Add the clang library to the repo (with some of my changes, too).

1 files changed, 6926 insertions, 0 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
new file mode 100644
index 0000000..66a88b0
--- /dev/null
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -0,0 +1,6926 @@
+//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Expr constant evaluator.
+//
+// Constant expression evaluation produces four main results:
+//
+//  * A success/failure flag indicating whether constant folding was successful.
+//    This is the 'bool' return value used by most of the code in this file. A
+//    'false' return value indicates that constant folding has failed, and any
+//    appropriate diagnostic has already been produced.
+//
+//  * An evaluated result, valid only if constant folding has not failed.
+//
+//  * A flag indicating if evaluation encountered (unevaluated) side-effects.
+//    These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
+//    where it is possible to determine the evaluated result regardless.
+//
+//  * A set of notes indicating why the evaluation was not a constant expression
+//    (under the C++11 rules only, at the moment), or, if folding failed too,
+//    why the expression could not be folded.
+//
+// If we are checking for a potential constant expression, failure to constant
+// fold a potential constant sub-expression will be indicated by a 'false'
+// return value (the expression could not be folded) and no diagnostic (the
+// expression is not necessarily non-constant).
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/APValue.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/CharUnits.h"
+#include "clang/AST/RecordLayout.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/AST/TypeLoc.h"
+#include "clang/AST/ASTDiagnostic.h"
+#include "clang/AST/Expr.h"
+#include "clang/Basic/Builtins.h"
+#include "clang/Basic/TargetInfo.h"
+#include "llvm/ADT/SmallString.h"
+#include <cstring>
+#include <functional>
+
+using namespace clang;
+using llvm::APSInt;
+using llvm::APFloat;
+
+static bool IsGlobalLValue(APValue::LValueBase B);
+
+namespace {
+  struct LValue;
+  struct CallStackFrame;
+  struct EvalInfo;
+
+  static QualType getType(APValue::LValueBase B) {
+    if (!B) return QualType();
+    if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>())
+      return D->getType();
+    return B.get<const Expr*>()->getType();
+  }
+
+  /// Get an LValue path entry, which is known to not be an array index, as a
+  /// field or base class.
+  static
+  APValue::BaseOrMemberType getAsBaseOrMember(APValue::LValuePathEntry E) {
+    APValue::BaseOrMemberType Value;
+    Value.setFromOpaqueValue(E.BaseOrMember);
+    return Value;
+  }
+
+  /// Get an LValue path entry, which is known to not be an array index, as a
+  /// field declaration.
+  static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
+    return dyn_cast<FieldDecl>(getAsBaseOrMember(E).getPointer());
+  }
+  /// Get an LValue path entry, which is known to not be an array index, as a
+  /// base class declaration.
+  static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
+    return dyn_cast<CXXRecordDecl>(getAsBaseOrMember(E).getPointer());
+  }
+  /// Determine whether this LValue path entry for a base class names a virtual
+  /// base class.
+  static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
+    return getAsBaseOrMember(E).getInt();
+  }
+
+  /// Find the path length and type of the most-derived subobject in the given
+  /// path, and find the size of the containing array, if any.
+  static
+  unsigned findMostDerivedSubobject(ASTContext &Ctx, QualType Base,
+                                    ArrayRef<APValue::LValuePathEntry> Path,
+                                    uint64_t &ArraySize, QualType &Type) {
+    unsigned MostDerivedLength = 0;
+    Type = Base;
+    for (unsigned I = 0, N = Path.size(); I != N; ++I) {
+      if (Type->isArrayType()) {
+        const ConstantArrayType *CAT =
+          cast<ConstantArrayType>(Ctx.getAsArrayType(Type));
+        Type = CAT->getElementType();
+        ArraySize = CAT->getSize().getZExtValue();
+        MostDerivedLength = I + 1;
+      } else if (Type->isAnyComplexType()) {
+        const ComplexType *CT = Type->castAs<ComplexType>();
+        Type = CT->getElementType();
+        ArraySize = 2;
+        MostDerivedLength = I + 1;
+      } else if (const FieldDecl *FD = getAsField(Path[I])) {
+        Type = FD->getType();
+        ArraySize = 0;
+        MostDerivedLength = I + 1;
+      } else {
+        // Path[I] describes a base class.
+        ArraySize = 0;
+      }
+    }
+    return MostDerivedLength;
+  }
+
+  // The order of this enum is important for diagnostics.
+  enum CheckSubobjectKind {
+    CSK_Base, CSK_Derived, CSK_Field, CSK_ArrayToPointer, CSK_ArrayIndex,
+    CSK_This, CSK_Real, CSK_Imag
+  };
+
+  /// A path from a glvalue to a subobject of that glvalue.
+  struct SubobjectDesignator {
+    /// True if the subobject was named in a manner not supported by C++11. Such
+    /// lvalues can still be folded, but they are not core constant expressions
+    /// and we cannot perform lvalue-to-rvalue conversions on them.
+    bool Invalid : 1;
+
+    /// Is this a pointer one past the end of an object?
+    bool IsOnePastTheEnd : 1;
+
+    /// The length of the path to the most-derived object of which this is a
+    /// subobject.
+    unsigned MostDerivedPathLength : 30;
+
+    /// The size of the array of which the most-derived object is an element, or
+    /// 0 if the most-derived object is not an array element.
+    uint64_t MostDerivedArraySize;
+
+    /// The type of the most derived object referred to by this address.
+    QualType MostDerivedType;
+
+    typedef APValue::LValuePathEntry PathEntry;
+
+    /// The entries on the path from the glvalue to the designated subobject.
+    SmallVector<PathEntry, 8> Entries;
+
+    SubobjectDesignator() : Invalid(true) {}
+
+    explicit SubobjectDesignator(QualType T)
+      : Invalid(false), IsOnePastTheEnd(false), MostDerivedPathLength(0),
+        MostDerivedArraySize(0), MostDerivedType(T) {}
+
+    SubobjectDesignator(ASTContext &Ctx, const APValue &V)
+      : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
+        MostDerivedPathLength(0), MostDerivedArraySize(0) {
+      if (!Invalid) {
+        IsOnePastTheEnd = V.isLValueOnePastTheEnd();
+        ArrayRef<PathEntry> VEntries = V.getLValuePath();
+        Entries.insert(Entries.end(), VEntries.begin(), VEntries.end());
+        if (V.getLValueBase())
+          MostDerivedPathLength =
+              findMostDerivedSubobject(Ctx, getType(V.getLValueBase()),
+                                       V.getLValuePath(), MostDerivedArraySize,
+                                       MostDerivedType);
+      }
+    }
+
+    void setInvalid() {
+      Invalid = true;
+      Entries.clear();
+    }
+
+    /// Determine whether this is a one-past-the-end pointer.
+    bool isOnePastTheEnd() const {
+      if (IsOnePastTheEnd)
+        return true;
+      if (MostDerivedArraySize &&
+          Entries[MostDerivedPathLength - 1].ArrayIndex == MostDerivedArraySize)
+        return true;
+      return false;
+    }
+
+    /// Check that this refers to a valid subobject.
+    bool isValidSubobject() const {
+      if (Invalid)
+        return false;
+      return !isOnePastTheEnd();
+    }
+    /// Check that this refers to a valid subobject, and if not, produce a
+    /// relevant diagnostic and set the designator as invalid.
+    bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);
+
+    /// Update this designator to refer to the first element within this array.
+    void addArrayUnchecked(const ConstantArrayType *CAT) {
+      PathEntry Entry;
+      Entry.ArrayIndex = 0;
+      Entries.push_back(Entry);
+
+      // This is a most-derived object.
+      MostDerivedType = CAT->getElementType();
+      MostDerivedArraySize = CAT->getSize().getZExtValue();
+      MostDerivedPathLength = Entries.size();
+    }
+    /// Update this designator to refer to the given base or member of this
+    /// object.
+    void addDeclUnchecked(const Decl *D, bool Virtual = false) {
+      PathEntry Entry;
+      APValue::BaseOrMemberType Value(D, Virtual);
+      Entry.BaseOrMember = Value.getOpaqueValue();
+      Entries.push_back(Entry);
+
+      // If this isn't a base class, it's a new most-derived object.
+      if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
+        MostDerivedType = FD->getType();
+        MostDerivedArraySize = 0;
+        MostDerivedPathLength = Entries.size();
+      }
+    }
+    /// Update this designator to refer to the given complex component.
+    void addComplexUnchecked(QualType EltTy, bool Imag) {
+      PathEntry Entry;
+      Entry.ArrayIndex = Imag;
+      Entries.push_back(Entry);
+
+      // This is technically a most-derived object, though in practice this
+      // is unlikely to matter.
+      MostDerivedType = EltTy;
+      MostDerivedArraySize = 2;
+      MostDerivedPathLength = Entries.size();
+    }
+    void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E, uint64_t N);
+    /// Add N to the address of this subobject.
