From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Fri, 4 Oct 2019 01:25:59 +0000 (+0000)
Subject: Properly handle instantiation-dependent array bounds.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=38c1f7c254e6e699d3e45e446fa4515418a00c9a;p=clang

Properly handle instantiation-dependent array bounds.

We previously failed to treat an array with an instantiation-dependent
but not value-dependent bound as being an instantiation-dependent type.
We now track the array bound expression as part of a constant array type
if it's an instantiation-dependent expression.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@373685 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/AST/ASTContext.h b/include/clang/AST/ASTContext.h
index 66bd4aa1e3..5105b9c35c 100644
--- a/include/clang/AST/ASTContext.h
+++ b/include/clang/AST/ASTContext.h
@@ -185,7 +185,8 @@ private:
   mutable llvm::FoldingSet<LValueReferenceType> LValueReferenceTypes;
   mutable llvm::FoldingSet<RValueReferenceType> RValueReferenceTypes;
   mutable llvm::FoldingSet<MemberPointerType> MemberPointerTypes;
-  mutable llvm::FoldingSet<ConstantArrayType> ConstantArrayTypes;
+  mutable llvm::ContextualFoldingSet<ConstantArrayType, ASTContext &>
+      ConstantArrayTypes;
   mutable llvm::FoldingSet<IncompleteArrayType> IncompleteArrayTypes;
   mutable std::vector<VariableArrayType*> VariableArrayTypes;
   mutable llvm::FoldingSet<DependentSizedArrayType> DependentSizedArrayTypes;
@@ -1330,6 +1331,7 @@ public:
   /// Return the unique reference to the type for a constant array of
   /// the specified element type.
   QualType getConstantArrayType(QualType EltTy, const llvm::APInt &ArySize,
+                                const Expr *SizeExpr,
                                 ArrayType::ArraySizeModifier ASM,
                                 unsigned IndexTypeQuals) const;
 
diff --git a/include/clang/AST/RecursiveASTVisitor.h b/include/clang/AST/RecursiveASTVisitor.h
index 7d5faf2b8c..426c256b6a 100644
--- a/include/clang/AST/RecursiveASTVisitor.h
+++ b/include/clang/AST/RecursiveASTVisitor.h
@@ -959,8 +959,11 @@ DEF_TRAVERSE_TYPE(AdjustedType, { TRY_TO(TraverseType(T->getOriginalType())); })
 
 DEF_TRAVERSE_TYPE(DecayedType, { TRY_TO(TraverseType(T->getOriginalType())); })
 
-DEF_TRAVERSE_TYPE(ConstantArrayType,
-                  { TRY_TO(TraverseType(T->getElementType())); })
+DEF_TRAVERSE_TYPE(ConstantArrayType, {
+  TRY_TO(TraverseType(T->getElementType()));
+  if (T->getSizeExpr())
+    TRY_TO(TraverseStmt(const_cast<Expr*>(T->getSizeExpr())));
+})
 
 DEF_TRAVERSE_TYPE(IncompleteArrayType,
                   { TRY_TO(TraverseType(T->getElementType())); })
diff --git a/include/clang/AST/Type.h b/include/clang/AST/Type.h
index 2f00034c0e..ecbbd73e19 100644
--- a/include/clang/AST/Type.h
+++ b/include/clang/AST/Type.h
@@ -1513,6 +1513,15 @@ protected:
     unsigned SizeModifier : 3;
   };
 
+  class ConstantArrayTypeBitfields {
+    friend class ConstantArrayType;
+
+    unsigned : NumTypeBits + 3 + 3;
+
+    /// Whether we have a stored size expression.
+    unsigned HasStoredSizeExpr : 1;
+  };
+
   class BuiltinTypeBitfields {
     friend class BuiltinType;
 
@@ -1734,6 +1743,7 @@ protected:
   union {
     TypeBitfields TypeBits;
     ArrayTypeBitfields ArrayTypeBits;
+    ConstantArrayTypeBitfields ConstantArrayTypeBits;
     AttributedTypeBitfields AttributedTypeBits;
     AutoTypeBitfields AutoTypeBits;
     BuiltinTypeBitfields BuiltinTypeBits;
@@ -2864,22 +2874,8 @@ private:
 protected:
   friend class ASTContext; // ASTContext creates these.
 
-  // C++ [temp.dep.type]p1:
-  //   A type is dependent if it is...
-  //     - an array type constructed from any dependent type or whose
-  //       size is specified by a constant expression that is
-  //       value-dependent,
-  ArrayType(TypeClass tc, QualType et, QualType can,
-            ArraySizeModifier sm, unsigned tq,
-            bool ContainsUnexpandedParameterPack)
-      : Type(tc, can, et->isDependentType() || tc == DependentSizedArray,
-             et->isInstantiationDependentType() || tc == DependentSizedArray,
-             (tc == VariableArray || et->isVariablyModifiedType()),
-             ContainsUnexpandedParameterPack),
-        ElementType(et) {
-    ArrayTypeBits.IndexTypeQuals = tq;
-    ArrayTypeBits.SizeModifier = sm;
-  }
+  ArrayType(TypeClass tc, QualType et, QualType can, ArraySizeModifier sm,
+            unsigned tq, const Expr *sz = nullptr);
 
 public:
   QualType getElementType() const { return ElementType; }
@@ -2907,25 +2903,35 @@ public:
 /// Represents the canonical version of C arrays with a specified constant size.
 /// For example, the canonical type for 'int A[4 + 4*100]' is a
 /// ConstantArrayType where the element type is 'int' and the size is 404.
-class ConstantArrayType : public ArrayType {
+class ConstantArrayType final
+    : public ArrayType,
+      private llvm::TrailingObjects<ConstantArrayType, const Expr *> {
+  friend class ASTContext; // ASTContext creates these.
+  friend TrailingObjects;
+
   llvm::APInt Size; // Allows us to unique the type.
 
   ConstantArrayType(QualType et, QualType can, const llvm::APInt &size,
-                    ArraySizeModifier sm, unsigned tq)
-      : ArrayType(ConstantArray, et, can, sm, tq,
-                  et->containsUnexpandedParameterPack()),
-        Size(size) {}
-
-protected:
-  friend class ASTContext; // ASTContext creates these.
+                    const Expr *sz, ArraySizeModifier sm, unsigned tq)
+      : ArrayType(ConstantArray, et, can, sm, tq, sz), Size(size) {
+    ConstantArrayTypeBits.HasStoredSizeExpr = sz != nullptr;
+    if (ConstantArrayTypeBits.HasStoredSizeExpr) {
+      assert(!can.isNull() && "canonical constant array should not have size");
+      *getTrailingObjects<const Expr*>() = sz;
+    }
+  }
 
-  ConstantArrayType(TypeClass tc, QualType et, QualType can,
-                    const llvm::APInt &size, ArraySizeModifier sm, unsigned tq)
-      : ArrayType(tc, et, can, sm, tq, et->containsUnexpandedParameterPack()),
-        Size(size) {}
+  unsigned numTrailingObjects(OverloadToken<const Expr*>) const {
+    return ConstantArrayTypeBits.HasStoredSizeExpr;
+  }
 
 public:
   const llvm::APInt &getSize() const { return Size; }
+  const Expr *getSizeExpr() const {
+    return ConstantArrayTypeBits.HasStoredSizeExpr
+               ? *getTrailingObjects<const Expr *>()
+               : nullptr;
+  }
   bool isSugared() const { return false; }
   QualType desugar() const { return QualType(this, 0); }
 
