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diff --git a/contrib/llvm-project/clang/lib/CodeGen/CGExprAgg.cpp b/contrib/llvm-project/clang/lib/CodeGen/CGExprAgg.cpp
new file mode 100644
index 000000000000..0a57870a7c58
--- /dev/null
+++ b/contrib/llvm-project/clang/lib/CodeGen/CGExprAgg.cpp
@@ -0,0 +1,2023 @@
+//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code to emit Aggregate Expr nodes as LLVM code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+#include "CGCXXABI.h"
+#include "CGObjCRuntime.h"
+#include "CodeGenModule.h"
+#include "ConstantEmitter.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/StmtVisitor.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/IntrinsicInst.h"
+using namespace clang;
+using namespace CodeGen;
+
+//===----------------------------------------------------------------------===//
+//                        Aggregate Expression Emitter
+//===----------------------------------------------------------------------===//
+
+namespace  {
+class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
+  CodeGenFunction &CGF;
+  CGBuilderTy &Builder;
+  AggValueSlot Dest;
+  bool IsResultUnused;
+
+  AggValueSlot EnsureSlot(QualType T) {
+    if (!Dest.isIgnored()) return Dest;
+    return CGF.CreateAggTemp(T, "agg.tmp.ensured");
+  }
+  void EnsureDest(QualType T) {
+    if (!Dest.isIgnored()) return;
+    Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured");
+  }
+
+  // Calls `Fn` with a valid return value slot, potentially creating a temporary
+  // to do so. If a temporary is created, an appropriate copy into `Dest` will
+  // be emitted, as will lifetime markers.
+  //
+  // The given function should take a ReturnValueSlot, and return an RValue that
+  // points to said slot.
+  void withReturnValueSlot(const Expr *E,
+                           llvm::function_ref<RValue(ReturnValueSlot)> Fn);
+
+public:
+  AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, bool IsResultUnused)
+    : CGF(cgf), Builder(CGF.Builder), Dest(Dest),
+    IsResultUnused(IsResultUnused) { }
+
+  //===--------------------------------------------------------------------===//
+  //                               Utilities
+  //===--------------------------------------------------------------------===//
+
+  /// EmitAggLoadOfLValue - Given an expression with aggregate type that
+  /// represents a value lvalue, this method emits the address of the lvalue,
+  /// then loads the result into DestPtr.
+  void EmitAggLoadOfLValue(const Expr *E);
+
+  enum ExprValueKind {
+    EVK_RValue,
+    EVK_NonRValue
+  };
+
+  /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
+  /// SrcIsRValue is true if source comes from an RValue.
+  void EmitFinalDestCopy(QualType type, const LValue &src,
+                         ExprValueKind SrcValueKind = EVK_NonRValue);
+  void EmitFinalDestCopy(QualType type, RValue src);
+  void EmitCopy(QualType type, const AggValueSlot &dest,
+                const AggValueSlot &src);
+
+  void EmitMoveFromReturnSlot(const Expr *E, RValue Src);
+
+  void EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
+                     QualType ArrayQTy, InitListExpr *E);
+
+  AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) {
+    if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T))
+      return AggValueSlot::NeedsGCBarriers;
+    return AggValueSlot::DoesNotNeedGCBarriers;
+  }
+
+  bool TypeRequiresGCollection(QualType T);
+
+  //===--------------------------------------------------------------------===//
+  //                            Visitor Methods
+  //===--------------------------------------------------------------------===//
+
+  void Visit(Expr *E) {
+    ApplyDebugLocation DL(CGF, E);
+    StmtVisitor<AggExprEmitter>::Visit(E);
+  }
+
+  void VisitStmt(Stmt *S) {
+    CGF.ErrorUnsupported(S, "aggregate expression");
+  }
+  void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
+  void VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
+    Visit(GE->getResultExpr());
+  }
+  void VisitCoawaitExpr(CoawaitExpr *E) {
+    CGF.EmitCoawaitExpr(*E, Dest, IsResultUnused);
+  }
+  void VisitCoyieldExpr(CoyieldExpr *E) {
+    CGF.EmitCoyieldExpr(*E, Dest, IsResultUnused);
+  }
+  void VisitUnaryCoawait(UnaryOperator *E) { Visit(E->getSubExpr()); }
+  void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
+  void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
+    return Visit(E->getReplacement());
+  }
+
+  void VisitConstantExpr(ConstantExpr *E) {
+    return Visit(E->getSubExpr());
+  }
+
+  // l-values.
+  void VisitDeclRefExpr(DeclRefExpr *E) { EmitAggLoadOfLValue(E); }
+  void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
+  void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
+  void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
+  void VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
+  void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
+    EmitAggLoadOfLValue(E);
+  }
+  void VisitPredefinedExpr(const PredefinedExpr *E) {
+    EmitAggLoadOfLValue(E);
+  }
+
+  // Operators.
+  void VisitCastExpr(CastExpr *E);
+  void VisitCallExpr(const CallExpr *E);
+  void VisitStmtExpr(const StmtExpr *E);
+  void VisitBinaryOperator(const BinaryOperator *BO);
+  void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
+  void VisitBinAssign(const BinaryOperator *E);
+  void VisitBinComma(const BinaryOperator *E);
+  void VisitBinCmp(const BinaryOperator *E);
+
+  void VisitObjCMessageExpr(ObjCMessageExpr *E);
+  void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
+    EmitAggLoadOfLValue(E);
+  }
+
+  void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E);
+  void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO);
+  void VisitChooseExpr(const ChooseExpr *CE);
+  void VisitInitListExpr(InitListExpr *E);
+  void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
+                              llvm::Value *outerBegin = nullptr);
+  void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
+  void VisitNoInitExpr(NoInitExpr *E) { } // Do nothing.
+  void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
+    CodeGenFunction::CXXDefaultArgExprScope Scope(CGF, DAE);
+    Visit(DAE->getExpr());
+  }
+  void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
+    CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE);
+    Visit(DIE->getExpr());
+  }
+  void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
+  void VisitCXXConstructExpr(const CXXConstructExpr *E);
+  void VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
+  void VisitLambdaExpr(LambdaExpr *E);
+  void VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E);
+  void VisitExprWithCleanups(ExprWithCleanups *E);
+  void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
+  void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
+  void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E);
+  void VisitOpaqueValueExpr(OpaqueValueExpr *E);
+
+  void VisitPseudoObjectExpr(PseudoObjectExpr *E) {
+    if (E->isGLValue()) {
+      LValue LV = CGF.EmitPseudoObjectLValue(E);
+      return EmitFinalDestCopy(E->getType(), LV);
+    }
+
+    CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType()));
+  }
+
+  void VisitVAArgExpr(VAArgExpr *E);
+
+  void EmitInitializationToLValue(Expr *E, LValue Address);
+  void EmitNullInitializationToLValue(LValue Address);
+  //  case Expr::ChooseExprClass:
+  void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
+  void VisitAtomicExpr(AtomicExpr *E) {
+    RValue Res = CGF.EmitAtomicExpr(E);
+    EmitFinalDestCopy(E->getType(), Res);
+  }
+};
+}  // end anonymous namespace.
+
+//===----------------------------------------------------------------------===//
+//                                Utilities
+//===----------------------------------------------------------------------===//
+
+/// EmitAggLoadOfLValue - Given an expression with aggregate type that
+/// represents a value lvalue, this method emits the address of the lvalue,
+/// then loads the result into DestPtr.
+void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
+  LValue LV = CGF.EmitLValue(E);
+
+  // If the type of the l-value is atomic, then do an atomic load.
+  if (LV.getType()->isAtomicType() || CGF.LValueIsSuitableForInlineAtomic(LV)) {
+    CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest);
+    return;
+  }
+
+  EmitFinalDestCopy(E->getType(), LV);
+}
+
+/// True if the given aggregate type requires special GC API calls.
+bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
+  // Only record types have members that might require garbage collection.
+  const RecordType *RecordTy = T->getAs<RecordType>();
+  if (!RecordTy) return false;
+
+  // Don't mess with non-trivial C++ types.
+  RecordDecl *Record = RecordTy->getDecl();
+  if (isa<CXXRecordDecl>(Record) &&
+      (cast<CXXRecordDecl>(Record)->hasNonTrivialCopyConstructor() ||
+       !cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
+    return false;
+
+  // Check whether the type has an object member.
+  return Record->hasObjectMember();
+}
+
+void AggExprEmitter::withReturnValueSlot(
+    const Expr *E, llvm::function_ref<RValue(ReturnValueSlot)> EmitCall) {
+  QualType RetTy = E->getType();
+  bool RequiresDestruction =
+      Dest.isIgnored() &&
+      RetTy.isDestructedType() == QualType::DK_nontrivial_c_struct;
+
+  // If it makes no observable difference, save a memcpy + temporary.
+  //
+  // We need to always provide our own temporary if destruction is required.
+  // Otherwise, EmitCall will emit its own, notice that it's "unused", and end
+  // its lifetime before we have the chance to emit a proper destructor call.