+    void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) {
+      if (Invalid) return;
+      if (MostDerivedPathLength == Entries.size() && MostDerivedArraySize) {
+        Entries.back().ArrayIndex += N;
+        if (Entries.back().ArrayIndex > MostDerivedArraySize) {
+          diagnosePointerArithmetic(Info, E, Entries.back().ArrayIndex);
+          setInvalid();
+        }
+        return;
+      }
+      // [expr.add]p4: For the purposes of these operators, a pointer to a
+      // nonarray object behaves the same as a pointer to the first element of
+      // an array of length one with the type of the object as its element type.
+      if (IsOnePastTheEnd && N == (uint64_t)-1)
+        IsOnePastTheEnd = false;
+      else if (!IsOnePastTheEnd && N == 1)
+        IsOnePastTheEnd = true;
+      else if (N != 0) {
+        diagnosePointerArithmetic(Info, E, uint64_t(IsOnePastTheEnd) + N);
+        setInvalid();
+      }
+    }
+  };
+
+  /// A stack frame in the constexpr call stack.
+  struct CallStackFrame {
+    EvalInfo &Info;
+
+    /// Parent - The caller of this stack frame.
+    CallStackFrame *Caller;
+
+    /// CallLoc - The location of the call expression for this call.
+    SourceLocation CallLoc;
+
+    /// Callee - The function which was called.
+    const FunctionDecl *Callee;
+
+    /// Index - The call index of this call.
+    unsigned Index;
+
+    /// This - The binding for the this pointer in this call, if any.
+    const LValue *This;
+
+    /// ParmBindings - Parameter bindings for this function call, indexed by
+    /// parameters' function scope indices.
+    const APValue *Arguments;
+
+    typedef llvm::DenseMap<const Expr*, APValue> MapTy;
+    typedef MapTy::const_iterator temp_iterator;
+    /// Temporaries - Temporary lvalues materialized within this stack frame.
+    MapTy Temporaries;
+
+    CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
+                   const FunctionDecl *Callee, const LValue *This,
+                   const APValue *Arguments);
+    ~CallStackFrame();
+  };
+
+  /// A partial diagnostic which we might know in advance that we are not going
+  /// to emit.
+  class OptionalDiagnostic {
+    PartialDiagnostic *Diag;
+
+  public:
+    explicit OptionalDiagnostic(PartialDiagnostic *Diag = 0) : Diag(Diag) {}
+
+    template<typename T>
+    OptionalDiagnostic &operator<<(const T &v) {
+      if (Diag)
+        *Diag << v;
+      return *this;
+    }
+
+    OptionalDiagnostic &operator<<(const APSInt &I) {
+      if (Diag) {
+        llvm::SmallVector<char, 32> Buffer;
+        I.toString(Buffer);
+        *Diag << StringRef(Buffer.data(), Buffer.size());
+      }
+      return *this;
+    }
+
+    OptionalDiagnostic &operator<<(const APFloat &F) {
+      if (Diag) {
+        llvm::SmallVector<char, 32> Buffer;
+        F.toString(Buffer);
+        *Diag << StringRef(Buffer.data(), Buffer.size());
+      }
+      return *this;
+    }
+  };
+
+  /// EvalInfo - This is a private struct used by the evaluator to capture
+  /// information about a subexpression as it is folded.  It retains information
+  /// about the AST context, but also maintains information about the folded
+  /// expression.
+  ///
+  /// If an expression could be evaluated, it is still possible it is not a C
+  /// "integer constant expression" or constant expression.  If not, this struct
+  /// captures information about how and why not.
+  ///
+  /// One bit of information passed *into* the request for constant folding
+  /// indicates whether the subexpression is "evaluated" or not according to C
+  /// rules.  For example, the RHS of (0 && foo()) is not evaluated.  We can
+  /// evaluate the expression regardless of what the RHS is, but C only allows
+  /// certain things in certain situations.
+  struct EvalInfo {
+    ASTContext &Ctx;
+
+    /// EvalStatus - Contains information about the evaluation.
+    Expr::EvalStatus &EvalStatus;
+
+    /// CurrentCall - The top of the constexpr call stack.
+    CallStackFrame *CurrentCall;
+
+    /// CallStackDepth - The number of calls in the call stack right now.
+    unsigned CallStackDepth;
+
+    /// NextCallIndex - The next call index to assign.
+    unsigned NextCallIndex;
+
+    typedef llvm::DenseMap<const OpaqueValueExpr*, APValue> MapTy;
+    /// OpaqueValues - Values used as the common expression in a
+    /// BinaryConditionalOperator.
+    MapTy OpaqueValues;
+
+    /// BottomFrame - The frame in which evaluation started. This must be
+    /// initialized after CurrentCall and CallStackDepth.
+    CallStackFrame BottomFrame;
+
+    /// EvaluatingDecl - This is the declaration whose initializer is being
+    /// evaluated, if any.
+    const VarDecl *EvaluatingDecl;
+
+    /// EvaluatingDeclValue - This is the value being constructed for the
+    /// declaration whose initializer is being evaluated, if any.
+    APValue *EvaluatingDeclValue;
+
+    /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
+    /// notes attached to it will also be stored, otherwise they will not be.
+    bool HasActiveDiagnostic;
+
+    /// CheckingPotentialConstantExpression - Are we checking whether the
+    /// expression is a potential constant expression? If so, some diagnostics
+    /// are suppressed.
+    bool CheckingPotentialConstantExpression;
+
+    EvalInfo(const ASTContext &C, Expr::EvalStatus &S)
+      : Ctx(const_cast<ASTContext&>(C)), EvalStatus(S), CurrentCall(0),
+        CallStackDepth(0), NextCallIndex(1),
+        BottomFrame(*this, SourceLocation(), 0, 0, 0),
+        EvaluatingDecl(0), EvaluatingDeclValue(0), HasActiveDiagnostic(false),
+        CheckingPotentialConstantExpression(false) {}
+
+    const APValue *getOpaqueValue(const OpaqueValueExpr *e) const {
+      MapTy::const_iterator i = OpaqueValues.find(e);
+      if (i == OpaqueValues.end()) return 0;
+      return &i->second;
+    }
+
+    void setEvaluatingDecl(const VarDecl *VD, APValue &Value) {
+      EvaluatingDecl = VD;
+      EvaluatingDeclValue = &Value;
+    }
+
+    const LangOptions &getLangOpts() const { return Ctx.getLangOpts(); }
+
+    bool CheckCallLimit(SourceLocation Loc) {
+      // Don't perform any constexpr calls (other than the call we're checking)
+      // when checking a potential constant expression.
+      if (CheckingPotentialConstantExpression && CallStackDepth > 1)
+        return false;
+      if (NextCallIndex == 0) {
+        // NextCallIndex has wrapped around.
+        Diag(Loc, diag::note_constexpr_call_limit_exceeded);
+        return false;
+      }
+      if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
+        return true;
+      Diag(Loc, diag::note_constexpr_depth_limit_exceeded)
+        << getLangOpts().ConstexprCallDepth;
+      return false;
+    }
+
+    CallStackFrame *getCallFrame(unsigned CallIndex) {
+      assert(CallIndex && "no call index in getCallFrame");
+      // We will eventually hit BottomFrame, which has Index 1, so Frame can't
+      // be null in this loop.
+      CallStackFrame *Frame = CurrentCall;
+      while (Frame->Index > CallIndex)
+        Frame = Frame->Caller;
+      return (Frame->Index == CallIndex) ? Frame : 0;
+    }
+
+  private:
+    /// Add a diagnostic to the diagnostics list.
+    PartialDiagnostic &addDiag(SourceLocation Loc, diag::kind DiagId) {
+      PartialDiagnostic PD(DiagId, Ctx.getDiagAllocator());
+      EvalStatus.Diag->push_back(std::make_pair(Loc, PD));
+      return EvalStatus.Diag->back().second;
+    }
+
+    /// Add notes containing a call stack to the current point of evaluation.
+    void addCallStack(unsigned Limit);
+
+  public:
+    /// Diagnose that the evaluation cannot be folded.
+    OptionalDiagnostic Diag(SourceLocation Loc, diag::kind DiagId
+                              = diag::note_invalid_subexpr_in_const_expr,
+                            unsigned ExtraNotes = 0) {
+      // If we have a prior diagnostic, it will be noting that the expression
+      // isn't a constant expression. This diagnostic is more important.
+      // FIXME: We might want to show both diagnostics to the user.
+      if (EvalStatus.Diag) {
+        unsigned CallStackNotes = CallStackDepth - 1;
+        unsigned Limit = Ctx.getDiagnostics().getConstexprBacktraceLimit();
+        if (Limit)
+          CallStackNotes = std::min(CallStackNotes, Limit + 1);
+        if (CheckingPotentialConstantExpression)
+          CallStackNotes = 0;
+
+        HasActiveDiagnostic = true;
+        EvalStatus.Diag->clear();
+        EvalStatus.Diag->reserve(1 + ExtraNotes + CallStackNotes);
+        addDiag(Loc, DiagId);
+        if (!CheckingPotentialConstantExpression)
+          addCallStack(Limit);
+        return OptionalDiagnostic(&(*EvalStatus.Diag)[0].second);
+      }
+      HasActiveDiagnostic = false;
+      return OptionalDiagnostic();
+    }
+
+    OptionalDiagnostic Diag(const Expr *E, diag::kind DiagId
+                              = diag::note_invalid_subexpr_in_const_expr,
+                            unsigned ExtraNotes = 0) {
+      if (EvalStatus.Diag)
+        return Diag(E->getExprLoc(), DiagId, ExtraNotes);
+      HasActiveDiagnostic = false;
+      return OptionalDiagnostic();
+    }
+
+    /// Diagnose that the evaluation does not produce a C++11 core constant
+    /// expression.