@@ -2939,19 +2945,15 @@ public:
   /// can require, which limits the maximum size of the array.
   static unsigned getMaxSizeBits(const ASTContext &Context);
 
-  void Profile(llvm::FoldingSetNodeID &ID) {
-    Profile(ID, getElementType(), getSize(),
+  void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Ctx) {
+    Profile(ID, Ctx, getElementType(), getSize(), getSizeExpr(),
             getSizeModifier(), getIndexTypeCVRQualifiers());
   }
 
-  static void Profile(llvm::FoldingSetNodeID &ID, QualType ET,
-                      const llvm::APInt &ArraySize, ArraySizeModifier SizeMod,
-                      unsigned TypeQuals) {
-    ID.AddPointer(ET.getAsOpaquePtr());
-    ID.AddInteger(ArraySize.getZExtValue());
-    ID.AddInteger(SizeMod);
-    ID.AddInteger(TypeQuals);
-  }
+  static void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Ctx,
+                      QualType ET, const llvm::APInt &ArraySize,
+                      const Expr *SizeExpr, ArraySizeModifier SizeMod,
+                      unsigned TypeQuals);
 
   static bool classof(const Type *T) {
     return T->getTypeClass() == ConstantArray;
@@ -2966,8 +2968,7 @@ class IncompleteArrayType : public ArrayType {
 
   IncompleteArrayType(QualType et, QualType can,
                       ArraySizeModifier sm, unsigned tq)
-      : ArrayType(IncompleteArray, et, can, sm, tq,
-                  et->containsUnexpandedParameterPack()) {}
+      : ArrayType(IncompleteArray, et, can, sm, tq) {}
 
 public:
   friend class StmtIteratorBase;
@@ -3019,8 +3020,7 @@ class VariableArrayType : public ArrayType {
   VariableArrayType(QualType et, QualType can, Expr *e,
                     ArraySizeModifier sm, unsigned tq,
                     SourceRange brackets)
-      : ArrayType(VariableArray, et, can, sm, tq,
-                  et->containsUnexpandedParameterPack()),
+      : ArrayType(VariableArray, et, can, sm, tq, e),
         SizeExpr((Stmt*) e), Brackets(brackets) {}
 
 public:
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index fd84209463..a41b64ffcc 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -829,7 +829,8 @@ static bool isAddrSpaceMapManglingEnabled(const TargetInfo &TI,
 ASTContext::ASTContext(LangOptions &LOpts, SourceManager &SM,
                        IdentifierTable &idents, SelectorTable &sels,
                        Builtin::Context &builtins)
-    : FunctionProtoTypes(this_()), TemplateSpecializationTypes(this_()),
+    : ConstantArrayTypes(this_()), FunctionProtoTypes(this_()),
+      TemplateSpecializationTypes(this_()),
       DependentTemplateSpecializationTypes(this_()),
       SubstTemplateTemplateParmPacks(this_()), SourceMgr(SM), LangOpts(LOpts),
       SanitizerBL(new SanitizerBlacklist(LangOpts.SanitizerBlacklistFiles, SM)),
@@ -3165,31 +3166,38 @@ QualType ASTContext::getMemberPointerType(QualType T, const Type *Cls) const {
 /// array of the specified element type.
 QualType ASTContext::getConstantArrayType(QualType EltTy,
                                           const llvm::APInt &ArySizeIn,
+                                          const Expr *SizeExpr,
                                           ArrayType::ArraySizeModifier ASM,
                                           unsigned IndexTypeQuals) const {
   assert((EltTy->isDependentType() ||
           EltTy->isIncompleteType() || EltTy->isConstantSizeType()) &&
          "Constant array of VLAs is illegal!");
 
+  // We only need the size as part of the type if it's instantiation-dependent.
+  if (SizeExpr && !SizeExpr->isInstantiationDependent())
+    SizeExpr = nullptr;
+
   // Convert the array size into a canonical width matching the pointer size for
   // the target.
   llvm::APInt ArySize(ArySizeIn);
   ArySize = ArySize.zextOrTrunc(Target->getMaxPointerWidth());
 
   llvm::FoldingSetNodeID ID;
-  ConstantArrayType::Profile(ID, EltTy, ArySize, ASM, IndexTypeQuals);
+  ConstantArrayType::Profile(ID, *this, EltTy, ArySize, SizeExpr, ASM,
+                             IndexTypeQuals);
 
   void *InsertPos = nullptr;
   if (ConstantArrayType *ATP =
       ConstantArrayTypes.FindNodeOrInsertPos(ID, InsertPos))
     return QualType(ATP, 0);
 
-  // If the element type isn't canonical or has qualifiers, this won't
-  // be a canonical type either, so fill in the canonical type field.
+  // If the element type isn't canonical or has qualifiers, or the array bound
+  // is instantiation-dependent, this won't be a canonical type either, so fill
+  // in the canonical type field.
   QualType Canon;
-  if (!EltTy.isCanonical() || EltTy.hasLocalQualifiers()) {
+  if (!EltTy.isCanonical() || EltTy.hasLocalQualifiers() || SizeExpr) {
     SplitQualType canonSplit = getCanonicalType(EltTy).split();
-    Canon = getConstantArrayType(QualType(canonSplit.Ty, 0), ArySize,
+    Canon = getConstantArrayType(QualType(canonSplit.Ty, 0), ArySize, nullptr,
                                  ASM, IndexTypeQuals);
     Canon = getQualifiedType(Canon, canonSplit.Quals);
 
@@ -3199,8 +3207,11 @@ QualType ASTContext::getConstantArrayType(QualType EltTy,
     assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
   }
 
-  auto *New = new (*this,TypeAlignment)
-    ConstantArrayType(EltTy, Canon, ArySize, ASM, IndexTypeQuals);
+  void *Mem = Allocate(
+      ConstantArrayType::totalSizeToAlloc<const Expr *>(SizeExpr ? 1 : 0),
+      TypeAlignment);
+  auto *New = new (Mem)
+    ConstantArrayType(EltTy, Canon, ArySize, SizeExpr, ASM, IndexTypeQuals);
   ConstantArrayTypes.InsertNode(New, InsertPos);
   Types.push_back(New);
   return QualType(New, 0);
@@ -3297,6 +3308,7 @@ QualType ASTContext::getVariableArrayDecayedType(QualType type) const {
     result = getConstantArrayType(
                  getVariableArrayDecayedType(cat->getElementType()),
                                   cat->getSize(),
+                                  cat->getSizeExpr(),
                                   cat->getSizeModifier(),
                                   cat->getIndexTypeCVRQualifiers());
     break;
@@ -5192,7 +5204,7 @@ QualType ASTContext::getUnqualifiedArrayType(QualType type,
 
   if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
     return getConstantArrayType(unqualElementType, CAT->getSize(),
-                                CAT->getSizeModifier(), 0);
+                                CAT->getSizeExpr(), CAT->getSizeModifier(), 0);
   }
 