+  bool UseTemp = Dest.isPotentiallyAliased() || Dest.requiresGCollection() ||
+                 (RequiresDestruction && !Dest.getAddress().isValid());
+
+  Address RetAddr = Address::invalid();
+  Address RetAllocaAddr = Address::invalid();
+
+  EHScopeStack::stable_iterator LifetimeEndBlock;
+  llvm::Value *LifetimeSizePtr = nullptr;
+  llvm::IntrinsicInst *LifetimeStartInst = nullptr;
+  if (!UseTemp) {
+    RetAddr = Dest.getAddress();
+  } else {
+    RetAddr = CGF.CreateMemTemp(RetTy, "tmp", &RetAllocaAddr);
+    uint64_t Size =
+        CGF.CGM.getDataLayout().getTypeAllocSize(CGF.ConvertTypeForMem(RetTy));
+    LifetimeSizePtr = CGF.EmitLifetimeStart(Size, RetAllocaAddr.getPointer());
+    if (LifetimeSizePtr) {
+      LifetimeStartInst =
+          cast<llvm::IntrinsicInst>(std::prev(Builder.GetInsertPoint()));
+      assert(LifetimeStartInst->getIntrinsicID() ==
+                 llvm::Intrinsic::lifetime_start &&
+             "Last insertion wasn't a lifetime.start?");
+
+      CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>(
+          NormalEHLifetimeMarker, RetAllocaAddr, LifetimeSizePtr);
+      LifetimeEndBlock = CGF.EHStack.stable_begin();
+    }
+  }
+
+  RValue Src =
+      EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused));
+
+  if (RequiresDestruction)
+    CGF.pushDestroy(RetTy.isDestructedType(), Src.getAggregateAddress(), RetTy);
+
+  if (!UseTemp)
+    return;
+
+  assert(Dest.getPointer() != Src.getAggregatePointer());
+  EmitFinalDestCopy(E->getType(), Src);
+
+  if (!RequiresDestruction && LifetimeStartInst) {
+    // If there's no dtor to run, the copy was the last use of our temporary.
+    // Since we're not guaranteed to be in an ExprWithCleanups, clean up
+    // eagerly.
+    CGF.DeactivateCleanupBlock(LifetimeEndBlock, LifetimeStartInst);
+    CGF.EmitLifetimeEnd(LifetimeSizePtr, RetAllocaAddr.getPointer());
+  }
+}
+
+/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
+void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src) {
+  assert(src.isAggregate() && "value must be aggregate value!");
+  LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddress(), type);
+  EmitFinalDestCopy(type, srcLV, EVK_RValue);
+}
+
+/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
+void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src,
+                                       ExprValueKind SrcValueKind) {
+  // If Dest is ignored, then we're evaluating an aggregate expression
+  // in a context that doesn't care about the result.  Note that loads
+  // from volatile l-values force the existence of a non-ignored
+  // destination.
+  if (Dest.isIgnored())
+    return;
+
+  // Copy non-trivial C structs here.
+  LValue DstLV = CGF.MakeAddrLValue(
+      Dest.getAddress(), Dest.isVolatile() ? type.withVolatile() : type);
+
+  if (SrcValueKind == EVK_RValue) {
+    if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct) {
+      if (Dest.isPotentiallyAliased())
+        CGF.callCStructMoveAssignmentOperator(DstLV, src);
+      else
+        CGF.callCStructMoveConstructor(DstLV, src);
+      return;
+    }
+  } else {
+    if (type.isNonTrivialToPrimitiveCopy() == QualType::PCK_Struct) {
+      if (Dest.isPotentiallyAliased())
+        CGF.callCStructCopyAssignmentOperator(DstLV, src);
+      else
+        CGF.callCStructCopyConstructor(DstLV, src);
+      return;
+    }
+  }
+
+  AggValueSlot srcAgg =
+    AggValueSlot::forLValue(src, AggValueSlot::IsDestructed,
+                            needsGC(type), AggValueSlot::IsAliased,
+                            AggValueSlot::MayOverlap);
+  EmitCopy(type, Dest, srcAgg);
+}
+
+/// Perform a copy from the source into the destination.
+///
+/// \param type - the type of the aggregate being copied; qualifiers are
+///   ignored
+void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
+                              const AggValueSlot &src) {
+  if (dest.requiresGCollection()) {
+    CharUnits sz = dest.getPreferredSize(CGF.getContext(), type);
+    llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity());
+    CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
+                                                      dest.getAddress(),
+                                                      src.getAddress(),
+                                                      size);
+    return;
+  }
+
+  // If the result of the assignment is used, copy the LHS there also.
+  // It's volatile if either side is.  Use the minimum alignment of
+  // the two sides.
+  LValue DestLV = CGF.MakeAddrLValue(dest.getAddress(), type);
+  LValue SrcLV = CGF.MakeAddrLValue(src.getAddress(), type);
+  CGF.EmitAggregateCopy(DestLV, SrcLV, type, dest.mayOverlap(),
+                        dest.isVolatile() || src.isVolatile());
+}
+
+/// Emit the initializer for a std::initializer_list initialized with a
+/// real initializer list.
+void
+AggExprEmitter::VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E) {
+  // Emit an array containing the elements.  The array is externally destructed
+  // if the std::initializer_list object is.
+  ASTContext &Ctx = CGF.getContext();
+  LValue Array = CGF.EmitLValue(E->getSubExpr());
+  assert(Array.isSimple() && "initializer_list array not a simple lvalue");
+  Address ArrayPtr = Array.getAddress();
+
+  const ConstantArrayType *ArrayType =
+      Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
+  assert(ArrayType && "std::initializer_list constructed from non-array");
+
+  // FIXME: Perform the checks on the field types in SemaInit.
+  RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
+  RecordDecl::field_iterator Field = Record->field_begin();
+  if (Field == Record->field_end()) {
+    CGF.ErrorUnsupported(E, "weird std::initializer_list");
+    return;
+  }
+
+  // Start pointer.
+  if (!Field->getType()->isPointerType() ||
+      !Ctx.hasSameType(Field->getType()->getPointeeType(),
+                       ArrayType->getElementType())) {
+    CGF.ErrorUnsupported(E, "weird std::initializer_list");
+    return;
+  }
+
+  AggValueSlot Dest = EnsureSlot(E->getType());
+  LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
+  LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
+  llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0);
+  llvm::Value *IdxStart[] = { Zero, Zero };
+  llvm::Value *ArrayStart =
+      Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxStart, "arraystart");
+  CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start);
+  ++Field;
+
+  if (Field == Record->field_end()) {
+    CGF.ErrorUnsupported(E, "weird std::initializer_list");
+    return;
+  }
+
+  llvm::Value *Size = Builder.getInt(ArrayType->getSize());
+  LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field);
+  if (Field->getType()->isPointerType() &&
+      Ctx.hasSameType(Field->getType()->getPointeeType(),
+                      ArrayType->getElementType())) {
+    // End pointer.
+    llvm::Value *IdxEnd[] = { Zero, Size };
+    llvm::Value *ArrayEnd =
+        Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxEnd, "arrayend");
+    CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength);
+  } else if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) {
+    // Length.
+    CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength);
+  } else {
+    CGF.ErrorUnsupported(E, "weird std::initializer_list");
+    return;
+  }
+}
+
+/// Determine if E is a trivial array filler, that is, one that is
+/// equivalent to zero-initialization.
+static bool isTrivialFiller(Expr *E) {
+  if (!E)
+    return true;
+
+  if (isa<ImplicitValueInitExpr>(E))
+    return true;
+
+  if (auto *ILE = dyn_cast<InitListExpr>(E)) {
+    if (ILE->getNumInits())
+      return false;
+    return isTrivialFiller(ILE->getArrayFiller());
+  }
+
+  if (auto *Cons = dyn_cast_or_null<CXXConstructExpr>(E))
+    return Cons->getConstructor()->isDefaultConstructor() &&
+           Cons->getConstructor()->isTrivial();
+
+  // FIXME: Are there other cases where we can avoid emitting an initializer?
+  return false;
+}
+
+/// Emit initialization of an array from an initializer list.
+void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
+                                   QualType ArrayQTy, InitListExpr *E) {
+  uint64_t NumInitElements = E->getNumInits();
+
+  uint64_t NumArrayElements = AType->getNumElements();
+  assert(NumInitElements <= NumArrayElements);
+
+  QualType elementType =
+      CGF.getContext().getAsArrayType(ArrayQTy)->getElementType();
+
+  // DestPtr is an array*.  Construct an elementType* by drilling
+  // down a level.
+  llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
+  llvm::Value *indices[] = { zero, zero };
+  llvm::Value *begin =
+    Builder.CreateInBoundsGEP(DestPtr.getPointer(), indices, "arrayinit.begin");
+
+  CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
+  CharUnits elementAlign =
+    DestPtr.getAlignment().alignmentOfArrayElement(elementSize);
+
+  // Consider initializing the array by copying from a global. For this to be
+  // more efficient than per-element initialization, the size of the elements
+  // with explicit initializers should be large enough.
+  if (NumInitElements * elementSize.getQuantity() > 16 &&
+      elementType.isTriviallyCopyableType(CGF.getContext())) {
+    CodeGen::CodeGenModule &CGM = CGF.CGM;
+    ConstantEmitter Emitter(CGM);
+    LangAS AS = ArrayQTy.getAddressSpace();
+    if (llvm::Constant *C = Emitter.tryEmitForInitializer(E, AS, ArrayQTy)) {
+      auto GV = new llvm::GlobalVariable(
+          CGM.getModule(), C->getType(),
+          CGM.isTypeConstant(ArrayQTy, /* ExcludeCtorDtor= */ true),
+          llvm::GlobalValue::PrivateLinkage, C, "constinit",
+          /* InsertBefore= */ nullptr, llvm::GlobalVariable::NotThreadLocal,
+          CGM.getContext().getTargetAddressSpace(AS));
+      Emitter.finalize(GV);
+      CharUnits Align = CGM.getContext().getTypeAlignInChars(ArrayQTy);
+      GV->setAlignment(Align.getQuantity());
+      EmitFinalDestCopy(ArrayQTy, CGF.MakeAddrLValue(GV, ArrayQTy, Align));
+      return;
+    }
+  }
+
+  // Exception safety requires us to destroy all the
+  // already-constructed members if an initializer throws.
