+/// PerformInsertVectorEltInMemory - Some target cannot handle a variable
+/// insertion index for the INSERT_VECTOR_ELT instruction. In this case, it
+/// is necessary to spill the vector being inserted into to memory, perform
+/// the insert there, and then read the result back.
+SDOperand SelectionDAGLegalize::
+PerformInsertVectorEltInMemory(SDOperand Vec, SDOperand Val, SDOperand Idx) {
+ SDOperand Tmp1 = Vec;
+ SDOperand Tmp2 = Val;
+ SDOperand Tmp3 = Idx;
+
+ // If the target doesn't support this, we have to spill the input vector
+ // to a temporary stack slot, update the element, then reload it. This is
+ // badness. We could also load the value into a vector register (either
+ // with a "move to register" or "extload into register" instruction, then
+ // permute it into place, if the idx is a constant and if the idx is
+ // supported by the target.
+ MVT VT = Tmp1.getValueType();
+ MVT EltVT = VT.getVectorElementType();
+ MVT IdxVT = Tmp3.getValueType();
+ MVT PtrVT = TLI.getPointerTy();
+ SDOperand StackPtr = DAG.CreateStackTemporary(VT);
+
+ FrameIndexSDNode *StackPtrFI = cast<FrameIndexSDNode>(StackPtr.Val);
+ int SPFI = StackPtrFI->getIndex();
+
+ // Store the vector.
+ SDOperand Ch = DAG.getStore(DAG.getEntryNode(), Tmp1, StackPtr,
+ PseudoSourceValue::getFixedStack(),
+ SPFI);
+
+ // Truncate or zero extend offset to target pointer type.
+ unsigned CastOpc = IdxVT.bitsGT(PtrVT) ? ISD::TRUNCATE : ISD::ZERO_EXTEND;
+ Tmp3 = DAG.getNode(CastOpc, PtrVT, Tmp3);
+ // Add the offset to the index.
+ unsigned EltSize = EltVT.getSizeInBits()/8;
+ Tmp3 = DAG.getNode(ISD::MUL, IdxVT, Tmp3,DAG.getConstant(EltSize, IdxVT));
+ SDOperand StackPtr2 = DAG.getNode(ISD::ADD, IdxVT, Tmp3, StackPtr);
+ // Store the scalar value.
+ Ch = DAG.getTruncStore(Ch, Tmp2, StackPtr2,
+ PseudoSourceValue::getFixedStack(), SPFI, EltVT);
+ // Load the updated vector.
+ return DAG.getLoad(VT, Ch, StackPtr, PseudoSourceValue::getFixedStack(),SPFI);
+}
+