   if (const auto *IAT = dyn_cast<IncompleteArrayType>(AT)) {
@@ -5565,6 +5577,7 @@ const ArrayType *ASTContext::getAsArrayType(QualType T) const {
 
   if (const auto *CAT = dyn_cast<ConstantArrayType>(ATy))
     return cast<ArrayType>(getConstantArrayType(NewEltTy, CAT->getSize(),
+                                                CAT->getSizeExpr(),
                                                 CAT->getSizeModifier(),
                                            CAT->getIndexTypeCVRQualifiers()));
   if (const auto *IAT = dyn_cast<IncompleteArrayType>(ATy))
@@ -7471,7 +7484,7 @@ static TypedefDecl *CreatePowerABIBuiltinVaListDecl(const ASTContext *Context) {
   llvm::APInt Size(Context->getTypeSize(Context->getSizeType()), 1);
   QualType VaListTagArrayType
     = Context->getConstantArrayType(VaListTagTypedefType,
-                                    Size, ArrayType::Normal, 0);
+                                    Size, nullptr, ArrayType::Normal, 0);
   return Context->buildImplicitTypedef(VaListTagArrayType, "__builtin_va_list");
 }
 
@@ -7524,16 +7537,16 @@ CreateX86_64ABIBuiltinVaListDecl(const ASTContext *Context) {
 
   // typedef struct __va_list_tag __builtin_va_list[1];
   llvm::APInt Size(Context->getTypeSize(Context->getSizeType()), 1);
-  QualType VaListTagArrayType =
-      Context->getConstantArrayType(VaListTagType, Size, ArrayType::Normal, 0);
+  QualType VaListTagArrayType = Context->getConstantArrayType(
+      VaListTagType, Size, nullptr, ArrayType::Normal, 0);
   return Context->buildImplicitTypedef(VaListTagArrayType, "__builtin_va_list");
 }
 
 static TypedefDecl *CreatePNaClABIBuiltinVaListDecl(const ASTContext *Context) {
   // typedef int __builtin_va_list[4];
   llvm::APInt Size(Context->getTypeSize(Context->getSizeType()), 4);
-  QualType IntArrayType =
-      Context->getConstantArrayType(Context->IntTy, Size, ArrayType::Normal, 0);
+  QualType IntArrayType = Context->getConstantArrayType(
+      Context->IntTy, Size, nullptr, ArrayType::Normal, 0);
   return Context->buildImplicitTypedef(IntArrayType, "__builtin_va_list");
 }
 
@@ -7627,8 +7640,8 @@ CreateSystemZBuiltinVaListDecl(const ASTContext *Context) {
 
   // typedef __va_list_tag __builtin_va_list[1];
   llvm::APInt Size(Context->getTypeSize(Context->getSizeType()), 1);
-  QualType VaListTagArrayType =
-      Context->getConstantArrayType(VaListTagType, Size, ArrayType::Normal, 0);
+  QualType VaListTagArrayType = Context->getConstantArrayType(
+      VaListTagType, Size, nullptr, ArrayType::Normal, 0);
 
   return Context->buildImplicitTypedef(VaListTagArrayType, "__builtin_va_list");
 }
@@ -9072,10 +9085,14 @@ QualType ASTContext::mergeTypes(QualType LHS, QualType RHS,
       return LHS;
     if (RCAT && getCanonicalType(RHSElem) == getCanonicalType(ResultType))
       return RHS;
-    if (LCAT) return getConstantArrayType(ResultType, LCAT->getSize(),
-                                          ArrayType::ArraySizeModifier(), 0);
-    if (RCAT) return getConstantArrayType(ResultType, RCAT->getSize(),
-                                          ArrayType::ArraySizeModifier(), 0);
+    if (LCAT)
+      return getConstantArrayType(ResultType, LCAT->getSize(),
+                                  LCAT->getSizeExpr(),
+                                  ArrayType::ArraySizeModifier(), 0);
+    if (RCAT)
+      return getConstantArrayType(ResultType, RCAT->getSize(),
+                                  RCAT->getSizeExpr(),
+                                  ArrayType::ArraySizeModifier(), 0);
     if (LVAT && getCanonicalType(LHSElem) == getCanonicalType(ResultType))
       return LHS;
     if (RVAT && getCanonicalType(RHSElem) == getCanonicalType(ResultType))
@@ -10317,7 +10334,7 @@ QualType ASTContext::getStringLiteralArrayType(QualType EltTy,
 
   // Get an array type for the string, according to C99 6.4.5. This includes
   // the null terminator character.
-  return getConstantArrayType(EltTy, llvm::APInt(32, Length + 1),
+  return getConstantArrayType(EltTy, llvm::APInt(32, Length + 1), nullptr,
                               ArrayType::Normal, /*IndexTypeQuals*/ 0);
 }
 
diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index 057444ac99..e483216e8f 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -1098,14 +1098,16 @@ ASTNodeImporter::VisitMemberPointerType(const MemberPointerType *T) {
 
 ExpectedType
 ASTNodeImporter::VisitConstantArrayType(const ConstantArrayType *T) {
-  ExpectedType ToElementTypeOrErr = import(T->getElementType());
-  if (!ToElementTypeOrErr)
-    return ToElementTypeOrErr.takeError();
+  QualType ToElementType;
+  const Expr *ToSizeExpr;
+  if (auto Imp = importSeq(T->getElementType(), T->getSizeExpr()))
+    std::tie(ToElementType, ToSizeExpr) = *Imp;
+  else
+    return Imp.takeError();
 
-  return Importer.getToContext().getConstantArrayType(*ToElementTypeOrErr,
-                                                      T->getSize(),
-                                                      T->getSizeModifier(),
-                                               T->getIndexTypeCVRQualifiers());
+  return Importer.getToContext().getConstantArrayType(
+      ToElementType, T->getSize(), ToSizeExpr, T->getSizeModifier(),
+      T->getIndexTypeCVRQualifiers());
 }
 
 ExpectedType
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 169e7ae1e1..8c56a3cc55 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -6004,8 +6004,8 @@ static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E,
     return false;
   }
 
-  QualType AllocType =
-      Info.Ctx.getConstantArrayType(ElemType, Size, ArrayType::Normal, 0);
+  QualType AllocType = Info.Ctx.getConstantArrayType(ElemType, Size, nullptr,
+                                                     ArrayType::Normal, 0);
   APValue *Val = Info.createHeapAlloc(E, AllocType, Result);
   *Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue());
   Result.addArray(Info, E, cast<ConstantArrayType>(AllocType));
@@ -8561,7 +8561,7 @@ bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) {
         ResizedArrayILE = cast<InitListExpr>(Init);
     }
 
-    AllocType = Info.Ctx.getConstantArrayType(AllocType, ArrayBound,
+    AllocType = Info.Ctx.getConstantArrayType(AllocType, ArrayBound, nullptr,
                                               ArrayType::Normal, 0);
   } else {
     assert(!AllocType->isArrayType() &&
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 8ab2f1e271..4fed5b410b 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -109,6 +109,33 @@ bool QualType::isConstant(QualType T, const ASTContext &Ctx) {
   return T.getAddressSpace() == LangAS::opencl_constant;
 }
 
