+static Value *extractVector(IRBuilder<> &IRB, Value *V,
+ unsigned BeginIndex, unsigned EndIndex,
+ const Twine &Name) {
+ VectorType *VecTy = cast<VectorType>(V->getType());
+ unsigned NumElements = EndIndex - BeginIndex;
+ assert(NumElements <= VecTy->getNumElements() && "Too many elements!");
+
+ if (NumElements == VecTy->getNumElements())
+ return V;
+
+ if (NumElements == 1) {
+ V = IRB.CreateExtractElement(V, IRB.getInt32(BeginIndex),
+ Name + ".extract");
+ DEBUG(dbgs() << " extract: " << *V << "\n");
+ return V;
+ }
+
+ SmallVector<Constant*, 8> Mask;
+ Mask.reserve(NumElements);
+ for (unsigned i = BeginIndex; i != EndIndex; ++i)
+ Mask.push_back(IRB.getInt32(i));
+ V = IRB.CreateShuffleVector(V, UndefValue::get(V->getType()),
+ ConstantVector::get(Mask),
+ Name + ".extract");
+ DEBUG(dbgs() << " shuffle: " << *V << "\n");
+ return V;
+}
+
+static Value *insertVector(IRBuilder<> &IRB, Value *Old, Value *V,
+ unsigned BeginIndex, const Twine &Name) {
+ VectorType *VecTy = cast<VectorType>(Old->getType());
+ assert(VecTy && "Can only insert a vector into a vector");
+
+ VectorType *Ty = dyn_cast<VectorType>(V->getType());
+ if (!Ty) {
+ // Single element to insert.
+ V = IRB.CreateInsertElement(Old, V, IRB.getInt32(BeginIndex),
+ Name + ".insert");
+ DEBUG(dbgs() << " insert: " << *V << "\n");
+ return V;
+ }
+
+ assert(Ty->getNumElements() <= VecTy->getNumElements() &&
+ "Too many elements!");
+ if (Ty->getNumElements() == VecTy->getNumElements()) {
+ assert(V->getType() == VecTy && "Vector type mismatch");
+ return V;
+ }
+ unsigned EndIndex = BeginIndex + Ty->getNumElements();
+
+ // When inserting a smaller vector into the larger to store, we first
+ // use a shuffle vector to widen it with undef elements, and then
+ // a second shuffle vector to select between the loaded vector and the
+ // incoming vector.
+ SmallVector<Constant*, 8> Mask;
+ Mask.reserve(VecTy->getNumElements());
+ for (unsigned i = 0; i != VecTy->getNumElements(); ++i)
+ if (i >= BeginIndex && i < EndIndex)
+ Mask.push_back(IRB.getInt32(i - BeginIndex));
+ else
+ Mask.push_back(UndefValue::get(IRB.getInt32Ty()));
+ V = IRB.CreateShuffleVector(V, UndefValue::get(V->getType()),
+ ConstantVector::get(Mask),
+ Name + ".expand");
+ DEBUG(dbgs() << " shuffle1: " << *V << "\n");
+
+ Mask.clear();
+ for (unsigned i = 0; i != VecTy->getNumElements(); ++i)
+ if (i >= BeginIndex && i < EndIndex)
+ Mask.push_back(IRB.getInt32(i));
+ else
+ Mask.push_back(IRB.getInt32(i + VecTy->getNumElements()));
+ V = IRB.CreateShuffleVector(V, Old, ConstantVector::get(Mask),
+ Name + "insert");
+ DEBUG(dbgs() << " shuffle2: " << *V << "\n");
+ return V;
+}
+