+  // For that, we'll need an EH cleanup.
+  QualType::DestructionKind dtorKind = elementType.isDestructedType();
+  Address endOfInit = Address::invalid();
+  EHScopeStack::stable_iterator cleanup;
+  llvm::Instruction *cleanupDominator = nullptr;
+  if (CGF.needsEHCleanup(dtorKind)) {
+    // In principle we could tell the cleanup where we are more
+    // directly, but the control flow can get so varied here that it
+    // would actually be quite complex.  Therefore we go through an
+    // alloca.
+    endOfInit = CGF.CreateTempAlloca(begin->getType(), CGF.getPointerAlign(),
+                                     "arrayinit.endOfInit");
+    cleanupDominator = Builder.CreateStore(begin, endOfInit);
+    CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType,
+                                         elementAlign,
+                                         CGF.getDestroyer(dtorKind));
+    cleanup = CGF.EHStack.stable_begin();
+
+  // Otherwise, remember that we didn't need a cleanup.
+  } else {
+    dtorKind = QualType::DK_none;
+  }
+
+  llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1);
+
+  // The 'current element to initialize'.  The invariants on this
+  // variable are complicated.  Essentially, after each iteration of
+  // the loop, it points to the last initialized element, except
+  // that it points to the beginning of the array before any
+  // elements have been initialized.
+  llvm::Value *element = begin;
+
+  // Emit the explicit initializers.
+  for (uint64_t i = 0; i != NumInitElements; ++i) {
+    // Advance to the next element.
+    if (i > 0) {
+      element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element");
+
+      // Tell the cleanup that it needs to destroy up to this
+      // element.  TODO: some of these stores can be trivially
+      // observed to be unnecessary.
+      if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
+    }
+
+    LValue elementLV =
+      CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
+    EmitInitializationToLValue(E->getInit(i), elementLV);
+  }
+
+  // Check whether there's a non-trivial array-fill expression.
+  Expr *filler = E->getArrayFiller();
+  bool hasTrivialFiller = isTrivialFiller(filler);
+
+  // Any remaining elements need to be zero-initialized, possibly
+  // using the filler expression.  We can skip this if the we're
+  // emitting to zeroed memory.
+  if (NumInitElements != NumArrayElements &&
+      !(Dest.isZeroed() && hasTrivialFiller &&
+        CGF.getTypes().isZeroInitializable(elementType))) {
+
+    // Use an actual loop.  This is basically
+    //   do { *array++ = filler; } while (array != end);
+
+    // Advance to the start of the rest of the array.
+    if (NumInitElements) {
+      element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start");
+      if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit);
+    }
+
+    // Compute the end of the array.
+    llvm::Value *end = Builder.CreateInBoundsGEP(begin,
+                      llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements),
+                                                 "arrayinit.end");
+
+    llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
+    llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
+
+    // Jump into the body.
+    CGF.EmitBlock(bodyBB);
+    llvm::PHINode *currentElement =
+      Builder.CreatePHI(element->getType(), 2, "arrayinit.cur");
+    currentElement->addIncoming(element, entryBB);
+
+    // Emit the actual filler expression.
+    {
+      // C++1z [class.temporary]p5:
+      //   when a default constructor is called to initialize an element of
+      //   an array with no corresponding initializer [...] the destruction of
+      //   every temporary created in a default argument is sequenced before
+      //   the construction of the next array element, if any
+      CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
+      LValue elementLV =
+        CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType);
+      if (filler)
+        EmitInitializationToLValue(filler, elementLV);
+      else
+        EmitNullInitializationToLValue(elementLV);
+    }
+
+    // Move on to the next element.
+    llvm::Value *nextElement =
+      Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next");
+
+    // Tell the EH cleanup that we finished with the last element.
+    if (endOfInit.isValid()) Builder.CreateStore(nextElement, endOfInit);
+
+    // Leave the loop if we're done.
+    llvm::Value *done = Builder.CreateICmpEQ(nextElement, end,
+                                             "arrayinit.done");
+    llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
+    Builder.CreateCondBr(done, endBB, bodyBB);
+    currentElement->addIncoming(nextElement, Builder.GetInsertBlock());
+
+    CGF.EmitBlock(endBB);
+  }
+
+  // Leave the partial-array cleanup if we entered one.
+  if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator);
+}
+
+//===----------------------------------------------------------------------===//
+//                            Visitor Methods
+//===----------------------------------------------------------------------===//
+
+void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){
+  Visit(E->GetTemporaryExpr());
+}
+
+void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) {
+  // If this is a unique OVE, just visit its source expression.
+  if (e->isUnique())
+    Visit(e->getSourceExpr());
+  else
+    EmitFinalDestCopy(e->getType(), CGF.getOrCreateOpaqueLValueMapping(e));
+}
+
+void
+AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
+  if (Dest.isPotentiallyAliased() &&
+      E->getType().isPODType(CGF.getContext())) {
+    // For a POD type, just emit a load of the lvalue + a copy, because our
+    // compound literal might alias the destination.
+    EmitAggLoadOfLValue(E);
+    return;
+  }
+
+  AggValueSlot Slot = EnsureSlot(E->getType());
+  CGF.EmitAggExpr(E->getInitializer(), Slot);
+}
+
+/// Attempt to look through various unimportant expressions to find a
+/// cast of the given kind.
+static Expr *findPeephole(Expr *op, CastKind kind) {
+  while (true) {
+    op = op->IgnoreParens();
+    if (CastExpr *castE = dyn_cast<CastExpr>(op)) {
+      if (castE->getCastKind() == kind)
+        return castE->getSubExpr();
+      if (castE->getCastKind() == CK_NoOp)
+        continue;
+    }
+    return nullptr;
+  }
+}
+
+void AggExprEmitter::VisitCastExpr(CastExpr *E) {
+  if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
+    CGF.CGM.EmitExplicitCastExprType(ECE, &CGF);
+  switch (E->getCastKind()) {
+  case CK_Dynamic: {
+    // FIXME: Can this actually happen? We have no test coverage for it.
+    assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
+    LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(),
+                                      CodeGenFunction::TCK_Load);
+    // FIXME: Do we also need to handle property references here?
+    if (LV.isSimple())
+      CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
+    else
+      CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
+
+    if (!Dest.isIgnored())
+      CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
+    break;
+  }
+
+  case CK_ToUnion: {
+    // Evaluate even if the destination is ignored.
+    if (Dest.isIgnored()) {
+      CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
+                      /*ignoreResult=*/true);
+      break;
+    }
+
+    // GCC union extension
+    QualType Ty = E->getSubExpr()->getType();
+    Address CastPtr =
+      Builder.CreateElementBitCast(Dest.getAddress(), CGF.ConvertType(Ty));
+    EmitInitializationToLValue(E->getSubExpr(),
+                               CGF.MakeAddrLValue(CastPtr, Ty));
+    break;
+  }
+
+  case CK_LValueToRValueBitCast: {
+    if (Dest.isIgnored()) {
+      CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
+                      /*ignoreResult=*/true);
+      break;
+    }
+
+    LValue SourceLV = CGF.EmitLValue(E->getSubExpr());
+    Address SourceAddress =
+        Builder.CreateElementBitCast(SourceLV.getAddress(), CGF.Int8Ty);
+    Address DestAddress =
+        Builder.CreateElementBitCast(Dest.getAddress(), CGF.Int8Ty);
+    llvm::Value *SizeVal = llvm::ConstantInt::get(
+        CGF.SizeTy,
+        CGF.getContext().getTypeSizeInChars(E->getType()).getQuantity());
+    Builder.CreateMemCpy(DestAddress, SourceAddress, SizeVal);
+    break;
+  }
+
+  case CK_DerivedToBase:
+  case CK_BaseToDerived:
+  case CK_UncheckedDerivedToBase: {
+    llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: "
+                "should have been unpacked before we got here");
+  }
+
+  case CK_NonAtomicToAtomic:
+  case CK_AtomicToNonAtomic: {
+    bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic);
+
+    // Determine the atomic and value types.
+    QualType atomicType = E->getSubExpr()->getType();
+    QualType valueType = E->getType();
+    if (isToAtomic) std::swap(atomicType, valueType);
+
+    assert(atomicType->isAtomicType());
+    assert(CGF.getContext().hasSameUnqualifiedType(valueType,
+                          atomicType->castAs<AtomicType>()->getValueType()));
+
+    // Just recurse normally if we're ignoring the result or the
+    // atomic type doesn't change representation.
+    if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) {
+      return Visit(E->getSubExpr());
+    }
+
+    CastKind peepholeTarget =
+      (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic);
+
+    // These two cases are reverses of each other; try to peephole them.
+    if (Expr *op = findPeephole(E->getSubExpr(), peepholeTarget)) {
+      assert(CGF.getContext().hasSameUnqualifiedType(op->getType(),
+                                                     E->getType()) &&
+           "peephole significantly changed types?");
+      return Visit(op);
+    }
+
+    // If we're converting an r-value of non-atomic type to an r-value
+    // of atomic type, just emit directly into the relevant sub-object.
+    if (isToAtomic) {
+      AggValueSlot valueDest = Dest;
+      if (!valueDest.isIgnored() && CGF.CGM.isPaddedAtomicType(atomicType)) {
+        // Zero-initialize.  (Strictly speaking, we only need to initialize
+        // the padding at the end, but this is simpler.)
+        if (!Dest.isZeroed())
+          CGF.EmitNullInitialization(Dest.getAddress(), atomicType);
+
+        // Build a GEP to refer to the subobject.
