Remove CompositeType class

[efriedma]

Summary

The existence of the class is more confusing than helpful, I think; the commonality is mostly just "GEP is legal", which can be queried using APIs on GetElementPtrInst.

[sdesmalen]

Thanks for working on this @efriedma!

llvm/include/llvm/IR/Instructions.h

1020

Please add some comments/documentation for these methods.

llvm/lib/IR/Instructions.cpp

1661–1662

Is there a reason you didn't just call this getTypeAtIndex ?

1667

Maybe I'm misunderstanding this method, but checking that the indexed type is of type integer, does that exclude the case:

getelementptr float, float* %ptr, i64 0

?

1681

nit: can this use const IndexTy &?

[efriedma]

llvm/lib/IR/Instructions.cpp

1661–1662

I guess I could call it that; didn't really think much about the name. (I originally thought of it as splitting out each "step" of getIndexedType into a separate method.)

1667

The point of the isIntOrIntVectorTy() check is to exclude something silly like a float index into an array. It has nothing to do with the type of the pointer.

1681

Yes, but it wouldn't really matter; IndexTy is cheap to copy.

[sdesmalen]

llvm/lib/IR/Instructions.cpp

1667

Right, it's calling isIntOrIntVectorTy on the Idx, not Ty, I misread that.

[efriedma]

Address review comments.

[sdesmalen]

Thanks for the changes, the patch looks good to me!

[efriedma]

Add one missing change in clang unittests

[nhaehnle]

LGTM

clang/unittests/CodeGen/CodeGenExternalTest.cpp

if (FunctionDecl *fd = dyn_cast<FunctionDecl>(decl)) {
         // Check convertTypeForMemory
         llvm::Type *llvmTy = CodeGen::convertTypeForMemory(CGM, qType);
         ASSERT_TRUE(llvmTy != NULL);
         if (DebugThisTest) {
           llvmTy->print(dbgs(), true);
           dbgs() << "\n";
         }
 
-        llvm::CompositeType* structTy = dyn_cast<CompositeType>(llvmTy);
+        auto* structTy = dyn_cast<llvm::StructType>(llvmTy);
         ASSERT_TRUE(structTy != NULL);
 
         // Check getLLVMFieldNumber
         FieldDecl *xField = NULL;
         FieldDecl *yField = NULL;
         FieldDecl *zField = NULL;
 
         for (auto field : rd->fields()) {

llvm/include/llvm/IR/Constants.h

 /// Subclasses are \a ConstantStruct, \a ConstantArray, and \a
 /// ConstantVector.
 ///
 /// \note Some subclasses of \a ConstantData are semantically aggregates --
 /// such as \a ConstantDataArray -- but are not subclasses of this because they
 /// use operands.
 class ConstantAggregate : public Constant {
 protected:
-  ConstantAggregate(CompositeType *T, ValueTy VT, ArrayRef<Constant *> V);
+  ConstantAggregate(Type *T, ValueTy VT, ArrayRef<Constant *> V);
 
 public:
   /// Transparently provide more efficient getOperand methods.
   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Value *V) {
     return V->getValueID() >= ConstantAggregateFirstVal &&

llvm/include/llvm/IR/DerivedTypes.h

public:
 
   explicit operator bool() { return Callee; }
 
 private:
   FunctionType *FnTy = nullptr;
   Value *Callee = nullptr;
 };
 
-/// Common super class of ArrayType, StructType and VectorType.
-class CompositeType : public Type {
-protected:
-  explicit CompositeType(LLVMContext &C, TypeID tid) : Type(C, tid) {}
-
-public:
-  /// Given an index value into the type, return the type of the element.
-  Type *getTypeAtIndex(const Value *V) const;
-  Type *getTypeAtIndex(unsigned Idx) const;
-  bool indexValid(const Value *V) const;
-  bool indexValid(unsigned Idx) const;
-
-  /// Methods for support type inquiry through isa, cast, and dyn_cast.
-  static bool classof(const Type *T) {
-    return T->getTypeID() == ArrayTyID ||
-           T->getTypeID() == StructTyID ||
-           T->getTypeID() == VectorTyID;
-  }
-};
-
 /// Class to represent struct types. There are two different kinds of struct
 /// types: Literal structs and Identified structs.
 ///
 /// Literal struct types (e.g. { i32, i32 }) are uniqued structurally, and must
 /// always have a body when created.  You can get one of these by using one of
 /// the StructType::get() forms.
 ///
 /// Identified structs (e.g. %foo or %42) may optionally have a name and are not
 /// uniqued.  The names for identified structs are managed at the LLVMContext
 /// level, so there can only be a single identified struct with a given name in
 /// a particular LLVMContext.  Identified structs may also optionally be opaque
 /// (have no body specified).  You get one of these by using one of the
 /// StructType::create() forms.
 ///
 /// Independent of what kind of struct you have, the body of a struct type are
 /// laid out in memory consecutively with the elements directly one after the
 /// other (if the struct is packed) or (if not packed) with padding between the
 /// elements as defined by DataLayout (which is required to match what the code
 /// generator for a target expects).
 ///
-class StructType : public CompositeType {
-  StructType(LLVMContext &C) : CompositeType(C, StructTyID) {}
+class StructType : public Type {
+  StructType(LLVMContext &C) : Type(C, StructTyID) {}
 
