
+  SDOperand Result =
+    TLI.EmitTargetCodeForMemcpy(*this, Chain, Dst, Src, Size, Align,
+                                AlwaysInline,
+                                DstSV, DstOff, SrcSV, SrcOff);
+  if (Result.Val)
+    return Result;
+
+  // If we really need inline code and the target declined to provide it,
+  // use a (potentially long) sequence of loads and stores.
+  if (AlwaysInline) {
+    assert(ConstantSize && "AlwaysInline requires a constant size!");
+    return getMemcpyLoadsAndStores(*this, Chain, Dst, Src,
+                                   ConstantSize->getValue(), Align, true,
+                                   DstSV, DstOff, SrcSV, SrcOff);
+  }
+
+  // Emit a library call.
+  TargetLowering::ArgListTy Args;
+  TargetLowering::ArgListEntry Entry;
+  Entry.Ty = TLI.getTargetData()->getIntPtrType();
+  Entry.Node = Dst; Args.push_back(Entry);
+  Entry.Node = Src; Args.push_back(Entry);
+  Entry.Node = Size; Args.push_back(Entry);
+  std::pair<SDOperand,SDOperand> CallResult =
+    TLI.LowerCallTo(Chain, Type::VoidTy,
+                    false, false, false, CallingConv::C, false,
+                    getExternalSymbol("memcpy", TLI.getPointerTy()),
+                    Args, *this);
+  return CallResult.second;
+}
+
+SDOperand SelectionDAG::getMemmove(SDOperand Ch