+// C++ [temp.dep.type]p1:
+//   A type is dependent if it is...
+//     - an array type constructed from any dependent type or whose
+//       size is specified by a constant expression that is
+//       value-dependent,
+ArrayType::ArrayType(TypeClass tc, QualType et, QualType can,
+                     ArraySizeModifier sm, unsigned tq, const Expr *sz)
+    // Note, we need to check for DependentSizedArrayType explicitly here
+    // because we use a DependentSizedArrayType with no size expression as the
+    // type of a dependent array of unknown bound with a dependent braced
+    // initializer:
+    //
+    //   template<int ...N> int arr[] = {N...};
+    : Type(tc, can,
+           et->isDependentType() || (sz && sz->isValueDependent()) ||
+               tc == DependentSizedArray,
+           et->isInstantiationDependentType() ||
+               (sz && sz->isInstantiationDependent()) ||
+               tc == DependentSizedArray,
+           (tc == VariableArray || et->isVariablyModifiedType()),
+           et->containsUnexpandedParameterPack() ||
+               (sz && sz->containsUnexpandedParameterPack())),
+      ElementType(et) {
+  ArrayTypeBits.IndexTypeQuals = tq;
+  ArrayTypeBits.SizeModifier = sm;
+}
+
 unsigned ConstantArrayType::getNumAddressingBits(const ASTContext &Context,
                                                  QualType ElementType,
                                                const llvm::APInt &NumElements) {
@@ -156,14 +183,26 @@ unsigned ConstantArrayType::getMaxSizeBits(const ASTContext &Context) {
   return Bits;
 }
 
+void ConstantArrayType::Profile(llvm::FoldingSetNodeID &ID,
+                                const ASTContext &Context, QualType ET,
+                                const llvm::APInt &ArraySize,
+                                const Expr *SizeExpr, ArraySizeModifier SizeMod,
+                                unsigned TypeQuals) {
+  ID.AddPointer(ET.getAsOpaquePtr());
+  ID.AddInteger(ArraySize.getZExtValue());
+  ID.AddInteger(SizeMod);
+  ID.AddInteger(TypeQuals);
+  ID.AddBoolean(SizeExpr != 0);
+  if (SizeExpr)
+    SizeExpr->Profile(ID, Context, true);
+}
+
 DependentSizedArrayType::DependentSizedArrayType(const ASTContext &Context,
                                                  QualType et, QualType can,
                                                  Expr *e, ArraySizeModifier sm,
                                                  unsigned tq,
                                                  SourceRange brackets)
-    : ArrayType(DependentSizedArray, et, can, sm, tq,
-                (et->containsUnexpandedParameterPack() ||
-                 (e && e->containsUnexpandedParameterPack()))),
+    : ArrayType(DependentSizedArray, et, can, sm, tq, e),
       Context(Context), SizeExpr((Stmt*) e), Brackets(brackets) {}
 
 void DependentSizedArrayType::Profile(llvm::FoldingSetNodeID &ID,
@@ -860,7 +899,7 @@ public:
     if (elementType.getAsOpaquePtr() == T->getElementType().getAsOpaquePtr())
       return QualType(T, 0);
 
-    return Ctx.getConstantArrayType(elementType, T->getSize(),
+    return Ctx.getConstantArrayType(elementType, T->getSize(), T->getSizeExpr(),
                                     T->getSizeModifier(),
                                     T->getIndexTypeCVRQualifiers());
   }
@@ -3590,6 +3629,7 @@ static CachedProperties computeCachedProperties(const Type *T) {
 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class,Base) case Type::Class:
 #include "clang/AST/TypeNodes.inc"
     // Treat instantiation-dependent types as external.
+    if (!T->isInstantiationDependentType()) T->dump();
     assert(T->isInstantiationDependentType());
     return CachedProperties(ExternalLinkage, false);
 
diff --git a/lib/CodeGen/CGAtomic.cpp b/lib/CodeGen/CGAtomic.cpp
index f9915a1a8f..afddfb7660 100644
--- a/lib/CodeGen/CGAtomic.cpp
+++ b/lib/CodeGen/CGAtomic.cpp
@@ -102,8 +102,9 @@ namespace {
           llvm::APInt Size(
               /*numBits=*/32,
               C.toCharUnitsFromBits(AtomicSizeInBits).getQuantity());
-          AtomicTy = C.getConstantArrayType(C.CharTy, Size, ArrayType::Normal,
-                                            /*IndexTypeQuals=*/0);
+          AtomicTy =
+              C.getConstantArrayType(C.CharTy, Size, nullptr, ArrayType::Normal,
+                                     /*IndexTypeQuals=*/0);
         }
         AtomicAlign = ValueAlign = lvalue.getAlignment();
       } else if (lvalue.isVectorElt()) {
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 527e512e6a..905db49747 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -3791,7 +3791,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
         -> std::tuple<llvm::Value *, llvm::Value *, llvm::Value *> {
       llvm::APInt ArraySize(32, NumArgs - First);
       QualType SizeArrayTy = getContext().getConstantArrayType(
-          getContext().getSizeType(), ArraySize, ArrayType::Normal,
+          getContext().getSizeType(), ArraySize, nullptr, ArrayType::Normal,
           /*IndexTypeQuals=*/0);
       auto Tmp = CreateMemTemp(SizeArrayTy, "block_sizes");
       llvm::Value *TmpPtr = Tmp.getPointer();
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 576d1b6331..ca91618f16 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -3276,8 +3276,8 @@ void CGDebugInfo::collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
     llvm::APInt ConstVal(32, 1);
     QualType ET = CGM.getContext().getAsArrayType(T)->getElementType();
 
-    T = CGM.getContext().getConstantArrayType(ET, ConstVal, ArrayType::Normal,
-                                              0);
+    T = CGM.getContext().getConstantArrayType(ET, ConstVal, nullptr,
+                                              ArrayType::Normal, 0);
   }
 
   Name = VD->getName();
@@ -3873,8 +3873,8 @@ CGDebugInfo::EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
 
     if (NumPaddingBytes.isPositive()) {
       llvm::APInt pad(32, NumPaddingBytes.getQuantity());
-      FType = CGM.getContext().getConstantArrayType(CGM.getContext().CharTy,
-                                                    pad, ArrayType::Normal, 0);
+      FType = CGM.getContext().getConstantArrayType(
+          CGM.getContext().CharTy, pad, nullptr, ArrayType::Normal, 0);
       EltTys.push_back(CreateMemberType(Unit, FType, "", &FieldOffset));
     }
   }
diff --git a/lib/CodeGen/CGObjC.cpp b/lib/CodeGen/CGObjC.cpp
index 1dd7ec5223..1fa7267808 100644
--- a/lib/CodeGen/CGObjC.cpp
+++ b/lib/CodeGen/CGObjC.cpp
@@ -143,7 +143,7 @@ llvm::Value *CodeGenFunction::EmitObjCCollectionLiteral(const Expr *E,
                             NumElements);
   QualType ElementType = Context.getObjCIdType().withConst();
   QualType ElementArrayType
-    = Context.getConstantArrayType(ElementType, APNumElements,
+    = Context.getConstantArrayType(ElementType, APNumElements, nullptr,
                                    ArrayType::Normal, /*IndexTypeQuals=*/0);
 