   enum {
     /// This is the contents of the SubClassData field.
     SCDB_HasBody = 1,
     SCDB_Packed = 2,
     SCDB_IsLiteral = 4,
     SCDB_IsSized = 8
   };
public:
   bool isLayoutIdentical(StructType *Other) const;
 
   /// Random access to the elements
   unsigned getNumElements() const { return NumContainedTys; }
   Type *getElementType(unsigned N) const {
     assert(N < NumContainedTys && "Element number out of range!");
     return ContainedTys[N];
   }
+  /// Given an index value into the type, return the type of the element.
+  Type *getTypeAtIndex(const Value *V) const;
+  Type *getTypeAtIndex(unsigned N) const { return getElementType(N); }
+  bool indexValid(const Value *V) const;
+  bool indexValid(unsigned Idx) const { return Idx < getNumElements(); }
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast.
   static bool classof(const Type *T) {
     return T->getTypeID() == StructTyID;
   }
 };
 
 StringRef Type::getStructName() const {

 }
 
 /// This is the superclass of the array and vector type classes. Both of these
 /// represent "arrays" in memory. The array type represents a specifically sized
 /// array, and the vector type represents a specifically sized array that allows
 /// for use of SIMD instructions. SequentialType holds the common features of
 /// both, which stem from the fact that both lay their components out in memory
 /// identically.
-class SequentialType : public CompositeType {
+class SequentialType : public Type {
   Type *ContainedType;               ///< Storage for the single contained type.
   uint64_t NumElements;
 
 protected:
   SequentialType(TypeID TID, Type *ElType, uint64_t NumElements)
-    : CompositeType(ElType->getContext(), TID), ContainedType(ElType),
+      : Type(ElType->getContext(), TID), ContainedType(ElType),
         NumElements(NumElements) {
     ContainedTys = &ContainedType;
     NumContainedTys = 1;
   }
 
 public:
   SequentialType(const SequentialType &) = delete;
   SequentialType &operator=(const SequentialType &) = delete;
 

llvm/include/llvm/IR/Instructions.h

public:
 
   /// Returns the address space of this instruction's pointer type.
   unsigned getAddressSpace() const {
     // Note that this is always the same as the pointer operand's address space
     // and that is cheaper to compute, so cheat here.
     return getPointerAddressSpace();
   }
 
-  /// Returns the type of the element that would be loaded with
-  /// a load instruction with the specified parameters.
+  /// Returns the result type of a getelementptr with the given source
+  /// element type and indexes.
   ///
   /// Null is returned if the indices are invalid for the specified
-  /// pointer type.
-  ///
+  /// source element type.
   static Type *getIndexedType(Type *Ty, ArrayRef<Value *> IdxList);
   static Type *getIndexedType(Type *Ty, ArrayRef<Constant *> IdxList);
   static Type *getIndexedType(Type *Ty, ArrayRef<uint64_t> IdxList);
 
+  /// Return the type of the element at the given index of an indexable
+  /// type.  This is equivalent to "getIndexedType(Agg, {Zero, Idx})".
+  ///
+  /// Returns null if the type can't be indexed, or the given index is not
+  /// legal for the given type.
+  static Type *getTypeAtIndex(Type *Ty, Value *Idx);
+  static Type *getTypeAtIndex(Type *Ty, uint64_t Idx);
+
   inline op_iterator       idx_begin()       { return op_begin()+1; }
   inline const_op_iterator idx_begin() const { return op_begin()+1; }
   inline op_iterator       idx_end()         { return op_end(); }
   inline const_op_iterator idx_end()   const { return op_end(); }
 
   inline iterator_range<op_iterator> indices() {
     return make_range(idx_begin(), idx_end());
   }

llvm/lib/CodeGen/Analysis.cpp

if (BitsProvided < BitsRequired ||
       (!AllowDifferingSizes && BitsProvided != BitsRequired))
     return false;
 