+        Address valueAddr =
+            CGF.Builder.CreateStructGEP(valueDest.getAddress(), 0);
+        valueDest = AggValueSlot::forAddr(valueAddr,
+                                          valueDest.getQualifiers(),
+                                          valueDest.isExternallyDestructed(),
+                                          valueDest.requiresGCollection(),
+                                          valueDest.isPotentiallyAliased(),
+                                          AggValueSlot::DoesNotOverlap,
+                                          AggValueSlot::IsZeroed);
+      }
+
+      CGF.EmitAggExpr(E->getSubExpr(), valueDest);
+      return;
+    }
+
+    // Otherwise, we're converting an atomic type to a non-atomic type.
+    // Make an atomic temporary, emit into that, and then copy the value out.
+    AggValueSlot atomicSlot =
+      CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp");
+    CGF.EmitAggExpr(E->getSubExpr(), atomicSlot);
+
+    Address valueAddr = Builder.CreateStructGEP(atomicSlot.getAddress(), 0);
+    RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile());
+    return EmitFinalDestCopy(valueType, rvalue);
+  }
+  case CK_AddressSpaceConversion:
+     return Visit(E->getSubExpr());
+
+  case CK_LValueToRValue:
+    // If we're loading from a volatile type, force the destination
+    // into existence.
+    if (E->getSubExpr()->getType().isVolatileQualified()) {
+      EnsureDest(E->getType());
+      return Visit(E->getSubExpr());
+    }
+
+    LLVM_FALLTHROUGH;
+
+
+  case CK_NoOp:
+  case CK_UserDefinedConversion:
+  case CK_ConstructorConversion:
+    assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
+                                                   E->getType()) &&
+           "Implicit cast types must be compatible");
+    Visit(E->getSubExpr());
+    break;
+
+  case CK_LValueBitCast:
+    llvm_unreachable("should not be emitting lvalue bitcast as rvalue");
+
+  case CK_Dependent:
+  case CK_BitCast:
+  case CK_ArrayToPointerDecay:
+  case CK_FunctionToPointerDecay:
+  case CK_NullToPointer:
+  case CK_NullToMemberPointer:
+  case CK_BaseToDerivedMemberPointer:
+  case CK_DerivedToBaseMemberPointer:
+  case CK_MemberPointerToBoolean:
+  case CK_ReinterpretMemberPointer:
+  case CK_IntegralToPointer:
+  case CK_PointerToIntegral:
+  case CK_PointerToBoolean:
+  case CK_ToVoid:
+  case CK_VectorSplat:
+  case CK_IntegralCast:
+  case CK_BooleanToSignedIntegral:
+  case CK_IntegralToBoolean:
+  case CK_IntegralToFloating:
+  case CK_FloatingToIntegral:
+  case CK_FloatingToBoolean:
+  case CK_FloatingCast:
+  case CK_CPointerToObjCPointerCast:
+  case CK_BlockPointerToObjCPointerCast:
+  case CK_AnyPointerToBlockPointerCast:
+  case CK_ObjCObjectLValueCast:
+  case CK_FloatingRealToComplex:
+  case CK_FloatingComplexToReal:
+  case CK_FloatingComplexToBoolean:
+  case CK_FloatingComplexCast:
+  case CK_FloatingComplexToIntegralComplex:
+  case CK_IntegralRealToComplex:
+  case CK_IntegralComplexToReal:
+  case CK_IntegralComplexToBoolean:
+  case CK_IntegralComplexCast:
+  case CK_IntegralComplexToFloatingComplex:
+  case CK_ARCProduceObject:
+  case CK_ARCConsumeObject:
+  case CK_ARCReclaimReturnedObject:
+  case CK_ARCExtendBlockObject:
+  case CK_CopyAndAutoreleaseBlockObject:
+  case CK_BuiltinFnToFnPtr:
+  case CK_ZeroToOCLOpaqueType:
+
+  case CK_IntToOCLSampler:
+  case CK_FixedPointCast:
+  case CK_FixedPointToBoolean:
+  case CK_FixedPointToIntegral:
+  case CK_IntegralToFixedPoint:
+    llvm_unreachable("cast kind invalid for aggregate types");
+  }
+}
+
+void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
+  if (E->getCallReturnType(CGF.getContext())->isReferenceType()) {
+    EmitAggLoadOfLValue(E);
+    return;
+  }
+
+  withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
+    return CGF.EmitCallExpr(E, Slot);
+  });
+}
+
+void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
+  withReturnValueSlot(E, [&](ReturnValueSlot Slot) {
+    return CGF.EmitObjCMessageExpr(E, Slot);
+  });
+}
+
+void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
+  CGF.EmitIgnoredExpr(E->getLHS());
+  Visit(E->getRHS());
+}
+
+void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
+  CodeGenFunction::StmtExprEvaluation eval(CGF);
+  CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest);
+}
+
+enum CompareKind {
+  CK_Less,
+  CK_Greater,
+  CK_Equal,
+};
+
+static llvm::Value *EmitCompare(CGBuilderTy &Builder, CodeGenFunction &CGF,
+                                const BinaryOperator *E, llvm::Value *LHS,
+                                llvm::Value *RHS, CompareKind Kind,
+                                const char *NameSuffix = "") {
+  QualType ArgTy = E->getLHS()->getType();
+  if (const ComplexType *CT = ArgTy->getAs<ComplexType>())
+    ArgTy = CT->getElementType();
+
+  if (const auto *MPT = ArgTy->getAs<MemberPointerType>()) {
+    assert(Kind == CK_Equal &&
+           "member pointers may only be compared for equality");
+    return CGF.CGM.getCXXABI().EmitMemberPointerComparison(
+        CGF, LHS, RHS, MPT, /*IsInequality*/ false);
+  }
+
+  // Compute the comparison instructions for the specified comparison kind.
+  struct CmpInstInfo {
+    const char *Name;
+    llvm::CmpInst::Predicate FCmp;
+    llvm::CmpInst::Predicate SCmp;
+    llvm::CmpInst::Predicate UCmp;
+  };
+  CmpInstInfo InstInfo = [&]() -> CmpInstInfo {
+    using FI = llvm::FCmpInst;
+    using II = llvm::ICmpInst;
+    switch (Kind) {
+    case CK_Less:
+      return {"cmp.lt", FI::FCMP_OLT, II::ICMP_SLT, II::ICMP_ULT};
+    case CK_Greater:
+      return {"cmp.gt", FI::FCMP_OGT, II::ICMP_SGT, II::ICMP_UGT};
+    case CK_Equal:
+      return {"cmp.eq", FI::FCMP_OEQ, II::ICMP_EQ, II::ICMP_EQ};
+    }
+    llvm_unreachable("Unrecognised CompareKind enum");
+  }();
+
+  if (ArgTy->hasFloatingRepresentation())
+    return Builder.CreateFCmp(InstInfo.FCmp, LHS, RHS,
+                              llvm::Twine(InstInfo.Name) + NameSuffix);
+  if (ArgTy->isIntegralOrEnumerationType() || ArgTy->isPointerType()) {
+    auto Inst =
+        ArgTy->hasSignedIntegerRepresentation() ? InstInfo.SCmp : InstInfo.UCmp;
+    return Builder.CreateICmp(Inst, LHS, RHS,
+                              llvm::Twine(InstInfo.Name) + NameSuffix);
+  }
+
+  llvm_unreachable("unsupported aggregate binary expression should have "
+                   "already been handled");
+}
+
+void AggExprEmitter::VisitBinCmp(const BinaryOperator *E) {
+  using llvm::BasicBlock;
+  using llvm::PHINode;
+  using llvm::Value;
+  assert(CGF.getContext().hasSameType(E->getLHS()->getType(),
+                                      E->getRHS()->getType()));
+  const ComparisonCategoryInfo &CmpInfo =
+      CGF.getContext().CompCategories.getInfoForType(E->getType());
+  assert(CmpInfo.Record->isTriviallyCopyable() &&
+         "cannot copy non-trivially copyable aggregate");
+
+  QualType ArgTy = E->getLHS()->getType();
+
+  // TODO: Handle comparing these types.
+  if (ArgTy->isVectorType())
+    return CGF.ErrorUnsupported(
+        E, "aggregate three-way comparison with vector arguments");
+  if (!ArgTy->isIntegralOrEnumerationType() && !ArgTy->isRealFloatingType() &&
+      !ArgTy->isNullPtrType() && !ArgTy->isPointerType() &&
+      !ArgTy->isMemberPointerType() && !ArgTy->isAnyComplexType()) {
+    return CGF.ErrorUnsupported(E, "aggregate three-way comparison");
+  }
+  bool IsComplex = ArgTy->isAnyComplexType();
+
+  // Evaluate the operands to the expression and extract their values.