   // Allocate the temporary array(s).
@@ -1661,7 +1661,7 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
 
   QualType ItemsTy =
     getContext().getConstantArrayType(getContext().getObjCIdType(),
-                                      llvm::APInt(32, NumItems),
+                                      llvm::APInt(32, NumItems), nullptr,
                                       ArrayType::Normal, 0);
   Address ItemsPtr = CreateMemTemp(ItemsTy, "items.ptr");
 
diff --git a/lib/CodeGen/CGOpenMPRuntime.cpp b/lib/CodeGen/CGOpenMPRuntime.cpp
index bd74367b2e..e9cf692888 100644
--- a/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -3376,9 +3376,9 @@ void CGOpenMPRuntime::emitSingleRegion(CodeGenFunction &CGF,
   // <copy_func>, did_it);
   if (DidIt.isValid()) {
     llvm::APInt ArraySize(/*unsigned int numBits=*/32, CopyprivateVars.size());
-    QualType CopyprivateArrayTy =
-        C.getConstantArrayType(C.VoidPtrTy, ArraySize, ArrayType::Normal,
-                               /*IndexTypeQuals=*/0);
+    QualType CopyprivateArrayTy = C.getConstantArrayType(
+        C.VoidPtrTy, ArraySize, nullptr, ArrayType::Normal,
+        /*IndexTypeQuals=*/0);
     // Create a list of all private variables for copyprivate.
     Address CopyprivateList =
         CGF.CreateMemTemp(CopyprivateArrayTy, ".omp.copyprivate.cpr_list");
@@ -5362,7 +5362,7 @@ void CGOpenMPRuntime::emitTaskCall(CodeGenFunction &CGF, SourceLocation Loc,
     // Define type kmp_depend_info[<Dependences.size()>];
     QualType KmpDependInfoArrayTy = C.getConstantArrayType(
         KmpDependInfoTy, llvm::APInt(/*numBits=*/64, NumDependencies),
-        ArrayType::Normal, /*IndexTypeQuals=*/0);
+        nullptr, ArrayType::Normal, /*IndexTypeQuals=*/0);
     // kmp_depend_info[<Dependences.size()>] deps;
     DependenciesArray =
         CGF.CreateMemTemp(KmpDependInfoArrayTy, ".dep.arr.addr");
@@ -5883,7 +5883,7 @@ void CGOpenMPRuntime::emitReduction(CodeGenFunction &CGF, SourceLocation Loc,
   }
   llvm::APInt ArraySize(/*unsigned int numBits=*/32, Size);
   QualType ReductionArrayTy =
-      C.getConstantArrayType(C.VoidPtrTy, ArraySize, ArrayType::Normal,
+      C.getConstantArrayType(C.VoidPtrTy, ArraySize, nullptr, ArrayType::Normal,
                              /*IndexTypeQuals=*/0);
   Address ReductionList =
       CGF.CreateMemTemp(ReductionArrayTy, ".omp.reduction.red_list");
@@ -6355,7 +6355,7 @@ llvm::Value *CGOpenMPRuntime::emitTaskReductionInit(
   unsigned Size = Data.ReductionVars.size();
   llvm::APInt ArraySize(/*numBits=*/64, Size);
   QualType ArrayRDType = C.getConstantArrayType(
-      RDType, ArraySize, ArrayType::Normal, /*IndexTypeQuals=*/0);
+      RDType, ArraySize, nullptr, ArrayType::Normal, /*IndexTypeQuals=*/0);
   // kmp_task_red_input_t .rd_input.[Size];
   Address TaskRedInput = CGF.CreateMemTemp(ArrayRDType, ".rd_input.");
   ReductionCodeGen RCG(Data.ReductionVars, Data.ReductionCopies,
@@ -8711,9 +8711,9 @@ emitOffloadingArrays(CodeGenFunction &CGF,
       }
 
     llvm::APInt PointerNumAP(32, Info.NumberOfPtrs, /*isSigned=*/true);
-    QualType PointerArrayType =
-        Ctx.getConstantArrayType(Ctx.VoidPtrTy, PointerNumAP, ArrayType::Normal,
-                                 /*IndexTypeQuals=*/0);
+    QualType PointerArrayType = Ctx.getConstantArrayType(
+        Ctx.VoidPtrTy, PointerNumAP, nullptr, ArrayType::Normal,
+        /*IndexTypeQuals=*/0);
 
     Info.BasePointersArray =
         CGF.CreateMemTemp(PointerArrayType, ".offload_baseptrs").getPointer();
@@ -8726,9 +8726,9 @@ emitOffloadingArrays(CodeGenFunction &CGF,
     QualType Int64Ty =
         Ctx.getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/1);
     if (hasRuntimeEvaluationCaptureSize) {
-      QualType SizeArrayType =
-          Ctx.getConstantArrayType(Int64Ty, PointerNumAP, ArrayType::Normal,
-                                   /*IndexTypeQuals=*/0);
+      QualType SizeArrayType = Ctx.getConstantArrayType(
+          Int64Ty, PointerNumAP, nullptr, ArrayType::Normal,
+          /*IndexTypeQuals=*/0);
       Info.SizesArray =
           CGF.CreateMemTemp(SizeArrayType, ".offload_sizes").getPointer();
     } else {
@@ -10967,7 +10967,7 @@ void CGOpenMPRuntime::emitDoacrossInit(CodeGenFunction &CGF,
   }
   llvm::APInt Size(/*numBits=*/32, NumIterations.size());
   QualType ArrayTy =
-      C.getConstantArrayType(KmpDimTy, Size, ArrayType::Normal, 0);
+      C.getConstantArrayType(KmpDimTy, Size, nullptr, ArrayType::Normal, 0);
 