   return true;
 }
 
 /// For an aggregate type, determine whether a given index is within bounds or
 /// not.
-static bool indexReallyValid(CompositeType *T, unsigned Idx) {
+static bool indexReallyValid(Type *T, unsigned Idx) {
   if (ArrayType *AT = dyn_cast<ArrayType>(T))
     return Idx < AT->getNumElements();
 
   return Idx < cast<StructType>(T)->getNumElements();
 }
 
 /// Move the given iterators to the next leaf type in depth first traversal.
 ///
 /// Performs a depth-first traversal of the type as specified by its arguments,
 /// stopping at the next leaf node (which may be a legitimate scalar type or an
 /// empty struct or array).
 ///
 /// @param SubTypes List of the partial components making up the type from
 /// outermost to innermost non-empty aggregate. The element currently
 /// represented is SubTypes.back()->getTypeAtIndex(Path.back() - 1).
 ///
 /// @param Path Set of extractvalue indices leading from the outermost type
 /// (SubTypes[0]) to the leaf node currently represented.
 ///
 /// @returns true if a new type was found, false otherwise. Calling this
 /// function again on a finished iterator will repeatedly return
 /// false. SubTypes.back()->getTypeAtIndex(Path.back()) is either an empty
 /// aggregate or a non-aggregate
-static bool advanceToNextLeafType(SmallVectorImpl<CompositeType *> &SubTypes,
+static bool advanceToNextLeafType(SmallVectorImpl<Type *> &SubTypes,
                                   SmallVectorImpl<unsigned> &Path) {
   // First march back up the tree until we can successfully increment one of the
   // coordinates in Path.
   while (!Path.empty() && !indexReallyValid(SubTypes.back(), Path.back() + 1)) {
     Path.pop_back();
     SubTypes.pop_back();
   }
 
   // If we reached the top, then the iterator is done.
   if (Path.empty())
     return false;
 
   // We know there's *some* valid leaf now, so march back down the tree picking
   // out the left-most element at each node.
   ++Path.back();
-  Type *DeeperType = SubTypes.back()->getTypeAtIndex(Path.back());
+  Type *DeeperType =
+      ExtractValueInst::getIndexedType(SubTypes.back(), Path.back());
   while (DeeperType->isAggregateType()) {
-    CompositeType *CT = cast<CompositeType>(DeeperType);
-    if (!indexReallyValid(CT, 0))
+    if (!indexReallyValid(DeeperType, 0))
       return true;
 
-    SubTypes.push_back(CT);
+    SubTypes.push_back(DeeperType);
     Path.push_back(0);
 
-    DeeperType = CT->getTypeAtIndex(0U);
+    DeeperType = ExtractValueInst::getIndexedType(DeeperType, 0);
   }
 
   return true;
 }
 
 /// Find the first non-empty, scalar-like type in Next and setup the iterator
 /// components.
 ///
 /// Assuming Next is an aggregate of some kind, this function will traverse the
 /// tree from left to right (i.e. depth-first) looking for the first
 /// non-aggregate type which will play a role in function return.
 ///
 /// For example, if Next was {[0 x i64], {{}, i32, {}}, i32} then we would setup
 /// Path as [1, 1] and SubTypes as [Next, {{}, i32, {}}] to represent the first
 /// i32 in that type.
-static bool firstRealType(Type *Next,
-                          SmallVectorImpl<CompositeType *> &SubTypes,
+static bool firstRealType(Type *Next, SmallVectorImpl<Type *> &SubTypes,
                           SmallVectorImpl<unsigned> &Path) {
   // First initialise the iterator components to the first "leaf" node
   // (i.e. node with no valid sub-type at any index, so {} does count as a leaf
   // despite nominally being an aggregate).
-  while (Next->isAggregateType() &&
-         indexReallyValid(cast<CompositeType>(Next), 0)) {
-    SubTypes.push_back(cast<CompositeType>(Next));
+  while (Type *FirstInner = ExtractValueInst::getIndexedType(Next, 0)) {
+    SubTypes.push_back(Next);
     Path.push_back(0);
-    Next = cast<CompositeType>(Next)->getTypeAtIndex(0U);
+    Next = FirstInner;
   }
 
   // If there's no Path now, Next was originally scalar already (or empty
   // leaf). We're done.
   if (Path.empty())
     return true;
 
