Pull in r211435 from upstream llvm trunk (by Benjamin Kramer):

  Legalizer: Add support for splitting insert_subvectors.

  We handle this by spilling the whole thing to the stack and doing the
  insertion as a store.

  PR19492. This happens in real code because the vectorizer creates
  v2i128 when AVX is enabled.

This fixes a "fatal error: error in backend: Do not know how to split
the result of this operator!" message encountered during compilation of
the net-p2p/libtorrent-rasterbar port.

Introduced here: http://svnweb.freebsd.org/changeset/base/267704

Index: lib/CodeGen/SelectionDAG/LegalizeTypes.h
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -569,6 +569,7 @@ class LLVM_LIBRARY_VISIBILITY DAGTypeLegalizer {
   void SplitVecRes_BUILD_VECTOR(SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitVecRes_CONCAT_VECTORS(SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitVecRes_EXTRACT_SUBVECTOR(SDNode *N, SDValue &Lo, SDValue &Hi);
+  void SplitVecRes_INSERT_SUBVECTOR(SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitVecRes_FPOWI(SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitVecRes_INSERT_VECTOR_ELT(SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitVecRes_LOAD(LoadSDNode *N, SDValue &Lo, SDValue &Hi);
Index: lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -506,6 +506,7 @@ void DAGTypeLegalizer::SplitVectorResult(SDNode *N
   case ISD::BUILD_VECTOR:      SplitVecRes_BUILD_VECTOR(N, Lo, Hi); break;
   case ISD::CONCAT_VECTORS:    SplitVecRes_CONCAT_VECTORS(N, Lo, Hi); break;
   case ISD::EXTRACT_SUBVECTOR: SplitVecRes_EXTRACT_SUBVECTOR(N, Lo, Hi); break;
+  case ISD::INSERT_SUBVECTOR:  SplitVecRes_INSERT_SUBVECTOR(N, Lo, Hi); break;
   case ISD::FP_ROUND_INREG:    SplitVecRes_InregOp(N, Lo, Hi); break;
   case ISD::FPOWI:             SplitVecRes_FPOWI(N, Lo, Hi); break;
   case ISD::INSERT_VECTOR_ELT: SplitVecRes_INSERT_VECTOR_ELT(N, Lo, Hi); break;
@@ -725,6 +726,43 @@ void DAGTypeLegalizer::SplitVecRes_EXTRACT_SUBVECT
                                    TLI.getVectorIdxTy()));
 }
 
+void DAGTypeLegalizer::SplitVecRes_INSERT_SUBVECTOR(SDNode *N, SDValue &Lo,
+                                                    SDValue &Hi) {
+  SDValue Vec = N->getOperand(0);
+  SDValue SubVec = N->getOperand(1);
+  SDValue Idx = N->getOperand(2);
+  SDLoc dl(N);
+  GetSplitVector(Vec, Lo, Hi);
+
+  // Spill the vector to the stack.
+  EVT VecVT = Vec.getValueType();
+  EVT SubVecVT = VecVT.getVectorElementType();
+  SDValue StackPtr = DAG.CreateStackTemporary(VecVT);
+  SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Vec, StackPtr,
+                               MachinePointerInfo(), false, false, 0);
+
+  // Store the new subvector into the specified index.
+  SDValue SubVecPtr = GetVectorElementPointer(StackPtr, SubVecVT, Idx);
+  Type *VecType = VecVT.getTypeForEVT(*DAG.getContext());
+  unsigned Alignment = TLI.getDataLayout()->getPrefTypeAlignment(VecType);
+  Store = DAG.getStore(Store, dl, SubVec, SubVecPtr, MachinePointerInfo(),
+                       false, false, 0);
+
+  // Load the Lo part from the stack slot.
+  Lo = DAG.getLoad(Lo.getValueType(), dl, Store, StackPtr, MachinePointerInfo(),
+                   false, false, false, 0);
+
+  // Increment the pointer to the other part.
+  unsigned IncrementSize = Lo.getValueType().getSizeInBits() / 8;
+  StackPtr =
+      DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(), StackPtr,
+                  DAG.getConstant(IncrementSize, StackPtr.getValueType()));
+
+  // Load the Hi part from the stack slot.
+  Hi = DAG.getLoad(Hi.getValueType(), dl, Store, StackPtr, MachinePointerInfo(),
+                   false, false, false, MinAlign(Alignment, IncrementSize));
+}
+
 void DAGTypeLegalizer::SplitVecRes_FPOWI(SDNode *N, SDValue &Lo,
                                          SDValue &Hi) {
   SDLoc dl(N);
Index: test/CodeGen/X86/vec_split.ll
===================================================================
--- test/CodeGen/X86/vec_split.ll
+++ test/CodeGen/X86/vec_split.ll
@@ -40,3 +40,36 @@ define <32 x i16> @split32(<32 x i16> %a, <32 x i1
   %2 = select <32 x i1> %1, <32 x i16> %a, <32 x i16> %b
   ret <32 x i16> %2
 }
+
+; PR19492
+define i128 @split128(<2 x i128> %a, <2 x i128> %b) {
+; SSE4-LABEL: split128:
+; SSE4: addq
+; SSE4: adcq
+; SSE4: addq
+; SSE4: adcq
+; SSE4: addq
+; SSE4: adcq
+; SSE4: ret
+; AVX1-LABEL: split128:
+; AVX1: addq
+; AVX1: adcq
+; AVX1: addq
+; AVX1: adcq
+; AVX1: addq
+; AVX1: adcq
+; AVX1: ret
+; AVX2-LABEL: split128:
+; AVX2: addq
+; AVX2: adcq
+; AVX2: addq
+; AVX2: adcq
+; AVX2: addq
+; AVX2: adcq
+; AVX2: ret
+  %add = add nsw <2 x i128> %a, %b
+  %rdx.shuf = shufflevector <2 x i128> %add, <2 x i128> undef, <2 x i32> <i32 undef, i32 0>
+  %bin.rdx = add <2 x i128> %add, %rdx.shuf
+  %e = extractelement <2 x i128> %bin.rdx, i32 1
+  ret i128 %e
+}