   Address DimsAddr = CGF.CreateMemTemp(ArrayTy, "dims");
   CGF.EmitNullInitialization(DimsAddr, ArrayTy);
@@ -11018,7 +11018,7 @@ void CGOpenMPRuntime::emitDoacrossOrdered(CodeGenFunction &CGF,
       CGM.getContext().getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/1);
   llvm::APInt Size(/*numBits=*/32, C->getNumLoops());
   QualType ArrayTy = CGM.getContext().getConstantArrayType(
-      Int64Ty, Size, ArrayType::Normal, 0);
+      Int64Ty, Size, nullptr, ArrayType::Normal, 0);
   Address CntAddr = CGF.CreateMemTemp(ArrayTy, ".cnt.addr");
   for (unsigned I = 0, E = C->getNumLoops(); I < E; ++I) {
     const Expr *CounterVal = C->getLoopData(I);
diff --git a/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp b/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
index 746852485b..9e70a5a9bc 100644
--- a/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
+++ b/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
@@ -280,7 +280,8 @@ static RecordDecl *buildRecordForGlobalizedVars(
       }
     } else {
       llvm::APInt ArraySize(32, BufSize);
-      Type = C.getConstantArrayType(Type, ArraySize, ArrayType::Normal, 0);
+      Type = C.getConstantArrayType(Type, ArraySize, nullptr, ArrayType::Normal,
+                                    0);
       Field = FieldDecl::Create(
           C, GlobalizedRD, Loc, Loc, VD->getIdentifier(), Type,
           C.getTrivialTypeSourceInfo(Type, SourceLocation()),
@@ -4269,7 +4270,7 @@ void CGOpenMPRuntimeNVPTX::emitReduction(
   }
   llvm::APInt ArraySize(/*unsigned int numBits=*/32, Size);
   QualType ReductionArrayTy =
-      C.getConstantArrayType(C.VoidPtrTy, ArraySize, ArrayType::Normal,
+      C.getConstantArrayType(C.VoidPtrTy, ArraySize, nullptr, ArrayType::Normal,
                              /*IndexTypeQuals=*/0);
   Address ReductionList =
       CGF.CreateMemTemp(ReductionArrayTy, ".omp.reduction.red_list");
@@ -5056,7 +5057,7 @@ void CGOpenMPRuntimeNVPTX::clear() {
       Size = llvm::alignTo(Size, RecAlignment);
       llvm::APInt ArySize(/*numBits=*/64, Size);
       QualType SubTy = C.getConstantArrayType(
-          C.CharTy, ArySize, ArrayType::Normal, /*IndexTypeQuals=*/0);
+          C.CharTy, ArySize, nullptr, ArrayType::Normal, /*IndexTypeQuals=*/0);
       const bool UseSharedMemory = Size <= SharedMemorySize;
       auto *Field =
           FieldDecl::Create(C, UseSharedMemory ? SharedStaticRD : StaticRD,
@@ -5083,7 +5084,7 @@ void CGOpenMPRuntimeNVPTX::clear() {
     if (!SharedStaticRD->field_empty()) {
       llvm::APInt ArySize(/*numBits=*/64, SharedMemorySize);
       QualType SubTy = C.getConstantArrayType(
-          C.CharTy, ArySize, ArrayType::Normal, /*IndexTypeQuals=*/0);
+          C.CharTy, ArySize, nullptr, ArrayType::Normal, /*IndexTypeQuals=*/0);
       auto *Field = FieldDecl::Create(
           C, SharedStaticRD, SourceLocation(), SourceLocation(), nullptr, SubTy,
           C.getTrivialTypeSourceInfo(SubTy, SourceLocation()),
@@ -5116,11 +5117,12 @@ void CGOpenMPRuntimeNVPTX::clear() {
       std::pair<unsigned, unsigned> SMsBlockPerSM = getSMsBlocksPerSM(CGM);
       llvm::APInt Size1(32, SMsBlockPerSM.second);
       QualType Arr1Ty =
-          C.getConstantArrayType(StaticTy, Size1, ArrayType::Normal,
+          C.getConstantArrayType(StaticTy, Size1, nullptr, ArrayType::Normal,
                                  /*IndexTypeQuals=*/0);
       llvm::APInt Size2(32, SMsBlockPerSM.first);
-      QualType Arr2Ty = C.getConstantArrayType(Arr1Ty, Size2, ArrayType::Normal,
-                                               /*IndexTypeQuals=*/0);
+      QualType Arr2Ty =
+          C.getConstantArrayType(Arr1Ty, Size2, nullptr, ArrayType::Normal,
+                                 /*IndexTypeQuals=*/0);
       llvm::Type *LLVMArr2Ty = CGM.getTypes().ConvertTypeForMem(Arr2Ty);
       // FIXME: nvlink does not handle weak linkage correctly (object with the
       // different size are reported as erroneous).
diff --git a/lib/CodeGen/CGStmtOpenMP.cpp b/lib/CodeGen/CGStmtOpenMP.cpp
index bb6323e118..1ab6a8d963 100644
--- a/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/lib/CodeGen/CGStmtOpenMP.cpp
@@ -3158,7 +3158,7 @@ void CodeGenFunction::EmitOMPTargetTaskBasedDirective(
         getContext(), getContext().getTranslationUnitDecl(), /*NumParams=*/0);
     llvm::APInt ArrSize(/*numBits=*/32, InputInfo.NumberOfTargetItems);
     QualType BaseAndPointersType = getContext().getConstantArrayType(
-        getContext().VoidPtrTy, ArrSize, ArrayType::Normal,
+        getContext().VoidPtrTy, ArrSize, nullptr, ArrayType::Normal,
         /*IndexTypeQuals=*/0);
     BPVD = createImplicitFirstprivateForType(
         getContext(), Data, BaseAndPointersType, CD, S.getBeginLoc());
@@ -3166,7 +3166,7 @@ void CodeGenFunction::EmitOMPTargetTaskBasedDirective(
         getContext(), Data, BaseAndPointersType, CD, S.getBeginLoc());
     QualType SizesType = getContext().getConstantArrayType(
         getContext().getIntTypeForBitwidth(/*DestWidth=*/64, /*Signed=*/1),
-        ArrSize, ArrayType::Normal,
+        ArrSize, nullptr, ArrayType::Normal,
         /*IndexTypeQuals=*/0);
     SVD = createImplicitFirstprivateForType(getContext(), Data, SizesType, CD,
                                             S.getBeginLoc());
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index f8b4ffa024..140f8c38cf 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -4771,7 +4771,7 @@ QualType CodeGenModule::getObjCFastEnumerationStateType() {
       Context.getPointerType(Context.getObjCIdType()),
       Context.getPointerType(Context.UnsignedLongTy),
       Context.getConstantArrayType(Context.UnsignedLongTy,
-                           llvm::APInt(32, 5), ArrayType::Normal, 0)
+                           llvm::APInt(32, 5), nullptr, ArrayType::Normal, 0)
     };
 
     for (size_t i = 0; i < 4; ++i) {
diff --git a/lib/Frontend/Rewrite/RewriteModernObjC.cpp b/lib/Frontend/Rewrite/RewriteModernObjC.cpp
index a11fed56fc..0c2ab7a453 100644
--- a/lib/Frontend/Rewrite/RewriteModernObjC.cpp
+++ b/lib/Frontend/Rewrite/RewriteModernObjC.cpp
@@ -597,8 +597,8 @@ namespace {
 
     StringLiteral *getStringLiteral(StringRef Str) {
       QualType StrType = Context->getConstantArrayType(
-          Context->CharTy, llvm::APInt(32, Str.size() + 1), ArrayType::Normal,
-          0);
+          Context->CharTy, llvm::APInt(32, Str.size() + 1), nullptr,
+          ArrayType::Normal, 0);
       return StringLiteral::Create(*Context, Str, StringLiteral::Ascii,
                                    /*Pascal=*/false, StrType, SourceLocation());
     }
diff --git a/lib/Frontend/Rewrite/RewriteObjC.cpp b/lib/Frontend/Rewrite/RewriteObjC.cpp
index 0fd0c7f503..dd57976df7 100644
--- a/lib/Frontend/Rewrite/RewriteObjC.cpp
+++ b/lib/Frontend/Rewrite/RewriteObjC.cpp
@@ -497,8 +497,8 @@ namespace {
 