   // Otherwise, use normal iteration to keep looking through the tree until we
   // find a non-aggregate type.
-  while (SubTypes.back()->getTypeAtIndex(Path.back())->isAggregateType()) {
+  while (ExtractValueInst::getIndexedType(SubTypes.back(), Path.back())
+             ->isAggregateType()) {
     if (!advanceToNextLeafType(SubTypes, Path))
       return false;
   }
 
   return true;
 }
 
 /// Set the iterator data-structures to the next non-empty, non-aggregate
 /// subtype.
-static bool nextRealType(SmallVectorImpl<CompositeType *> &SubTypes,
+static bool nextRealType(SmallVectorImpl<Type *> &SubTypes,
                          SmallVectorImpl<unsigned> &Path) {
   do {
     if (!advanceToNextLeafType(SubTypes, Path))
       return false;
 
     assert(!Path.empty() && "found a leaf but didn't set the path?");
-  } while (SubTypes.back()->getTypeAtIndex(Path.back())->isAggregateType());
+  } while (ExtractValueInst::getIndexedType(SubTypes.back(), Path.back())
+               ->isAggregateType());
 
   return true;
 }
 
 
 /// Test if the given instruction is in a position to be optimized
 /// with a tail-call. This roughly means that it's in a block with
 /// a return and there's nothing that needs to be scheduled
if (((IID == Intrinsic::memcpy &&
          (IID == Intrinsic::memset &&
           TLI.getLibcallName(RTLIB::MEMSET) == StringRef("memset"))) &&
         (RetVal == Call->getArgOperand(0) ||
          isPointerBitcastEqualTo(RetVal, Call->getArgOperand(0))))
       return true;
   }
 
   SmallVector<unsigned, 4> RetPath, CallPath;
-  SmallVector<CompositeType *, 4> RetSubTypes, CallSubTypes;
+  SmallVector<Type *, 4> RetSubTypes, CallSubTypes;
 
   bool RetEmpty = !firstRealType(RetVal->getType(), RetSubTypes, RetPath);
   bool CallEmpty = !firstRealType(CallVal->getType(), CallSubTypes, CallPath);
 
   // Nothing's actually returned, it doesn't matter what the callee put there
   // it's a valid tail call.
   if (RetEmpty)
     return true;
 
   // Iterate pairwise through each of the value types making up the tail call
   // and the corresponding return. For each one we want to know whether it's
   // essentially going directly from the tail call to the ret, via operations
   // that end up not generating any code.
   //
   // We allow a certain amount of covariance here. For example it's permitted
   // for the tail call to define more bits than the ret actually cares about
   // (e.g. via a truncate).
   do {
     if (CallEmpty) {
       // We've exhausted the values produced by the tail call instruction, the
       // rest are essentially undef. The type doesn't really matter, but we need
       // *something*.
-      Type *SlotType = RetSubTypes.back()->getTypeAtIndex(RetPath.back());
+      Type *SlotType =
+          ExtractValueInst::getIndexedType(RetSubTypes.back(), RetPath.back());
       CallVal = UndefValue::get(SlotType);
     }
 
     // The manipulations performed when we're looking through an insertvalue or
     // an extractvalue would happen at the front of the RetPath list, so since
     // we have to copy it anyway it's more efficient to create a reversed copy.
     SmallVector<unsigned, 4> TmpRetPath(RetPath.rbegin(), RetPath.rend());
     SmallVector<unsigned, 4> TmpCallPath(CallPath.rbegin(), CallPath.rend());

llvm/lib/FuzzMutate/Operations.cpp

for (int I = 0, E = STy->getNumElements(); I < E; ++I)
       makeConstantsWithType(STy->getTypeAtIndex(I), Result);
     return Result;
   };
   return {Pred, Make};
 }
 
 static SourcePred validInsertValueIndex() {
   auto Pred = [](ArrayRef<Value *> Cur, const Value *V) {
-    auto *CTy = cast<CompositeType>(Cur[0]->getType());
     if (auto *CI = dyn_cast<ConstantInt>(V))
-      if (CI->getBitWidth() == 32 &&
-          CTy->getTypeAtIndex(CI->getZExtValue()) == Cur[1]->getType())
-        return true;
+      if (CI->getBitWidth() == 32) {
+        Type *Indexed = ExtractValueInst::getIndexedType(Cur[0]->getType(),
+                                                         CI->getZExtValue());
+        return Indexed == Cur[1]->getType();
+      }
     return false;
   };
   auto Make = [](ArrayRef<Value *> Cur, ArrayRef<Type *> Ts) {
     std::vector<Constant *> Result;
     auto *Int32Ty = Type::getInt32Ty(Cur[0]->getContext());
-    auto *CTy = cast<CompositeType>(Cur[0]->getType());
-    for (int I = 0, E = getAggregateNumElements(CTy); I < E; ++I)
-      if (CTy->getTypeAtIndex(I) == Cur[1]->getType())
+    auto *BaseTy = Cur[0]->getType();
+    int I = 0;
+    while (Type *Indexed = ExtractValueInst::getIndexedType(BaseTy, I)) {
+      if (Indexed == Cur[1]->getType())
         Result.push_back(ConstantInt::get(Int32Ty, I));
+      ++I;
+    }
     return Result;
   };
   return {Pred, Make};
 }
 