+  auto EmitOperand = [&](Expr *E) -> std::pair<Value *, Value *> {
+    RValue RV = CGF.EmitAnyExpr(E);
+    if (RV.isScalar())
+      return {RV.getScalarVal(), nullptr};
+    if (RV.isAggregate())
+      return {RV.getAggregatePointer(), nullptr};
+    assert(RV.isComplex());
+    return RV.getComplexVal();
+  };
+  auto LHSValues = EmitOperand(E->getLHS()),
+       RHSValues = EmitOperand(E->getRHS());
+
+  auto EmitCmp = [&](CompareKind K) {
+    Value *Cmp = EmitCompare(Builder, CGF, E, LHSValues.first, RHSValues.first,
+                             K, IsComplex ? ".r" : "");
+    if (!IsComplex)
+      return Cmp;
+    assert(K == CompareKind::CK_Equal);
+    Value *CmpImag = EmitCompare(Builder, CGF, E, LHSValues.second,
+                                 RHSValues.second, K, ".i");
+    return Builder.CreateAnd(Cmp, CmpImag, "and.eq");
+  };
+  auto EmitCmpRes = [&](const ComparisonCategoryInfo::ValueInfo *VInfo) {
+    return Builder.getInt(VInfo->getIntValue());
+  };
+
+  Value *Select;
+  if (ArgTy->isNullPtrType()) {
+    Select = EmitCmpRes(CmpInfo.getEqualOrEquiv());
+  } else if (CmpInfo.isEquality()) {
+    Select = Builder.CreateSelect(
+        EmitCmp(CK_Equal), EmitCmpRes(CmpInfo.getEqualOrEquiv()),
+        EmitCmpRes(CmpInfo.getNonequalOrNonequiv()), "sel.eq");
+  } else if (!CmpInfo.isPartial()) {
+    Value *SelectOne =
+        Builder.CreateSelect(EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()),
+                             EmitCmpRes(CmpInfo.getGreater()), "sel.lt");
+    Select = Builder.CreateSelect(EmitCmp(CK_Equal),
+                                  EmitCmpRes(CmpInfo.getEqualOrEquiv()),
+                                  SelectOne, "sel.eq");
+  } else {
+    Value *SelectEq = Builder.CreateSelect(
+        EmitCmp(CK_Equal), EmitCmpRes(CmpInfo.getEqualOrEquiv()),
+        EmitCmpRes(CmpInfo.getUnordered()), "sel.eq");
+    Value *SelectGT = Builder.CreateSelect(EmitCmp(CK_Greater),
+                                           EmitCmpRes(CmpInfo.getGreater()),
+                                           SelectEq, "sel.gt");
+    Select = Builder.CreateSelect(
+        EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()), SelectGT, "sel.lt");
+  }
+  // Create the return value in the destination slot.
+  EnsureDest(E->getType());
+  LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
+
+  // Emit the address of the first (and only) field in the comparison category
+  // type, and initialize it from the constant integer value selected above.
+  LValue FieldLV = CGF.EmitLValueForFieldInitialization(
+      DestLV, *CmpInfo.Record->field_begin());
+  CGF.EmitStoreThroughLValue(RValue::get(Select), FieldLV, /*IsInit*/ true);
+
+  // All done! The result is in the Dest slot.
+}
+
+void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
+  if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI)
+    VisitPointerToDataMemberBinaryOperator(E);
+  else
+    CGF.ErrorUnsupported(E, "aggregate binary expression");
+}
+
+void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
+                                                    const BinaryOperator *E) {
+  LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
+  EmitFinalDestCopy(E->getType(), LV);
+}
+
+/// Is the value of the given expression possibly a reference to or
+/// into a __block variable?
+static bool isBlockVarRef(const Expr *E) {
+  // Make sure we look through parens.
+  E = E->IgnoreParens();
+
+  // Check for a direct reference to a __block variable.
+  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
+    const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
+    return (var && var->hasAttr<BlocksAttr>());
+  }
+
+  // More complicated stuff.
+
+  // Binary operators.
+  if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) {
+    // For an assignment or pointer-to-member operation, just care
+    // about the LHS.
+    if (op->isAssignmentOp() || op->isPtrMemOp())
+      return isBlockVarRef(op->getLHS());
+
+    // For a comma, just care about the RHS.
+    if (op->getOpcode() == BO_Comma)
+      return isBlockVarRef(op->getRHS());
+
+    // FIXME: pointer arithmetic?
+    return false;
+
+  // Check both sides of a conditional operator.
+  } else if (const AbstractConditionalOperator *op
+               = dyn_cast<AbstractConditionalOperator>(E)) {
+    return isBlockVarRef(op->getTrueExpr())
+        || isBlockVarRef(op->getFalseExpr());
+
+  // OVEs are required to support BinaryConditionalOperators.
+  } else if (const OpaqueValueExpr *op
+               = dyn_cast<OpaqueValueExpr>(E)) {
+    if (const Expr *src = op->getSourceExpr())
+      return isBlockVarRef(src);
+
+  // Casts are necessary to get things like (*(int*)&var) = foo().
+  // We don't really care about the kind of cast here, except
+  // we don't want to look through l2r casts, because it's okay
+  // to get the *value* in a __block variable.
+  } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) {
+    if (cast->getCastKind() == CK_LValueToRValue)
+      return false;
+    return isBlockVarRef(cast->getSubExpr());
+
+  // Handle unary operators.  Again, just aggressively look through
+  // it, ignoring the operation.
+  } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) {
+    return isBlockVarRef(uop->getSubExpr());
+
+  // Look into the base of a field access.
+  } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
+    return isBlockVarRef(mem->getBase());
+
+  // Look into the base of a subscript.
+  } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) {
+    return isBlockVarRef(sub->getBase());
+  }
+
+  return false;
+}
+
+void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
+  // For an assignment to work, the value on the right has
+  // to be compatible with the value on the left.
+  assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
+                                                 E->getRHS()->getType())
+         && "Invalid assignment");
+
+  // If the LHS might be a __block variable, and the RHS can
+  // potentially cause a block copy, we need to evaluate the RHS first
+  // so that the assignment goes the right place.
+  // This is pretty semantically fragile.
+  if (isBlockVarRef(E->getLHS()) &&
+      E->getRHS()->HasSideEffects(CGF.getContext())) {
+    // Ensure that we have a destination, and evaluate the RHS into that.
+    EnsureDest(E->getRHS()->getType());
+    Visit(E->getRHS());
+
+    // Now emit the LHS and copy into it.
+    LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
+
+    // That copy is an atomic copy if the LHS is atomic.
+    if (LHS.getType()->isAtomicType() ||
+        CGF.LValueIsSuitableForInlineAtomic(LHS)) {
+      CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
+      return;
+    }
+
+    EmitCopy(E->getLHS()->getType(),
+             AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
+                                     needsGC(E->getLHS()->getType()),
+                                     AggValueSlot::IsAliased,
+                                     AggValueSlot::MayOverlap),
+             Dest);
+    return;
+  }
+
+  LValue LHS = CGF.EmitLValue(E->getLHS());
+
+  // If we have an atomic type, evaluate into the destination and then
+  // do an atomic copy.
+  if (LHS.getType()->isAtomicType() ||
+      CGF.LValueIsSuitableForInlineAtomic(LHS)) {
+    EnsureDest(E->getRHS()->getType());
+    Visit(E->getRHS());
+    CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
+    return;
+  }
+
+  // Codegen the RHS so that it stores directly into the LHS.
+  AggValueSlot LHSSlot =
+    AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
+                            needsGC(E->getLHS()->getType()),
+                            AggValueSlot::IsAliased,
+                            AggValueSlot::MayOverlap);
+  // A non-volatile aggregate destination might have volatile member.
+  if (!LHSSlot.isVolatile() &&
+      CGF.hasVolatileMember(E->getLHS()->getType()))
+    LHSSlot.setVolatile(true);
+
+  CGF.EmitAggExpr(E->getRHS(), LHSSlot);
+
+  // Copy into the destination if the assignment isn't ignored.
+  EmitFinalDestCopy(E->getType(), LHS);
+}
+
+void AggExprEmitter::
+VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
+  llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
+  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
+  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
+
+  // Bind the common expression if necessary.
+  CodeGenFunction::OpaqueValueMapping binding(CGF, E);
+
+  CodeGenFunction::ConditionalEvaluation eval(CGF);
+  CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock,
+                           CGF.getProfileCount(E));
+
+  // Save whether the destination's lifetime is externally managed.
+  bool isExternallyDestructed = Dest.isExternallyDestructed();
+
+  eval.begin(CGF);
+  CGF.EmitBlock(LHSBlock);
+  CGF.incrementProfileCounter(E);
+  Visit(E->getTrueExpr());
+  eval.end(CGF);
+
+  assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!");
+  CGF.Builder.CreateBr(ContBlock);
+
+  // If the result of an agg expression is unused, then the emission
+  // of the LHS might need to create a destination slot.  That's fine
+  // with us, and we can safely emit the RHS into the same slot, but
+  // we shouldn't claim that it's already being destructed.
+  Dest.setExternallyDestructed(isExternallyDestructed);
+
+  eval.begin(CGF);
+  CGF.EmitBlock(RHSBlock);
+  Visit(E->getFalseExpr());
+  eval.end(CGF);
+
+  CGF.EmitBlock(ContBlock);
+}
+
+void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
+  Visit(CE->getChosenSubExpr());
+}
+
+void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
+  Address ArgValue = Address::invalid();
+  Address ArgPtr = CGF.EmitVAArg(VE, ArgValue);
+
+  // If EmitVAArg fails, emit an error.
+  if (!ArgPtr.isValid()) {
+    CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
+    return;
+  }
+
+  EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType()));
+}
+
+void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
+  // Ensure that we have a slot, but if we already do, remember
+  // whether it was externally destructed.
+  bool wasExternallyDestructed = Dest.isExternallyDestructed();
+  EnsureDest(E->getType());
+
+  // We're going to push a destructor if there isn't already one.
+  Dest.setExternallyDestructed();
+
+  Visit(E->getSubExpr());
+
+  // Push that destructor we promised.
+  if (!wasExternallyDestructed)
+    CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddress());
+}
+
+void
+AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
+  AggValueSlot Slot = EnsureSlot(E->getType());
+  CGF.EmitCXXConstructExpr(E, Slot);
+}
+
+void AggExprEmitter::VisitCXXInheritedCtorInitExpr(
+    const CXXInheritedCtorInitExpr *E) {
+  AggValueSlot Slot = EnsureSlot(E->getType());
+  CGF.EmitInheritedCXXConstructorCall(
+      E->getConstructor(), E->constructsVBase(), Slot.getAddress(),
+      E->inheritedFromVBase(), E);
+}
+
+void
+AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
+  AggValueSlot Slot = EnsureSlot(E->getType());
+  LValue SlotLV = CGF.MakeAddrLValue(Slot.getAddress(), E->getType());
+
+  // We'll need to enter cleanup scopes in case any of the element
+  // initializers throws an exception.