     StringLiteral *getStringLiteral(StringRef Str) {
       QualType StrType = Context->getConstantArrayType(
-          Context->CharTy, llvm::APInt(32, Str.size() + 1), ArrayType::Normal,
-          0);
+          Context->CharTy, llvm::APInt(32, Str.size() + 1), nullptr,
+          ArrayType::Normal, 0);
       return StringLiteral::Create(*Context, Str, StringLiteral::Ascii,
                                    /*Pascal=*/false, StrType, SourceLocation());
     }
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index c2070995f3..d1b8e958e6 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -1111,8 +1111,8 @@ void Sema::ActOnEndOfTranslationUnit() {
       // Set the length of the array to 1 (C99 6.9.2p5).
       Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
       llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
-      QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
-                                                One, ArrayType::Normal, 0);
+      QualType T = Context.getConstantArrayType(ArrayT->getElementType(), One,
+                                                nullptr, ArrayType::Normal, 0);
       VD->setType(T);
     } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
                                    diag::err_tentative_def_incomplete_type))
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 9a0fb20353..7a169ba51a 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -5758,8 +5758,8 @@ static QualType TryToFixInvalidVariablyModifiedType(QualType T,
     return QualType();
   }
 
-  return Context.getConstantArrayType(VLATy->getElementType(),
-                                      Res, ArrayType::Normal, 0);
+  return Context.getConstantArrayType(
+      VLATy->getElementType(), Res, VLATy->getSizeExpr(), ArrayType::Normal, 0);
 }
 
 static void
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index d75c8240a1..667441cbaa 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -3207,13 +3207,15 @@ ExprResult Sema::BuildPredefinedExpr(SourceLocation Loc,
       SmallString<32> RawChars;
       ConvertUTF8ToWideString(Context.getTypeSizeInChars(ResTy).getQuantity(),
                               Str, RawChars);
-      ResTy = Context.getConstantArrayType(ResTy, LengthI, ArrayType::Normal,
+      ResTy = Context.getConstantArrayType(ResTy, LengthI, nullptr,
+                                           ArrayType::Normal,
                                            /*IndexTypeQuals*/ 0);
       SL = StringLiteral::Create(Context, RawChars, StringLiteral::Wide,
                                  /*Pascal*/ false, ResTy, Loc);
     } else {
       ResTy = Context.adjustStringLiteralBaseType(Context.CharTy.withConst());
-      ResTy = Context.getConstantArrayType(ResTy, LengthI, ArrayType::Normal,
+      ResTy = Context.getConstantArrayType(ResTy, LengthI, nullptr,
+                                           ArrayType::Normal,
                                            /*IndexTypeQuals*/ 0);
       SL = StringLiteral::Create(Context, Str, StringLiteral::Ascii,
                                  /*Pascal*/ false, ResTy, Loc);
@@ -3453,7 +3455,7 @@ ExprResult Sema::ActOnNumericConstant(const Token &Tok, Scope *UDLScope) {
       unsigned Length = Literal.getUDSuffixOffset();
       QualType StrTy = Context.getConstantArrayType(
           Context.adjustStringLiteralBaseType(Context.CharTy.withConst()),
-          llvm::APInt(32, Length + 1), ArrayType::Normal, 0);
+          llvm::APInt(32, Length + 1), nullptr, ArrayType::Normal, 0);
       Expr *Lit = StringLiteral::Create(
           Context, StringRef(TokSpelling.data(), Length), StringLiteral::Ascii,
           /*Pascal*/false, StrTy, &TokLoc, 1);
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index a25e86b95c..476afce01e 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -2111,9 +2111,10 @@ Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
     QualType InitType;
     if (KnownArraySize)
       InitType = Context.getConstantArrayType(
-          AllocType, llvm::APInt(Context.getTypeSize(Context.getSizeType()),
-                                 *KnownArraySize),
-          ArrayType::Normal, 0);
+          AllocType,
+          llvm::APInt(Context.getTypeSize(Context.getSizeType()),
+                      *KnownArraySize),
+          *ArraySize, ArrayType::Normal, 0);
     else if (ArraySize)
       InitType =
           Context.getIncompleteArrayType(AllocType, ArrayType::Normal, 0);
diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index fb91f0b769..e18621e42a 100644
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -67,7 +67,7 @@ ExprResult Sema::ParseObjCStringLiteral(SourceLocation *AtLocs,
     const ConstantArrayType *CAT = Context.getAsConstantArrayType(S->getType());
     assert(CAT && "String literal not of constant array type!");
     QualType StrTy = Context.getConstantArrayType(
-        CAT->getElementType(), llvm::APInt(32, StrBuf.size() + 1),
+        CAT->getElementType(), llvm::APInt(32, StrBuf.size() + 1), nullptr,
         CAT->getSizeModifier(), CAT->getIndexTypeCVRQualifiers());
     S = StringLiteral::Create(Context, StrBuf, StringLiteral::Ascii,
                               /*Pascal=*/false, StrTy, &StrLocs[0],
diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 00b7e9b1c0..6255e1bf0c 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -198,7 +198,7 @@ static void CheckStringInit(Expr *Str, QualType &DeclT, const ArrayType *AT,
     llvm::APInt ConstVal(32, StrLength);
     // Return a new array type (C99 6.7.8p22).
     DeclT = S.Context.getConstantArrayType(IAT->getElementType(),
-                                           ConstVal,
+                                           ConstVal, nullptr,
                                            ArrayType::Normal, 0);
     updateStringLiteralType(Str, DeclT);
     return;
@@ -1935,8 +1935,8 @@ void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
       SemaRef.Diag(IList->getBeginLoc(), diag::ext_typecheck_zero_array_size);
     }
 
-    DeclType = SemaRef.Context.getConstantArrayType(elementType, maxElements,
-                                                     ArrayType::Normal, 0);
+    DeclType = SemaRef.Context.getConstantArrayType(
+        elementType, maxElements, nullptr, ArrayType::Normal, 0);
   }
   if (!hadError) {
     // If there are any members of the array that get value-initialized, check
@@ -3827,9 +3827,10 @@ static bool TryInitializerListConstruction(Sema &S,
 
   // Try initializing a temporary array from the init list.
   QualType ArrayType = S.Context.getConstantArrayType(
-      E.withConst(), llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
-                                 List->getNumInits()),
-      clang::ArrayType::Normal, 0);
+      E.withConst(),
+      llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
+                  List->getNumInits()),
+      nullptr, clang::ArrayType::Normal, 0);
   InitializedEntity HiddenArray =
       InitializedEntity::InitializeTemporary(ArrayType);
   InitializationKind Kind = InitializationKind::CreateDirectList(
@@ -8407,6 +8408,7 @@ ExprResult InitializationSequence::Perform(Sema &S,
             *ResultType = S.Context.getConstantArrayType(
                                              IncompleteDest->getElementType(),
                                              ConstantSource->getSize(),
+                                             ConstantSource->getSizeExpr(),
                                              ArrayType::Normal, 0);
           }
         }
@@ -8649,7 +8651,7 @@ static void diagnoseListInit(Sema &S, const InitializedEntity &Entity,
         E.withConst(),
         llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
                     InitList->getNumInits()),
-        clang::ArrayType::Normal, 0);
+        nullptr, clang::ArrayType::Normal, 0);
     InitializedEntity HiddenArray =
         InitializedEntity::InitializeTemporary(ArrayType);
     return diagnoseListInit(S, HiddenArray, InitList);
diff --git a/lib/Sema/SemaOpenMP.cpp b/lib/Sema/SemaOpenMP.cpp
index 2b659f7f11..7ec5ba335f 100644
--- a/lib/Sema/SemaOpenMP.cpp
+++ b/lib/Sema/SemaOpenMP.cpp
@@ -13015,8 +13015,9 @@ static bool actOnOMPReductionKindClause(
       // If we don't have a single element, we must emit a constant array type.
       if (ConstantLengthOASE && !SingleElement) {
         for (llvm::APSInt &Size : ArraySizes)
-          PrivateTy = Context.getConstantArrayType(
-              PrivateTy, Size, ArrayType::Normal, /*IndexTypeQuals=*/0);
+          PrivateTy = Context.getConstantArrayType(PrivateTy, Size, nullptr,
+                                                   ArrayType::Normal,
+                                                   /*IndexTypeQuals=*/0);
       }
     }
 