 OpDescriptor llvm::fuzzerop::insertValueDescriptor(unsigned Weight) {
   auto buildInsert = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
     // TODO: It's pretty inefficient to shuffle this all through constants.

llvm/lib/IR/ConstantFold.cpp

Constant *llvm::ConstantFoldGetElementPtr(Type *PointeeTy, Constant *C,
   }
 
   // Check to see if any array indices are not within the corresponding
   // notional array or vector bounds. If so, try to determine if they can be
   // factored out into preceding dimensions.
   SmallVector<Constant *, 8> NewIdxs;
   Type *Ty = PointeeTy;
   Type *Prev = C->getType();
+  auto GEPIter = gep_type_begin(PointeeTy, Idxs);
   bool Unknown =
       !isa<ConstantInt>(Idxs[0]) && !isa<ConstantDataVector>(Idxs[0]);
   for (unsigned i = 1, e = Idxs.size(); i != e;
-       Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
+       Prev = Ty, Ty = (++GEPIter).getIndexedType(), ++i) {
     if (!isa<ConstantInt>(Idxs[i]) && !isa<ConstantDataVector>(Idxs[i])) {
       // We don't know if it's in range or not.
       Unknown = true;
       continue;
     }
     if (!isa<ConstantInt>(Idxs[i - 1]) && !isa<ConstantDataVector>(Idxs[i - 1]))
       // Skip if the type of the previous index is not supported.
       continue;

llvm/lib/IR/Constants.cpp

else if (CFP->getType()->isFloatTy())
       return getFPSequenceIfElementsMatch<SequenceTy, uint32_t>(V);
     else if (CFP->getType()->isDoubleTy())
       return getFPSequenceIfElementsMatch<SequenceTy, uint64_t>(V);
   }
 
   return nullptr;
 }
 
-ConstantAggregate::ConstantAggregate(CompositeType *T, ValueTy VT,
+ConstantAggregate::ConstantAggregate(Type *T, ValueTy VT,
                                      ArrayRef<Constant *> V)
     : Constant(T, VT, OperandTraits<ConstantAggregate>::op_end(this) - V.size(),
                V.size()) {
   llvm::copy(V, op_begin());
 
   // Check that types match, unless this is an opaque struct.
-  if (auto *ST = dyn_cast<StructType>(T))
+  if (auto *ST = dyn_cast<StructType>(T)) {
     if (ST->isOpaque())
       return;
     for (unsigned I = 0, E = V.size(); I != E; ++I)
-    assert(V[I]->getType() == T->getTypeAtIndex(I) &&
-           "Initializer for composite element doesn't match!");
+      assert(V[I]->getType() == ST->getTypeAtIndex(I) &&
+             "Initializer for struct element doesn't match!");
+  }
 }
 
 ConstantArray::ConstantArray(ArrayType *T, ArrayRef<Constant *> V)
     : ConstantAggregate(T, ConstantArrayVal, V) {
   assert(V.size() == T->getNumElements() &&
          "Invalid initializer for constant array");
 }
 

llvm/lib/IR/Instructions.cpp

: Instruction(GEPI.getType(), GetElementPtr,
                   OperandTraits<GetElementPtrInst>::op_end(this) -
                       GEPI.getNumOperands(),
                   GEPI.getNumOperands()),
       SourceElementType(GEPI.SourceElementType),
       ResultElementType(GEPI.ResultElementType) {
   std::copy(GEPI.op_begin(), GEPI.op_end(), op_begin());
   SubclassOptionalData = GEPI.SubclassOptionalData;
 }
 
-/// getIndexedType - Returns the type of the element that would be accessed with
-/// a gep instruction with the specified parameters.
-///
-/// The Idxs pointer should point to a continuous piece of memory containing the
-/// indices, either as Value* or uint64_t.
-///
-/// A null type is returned if the indices are invalid for the specified
-/// pointer type.
-///
-template <typename IndexTy>
-static Type *getIndexedTypeInternal(Type *Agg, ArrayRef<IndexTy> IdxList) {
-  // Handle the special case of the empty set index set, which is always valid.
-  if (IdxList.empty())
-    return Agg;
+Type *GetElementPtrInst::getTypeAtIndex(Type *Ty, Value *Idx) {
+  if (auto Struct = dyn_cast<StructType>(Ty)) {
+    if (!Struct->indexValid(Idx))
+      return nullptr;
+    return Struct->getTypeAtIndex(Idx);
+  }
+  if (!Idx->getType()->isIntOrIntVectorTy())
+    return nullptr;
+  if (auto Array = dyn_cast<ArrayType>(Ty))
+    return Array->getElementType();
+  if (auto Vector = dyn_cast<VectorType>(Ty))
+    return Vector->getElementType();
+  return nullptr;
+}
 