+  SmallVector<EHScopeStack::stable_iterator, 16> Cleanups;
+  llvm::Instruction *CleanupDominator = nullptr;
+
+  CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
+  for (LambdaExpr::const_capture_init_iterator i = E->capture_init_begin(),
+                                               e = E->capture_init_end();
+       i != e; ++i, ++CurField) {
+    // Emit initialization
+    LValue LV = CGF.EmitLValueForFieldInitialization(SlotLV, *CurField);
+    if (CurField->hasCapturedVLAType()) {
+      CGF.EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
+      continue;
+    }
+
+    EmitInitializationToLValue(*i, LV);
+
+    // Push a destructor if necessary.
+    if (QualType::DestructionKind DtorKind =
+            CurField->getType().isDestructedType()) {
+      assert(LV.isSimple());
+      if (CGF.needsEHCleanup(DtorKind)) {
+        if (!CleanupDominator)
+          CleanupDominator = CGF.Builder.CreateAlignedLoad(
+              CGF.Int8Ty,
+              llvm::Constant::getNullValue(CGF.Int8PtrTy),
+              CharUnits::One()); // placeholder
+
+        CGF.pushDestroy(EHCleanup, LV.getAddress(), CurField->getType(),
+                        CGF.getDestroyer(DtorKind), false);
+        Cleanups.push_back(CGF.EHStack.stable_begin());
+      }
+    }
+  }
+
+  // Deactivate all the partial cleanups in reverse order, which
+  // generally means popping them.
+  for (unsigned i = Cleanups.size(); i != 0; --i)
+    CGF.DeactivateCleanupBlock(Cleanups[i-1], CleanupDominator);
+
+  // Destroy the placeholder if we made one.
+  if (CleanupDominator)
+    CleanupDominator->eraseFromParent();
+}
+
+void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
+  CGF.enterFullExpression(E);
+  CodeGenFunction::RunCleanupsScope cleanups(CGF);
+  Visit(E->getSubExpr());
+}
+
+void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
+  QualType T = E->getType();
+  AggValueSlot Slot = EnsureSlot(T);
+  EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
+}
+
+void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
+  QualType T = E->getType();
+  AggValueSlot Slot = EnsureSlot(T);
+  EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T));
+}
+
+/// isSimpleZero - If emitting this value will obviously just cause a store of
+/// zero to memory, return true.  This can return false if uncertain, so it just
+/// handles simple cases.
+static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) {
+  E = E->IgnoreParens();
+
+  // 0
+  if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E))
+    return IL->getValue() == 0;
+  // +0.0
+  if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E))
+    return FL->getValue().isPosZero();
+  // int()
+  if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) &&
+      CGF.getTypes().isZeroInitializable(E->getType()))
+    return true;
+  // (int*)0 - Null pointer expressions.
+  if (const CastExpr *ICE = dyn_cast<CastExpr>(E))
+    return ICE->getCastKind() == CK_NullToPointer &&
+           CGF.getTypes().isPointerZeroInitializable(E->getType()) &&
+           !E->HasSideEffects(CGF.getContext());
+  // '\0'
+  if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E))
+    return CL->getValue() == 0;
+
+  // Otherwise, hard case: conservatively return false.
+  return false;
+}
+
+
+void
+AggExprEmitter::EmitInitializationToLValue(Expr *E, LValue LV) {
+  QualType type = LV.getType();
+  // FIXME: Ignore result?
+  // FIXME: Are initializers affected by volatile?
+  if (Dest.isZeroed() && isSimpleZero(E, CGF)) {
+    // Storing "i32 0" to a zero'd memory location is a noop.
+    return;
+  } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) {
+    return EmitNullInitializationToLValue(LV);
+  } else if (isa<NoInitExpr>(E)) {
+    // Do nothing.
+    return;
+  } else if (type->isReferenceType()) {
+    RValue RV = CGF.EmitReferenceBindingToExpr(E);
+    return CGF.EmitStoreThroughLValue(RV, LV);
+  }
+
+  switch (CGF.getEvaluationKind(type)) {
+  case TEK_Complex:
+    CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
+    return;
+  case TEK_Aggregate:
+    CGF.EmitAggExpr(E, AggValueSlot::forLValue(LV,
+                                               AggValueSlot::IsDestructed,
+                                      AggValueSlot::DoesNotNeedGCBarriers,
+                                               AggValueSlot::IsNotAliased,
+                                               AggValueSlot::MayOverlap,
+                                               Dest.isZeroed()));
+    return;
+  case TEK_Scalar:
+    if (LV.isSimple()) {
+      CGF.EmitScalarInit(E, /*D=*/nullptr, LV, /*Captured=*/false);
+    } else {
+      CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV);
+    }
+    return;
+  }
+  llvm_unreachable("bad evaluation kind");
+}
+
+void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) {
+  QualType type = lv.getType();
+
+  // If the destination slot is already zeroed out before the aggregate is
+  // copied into it, we don't have to emit any zeros here.
+  if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type))
+    return;
+
+  if (CGF.hasScalarEvaluationKind(type)) {
+    // For non-aggregates, we can store the appropriate null constant.
+    llvm::Value *null = CGF.CGM.EmitNullConstant(type);
+    // Note that the following is not equivalent to
+    // EmitStoreThroughBitfieldLValue for ARC types.
+    if (lv.isBitField()) {
+      CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv);
+    } else {
+      assert(lv.isSimple());
+      CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true);
+    }
+  } else {
+    // There's a potential optimization opportunity in combining
+    // memsets; that would be easy for arrays, but relatively
+    // difficult for structures with the current code.
+    CGF.EmitNullInitialization(lv.getAddress(), lv.getType());
+  }
+}
+
+void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
+#if 0
+  // FIXME: Assess perf here?  Figure out what cases are worth optimizing here
+  // (Length of globals? Chunks of zeroed-out space?).
+  //
+  // If we can, prefer a copy from a global; this is a lot less code for long
+  // globals, and it's easier for the current optimizers to analyze.
+  if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
+    llvm::GlobalVariable* GV =
+    new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
+                             llvm::GlobalValue::InternalLinkage, C, "");
+    EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType()));
+    return;
+  }
+#endif
+  if (E->hadArrayRangeDesignator())
+    CGF.ErrorUnsupported(E, "GNU array range designator extension");
+
+  if (E->isTransparent())
+    return Visit(E->getInit(0));
+
+  AggValueSlot Dest = EnsureSlot(E->getType());
+
+  LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
+
+  // Handle initialization of an array.
+  if (E->getType()->isArrayType()) {
+    auto AType = cast<llvm::ArrayType>(Dest.getAddress().getElementType());
+    EmitArrayInit(Dest.getAddress(), AType, E->getType(), E);
+    return;
+  }
+
+  assert(E->getType()->isRecordType() && "Only support structs/unions here!");
+
+  // Do struct initialization; this code just sets each individual member
+  // to the approprate value.  This makes bitfield support automatic;
+  // the disadvantage is that the generated code is more difficult for
+  // the optimizer, especially with bitfields.
+  unsigned NumInitElements = E->getNumInits();
+  RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl();
+
+  // We'll need to enter cleanup scopes in case any of the element
+  // initializers throws an exception.
+  SmallVector<EHScopeStack::stable_iterator, 16> cleanups;
+  llvm::Instruction *cleanupDominator = nullptr;
+  auto addCleanup = [&](const EHScopeStack::stable_iterator &cleanup) {
+    cleanups.push_back(cleanup);
+    if (!cleanupDominator) // create placeholder once needed
+      cleanupDominator = CGF.Builder.CreateAlignedLoad(
+          CGF.Int8Ty, llvm::Constant::getNullValue(CGF.Int8PtrTy),
+          CharUnits::One());
+  };
+
+  unsigned curInitIndex = 0;
+
+  // Emit initialization of base classes.
+  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(record)) {
+    assert(E->getNumInits() >= CXXRD->getNumBases() &&
+           "missing initializer for base class");
+    for (auto &Base : CXXRD->bases()) {
+      assert(!Base.isVirtual() && "should not see vbases here");
+      auto *BaseRD = Base.getType()->getAsCXXRecordDecl();
+      Address V = CGF.GetAddressOfDirectBaseInCompleteClass(
+          Dest.getAddress(), CXXRD, BaseRD,
+          /*isBaseVirtual*/ false);
+      AggValueSlot AggSlot = AggValueSlot::forAddr(
+          V, Qualifiers(),
+          AggValueSlot::IsDestructed,
+          AggValueSlot::DoesNotNeedGCBarriers,
+          AggValueSlot::IsNotAliased,
+          CGF.getOverlapForBaseInit(CXXRD, BaseRD, Base.isVirtual()));
+      CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot);
+
+      if (QualType::DestructionKind dtorKind =
+              Base.getType().isDestructedType()) {
+        CGF.pushDestroy(dtorKind, V, Base.getType());
+        addCleanup(CGF.EHStack.stable_begin());
+      }
+    }
+  }
+
+  // Prepare a 'this' for CXXDefaultInitExprs.
+  CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddress());
+
+  if (record->isUnion()) {
+    // Only initialize one field of a union. The field itself is
+    // specified by the initializer list.
+    if (!E->getInitializedFieldInUnion()) {
+      // Empty union; we have nothing to do.
+
+#ifndef NDEBUG
+      // Make sure that it's really an empty and not a failure of
+      // semantic analysis.