+    template<typename LocArg>
+    OptionalDiagnostic CCEDiag(LocArg Loc, diag::kind DiagId
+                                 = diag::note_invalid_subexpr_in_const_expr,
+                               unsigned ExtraNotes = 0) {
+      // Don't override a previous diagnostic.
+      if (!EvalStatus.Diag || !EvalStatus.Diag->empty()) {
+        HasActiveDiagnostic = false;
+        return OptionalDiagnostic();
+      }
+      return Diag(Loc, DiagId, ExtraNotes);
+    }
+
+    /// Add a note to a prior diagnostic.
+    OptionalDiagnostic Note(SourceLocation Loc, diag::kind DiagId) {
+      if (!HasActiveDiagnostic)
+        return OptionalDiagnostic();
+      return OptionalDiagnostic(&addDiag(Loc, DiagId));
+    }
+
+    /// Add a stack of notes to a prior diagnostic.
+    void addNotes(ArrayRef<PartialDiagnosticAt> Diags) {
+      if (HasActiveDiagnostic) {
+        EvalStatus.Diag->insert(EvalStatus.Diag->end(),
+                                Diags.begin(), Diags.end());
+      }
+    }
+
+    /// Should we continue evaluation as much as possible after encountering a
+    /// construct which can't be folded?
+    bool keepEvaluatingAfterFailure() {
+      return CheckingPotentialConstantExpression &&
+             EvalStatus.Diag && EvalStatus.Diag->empty();
+    }
+  };
+
+  /// Object used to treat all foldable expressions as constant expressions.
+  struct FoldConstant {
+    bool Enabled;
+
+    explicit FoldConstant(EvalInfo &Info)
+      : Enabled(Info.EvalStatus.Diag && Info.EvalStatus.Diag->empty() &&
+                !Info.EvalStatus.HasSideEffects) {
+    }
+    // Treat the value we've computed since this object was created as constant.
+    void Fold(EvalInfo &Info) {
+      if (Enabled && !Info.EvalStatus.Diag->empty() &&
+          !Info.EvalStatus.HasSideEffects)
+        Info.EvalStatus.Diag->clear();
+    }
+  };
+
+  /// RAII object used to suppress diagnostics and side-effects from a
+  /// speculative evaluation.
+  class SpeculativeEvaluationRAII {
+    EvalInfo &Info;
+    Expr::EvalStatus Old;
+
+  public:
+    SpeculativeEvaluationRAII(EvalInfo &Info,
+                              llvm::SmallVectorImpl<PartialDiagnosticAt>
+                                *NewDiag = 0)
+      : Info(Info), Old(Info.EvalStatus) {
+      Info.EvalStatus.Diag = NewDiag;
+    }
+    ~SpeculativeEvaluationRAII() {
+      Info.EvalStatus = Old;
+    }
+  };
+}
+
+bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
+                                         CheckSubobjectKind CSK) {
+  if (Invalid)
+    return false;
+  if (isOnePastTheEnd()) {
+    Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
+      << CSK;
+    setInvalid();
+    return false;
+  }
+  return true;
+}
+
+void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
+                                                    const Expr *E, uint64_t N) {
+  if (MostDerivedPathLength == Entries.size() && MostDerivedArraySize)
+    Info.CCEDiag(E, diag::note_constexpr_array_index)
+      << static_cast<int>(N) << /*array*/ 0
+      << static_cast<unsigned>(MostDerivedArraySize);
+  else
+    Info.CCEDiag(E, diag::note_constexpr_array_index)
+      << static_cast<int>(N) << /*non-array*/ 1;
+  setInvalid();
+}
+
+CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
+                               const FunctionDecl *Callee, const LValue *This,
+                               const APValue *Arguments)
+    : Info(Info), Caller(Info.CurrentCall), CallLoc(CallLoc), Callee(Callee),
+      Index(Info.NextCallIndex++), This(This), Arguments(Arguments) {
+  Info.CurrentCall = this;
+  ++Info.CallStackDepth;
+}
+
+CallStackFrame::~CallStackFrame() {
+  assert(Info.CurrentCall == this && "calls retired out of order");
+  --Info.CallStackDepth;
+  Info.CurrentCall = Caller;
+}
+
+/// Produce a string describing the given constexpr call.
+static void describeCall(CallStackFrame *Frame, llvm::raw_ostream &Out) {
+  unsigned ArgIndex = 0;
+  bool IsMemberCall = isa<CXXMethodDecl>(Frame->Callee) &&
+                      !isa<CXXConstructorDecl>(Frame->Callee) &&
+                      cast<CXXMethodDecl>(Frame->Callee)->isInstance();
+
+  if (!IsMemberCall)
+    Out << *Frame->Callee << '(';
+
+  for (FunctionDecl::param_const_iterator I = Frame->Callee->param_begin(),
+       E = Frame->Callee->param_end(); I != E; ++I, ++ArgIndex) {
+    if (ArgIndex > (unsigned)IsMemberCall)
+      Out << ", ";
+
+    const ParmVarDecl *Param = *I;
+    const APValue &Arg = Frame->Arguments[ArgIndex];
+    Arg.printPretty(Out, Frame->Info.Ctx, Param->getType());
+
+    if (ArgIndex == 0 && IsMemberCall)
+      Out << "->" << *Frame->Callee << '(';
+  }
+
+  Out << ')';
+}
+
+void EvalInfo::addCallStack(unsigned Limit) {
+  // Determine which calls to skip, if any.
+  unsigned ActiveCalls = CallStackDepth - 1;
+  unsigned SkipStart = ActiveCalls, SkipEnd = SkipStart;
+  if (Limit && Limit < ActiveCalls) {
+    SkipStart = Limit / 2 + Limit % 2;
+    SkipEnd = ActiveCalls - Limit / 2;
+  }
+
+  // Walk the call stack and add the diagnostics.
+  unsigned CallIdx = 0;
+  for (CallStackFrame *Frame = CurrentCall; Frame != &BottomFrame;
+       Frame = Frame->Caller, ++CallIdx) {
+    // Skip this call?
+    if (CallIdx >= SkipStart && CallIdx < SkipEnd) {
+      if (CallIdx == SkipStart) {
+        // Note that we're skipping calls.
+        addDiag(Frame->CallLoc, diag::note_constexpr_calls_suppressed)
+          << unsigned(ActiveCalls - Limit);
+      }
+      continue;
+    }
+
+    llvm::SmallVector<char, 128> Buffer;
+    llvm::raw_svector_ostream Out(Buffer);
+    describeCall(Frame, Out);
+    addDiag(Frame->CallLoc, diag::note_constexpr_call_here) << Out.str();
+  }
+}
+
+namespace {
+  struct ComplexValue {
+  private:
+    bool IsInt;
+
+  public:
+    APSInt IntReal, IntImag;
+    APFloat FloatReal, FloatImag;
+
+    ComplexValue() : FloatReal(APFloat::Bogus), FloatImag(APFloat::Bogus) {}
+
+    void makeComplexFloat() { IsInt = false; }
+    bool isComplexFloat() const { return !IsInt; }
+    APFloat &getComplexFloatReal() { return FloatReal; }
+    APFloat &getComplexFloatImag() { return FloatImag; }
+
+    void makeComplexInt() { IsInt = true; }
+    bool isComplexInt() const { return IsInt; }
+    APSInt &getComplexIntReal() { return IntReal; }
+    APSInt &getComplexIntImag() { return IntImag; }
+
+    void moveInto(APValue &v) const {
+      if (isComplexFloat())
+        v = APValue(FloatReal, FloatImag);
+      else
+        v = APValue(IntReal, IntImag);
+    }
+    void setFrom(const APValue &v) {
+      assert(v.isComplexFloat() || v.isComplexInt());
+      if (v.isComplexFloat()) {
+        makeComplexFloat();
+        FloatReal = v.getComplexFloatReal();
+        FloatImag = v.getComplexFloatImag();
+      } else {
+        makeComplexInt();
+        IntReal = v.getComplexIntReal();
+        IntImag = v.getComplexIntImag();
+      }
+    }
+  };
+
+  struct LValue {
+    APValue::LValueBase Base;
+    CharUnits Offset;
+    unsigned CallIndex;
+    SubobjectDesignator Designator;
+
+    const APValue::LValueBase getLValueBase() const { return Base; }
+    CharUnits &getLValueOffset() { return Offset; }
+    const CharUnits &getLValueOffset() const { return Offset; }
+    unsigned getLValueCallIndex() const { return CallIndex; }
+    SubobjectDesignator &getLValueDesignator() { return Designator; }
+    const SubobjectDesignator &getLValueDesignator() const { return Designator;}
+
+    void moveInto(APValue &V) const {
+      if (Designator.Invalid)
+        V = APValue(Base, Offset, APValue::NoLValuePath(), CallIndex);
+      else
+        V = APValue(Base, Offset, Designator.Entries,
+                    Designator.IsOnePastTheEnd, CallIndex);
+    }
+    void setFrom(ASTContext &Ctx, const APValue &V) {
+      assert(V.isLValue());
+      Base = V.getLValueBase();
+      Offset = V.getLValueOffset();
+      CallIndex = V.getLValueCallIndex();
+      Designator = SubobjectDesignator(Ctx, V);
+    }
+
+    void set(APValue::LValueBase B, unsigned I = 0) {
+      Base = B;
+      Offset = CharUnits::Zero();
+      CallIndex = I;
+      Designator = SubobjectDesignator(getType(B));
+    }
+
+    // Check that this LValue is not based on a null pointer. If it is, produce
+    // a diagnostic and mark the designator as invalid.