-  // If there is at least one index, the top level type must be sized, otherwise
-  // it cannot be 'stepped over'.
-  if (!Agg->isSized())
-    return nullptr;
+Type *GetElementPtrInst::getTypeAtIndex(Type *Ty, uint64_t Idx) {
+  if (auto Struct = dyn_cast<StructType>(Ty)) {
+    if (Idx >= Struct->getNumElements())
+      return nullptr;
+    return Struct->getElementType(Idx);
+  }
+  if (auto Array = dyn_cast<ArrayType>(Ty))
+    return Array->getElementType();
+  if (auto Vector = dyn_cast<VectorType>(Ty))
+    return Vector->getElementType();
+}
 
-  unsigned CurIdx = 1;
-  for (; CurIdx != IdxList.size(); ++CurIdx) {
-    CompositeType *CT = dyn_cast<CompositeType>(Agg);
-    if (!CT || CT->isPointerTy()) return nullptr;
-    IndexTy Index = IdxList[CurIdx];
-    if (!CT->indexValid(Index)) return nullptr;
-    Agg = CT->getTypeAtIndex(Index);
+template <typename IndexTy>
+static Type *getIndexedTypeInternal(Type *Ty, ArrayRef<IndexTy> IdxList) {
+  if (IdxList.empty())
+    return Ty;
+  for (IndexTy V : IdxList.slice(1)) {
+    Ty = GetElementPtrInst::getTypeAtIndex(Ty, V);
+    if (!Ty)
+      return Ty;
   }
-  return CurIdx == IdxList.size() ? Agg : nullptr;
+  return Ty;
 }
 
 Type *GetElementPtrInst::getIndexedType(Type *Ty, ArrayRef<Value *> IdxList) {
   return getIndexedTypeInternal(Ty, IdxList);
 }
 
 Type *GetElementPtrInst::getIndexedType(Type *Ty,
                                         ArrayRef<Constant *> IdxList) {
for (unsigned Index : Idxs) {
     // indexValid() always returns true for arrays because getelementptr allows
     // out-of-bounds indices. Since we don't allow those for extractvalue and
     // insertvalue we need to check array indexing manually.
     // Since the only other types we can index into are struct types it's just
     // as easy to check those manually as well.
     if (ArrayType *AT = dyn_cast<ArrayType>(Agg)) {
       if (Index >= AT->getNumElements())
         return nullptr;
+      Agg = AT->getElementType();
     } else if (StructType *ST = dyn_cast<StructType>(Agg)) {
       if (Index >= ST->getNumElements())
         return nullptr;
+      Agg = ST->getElementType(Index);
     } else {
       // Not a valid type to index into.
       return nullptr;
     }
-
-    Agg = cast<CompositeType>(Agg)->getTypeAtIndex(Index);
   }
   return const_cast<Type*>(Agg);
 }
 
 //===----------------------------------------------------------------------===//
 //                             UnaryOperator Class
 //===----------------------------------------------------------------------===//
 

llvm/lib/IR/Type.cpp

bool StructType::isLayoutIdentical(StructType *Other) const {
 
   return elements() == Other->elements();
 }
 
 StructType *Module::getTypeByName(StringRef Name) const {
   return getContext().pImpl->NamedStructTypes.lookup(Name);
 }
 
-//===----------------------------------------------------------------------===//
-//                       CompositeType Implementation
-//===----------------------------------------------------------------------===//
-
-Type *CompositeType::getTypeAtIndex(const Value *V) const {
-  if (auto *STy = dyn_cast<StructType>(this)) {
-    unsigned Idx =
-      (unsigned)cast<Constant>(V)->getUniqueInteger().getZExtValue();
-    assert(indexValid(Idx) && "Invalid structure index!");
-    return STy->getElementType(Idx);
-  }
-
-  return cast<SequentialType>(this)->getElementType();
-}
-
-Type *CompositeType::getTypeAtIndex(unsigned Idx) const{
-  if (auto *STy = dyn_cast<StructType>(this)) {
-    assert(indexValid(Idx) && "Invalid structure index!");
-    return STy->getElementType(Idx);
-  }
-
-  return cast<SequentialType>(this)->getElementType();
+Type *StructType::getTypeAtIndex(const Value *V) const {
+  unsigned Idx = (unsigned)cast<Constant>(V)->getUniqueInteger().getZExtValue();
+  return getElementType(Idx);
 }
 