+      for (const auto *Field : record->fields())
+        assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
+#endif
+      return;
+    }
+
+    // FIXME: volatility
+    FieldDecl *Field = E->getInitializedFieldInUnion();
+
+    LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field);
+    if (NumInitElements) {
+      // Store the initializer into the field
+      EmitInitializationToLValue(E->getInit(0), FieldLoc);
+    } else {
+      // Default-initialize to null.
+      EmitNullInitializationToLValue(FieldLoc);
+    }
+
+    return;
+  }
+
+  // Here we iterate over the fields; this makes it simpler to both
+  // default-initialize fields and skip over unnamed fields.
+  for (const auto *field : record->fields()) {
+    // We're done once we hit the flexible array member.
+    if (field->getType()->isIncompleteArrayType())
+      break;
+
+    // Always skip anonymous bitfields.
+    if (field->isUnnamedBitfield())
+      continue;
+
+    // We're done if we reach the end of the explicit initializers, we
+    // have a zeroed object, and the rest of the fields are
+    // zero-initializable.
+    if (curInitIndex == NumInitElements && Dest.isZeroed() &&
+        CGF.getTypes().isZeroInitializable(E->getType()))
+      break;
+
+
+    LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, field);
+    // We never generate write-barries for initialized fields.
+    LV.setNonGC(true);
+
+    if (curInitIndex < NumInitElements) {
+      // Store the initializer into the field.
+      EmitInitializationToLValue(E->getInit(curInitIndex++), LV);
+    } else {
+      // We're out of initializers; default-initialize to null
+      EmitNullInitializationToLValue(LV);
+    }
+
+    // Push a destructor if necessary.
+    // FIXME: if we have an array of structures, all explicitly
+    // initialized, we can end up pushing a linear number of cleanups.
+    bool pushedCleanup = false;
+    if (QualType::DestructionKind dtorKind
+          = field->getType().isDestructedType()) {
+      assert(LV.isSimple());
+      if (CGF.needsEHCleanup(dtorKind)) {
+        CGF.pushDestroy(EHCleanup, LV.getAddress(), field->getType(),
+                        CGF.getDestroyer(dtorKind), false);
+        addCleanup(CGF.EHStack.stable_begin());
+        pushedCleanup = true;
+      }
+    }
+
+    // If the GEP didn't get used because of a dead zero init or something
+    // else, clean it up for -O0 builds and general tidiness.
+    if (!pushedCleanup && LV.isSimple())
+      if (llvm::GetElementPtrInst *GEP =
+            dyn_cast<llvm::GetElementPtrInst>(LV.getPointer()))
+        if (GEP->use_empty())
+          GEP->eraseFromParent();
+  }
+
+  // Deactivate all the partial cleanups in reverse order, which
+  // generally means popping them.
+  assert((cleanupDominator || cleanups.empty()) &&
+         "Missing cleanupDominator before deactivating cleanup blocks");
+  for (unsigned i = cleanups.size(); i != 0; --i)
+    CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator);
+
+  // Destroy the placeholder if we made one.
+  if (cleanupDominator)
+    cleanupDominator->eraseFromParent();
+}
+
+void AggExprEmitter::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E,
+                                            llvm::Value *outerBegin) {
+  // Emit the common subexpression.
+  CodeGenFunction::OpaqueValueMapping binding(CGF, E->getCommonExpr());
+
+  Address destPtr = EnsureSlot(E->getType()).getAddress();
+  uint64_t numElements = E->getArraySize().getZExtValue();
+
+  if (!numElements)
+    return;
+
+  // destPtr is an array*. Construct an elementType* by drilling down a level.
+  llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
+  llvm::Value *indices[] = {zero, zero};
+  llvm::Value *begin = Builder.CreateInBoundsGEP(destPtr.getPointer(), indices,
+                                                 "arrayinit.begin");
+
+  // Prepare to special-case multidimensional array initialization: we avoid
+  // emitting multiple destructor loops in that case.
+  if (!outerBegin)
+    outerBegin = begin;
+  ArrayInitLoopExpr *InnerLoop = dyn_cast<ArrayInitLoopExpr>(E->getSubExpr());
+
+  QualType elementType =
+      CGF.getContext().getAsArrayType(E->getType())->getElementType();
+  CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
+  CharUnits elementAlign =
+      destPtr.getAlignment().alignmentOfArrayElement(elementSize);
+
+  llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
+  llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body");
+
+  // Jump into the body.
+  CGF.EmitBlock(bodyBB);
+  llvm::PHINode *index =
+      Builder.CreatePHI(zero->getType(), 2, "arrayinit.index");
+  index->addIncoming(zero, entryBB);
+  llvm::Value *element = Builder.CreateInBoundsGEP(begin, index);
+
+  // Prepare for a cleanup.
+  QualType::DestructionKind dtorKind = elementType.isDestructedType();
+  EHScopeStack::stable_iterator cleanup;
+  if (CGF.needsEHCleanup(dtorKind) && !InnerLoop) {
+    if (outerBegin->getType() != element->getType())
+      outerBegin = Builder.CreateBitCast(outerBegin, element->getType());
+    CGF.pushRegularPartialArrayCleanup(outerBegin, element, elementType,
+                                       elementAlign,
+                                       CGF.getDestroyer(dtorKind));
+    cleanup = CGF.EHStack.stable_begin();
+  } else {
+    dtorKind = QualType::DK_none;
+  }
+
+  // Emit the actual filler expression.
+  {
+    // Temporaries created in an array initialization loop are destroyed
+    // at the end of each iteration.
+    CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
+    CodeGenFunction::ArrayInitLoopExprScope Scope(CGF, index);
+    LValue elementLV =
+        CGF.MakeAddrLValue(Address(element, elementAlign), elementType);
+
+    if (InnerLoop) {
+      // If the subexpression is an ArrayInitLoopExpr, share its cleanup.
+      auto elementSlot = AggValueSlot::forLValue(
+          elementLV, AggValueSlot::IsDestructed,
+          AggValueSlot::DoesNotNeedGCBarriers,
+          AggValueSlot::IsNotAliased,
+          AggValueSlot::DoesNotOverlap);
+      AggExprEmitter(CGF, elementSlot, false)
+          .VisitArrayInitLoopExpr(InnerLoop, outerBegin);
+    } else
+      EmitInitializationToLValue(E->getSubExpr(), elementLV);
+  }
+
+  // Move on to the next element.
+  llvm::Value *nextIndex = Builder.CreateNUWAdd(
+      index, llvm::ConstantInt::get(CGF.SizeTy, 1), "arrayinit.next");
+  index->addIncoming(nextIndex, Builder.GetInsertBlock());
+
+  // Leave the loop if we're done.
+  llvm::Value *done = Builder.CreateICmpEQ(
+      nextIndex, llvm::ConstantInt::get(CGF.SizeTy, numElements),
+      "arrayinit.done");
+  llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end");
+  Builder.CreateCondBr(done, endBB, bodyBB);
+
+  CGF.EmitBlock(endBB);
+
+  // Leave the partial-array cleanup if we entered one.
+  if (dtorKind)
+    CGF.DeactivateCleanupBlock(cleanup, index);
+}
+
+void AggExprEmitter::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) {
+  AggValueSlot Dest = EnsureSlot(E->getType());
+
+  LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
+  EmitInitializationToLValue(E->getBase(), DestLV);
+  VisitInitListExpr(E->getUpdater());
+}
+
+//===----------------------------------------------------------------------===//
+//                        Entry Points into this File
+//===----------------------------------------------------------------------===//
+
+/// GetNumNonZeroBytesInInit - Get an approximate count of the number of
+/// non-zero bytes that will be stored when outputting the initializer for the
+/// specified initializer expression.
+static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) {
+  E = E->IgnoreParens();
+
+  // 0 and 0.0 won't require any non-zero stores!
+  if (isSimpleZero(E, CGF)) return CharUnits::Zero();
+
+  // If this is an initlist expr, sum up the size of sizes of the (present)
+  // elements.  If this is something weird, assume the whole thing is non-zero.
+  const InitListExpr *ILE = dyn_cast<InitListExpr>(E);
+  while (ILE && ILE->isTransparent())
+    ILE = dyn_cast<InitListExpr>(ILE->getInit(0));
+  if (!ILE || !CGF.getTypes().isZeroInitializable(ILE->getType()))
+    return CGF.getContext().getTypeSizeInChars(E->getType());
+
+  // InitListExprs for structs have to be handled carefully.  If there are
+  // reference members, we need to consider the size of the reference, not the
+  // referencee.  InitListExprs for unions and arrays can't have references.
+  if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
+    if (!RT->isUnionType()) {
+      RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
+      CharUnits NumNonZeroBytes = CharUnits::Zero();
+
+      unsigned ILEElement = 0;
+      if (auto *CXXRD = dyn_cast<CXXRecordDecl>(SD))
+        while (ILEElement != CXXRD->getNumBases())
+          NumNonZeroBytes +=
+              GetNumNonZeroBytesInInit(ILE->getInit(ILEElement++), CGF);
+      for (const auto *Field : SD->fields()) {
+        // We're done once we hit the flexible array member or run out of
+        // InitListExpr elements.
+        if (Field->getType()->isIncompleteArrayType() ||
+            ILEElement == ILE->getNumInits())
+          break;
+        if (Field->isUnnamedBitfield())
+          continue;
+
+        const Expr *E = ILE->getInit(ILEElement++);
+
+        // Reference values are always non-null and have the width of a pointer.