+    bool checkNullPointer(EvalInfo &Info, const Expr *E,
+                          CheckSubobjectKind CSK) {
+      if (Designator.Invalid)
+        return false;
+      if (!Base) {
+        Info.CCEDiag(E, diag::note_constexpr_null_subobject)
+          << CSK;
+        Designator.setInvalid();
+        return false;
+      }
+      return true;
+    }
+
+    // Check this LValue refers to an object. If not, set the designator to be
+    // invalid and emit a diagnostic.
+    bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
+      // Outside C++11, do not build a designator referring to a subobject of
+      // any object: we won't use such a designator for anything.
+      if (!Info.getLangOpts().CPlusPlus0x)
+        Designator.setInvalid();
+      return checkNullPointer(Info, E, CSK) &&
+             Designator.checkSubobject(Info, E, CSK);
+    }
+
+    void addDecl(EvalInfo &Info, const Expr *E,
+                 const Decl *D, bool Virtual = false) {
+      if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
+        Designator.addDeclUnchecked(D, Virtual);
+    }
+    void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
+      if (checkSubobject(Info, E, CSK_ArrayToPointer))
+        Designator.addArrayUnchecked(CAT);
+    }
+    void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
+      if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
+        Designator.addComplexUnchecked(EltTy, Imag);
+    }
+    void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) {
+      if (checkNullPointer(Info, E, CSK_ArrayIndex))
+        Designator.adjustIndex(Info, E, N);
+    }
+  };
+
+  struct MemberPtr {
+    MemberPtr() {}
+    explicit MemberPtr(const ValueDecl *Decl) :
+      DeclAndIsDerivedMember(Decl, false), Path() {}
+
+    /// The member or (direct or indirect) field referred to by this member
+    /// pointer, or 0 if this is a null member pointer.
+    const ValueDecl *getDecl() const {
+      return DeclAndIsDerivedMember.getPointer();
+    }
+    /// Is this actually a member of some type derived from the relevant class?
+    bool isDerivedMember() const {
+      return DeclAndIsDerivedMember.getInt();
+    }
+    /// Get the class which the declaration actually lives in.
+    const CXXRecordDecl *getContainingRecord() const {
+      return cast<CXXRecordDecl>(
+          DeclAndIsDerivedMember.getPointer()->getDeclContext());
+    }
+
+    void moveInto(APValue &V) const {
+      V = APValue(getDecl(), isDerivedMember(), Path);
+    }
+    void setFrom(const APValue &V) {
+      assert(V.isMemberPointer());
+      DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
+      DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
+      Path.clear();
+      ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
+      Path.insert(Path.end(), P.begin(), P.end());
+    }
+
+    /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
+    /// whether the member is a member of some class derived from the class type
+    /// of the member pointer.
+    llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
+    /// Path - The path of base/derived classes from the member declaration's
+    /// class (exclusive) to the class type of the member pointer (inclusive).
+    SmallVector<const CXXRecordDecl*, 4> Path;
+
+    /// Perform a cast towards the class of the Decl (either up or down the
+    /// hierarchy).
+    bool castBack(const CXXRecordDecl *Class) {
+      assert(!Path.empty());
+      const CXXRecordDecl *Expected;
+      if (Path.size() >= 2)
+        Expected = Path[Path.size() - 2];
+      else
+        Expected = getContainingRecord();
+      if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
+        // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
+        // if B does not contain the original member and is not a base or
+        // derived class of the class containing the original member, the result
+        // of the cast is undefined.
+        // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
+        // (D::*). We consider that to be a language defect.
+        return false;
+      }
+      Path.pop_back();
+      return true;
+    }
+    /// Perform a base-to-derived member pointer cast.
+    bool castToDerived(const CXXRecordDecl *Derived) {
+      if (!getDecl())
+        return true;
+      if (!isDerivedMember()) {
+        Path.push_back(Derived);
+        return true;
+      }
+      if (!castBack(Derived))
+        return false;
+      if (Path.empty())
+        DeclAndIsDerivedMember.setInt(false);
+      return true;
+    }
+    /// Perform a derived-to-base member pointer cast.
+    bool castToBase(const CXXRecordDecl *Base) {
+      if (!getDecl())
+        return true;
+      if (Path.empty())
+        DeclAndIsDerivedMember.setInt(true);
+      if (isDerivedMember()) {
+        Path.push_back(Base);
+        return true;
+      }
+      return castBack(Base);
+    }
+  };
+
+  /// Compare two member pointers, which are assumed to be of the same type.
+  static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
+    if (!LHS.getDecl() || !RHS.getDecl())
+      return !LHS.getDecl() && !RHS.getDecl();
+    if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
+      return false;
+    return LHS.Path == RHS.Path;
+  }
+
+  /// Kinds of constant expression checking, for diagnostics.
+  enum CheckConstantExpressionKind {
+    CCEK_Constant,    ///< A normal constant.
+    CCEK_ReturnValue, ///< A constexpr function return value.
+    CCEK_MemberInit   ///< A constexpr constructor mem-initializer.
+  };
+}
+
+static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
+static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
+                            const LValue &This, const Expr *E,
+                            CheckConstantExpressionKind CCEK = CCEK_Constant,
+                            bool AllowNonLiteralTypes = false);
+static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info);
+static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info);
+static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
+                                  EvalInfo &Info);
+static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
+static bool EvaluateInteger(const Expr *E, APSInt  &Result, EvalInfo &Info);
+static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
+                                    EvalInfo &Info);
+static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
+static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
+
+//===----------------------------------------------------------------------===//
+// Misc utilities
+//===----------------------------------------------------------------------===//
+
+/// Should this call expression be treated as a string literal?
+static bool IsStringLiteralCall(const CallExpr *E) {
+  unsigned Builtin = E->isBuiltinCall();
+  return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
+          Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
+}
+
+static bool IsGlobalLValue(APValue::LValueBase B) {
+  // C++11 [expr.const]p3 An address constant expression is a prvalue core
+  // constant expression of pointer type that evaluates to...
+
+  // ... a null pointer value, or a prvalue core constant expression of type
+  // std::nullptr_t.
+  if (!B) return true;
+
+  if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
+    // ... the address of an object with static storage duration,
+    if (const VarDecl *VD = dyn_cast<VarDecl>(D))
+      return VD->hasGlobalStorage();
+    // ... the address of a function,
+    return isa<FunctionDecl>(D);
+  }
+
+  const Expr *E = B.get<const Expr*>();
+  switch (E->getStmtClass()) {
+  default:
+    return false;
+  case Expr::CompoundLiteralExprClass: {
+    const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
+    return CLE->isFileScope() && CLE->isLValue();
+  }
+  // A string literal has static storage duration.
+  case Expr::StringLiteralClass:
+  case Expr::PredefinedExprClass:
+  case Expr::ObjCStringLiteralClass:
+  case Expr::ObjCEncodeExprClass:
+  case Expr::CXXTypeidExprClass:
+  case Expr::CXXUuidofExprClass:
+    return true;
+  case Expr::CallExprClass:
+    return IsStringLiteralCall(cast<CallExpr>(E));
+  // For GCC compatibility, &&label has static storage duration.
+  case Expr::AddrLabelExprClass:
+    return true;
+  // A Block literal expression may be used as the initialization value for
+  // Block variables at global or local static scope.
+  case Expr::BlockExprClass:
+    return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
+  case Expr::ImplicitValueInitExprClass:
+    // FIXME:
+    // We can never form an lvalue with an implicit value initialization as its
+    // base through expression evaluation, so these only appear in one case: the
+    // implicit variable declaration we invent when checking whether a constexpr
+    // constructor can produce a constant expression. We must assume that such
+    // an expression might be a global lvalue.
+    return true;
+  }
+}
+
+static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
+  assert(Base && "no location for a null lvalue");
+  const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
+  if (VD)
+    Info.Note(VD->getLocation(), diag::note_declared_at);
+  else
+    Info.Note(Base.dyn_cast<const Expr*>()->getExprLoc(),
+              diag::note_constexpr_temporary_here);
+}
+
+/// Check that this reference or pointer core constant expression is a valid
+/// value for an address or reference constant expression. Return true if we
+/// can fold this expression, whether or not it's a constant expression.