-bool CompositeType::indexValid(const Value *V) const {
-  if (auto *STy = dyn_cast<StructType>(this)) {
-    // Structure indexes require (vectors of) 32-bit integer constants.  In the
-    // vector case all of the indices must be equal.
-    if (!V->getType()->isIntOrIntVectorTy(32))
-      return false;
-    const Constant *C = dyn_cast<Constant>(V);
-    if (C && V->getType()->isVectorTy())
-      C = C->getSplatValue();
-    const ConstantInt *CU = dyn_cast_or_null<ConstantInt>(C);
-    return CU && CU->getZExtValue() < STy->getNumElements();
-  }
-
-  // Sequential types can be indexed by any integer.
-  return V->getType()->isIntOrIntVectorTy();
-}
-
-bool CompositeType::indexValid(unsigned Idx) const {
-  if (auto *STy = dyn_cast<StructType>(this))
-    return Idx < STy->getNumElements();
-  // Sequential types can be indexed by any integer.
-  return true;
+bool StructType::indexValid(const Value *V) const {
+  return CU && CU->getZExtValue() < getNumElements();
 }
 
 //===----------------------------------------------------------------------===//
 //                           ArrayType Implementation
 //===----------------------------------------------------------------------===//
 
 ArrayType::ArrayType(Type *ElType, uint64_t NumEl)
   : SequentialType(ArrayTyID, ElType, NumEl) {}

llvm/lib/Target/ARM/ARMISelLowering.cpp

case Intrinsic::arm_neon_vst1x4: {
     // volatile stores with NEON intrinsics not supported
     Info.flags = MachineMemOperand::MOStore;
     return true;
   }
   case Intrinsic::arm_mve_vld2q:
   case Intrinsic::arm_mve_vld4q: {
     Info.opc = ISD::INTRINSIC_W_CHAIN;
     // Conservatively set memVT to the entire set of vectors loaded.
-    Type *VecTy = cast<CompositeType>(I.getType())->getTypeAtIndex(1);
+    Type *VecTy = cast<StructType>(I.getType())->getElementType(1);
     unsigned Factor = Intrinsic == Intrinsic::arm_mve_vld2q ? 2 : 4;
     Info.memVT = EVT::getVectorVT(VecTy->getContext(), MVT::i64, Factor * 2);
     Info.ptrVal = I.getArgOperand(0);
     Info.offset = 0;
     Info.align = Align(VecTy->getScalarSizeInBits() / 8);
     // volatile loads with MVE intrinsics not supported
     Info.flags = MachineMemOperand::MOLoad;
     return true;

llvm/lib/Transforms/IPO/ArgumentPromotion.cpp

for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E;
               Type *IdxTy =
                   (ElTy->isStructTy() ? Type::getInt32Ty(F->getContext())
                                       : Type::getInt64Ty(F->getContext()));
               Ops.push_back(ConstantInt::get(IdxTy, II));
               // Keep track of the type we're currently indexing.
               if (auto *ElPTy = dyn_cast<PointerType>(ElTy))
                 ElTy = ElPTy->getElementType();
               else
-                ElTy = cast<CompositeType>(ElTy)->getTypeAtIndex(II);
+                ElTy = GetElementPtrInst::getTypeAtIndex(ElTy, II);
             }
             // And create a GEP to extract those indices.
             V = IRB.CreateGEP(ArgIndex.first, V, Ops, V->getName() + ".idx");
             Ops.clear();
           }
           // Since we're replacing a load make sure we take the alignment
           // of the previous load.
           LoadInst *newLoad =
bool ArgumentPromotionPass::isDenselyPacked(Type *type, const DataLayout &DL) {
   if (!type->isSized())
     return false;
 
   // If the alloc size is not equal to the storage size, then there are padding
   // bytes. For x86_fp80 on x86-64, size: 80 alloc size: 128.
   if (DL.getTypeSizeInBits(type) != DL.getTypeAllocSizeInBits(type))
     return false;
 
-  if (!isa<CompositeType>(type))
+  if (!isa<StructType>(type) && !isa<SequentialType>(type))
     return true;
 
   // For homogenous sequential types, check for padding within members.
   if (SequentialType *seqTy = dyn_cast<SequentialType>(type))
     return isDenselyPacked(seqTy->getElementType(), DL);
 