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index 3029e148dc..87a672c537 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -2290,7 +2290,7 @@ QualType Sema::BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
       }
     }
 
-    T = Context.getConstantArrayType(T, ConstVal, ASM, Quals);
+    T = Context.getConstantArrayType(T, ConstVal, ArraySize, ASM, Quals);
   }
 
   // OpenCL v1.2 s6.9.d: variable length arrays are not supported.
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 84e38c6d78..5ccd8cc889 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -795,6 +795,7 @@ public:
   QualType RebuildConstantArrayType(QualType ElementType,
                                     ArrayType::ArraySizeModifier SizeMod,
                                     const llvm::APInt &Size,
+                                    Expr *SizeExpr,
                                     unsigned IndexTypeQuals,
                                     SourceRange BracketsRange);
 
@@ -4726,12 +4727,25 @@ TreeTransform<Derived>::TransformConstantArrayType(TypeLocBuilder &TLB,
   if (ElementType.isNull())
     return QualType();
 
+  // Prefer the expression from the TypeLoc;  the other may have been uniqued.
+  Expr *OldSize = TL.getSizeExpr();
+  if (!OldSize)
+    OldSize = const_cast<Expr*>(T->getSizeExpr());
+  Expr *NewSize = nullptr;
+  if (OldSize) {
+    EnterExpressionEvaluationContext Unevaluated(
+        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
+    NewSize = getDerived().TransformExpr(OldSize).template getAs<Expr>();
+    NewSize = SemaRef.ActOnConstantExpression(NewSize).get();
+  }
+
   QualType Result = TL.getType();
   if (getDerived().AlwaysRebuild() ||
-      ElementType != T->getElementType()) {
+      ElementType != T->getElementType() ||
+      (T->getSizeExpr() && NewSize != OldSize)) {
     Result = getDerived().RebuildConstantArrayType(ElementType,
                                                    T->getSizeModifier(),
-                                                   T->getSize(),
+                                                   T->getSize(), NewSize,
                                              T->getIndexTypeCVRQualifiers(),
                                                    TL.getBracketsRange());
     if (Result.isNull())
@@ -4745,15 +4759,7 @@ TreeTransform<Derived>::TransformConstantArrayType(TypeLocBuilder &TLB,
   ArrayTypeLoc NewTL = TLB.push<ArrayTypeLoc>(Result);
   NewTL.setLBracketLoc(TL.getLBracketLoc());
   NewTL.setRBracketLoc(TL.getRBracketLoc());
-
-  Expr *Size = TL.getSizeExpr();
-  if (Size) {
-    EnterExpressionEvaluationContext Unevaluated(
-        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
-    Size = getDerived().TransformExpr(Size).template getAs<Expr>();
-    Size = SemaRef.ActOnConstantExpression(Size).get();
-  }
-  NewTL.setSizeExpr(Size);
+  NewTL.setSizeExpr(NewSize);
 
   return Result;
 }
@@ -12802,9 +12808,10 @@ QualType
 TreeTransform<Derived>::RebuildConstantArrayType(QualType ElementType,
                                                  ArrayType::ArraySizeModifier SizeMod,
                                                  const llvm::APInt &Size,
+                                                 Expr *SizeExpr,
                                                  unsigned IndexTypeQuals,
                                                  SourceRange BracketsRange) {
-  return getDerived().RebuildArrayType(ElementType, SizeMod, &Size, nullptr,
+  return getDerived().RebuildArrayType(ElementType, SizeMod, &Size, SizeExpr,
                                         IndexTypeQuals, BracketsRange);
 }
 
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index fcb437e0cb..55bec61693 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -6379,7 +6379,8 @@ QualType ASTReader::readTypeRecord(unsigned Index) {
     unsigned IndexTypeQuals = Record[2];
     unsigned Idx = 3;
     llvm::APInt Size = ReadAPInt(Record, Idx);
-    return Context.getConstantArrayType(ElementType, Size,
+    Expr *SizeExpr = ReadExpr(*Loc.F);
+    return Context.getConstantArrayType(ElementType, Size, SizeExpr,
                                          ASM, IndexTypeQuals);
   }
 
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index e1f3d50456..2d0a643877 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -238,6 +238,7 @@ void ASTTypeWriter::VisitArrayType(const ArrayType *T) {
 void ASTTypeWriter::VisitConstantArrayType(const ConstantArrayType *T) {
   VisitArrayType(T);
   Record.AddAPInt(T->getSize());
+  Record.AddStmt(const_cast<Expr*>(T->getSizeExpr()));
   Code = TYPE_CONSTANT_ARRAY;
 }
 
diff --git a/test/CodeGenCXX/microsoft-uuidof-mangling.cpp b/test/CodeGenCXX/microsoft-uuidof-mangling.cpp
index 9019aa8c92..10b19ddf56 100644
--- a/test/CodeGenCXX/microsoft-uuidof-mangling.cpp
+++ b/test/CodeGenCXX/microsoft-uuidof-mangling.cpp
@@ -24,7 +24,7 @@ struct __declspec(uuid("EAFA1952-66F8-438B-8FBA-AF1BBAE42191")) TestStruct
 
 template <class T> void test_uuidofType(void *arg[sizeof(__uuidof(T))] = 0) {}
 
-template <class T> void test_uuidofExpr(void *arg[sizeof(__uuidof(T::member))] = 0) {}
+template <class T> void test_uuidofExpr(void *arg[sizeof(__uuidof(typename T::member))] = 0) {}
 
 struct HasMember { typedef TestStruct member; };
 
diff --git a/test/SemaTemplate/temp_arg_nontype.cpp b/test/SemaTemplate/temp_arg_nontype.cpp
index 3249d0dc19..06eb5e0d78 100644
--- a/test/SemaTemplate/temp_arg_nontype.cpp
+++ b/test/SemaTemplate/temp_arg_nontype.cpp
@@ -488,9 +488,8 @@ namespace instantiation_dependent {
   template<typename T, __typeof(sizeof(0))> int &f(...);
   int &rf = f<struct incomplete, 0>(0);
 
-  // FIXME: This fails because we mishandle instantiation-dependent array bounds :(
   int arr[sizeof(sizeof(int))];
   template<typename T, int (*)[sizeof(sizeof(T))]> void g(int);
   template<typename T, int (*)[sizeof(sizeof(int))]> int &g(...);
-  int &rg = g<struct incomplete, &arr>(0); // expected-error {{cannot bind}}
+  int &rg = g<struct incomplete, &arr>(0);
 }