+static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
+                                          QualType Type, const LValue &LVal) {
+  bool IsReferenceType = Type->isReferenceType();
+
+  APValue::LValueBase Base = LVal.getLValueBase();
+  const SubobjectDesignator &Designator = LVal.getLValueDesignator();
+
+  // Check that the object is a global. Note that the fake 'this' object we
+  // manufacture when checking potential constant expressions is conservatively
+  // assumed to be global here.
+  if (!IsGlobalLValue(Base)) {
+    if (Info.getLangOpts().CPlusPlus0x) {
+      const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
+      Info.Diag(Loc, diag::note_constexpr_non_global, 1)
+        << IsReferenceType << !Designator.Entries.empty()
+        << !!VD << VD;
+      NoteLValueLocation(Info, Base);
+    } else {
+      Info.Diag(Loc);
+    }
+    // Don't allow references to temporaries to escape.
+    return false;
+  }
+  assert((Info.CheckingPotentialConstantExpression ||
+          LVal.getLValueCallIndex() == 0) &&
+         "have call index for global lvalue");
+
+  // Allow address constant expressions to be past-the-end pointers. This is
+  // an extension: the standard requires them to point to an object.
+  if (!IsReferenceType)
+    return true;
+
+  // A reference constant expression must refer to an object.
+  if (!Base) {
+    // FIXME: diagnostic
+    Info.CCEDiag(Loc);
+    return true;
+  }
+
+  // Does this refer one past the end of some object?
+  if (Designator.isOnePastTheEnd()) {
+    const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
+    Info.Diag(Loc, diag::note_constexpr_past_end, 1)
+      << !Designator.Entries.empty() << !!VD << VD;
+    NoteLValueLocation(Info, Base);
+  }
+
+  return true;
+}
+
+/// Check that this core constant expression is of literal type, and if not,
+/// produce an appropriate diagnostic.
+static bool CheckLiteralType(EvalInfo &Info, const Expr *E) {
+  if (!E->isRValue() || E->getType()->isLiteralType())
+    return true;
+
+  // Prvalue constant expressions must be of literal types.
+  if (Info.getLangOpts().CPlusPlus0x)
+    Info.Diag(E, diag::note_constexpr_nonliteral)
+      << E->getType();
+  else
+    Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+  return false;
+}
+
+/// Check that this core constant expression value is a valid value for a
+/// constant expression. If not, report an appropriate diagnostic. Does not
+/// check that the expression is of literal type.
+static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
+                                    QualType Type, const APValue &Value) {
+  // Core issue 1454: For a literal constant expression of array or class type,
+  // each subobject of its value shall have been initialized by a constant
+  // expression.
+  if (Value.isArray()) {
+    QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
+    for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
+      if (!CheckConstantExpression(Info, DiagLoc, EltTy,
+                                   Value.getArrayInitializedElt(I)))
+        return false;
+    }
+    if (!Value.hasArrayFiller())
+      return true;
+    return CheckConstantExpression(Info, DiagLoc, EltTy,
+                                   Value.getArrayFiller());
+  }
+  if (Value.isUnion() && Value.getUnionField()) {
+    return CheckConstantExpression(Info, DiagLoc,
+                                   Value.getUnionField()->getType(),
+                                   Value.getUnionValue());
+  }
+  if (Value.isStruct()) {
+    RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
+    if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
+      unsigned BaseIndex = 0;
+      for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
+             End = CD->bases_end(); I != End; ++I, ++BaseIndex) {
+        if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
+                                     Value.getStructBase(BaseIndex)))
+          return false;
+      }
+    }
+    for (RecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
+         I != E; ++I) {
+      if (!CheckConstantExpression(Info, DiagLoc, (*I)->getType(),
+                                   Value.getStructField((*I)->getFieldIndex())))
+        return false;
+    }
+  }
+
+  if (Value.isLValue()) {
+    LValue LVal;
+    LVal.setFrom(Info.Ctx, Value);
+    return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal);
+  }
+
+  // Everything else is fine.
+  return true;
+}
+
+const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
+  return LVal.Base.dyn_cast<const ValueDecl*>();
+}
+
+static bool IsLiteralLValue(const LValue &Value) {
+  return Value.Base.dyn_cast<const Expr*>() && !Value.CallIndex;
+}
+
+static bool IsWeakLValue(const LValue &Value) {
+  const ValueDecl *Decl = GetLValueBaseDecl(Value);
+  return Decl && Decl->isWeak();
+}
+
+static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
+  // A null base expression indicates a null pointer.  These are always
+  // evaluatable, and they are false unless the offset is zero.
+  if (!Value.getLValueBase()) {
+    Result = !Value.getLValueOffset().isZero();
+    return true;
+  }
+
+  // We have a non-null base.  These are generally known to be true, but if it's
+  // a weak declaration it can be null at runtime.
+  Result = true;
+  const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
+  return !Decl || !Decl->isWeak();
+}
+
+static bool HandleConversionToBool(const APValue &Val, bool &Result) {
+  switch (Val.getKind()) {
+  case APValue::Uninitialized:
+    return false;
+  case APValue::Int:
+    Result = Val.getInt().getBoolValue();
+    return true;
+  case APValue::Float:
+    Result = !Val.getFloat().isZero();
+    return true;
+  case APValue::ComplexInt:
+    Result = Val.getComplexIntReal().getBoolValue() ||
+             Val.getComplexIntImag().getBoolValue();
+    return true;
+  case APValue::ComplexFloat:
+    Result = !Val.getComplexFloatReal().isZero() ||
+             !Val.getComplexFloatImag().isZero();
+    return true;
+  case APValue::LValue:
+    return EvalPointerValueAsBool(Val, Result);
+  case APValue::MemberPointer:
+    Result = Val.getMemberPointerDecl();
+    return true;
+  case APValue::Vector:
+  case APValue::Array:
+  case APValue::Struct:
+  case APValue::Union:
+  case APValue::AddrLabelDiff:
+    return false;
+  }
+
+  llvm_unreachable("unknown APValue kind");
+}
+
+static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
+                                       EvalInfo &Info) {
+  assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition");
+  APValue Val;
+  if (!Evaluate(Val, Info, E))
+    return false;
+  return HandleConversionToBool(Val, Result);
+}
+
+template<typename T>
+static bool HandleOverflow(EvalInfo &Info, const Expr *E,
+                           const T &SrcValue, QualType DestType) {
+  Info.Diag(E, diag::note_constexpr_overflow)
+    << SrcValue << DestType;
+  return false;
+}
+
+static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
+                                 QualType SrcType, const APFloat &Value,
+                                 QualType DestType, APSInt &Result) {
+  unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
+  // Determine whether we are converting to unsigned or signed.
+  bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
+
+  Result = APSInt(DestWidth, !DestSigned);
+  bool ignored;
+  if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
+      & APFloat::opInvalidOp)
+    return HandleOverflow(Info, E, Value, DestType);
+  return true;
+}
+
+static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
+                                   QualType SrcType, QualType DestType,
+                                   APFloat &Result) {
+  APFloat Value = Result;
+  bool ignored;
+  if (Result.convert(Info.Ctx.getFloatTypeSemantics(DestType),
+                     APFloat::rmNearestTiesToEven, &ignored)
+      & APFloat::opOverflow)
+    return HandleOverflow(Info, E, Value, DestType);
+  return true;
+}
+
+static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
+                                 QualType DestType, QualType SrcType,
+                                 APSInt &Value) {
+  unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
+  APSInt Result = Value;
+  // Figure out if this is a truncate, extend or noop cast.
+  // If the input is signed, do a sign extend, noop, or truncate.
+  Result = Result.extOrTrunc(DestWidth);
+  Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
+  return Result;
+}
+
+static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
+                                 QualType SrcType, const APSInt &Value,
+                                 QualType DestType, APFloat &Result) {
+  Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
+  if (Result.convertFromAPInt(Value, Value.isSigned(),
+                              APFloat::rmNearestTiesToEven)
+      & APFloat::opOverflow)
+    return HandleOverflow(Info, E, Value, DestType);
+  return true;
+}
+
+static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
+                                  llvm::APInt &Res) {
+  APValue SVal;
+  if (!Evaluate(SVal, Info, E))
+    return false;
+  if (SVal.isInt()) {
+    Res = SVal.getInt();
+    return true;
+  }
+  if (SVal.isFloat()) {
+    Res = SVal.getFloat().bitcastToAPInt();
+    return true;
+  }
+  if (SVal.isVector()) {
+    QualType VecTy = E->getType();
+    unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
+    QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
+    unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
+    bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
+    Res = llvm::APInt::getNullValue(VecSize);
+    for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
+      APValue &Elt = SVal.getVectorElt(i);
+      llvm::APInt EltAsInt;
+      if (Elt.isInt()) {
+        EltAsInt = Elt.getInt();
+      } else if (Elt.isFloat()) {
+        EltAsInt = Elt.getFloat().bitcastToAPInt();
+      } else {
+        // Don't try to handle vectors of anything other than int or float
+        // (not sure if it's possible to hit this case).