   // Check for padding within and between elements of a struct.
   StructType *StructTy = cast<StructType>(type);

llvm/lib/Transforms/IPO/GlobalOpt.cpp

switch (Ty->getTypeID()) {
       }
       case Type::StructTyID: {
         StructType *STy = cast<StructType>(Ty);
         if (STy->isOpaque()) return true;
         for (StructType::element_iterator I = STy->element_begin(),
                  E = STy->element_end(); I != E; ++I) {
           Type *InnerTy = *I;
           if (isa<PointerType>(InnerTy)) return true;
-          if (isa<CompositeType>(InnerTy))
+          if (isa<StructType>(InnerTy) || isa<SequentialType>(InnerTy))
             Types.push_back(InnerTy);
         }
         break;
       }
     }
     if (--Limit == 0) return true;
   } while (!Types.empty());
   return false;

llvm/lib/Transforms/IPO/StripSymbols.cpp

static void RemoveDeadConstant(Constant *C) {
   assert(C->use_empty() && "Constant is not dead!");
   SmallPtrSet<Constant*, 4> Operands;
   for (Value *Op : C->operands())
     if (OnlyUsedBy(Op, C))
       Operands.insert(cast<Constant>(Op));
   if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
     if (!GV->hasLocalLinkage()) return;   // Don't delete non-static globals.
     GV->eraseFromParent();
-  }
-  else if (!isa<Function>(C))
-    if (isa<CompositeType>(C->getType()))
+  } else if (!isa<Function>(C)) {
+    // FIXME: Why does the type of the constant matter here?
+    if (isa<StructType>(C->getType()) || isa<ArrayType>(C->getType()) ||
+        isa<VectorType>(C->getType()))
       C->destroyConstant();
+  }
 
   // If the constant referenced anything, see if we can delete it as well.
   for (Constant *O : Operands)
     RemoveDeadConstant(O);
 }
 
 // Strip the symbol table of its names.
 //

llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp

Type *PointeeType =
         cast<PointerType>(Src->getType()->getScalarType())->getElementType();
     if (!PointeeType->isSized())
       return nullptr;
 
     // If the source and destination are pointers, and this cast is equivalent
     // to a getelementptr X, 0, 0, 0...  turn it into the appropriate gep.
     // This can enhance SROA and other transforms that want type-safe pointers.
     unsigned NumZeros = 0;
-    while (SrcElTy != DstElTy &&
-           isa<CompositeType>(SrcElTy) && !SrcElTy->isPointerTy() &&
-           SrcElTy->getNumContainedTypes() /* not "{}" */) {
-      SrcElTy = cast<CompositeType>(SrcElTy)->getTypeAtIndex(0U);
+    while (SrcElTy && SrcElTy != DstElTy) {
+      SrcElTy = GetElementPtrInst::getTypeAtIndex(SrcElTy, (uint64_t)0);
       ++NumZeros;
     }
 
     // If we found a path from the src to dest, create the getelementptr now.
     if (SrcElTy == DstElTy) {
       SmallVector<Value *, 8> Idxs(NumZeros + 1, Builder.getInt32(0));
       GetElementPtrInst *GEP =
           GetElementPtrInst::Create(SrcPTy->getElementType(), Src, Idxs);

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

for (auto I = PN->op_begin()+1, E = PN->op_end(); I !=E; ++I) {
             return nullptr;
           }
         }
 
         // Sink down a layer of the type for the next iteration.
         if (J > 0) {
           if (J == 1) {
             CurTy = Op1->getSourceElementType();
-          } else if (auto *CT = dyn_cast<CompositeType>(CurTy)) {
-            CurTy = CT->getTypeAtIndex(Op1->getOperand(J));
           } else {
-            CurTy = nullptr;
+            CurTy =
+                GetElementPtrInst::getTypeAtIndex(CurTy, Op1->getOperand(J));
           }
         }
       }
     }
 
     // If not all GEPs are identical we'll have to create a new PHI node.
     // Check that the old PHI node has only one use so that it will get
     // removed.

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

default:
       return;
   }
 }
 
 unsigned BoUpSLP::canMapToVector(Type *T, const DataLayout &DL) const {
   unsigned N = 1;
   Type *EltTy = T;
 
-  while (isa<CompositeType>(EltTy)) {
+  while (isa<StructType>(EltTy) || isa<SequentialType>(EltTy)) {
     if (auto *ST = dyn_cast<StructType>(EltTy)) {
       // Check that struct is homogeneous.
       for (const auto *Ty : ST->elements())
         if (Ty != *ST->element_begin())
           return 0;
       N *= ST->getNumElements();
       EltTy = *ST->element_begin();
     } else {