+        if (Field->getType()->isReferenceType())
+          NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits(
+              CGF.getTarget().getPointerWidth(0));
+        else
+          NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF);
+      }
+
+      return NumNonZeroBytes;
+    }
+  }
+
+
+  CharUnits NumNonZeroBytes = CharUnits::Zero();
+  for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
+    NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF);
+  return NumNonZeroBytes;
+}
+
+/// CheckAggExprForMemSetUse - If the initializer is large and has a lot of
+/// zeros in it, emit a memset and avoid storing the individual zeros.
+///
+static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E,
+                                     CodeGenFunction &CGF) {
+  // If the slot is already known to be zeroed, nothing to do.  Don't mess with
+  // volatile stores.
+  if (Slot.isZeroed() || Slot.isVolatile() || !Slot.getAddress().isValid())
+    return;
+
+  // C++ objects with a user-declared constructor don't need zero'ing.
+  if (CGF.getLangOpts().CPlusPlus)
+    if (const RecordType *RT = CGF.getContext()
+                       .getBaseElementType(E->getType())->getAs<RecordType>()) {
+      const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+      if (RD->hasUserDeclaredConstructor())
+        return;
+    }
+
+  // If the type is 16-bytes or smaller, prefer individual stores over memset.
+  CharUnits Size = Slot.getPreferredSize(CGF.getContext(), E->getType());
+  if (Size <= CharUnits::fromQuantity(16))
+    return;
+
+  // Check to see if over 3/4 of the initializer are known to be zero.  If so,
+  // we prefer to emit memset + individual stores for the rest.
+  CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF);
+  if (NumNonZeroBytes*4 > Size)
+    return;
+
+  // Okay, it seems like a good idea to use an initial memset, emit the call.
+  llvm::Constant *SizeVal = CGF.Builder.getInt64(Size.getQuantity());
+
+  Address Loc = Slot.getAddress();
+  Loc = CGF.Builder.CreateElementBitCast(Loc, CGF.Int8Ty);
+  CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, false);
+
+  // Tell the AggExprEmitter that the slot is known zero.
+  Slot.setZeroed();
+}
+
+
+
+
+/// EmitAggExpr - Emit the computation of the specified expression of aggregate
+/// type.  The result is computed into DestPtr.  Note that if DestPtr is null,
+/// the value of the aggregate expression is not needed.  If VolatileDest is
+/// true, DestPtr cannot be 0.
+void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) {
+  assert(E && hasAggregateEvaluationKind(E->getType()) &&
+         "Invalid aggregate expression to emit");
+  assert((Slot.getAddress().isValid() || Slot.isIgnored()) &&
+         "slot has bits but no address");
+
+  // Optimize the slot if possible.
+  CheckAggExprForMemSetUse(Slot, E, *this);
+
+  AggExprEmitter(*this, Slot, Slot.isIgnored()).Visit(const_cast<Expr*>(E));
+}
+
+LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
+  assert(hasAggregateEvaluationKind(E->getType()) && "Invalid argument!");
+  Address Temp = CreateMemTemp(E->getType());
+  LValue LV = MakeAddrLValue(Temp, E->getType());
+  EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsNotDestructed,
+                                         AggValueSlot::DoesNotNeedGCBarriers,
+                                         AggValueSlot::IsNotAliased,
+                                         AggValueSlot::DoesNotOverlap));
+  return LV;
+}
+
+AggValueSlot::Overlap_t
+CodeGenFunction::getOverlapForFieldInit(const FieldDecl *FD) {
+  if (!FD->hasAttr<NoUniqueAddressAttr>() || !FD->getType()->isRecordType())
+    return AggValueSlot::DoesNotOverlap;
+
+  // If the field lies entirely within the enclosing class's nvsize, its tail
+  // padding cannot overlap any already-initialized object. (The only subobjects
+  // with greater addresses that might already be initialized are vbases.)
+  const RecordDecl *ClassRD = FD->getParent();
+  const ASTRecordLayout &Layout = getContext().getASTRecordLayout(ClassRD);
+  if (Layout.getFieldOffset(FD->getFieldIndex()) +
+          getContext().getTypeSize(FD->getType()) <=
+      (uint64_t)getContext().toBits(Layout.getNonVirtualSize()))
+    return AggValueSlot::DoesNotOverlap;
+
+  // The tail padding may contain values we need to preserve.
+  return AggValueSlot::MayOverlap;
+}
+
+AggValueSlot::Overlap_t CodeGenFunction::getOverlapForBaseInit(
+    const CXXRecordDecl *RD, const CXXRecordDecl *BaseRD, bool IsVirtual) {
+  // If the most-derived object is a field declared with [[no_unique_address]],
+  // the tail padding of any virtual base could be reused for other subobjects
+  // of that field's class.
+  if (IsVirtual)
+    return AggValueSlot::MayOverlap;
+
+  // If the base class is laid out entirely within the nvsize of the derived
+  // class, its tail padding cannot yet be initialized, so we can issue
+  // stores at the full width of the base class.
+  const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
+  if (Layout.getBaseClassOffset(BaseRD) +
+          getContext().getASTRecordLayout(BaseRD).getSize() <=
+      Layout.getNonVirtualSize())
+    return AggValueSlot::DoesNotOverlap;
+
+  // The tail padding may contain values we need to preserve.
+  return AggValueSlot::MayOverlap;
+}
+
+void CodeGenFunction::EmitAggregateCopy(LValue Dest, LValue Src, QualType Ty,
+                                        AggValueSlot::Overlap_t MayOverlap,
+                                        bool isVolatile) {
+  assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
+
+  Address DestPtr = Dest.getAddress();
+  Address SrcPtr = Src.getAddress();
+
+  if (getLangOpts().CPlusPlus) {
+    if (const RecordType *RT = Ty->getAs<RecordType>()) {
+      CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
+      assert((Record->hasTrivialCopyConstructor() ||
+              Record->hasTrivialCopyAssignment() ||
+              Record->hasTrivialMoveConstructor() ||
+              Record->hasTrivialMoveAssignment() ||
+              Record->isUnion()) &&
+             "Trying to aggregate-copy a type without a trivial copy/move "
+             "constructor or assignment operator");
+      // Ignore empty classes in C++.
+      if (Record->isEmpty())
+        return;
+    }
+  }
+
+  // Aggregate assignment turns into llvm.memcpy.  This is almost valid per
+  // C99 6.5.16.1p3, which states "If the value being stored in an object is
+  // read from another object that overlaps in anyway the storage of the first
+  // object, then the overlap shall be exact and the two objects shall have
+  // qualified or unqualified versions of a compatible type."
+  //
+  // memcpy is not defined if the source and destination pointers are exactly
+  // equal, but other compilers do this optimization, and almost every memcpy
+  // implementation handles this case safely.  If there is a libc that does not
+  // safely handle this, we can add a target hook.
+
+  // Get data size info for this aggregate. Don't copy the tail padding if this
+  // might be a potentially-overlapping subobject, since the tail padding might
+  // be occupied by a different object. Otherwise, copying it is fine.
+  std::pair<CharUnits, CharUnits> TypeInfo;
+  if (MayOverlap)
+    TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
+  else
+    TypeInfo = getContext().getTypeInfoInChars(Ty);
+
+  llvm::Value *SizeVal = nullptr;
+  if (TypeInfo.first.isZero()) {
+    // But note that getTypeInfo returns 0 for a VLA.
+    if (auto *VAT = dyn_cast_or_null<VariableArrayType>(
+            getContext().getAsArrayType(Ty))) {
+      QualType BaseEltTy;
+      SizeVal = emitArrayLength(VAT, BaseEltTy, DestPtr);
+      TypeInfo = getContext().getTypeInfoInChars(BaseEltTy);
+      assert(!TypeInfo.first.isZero());
+      SizeVal = Builder.CreateNUWMul(
+          SizeVal,
+          llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity()));
+    }
+  }
+  if (!SizeVal) {
+    SizeVal = llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity());
+  }
+
+  // FIXME: If we have a volatile struct, the optimizer can remove what might
+  // appear to be `extra' memory ops:
+  //
+  // volatile struct { int i; } a, b;
+  //
+  // int main() {
+  //   a = b;
+  //   a = b;
+  // }
+  //
+  // we need to use a different call here.  We use isVolatile to indicate when
+  // either the source or the destination is volatile.
+
+  DestPtr = Builder.CreateElementBitCast(DestPtr, Int8Ty);
+  SrcPtr = Builder.CreateElementBitCast(SrcPtr, Int8Ty);
+
+  // Don't do any of the memmove_collectable tests if GC isn't set.
+  if (CGM.getLangOpts().getGC() == LangOptions::NonGC) {
+    // fall through
+  } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
+    RecordDecl *Record = RecordTy->getDecl();
+    if (Record->hasObjectMember()) {
+      CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
+                                                    SizeVal);
+      return;
+    }
+  } else if (Ty->isArrayType()) {
+    QualType BaseType = getContext().getBaseElementType(Ty);
+    if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
+      if (RecordTy->getDecl()->hasObjectMember()) {
+        CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
+                                                      SizeVal);
+        return;
+      }
+    }
+  }
+
+  auto Inst = Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, isVolatile);
+
+  // Determine the metadata to describe the position of any padding in this
+  // memcpy, as well as the TBAA tags for the members of the struct, in case
+  // the optimizer wishes to expand it in to scalar memory operations.
+  if (llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty))
+    Inst->setMetadata(llvm::LLVMContext::MD_tbaa_struct, TBAAStructTag);
+
+  if (CGM.getCodeGenOpts().NewStructPathTBAA) {
+    TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForMemoryTransfer(
+        Dest.getTBAAInfo(), Src.getTBAAInfo());
+    CGM.DecorateInstructionWithTBAA(Inst, TBAAInfo);
+  }
+}