+        Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+        return false;
+      }
+      unsigned BaseEltSize = EltAsInt.getBitWidth();
+      if (BigEndian)
+        Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
+      else
+        Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
+    }
+    return true;
+  }
+  // Give up if the input isn't an int, float, or vector.  For example, we
+  // reject "(v4i16)(intptr_t)&a".
+  Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+  return false;
+}
+
+/// Cast an lvalue referring to a base subobject to a derived class, by
+/// truncating the lvalue's path to the given length.
+static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
+                               const RecordDecl *TruncatedType,
+                               unsigned TruncatedElements) {
+  SubobjectDesignator &D = Result.Designator;
+
+  // Check we actually point to a derived class object.
+  if (TruncatedElements == D.Entries.size())
+    return true;
+  assert(TruncatedElements >= D.MostDerivedPathLength &&
+         "not casting to a derived class");
+  if (!Result.checkSubobject(Info, E, CSK_Derived))
+    return false;
+
+  // Truncate the path to the subobject, and remove any derived-to-base offsets.
+  const RecordDecl *RD = TruncatedType;
+  for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
+    const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
+    const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
+    if (isVirtualBaseClass(D.Entries[I]))
+      Result.Offset -= Layout.getVBaseClassOffset(Base);
+    else
+      Result.Offset -= Layout.getBaseClassOffset(Base);
+    RD = Base;
+  }
+  D.Entries.resize(TruncatedElements);
+  return true;
+}
+
+static void HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
+                                   const CXXRecordDecl *Derived,
+                                   const CXXRecordDecl *Base,
+                                   const ASTRecordLayout *RL = 0) {
+  if (!RL) RL = &Info.Ctx.getASTRecordLayout(Derived);
+  Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
+  Obj.addDecl(Info, E, Base, /*Virtual*/ false);
+}
+
+static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
+                             const CXXRecordDecl *DerivedDecl,
+                             const CXXBaseSpecifier *Base) {
+  const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
+
+  if (!Base->isVirtual()) {
+    HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
+    return true;
+  }
+
+  SubobjectDesignator &D = Obj.Designator;
+  if (D.Invalid)
+    return false;
+
+  // Extract most-derived object and corresponding type.
+  DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
+  if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
+    return false;
+
+  // Find the virtual base class.
+  const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
+  Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
+  Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
+  return true;
+}
+
+/// Update LVal to refer to the given field, which must be a member of the type
+/// currently described by LVal.
+static void HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
+                               const FieldDecl *FD,
+                               const ASTRecordLayout *RL = 0) {
+  if (!RL)
+    RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
+
+  unsigned I = FD->getFieldIndex();
+  LVal.Offset += Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I));
+  LVal.addDecl(Info, E, FD);
+}
+
+/// Update LVal to refer to the given indirect field.
+static void HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
+                                       LValue &LVal,
+                                       const IndirectFieldDecl *IFD) {
+  for (IndirectFieldDecl::chain_iterator C = IFD->chain_begin(),
+                                         CE = IFD->chain_end(); C != CE; ++C)
+    HandleLValueMember(Info, E, LVal, cast<FieldDecl>(*C));
+}
+
+/// Get the size of the given type in char units.
+static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
+                         QualType Type, CharUnits &Size) {
+  // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
+  // extension.
+  if (Type->isVoidType() || Type->isFunctionType()) {
+    Size = CharUnits::One();
+    return true;
+  }
+
+  if (!Type->isConstantSizeType()) {
+    // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
+    // FIXME: Better diagnostic.
+    Info.Diag(Loc);
+    return false;
+  }
+
+  Size = Info.Ctx.getTypeSizeInChars(Type);
+  return true;
+}
+
+/// Update a pointer value to model pointer arithmetic.
+/// \param Info - Information about the ongoing evaluation.
+/// \param E - The expression being evaluated, for diagnostic purposes.
+/// \param LVal - The pointer value to be updated.
+/// \param EltTy - The pointee type represented by LVal.
+/// \param Adjustment - The adjustment, in objects of type EltTy, to add.
+static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
+                                        LValue &LVal, QualType EltTy,
+                                        int64_t Adjustment) {
+  CharUnits SizeOfPointee;
+  if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
+    return false;
+
+  // Compute the new offset in the appropriate width.
+  LVal.Offset += Adjustment * SizeOfPointee;
+  LVal.adjustIndex(Info, E, Adjustment);
+  return true;
+}
+
+/// Update an lvalue to refer to a component of a complex number.
+/// \param Info - Information about the ongoing evaluation.
+/// \param LVal - The lvalue to be updated.
+/// \param EltTy - The complex number's component type.
+/// \param Imag - False for the real component, true for the imaginary.
+static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
+                                       LValue &LVal, QualType EltTy,
+                                       bool Imag) {
+  if (Imag) {
+    CharUnits SizeOfComponent;
+    if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
+      return false;
+    LVal.Offset += SizeOfComponent;
+  }
+  LVal.addComplex(Info, E, EltTy, Imag);
+  return true;
+}
+
+/// Try to evaluate the initializer for a variable declaration.
+static bool EvaluateVarDeclInit(EvalInfo &Info, const Expr *E,
+                                const VarDecl *VD,
+                                CallStackFrame *Frame, APValue &Result) {
+  // If this is a parameter to an active constexpr function call, perform
+  // argument substitution.
+  if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) {
+    // Assume arguments of a potential constant expression are unknown
+    // constant expressions.
+    if (Info.CheckingPotentialConstantExpression)
+      return false;
+    if (!Frame || !Frame->Arguments) {
+      Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+      return false;
+    }
+    Result = Frame->Arguments[PVD->getFunctionScopeIndex()];
+    return true;
+  }
+
+  // Dig out the initializer, and use the declaration which it's attached to.
+  const Expr *Init = VD->getAnyInitializer(VD);
+  if (!Init || Init->isValueDependent()) {
+    // If we're checking a potential constant expression, the variable could be
+    // initialized later.
+    if (!Info.CheckingPotentialConstantExpression)
+      Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+    return false;
+  }
+
+  // If we're currently evaluating the initializer of this declaration, use that
+  // in-flight value.
+  if (Info.EvaluatingDecl == VD) {
+    Result = *Info.EvaluatingDeclValue;
+    return !Result.isUninit();
+  }
+
+  // Never evaluate the initializer of a weak variable. We can't be sure that
+  // this is the definition which will be used.
+  if (VD->isWeak()) {
+    Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+    return false;
+  }
+
+  // Check that we can fold the initializer. In C++, we will have already done
+  // this in the cases where it matters for conformance.
+  llvm::SmallVector<PartialDiagnosticAt, 8> Notes;
+  if (!VD->evaluateValue(Notes)) {
+    Info.Diag(E, diag::note_constexpr_var_init_non_constant,
+              Notes.size() + 1) << VD;
+    Info.Note(VD->getLocation(), diag::note_declared_at);
+    Info.addNotes(Notes);
+    return false;
+  } else if (!VD->checkInitIsICE()) {
+    Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant,
+                 Notes.size() + 1) << VD;
+    Info.Note(VD->getLocation(), diag::note_declared_at);
+    Info.addNotes(Notes);
+  }
+
+  Result = *VD->getEvaluatedValue();
+  return true;
+}
+
+static bool IsConstNonVolatile(QualType T) {
+  Qualifiers Quals = T.getQualifiers();
+  return Quals.hasConst() && !Quals.hasVolatile();
+}
+
+/// Get the base index of the given base class within an APValue representing
+/// the given derived class.
+static unsigned getBaseIndex(const CXXRecordDecl *Derived,
+                             const CXXRecordDecl *Base) {
+  Base = Base->getCanonicalDecl();
+  unsigned Index = 0;
+  for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
+         E = Derived->bases_end(); I != E; ++I, ++Index) {
+    if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
+      return Index;
+  }
+
+  llvm_unreachable("base class missing from derived class's bases list");
+}
+
+/// Extract the value of a character from a string literal. CharType is used to
+/// determine the expected signedness of the result -- a string literal used to
+/// initialize an array of 'signed char' or 'unsigned char' might contain chars
+/// of the wrong signedness.
+static APSInt ExtractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
+                                            uint64_t Index, QualType CharType) {
+  // FIXME: Support PredefinedExpr, ObjCEncodeExpr, MakeStringConstant
+  const StringLiteral *S = dyn_cast<StringLiteral>(Lit);
+  assert(S && "unexpected string literal expression kind");
+  assert(CharType->isIntegerType() && "unexpected character type");
+
+  APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
+               CharType->isUnsignedIntegerType());
+  if (Index < S->getLength())
+    Value = S->getCodeUnit(Index);
+  return Value;
+}
+
+/// Extract the designated sub-object of an rvalue.
+static bool ExtractSubobject(EvalInfo &Info, const Expr *E,
+                             APValue &Obj, QualType ObjType,
+                             const SubobjectDesignator &Sub, QualType SubType) {
+  if (Sub.Invalid)
+    // A diagnostic will have already been produced.
+    return false;
+  if (Sub.isOnePastTheEnd()) {
+    Info.Diag(E, Info.getLangOpts().CPlusPlus0x ?
+                (unsigned)diag::note_constexpr_read_past_end :
+                (unsigned)diag::note_invalid_subexpr_in_const_expr);
+    return false;
+  }
+  if (Sub.Entries.empty())
+    return true;
+  if (Info.CheckingPotentialConstantExpression && Obj.isUninit())
+    // This object might be initialized later.
+    return false;
+
+  APValue *O = &Obj;
+  // Walk the designator's path to find the subobject.
+  for (unsigned I = 0, N = Sub.Entries.size(); I != N; ++I) {
+    if (ObjType->isArrayType()) {
+      // Next subobject is an array element.
+      const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
+      assert(CAT && "vla in literal type?");
+      uint64_t Index = Sub.Entries[I].ArrayIndex;
+      if (CAT->getSize().ule(Index)) {
+        // Note, it should not be possible to form a pointer with a valid
+        // designator which points more than one past the end of the array.
+        Info.Diag(E, Info.getLangOpts().CPlusPlus0x ?
+                    (unsigned)diag::note_constexpr_read_past_end :
+                    (unsigned)diag::note_invalid_subexpr_in_const_expr);
+        return false;
+      }
+      // An array object is represented as either an Array APValue or as an
+      // LValue which refers to a string literal.
+      if (O->isLValue()) {
+        assert(I == N - 1 && "extracting subobject of character?");
+        assert(!O->hasLValuePath() || O->getLValuePath().empty());
+        Obj = APValue(ExtractStringLiteralCharacter(
+          Info, O->getLValueBase().get<const Expr*>(), Index, SubType));
+        return true;
+      } else if (O->getArrayInitializedElts() > Index)
+        O = &O->getArrayInitializedElt(Index);
+      else
+        O = &O->getArrayFiller();
+      ObjType = CAT->getElementType();
+    } else if (ObjType->isAnyComplexType()) {
+      // Next subobject is a complex number.
+      uint64_t Index = Sub.Entries[I].ArrayIndex;
+      if (Index > 1) {
+        Info.Diag(E, Info.getLangOpts().CPlusPlus0x ?
+                    (unsigned)diag::note_constexpr_read_past_end :
+                    (unsigned)diag::note_invalid_subexpr_in_const_expr);
+        return false;
+      }
+      assert(I == N - 1 && "extracting subobject of scalar?");
+      if (O->isComplexInt()) {
+        Obj = APValue(Index ? O->getComplexIntImag()
+                            : O->getComplexIntReal());
+      } else {
+        assert(O->isComplexFloat());
+        Obj = APValue(Index ? O->getComplexFloatImag()
+                            : O->getComplexFloatReal());
+      }
+      return true;
+    } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
+      if (Field->isMutable()) {
+        Info.Diag(E, diag::note_constexpr_ltor_mutable, 1)
+          << Field;
+        Info.Note(Field->getLocation(), diag::note_declared_at);
+        return false;
+      }
+
+      // Next subobject is a class, struct or union field.
+      RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
+      if (RD->isUnion()) {
+        const FieldDecl *UnionField = O->getUnionField();
+        if (!UnionField ||
+            UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
+          Info.Diag(E, diag::note_constexpr_read_inactive_union_member)
+            << Field << !UnionField << UnionField;
+          return false;
+        }
+        O = &O->getUnionValue();
+      } else
+        O = &O->getStructField(Field->getFieldIndex());
+      ObjType = Field->getType();
+
+      if (ObjType.isVolatileQualified()) {
+        if (Info.getLangOpts().CPlusPlus) {
+          // FIXME: Include a description of the path to the volatile subobject.
+          Info.Diag(E, diag::note_constexpr_ltor_volatile_obj, 1)
+            << 2 << Field;
+          Info.Note(Field->getLocation(), diag::note_declared_at);
+        } else {
+          Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+        }
+        return false;
+      }
+    } else {
+      // Next subobject is a base class.
+      const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
+      const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
+      O = &O->getStructBase(getBaseIndex(Derived, Base));
+      ObjType = Info.Ctx.getRecordType(Base);
+    }
+
+    if (O->isUninit()) {
+      if (!Info.CheckingPotentialConstantExpression)
+        Info.Diag(E, diag::note_constexpr_read_uninit);
+      return false;
+    }
+  }
+
+  // This may look super-stupid, but it serves an important purpose: if we just
+  // swapped Obj and *O, we'd create an object which had itself as a subobject.
+  // To avoid the leak, we ensure that Tmp ends up owning the original complete
+  // object, which is destroyed by Tmp's destructor.
+  APValue Tmp;
+  O->swap(Tmp);
+  Obj.swap(Tmp);
+  return true;
+}
+
+/// Find the position where two subobject designators diverge, or equivalently
+/// the length of the common initial subsequence.
+static unsigned FindDesignatorMismatch(QualType ObjType,
+                                       const SubobjectDesignator &A,
+                                       const SubobjectDesignator &B,
+                                       bool &WasArrayIndex) {
+  unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
+  for (/**/; I != N; ++I) {
+    if (!ObjType.isNull() &&
+        (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
+      // Next subobject is an array element.
+      if (A.Entries[I].ArrayIndex != B.Entries[I].ArrayIndex) {
+        WasArrayIndex = true;
+        return I;
+      }
+      if (ObjType->isAnyComplexType())
+        ObjType = ObjType->castAs<ComplexType>()->getElementType();
+      else
+        ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
+    } else {
+      if (A.Entries[I].BaseOrMember != B.Entries[I].BaseOrMember) {
+        WasArrayIndex = false;
+        return I;
+      }
+      if (const FieldDecl *FD = getAsField(A.Entries[I]))
+        // Next subobject is a field.
+        ObjType = FD->getType();
+      else
+        // Next subobject is a base class.
+        ObjType = QualType();
+    }
+  }
+  WasArrayIndex = false;
+  return I;
+}
+
+/// Determine whether the given subobject designators refer to elements of the
+/// same array object.
+static bool AreElementsOfSameArray(QualType ObjType,
+                                   const SubobjectDesignator &A,
+                                   const SubobjectDesignator &B) {
+  if (A.Entries.size() != B.Entries.size())
+    return false;
+
+  bool IsArray = A.MostDerivedArraySize != 0;
+  if (IsArray && A.MostDerivedPathLength != A.Entries.size())
+    // A is a subobject of the array element.
+    return false;
+
+  // If A (and B) designates an array element, the last entry will be the array
+  // index. That doesn't have to match. Otherwise, we're in the 'implicit array
+  // of length 1' case, and the entire path must match.
+  bool WasArrayIndex;
+  unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
+  return CommonLength >= A.Entries.size() - IsArray;
+}
+
+/// HandleLValueToRValueConversion - Perform an lvalue-to-rvalue conversion on
+/// the given lvalue. This can also be used for 'lvalue-to-lvalue' conversions
+/// for looking up the glvalue referred to by an entity of reference type.
+///
+/// \param Info - Information about the ongoing evaluation.
+/// \param Conv - The expression for which we are performing the conversion.
+///               Used for diagnostics.
+/// \param Type - The type we expect this conversion to produce, before
+///               stripping cv-qualifiers in the case of a non-clas type.
+/// \param LVal - The glvalue on which we are attempting to perform this action.
+/// \param RVal - The produced value will be placed here.
+static bool HandleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv,
+                                           QualType Type,
+                                           const LValue &LVal, APValue &RVal) {
+  if (LVal.Designator.Invalid)
+    // A diagnostic will have already been produced.
+    return false;
+
+  const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
+
+  if (!LVal.Base) {
+    // FIXME: Indirection through a null pointer deserves a specific diagnostic.
+    Info.Diag(Conv, diag::note_invalid_subexpr_in_const_expr);
+    return false;
+  }
+
+  CallStackFrame *Frame = 0;
+  if (LVal.CallIndex) {
+    Frame = Info.getCallFrame(LVal.CallIndex);
+    if (!Frame) {
+      Info.Diag(Conv, diag::note_constexpr_lifetime_ended, 1) << !Base;
+      NoteLValueLocation(Info, LVal.Base);
+      return false;
+    }
+  }
+
+  // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
+  // is not a constant expression (even if the object is non-volatile). We also
+  // apply this rule to C++98, in order to conform to the expected 'volatile'
+  // semantics.
+  if (Type.isVolatileQualified()) {
+    if (Info.getLangOpts().CPlusPlus)
+      Info.Diag(Conv, diag::note_constexpr_ltor_volatile_type) << Type;
+    else
+      Info.Diag(Conv);
+    return false;
+  }
+
+  if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl*>()) {
+    // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
+    // In C++11, constexpr, non-volatile variables initialized with constant
+    // expressions are constant expressions too. Inside constexpr functions,
+    // parameters are constant expressions even if they're non-const.
+    // In C, such things can also be folded, although they are not ICEs.
+    const VarDecl *VD = dyn_cast<VarDecl>(D);
+    if (VD) {
+      if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
+        VD = VDef;
+    }
+    if (!VD || VD->isInvalidDecl()) {
+      Info.Diag(Conv);
+      return false;
+    }
+
+    // DR1313: If the object is volatile-qualified but the glvalue was not,
+    // behavior is undefined so the result is not a constant expression.
+    QualType VT = VD->getType();
+    if (VT.isVolatileQualified()) {
+      if (Info.getLangOpts().CPlusPlus) {
+        Info.Diag(Conv, diag::note_constexpr_ltor_volatile_obj, 1) << 1 << VD;
+        Info.Note(VD->getLocation(), diag::note_declared_at);
+      } else {
+        Info.Diag(Conv);
+      }
+      return false;
+    }
+
+    if (!isa<ParmVarDecl>(VD)) {
+      if (VD->isConstexpr()) {
+        // OK, we can read this variable.
+      } else if (VT->isIntegralOrEnumerationType()) {
+        if (!VT.isConstQualified()) {
+          if (Info.getLangOpts().CPlusPlus) {
+            Info.Diag(Conv, diag::note_constexpr_ltor_non_const_int, 1) << VD;
+            Info.Note(VD->getLocation(), diag::note_declared_at);
+          } else {
+            Info.Diag(Conv);
+          }
+          return false;
+        }
+      } else if (VT->isFloatingType() && VT.isConstQualified()) {
+        // We support folding of const floating-point types, in order to make
+        // static const data members of such types (supported as an extension)
+        // more useful.
+        if (Info.getLangOpts().CPlusPlus0x) {
+          Info.CCEDiag(Conv, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
+          Info.Note(VD->getLocation(), diag::note_declared_at);
+        } else {
+          Info.CCEDiag(Conv);
+        }
+      } else {
+        // FIXME: Allow folding of values of any literal type in all languages.
+        if (Info.getLangOpts().CPlusPlus0x) {
+          Info.Diag(Conv, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
+          Info.Note(VD->getLocation(), diag::note_declared_at);
+        } else {
+          Info.Diag(Conv);
+        }
+        return false;
+      }
+    }
+
+    if (!EvaluateVarDeclInit(Info, Conv, VD, Frame, RVal))
+      return false;
+
+    if (isa<ParmVarDecl>(VD) || !VD->getAnyInitializer()->isLValue())
+      return ExtractSubobject(Info, Conv, RVal, VT, LVal.Designator, Type);
+
+    // The declaration was initialized by an lvalue, with no lvalue-to-rvalue
+    // conversion. This happens when the declaration and the lvalue should be
+    // considered synonymous, for instance when initializing an array of char
+    // from a string literal. Continue as if the initializer lvalue was the
+    // value we were originally given.
+    assert(RVal.getLValueOffset().isZero() &&
+           "offset for lvalue init of non-reference");
+    Base = RVal.getLValueBase().get<const Expr*>();
+
+    if (unsigned CallIndex = RVal.getLValueCallIndex()) {
+      Frame = Info.getCallFrame(CallIndex);
+      if (!Frame) {
+        Info.Diag(Conv, diag::note_constexpr_lifetime_ended, 1) << !Base;
+        NoteLValueLocation(Info, RVal.getLValueBase());
+        return false;
+      }
+    } else {
+      Frame = 0;
+    }
+  }
+
+  // Volatile temporary objects cannot be read in constant expressions.
+  if (Base->getType().isVolatileQualified()) {
+    if (Info.getLangOpts().CPlusPlus) {
+      Info.Diag(Conv, diag::note_constexpr_ltor_volatile_obj, 1) << 0;
+      Info.Note(Base->getExprLoc(), diag::note_constexpr_temporary_here);
+    } else {
+      Info.Diag(Conv);
+    }
+    return false;
+  }
+
+  if (Frame) {
+    // If this is a temporary expression with a nontrivial initializer, grab the
+    // value from the relevant stack frame.
+    RVal = Frame->Temporaries[Base];
+  } else if (const CompoundLiteralExpr *CLE
+             = dyn_cast<CompoundLiteralExpr>(Base)) {
+    // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
+    // initializer until now for such expressions. Such an expression can't be
+    // an ICE in C, so this only matters for fold.
+    assert(!Info.getLangOpts().CPlusPlus && "lvalue compound literal in c++?");
+    if (!Evaluate(RVal, Info, CLE->getInitializer()))
+      return false;
+  } else if (isa<StringLiteral>(Base)) {
+    // We represent a string literal array as an lvalue pointing at the
+    // corresponding expression, rather than building an array of chars.
+    // FIXME: Support PredefinedExpr, ObjCEncodeExpr, MakeStringConstant
+    RVal = APValue(Base, CharUnits::Zero(), APValue::NoLValuePath(), 0);
+  } else {
+    Info.Diag(Conv, diag::note_invalid_subexpr_in_const_expr);
+    return false;
+  }
+
+  return ExtractSubobject(Info, Conv, RVal, Base->getType(), LVal.Designator,
+                          Type);
+}
+
+/// Build an lvalue for the object argument of a member function call.
+static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
+                                   LValue &This) {
+  if (Object->getType()->isPointerType())
+    return EvaluatePointer(Object, This, Info);
+
+  if (Object->isGLValue())
+    return EvaluateLValue(Object, This, Info);
+
+  if (Object->getType()->isLiteralType())
+    return EvaluateTemporary(Object, This, Info);
+
+  return false;
+}
+
+/// HandleMemberPointerAccess - Evaluate a member access operation and build an
+/// lvalue referring to the result.
+///
+/// \param Info - Information about the ongoing evaluation.
+/// \param BO - The member pointer access operation.
+/// \param LV - Filled in with a reference to the resulting object.
+/// \param IncludeMember - Specifies whether the member itself is included in
+///        the resulting LValue subobject designator. This is not possible when
+///        creating a bound member function.
+/// \return The field or method declaration to which the member pointer refers,
+///         or 0 if evaluation fails.
+static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
+                                                  const BinaryOperator *BO,
+                                                  LValue &LV,
+                                                  bool IncludeMember = true) {
+  assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI);
+
+  bool EvalObjOK = EvaluateObjectArgument(Info, BO->getLHS(), LV);
+  if (!EvalObjOK && !Info.keepEvaluatingAfterFailure())
+    return 0;
+
+  MemberPtr MemPtr;
+  if (!EvaluateMemberPointer(BO->getRHS(), MemPtr, Info))
+    return 0;
+
+  // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
+  // member value, the behavior is undefined.
+  if (!MemPtr.getDecl())
+    return 0;
+
+  if (!EvalObjOK)
+    return 0;
+
+  if (MemPtr.isDerivedMember()) {
+    // This is a member of some derived class. Truncate LV appropriately.
+    // The end of the derived-to-base path for the base object must match the
+    // derived-to-base path for the member pointer.
+    if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
+        LV.Designator.Entries.size())
+      return 0;
+    unsigned PathLengthToMember =
+        LV.Designator.Entries.size() - MemPtr.Path.size();
+    for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
+      const CXXRecordDecl *LVDecl = getAsBaseClass(
+          LV.Designator.Entries[PathLengthToMember + I]);
+      const CXXRecordDecl *MPDecl = MemPtr.Path[I];
+      if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl())
+        return 0;
+    }
+
+    // Truncate the lvalue to the appropriate derived class.
+    if (!CastToDerivedClass(Info, BO, LV, MemPtr.getContainingRecord(),
+                            PathLengthToMember))
+      return 0;
+  } else if (!MemPtr.Path.empty()) {
+    // Extend the LValue path with the member pointer's path.
+    LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
+                                  MemPtr.Path.size() + IncludeMember);
+
+    // Walk down to the appropriate base class.
+    QualType LVType = BO->getLHS()->getType();
+    if (const PointerType *PT = LVType->getAs<PointerType>())
+      LVType = PT->getPointeeType();
+    const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
+    assert(RD && "member pointer access on non-class-type expression");
+    // The first class in the path is that of the lvalue.
+    for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
+      const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
+      HandleLValueDirectBase(Info, BO, LV, RD, Base);
+      RD = Base;
+    }
+    // Finally cast to the class containing the member.
+    HandleLValueDirectBase(Info, BO, LV, RD, MemPtr.getContainingRecord());
+  }
+
+  // Add the member. Note that we cannot build bound member functions here.
+  if (IncludeMember) {
+    if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl()))
+      HandleLValueMember(Info, BO, LV, FD);
+    else if (const IndirectFieldDecl *IFD =
+               dyn_cast<IndirectFieldDecl>(MemPtr.getDecl()))
+      HandleLValueIndirectMember(Info, BO, LV, IFD);
+    else
+      llvm_unreachable("can't construct reference to bound member function");
+  }
+
+  return MemPtr.getDecl();
+}
+
+/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
+/// the provided lvalue, which currently refers to the base object.
+static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
+                                    LValue &Result) {
+  SubobjectDesignator &D = Result.Designator;
+  if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
+    return false;
+
+  QualType TargetQT = E->getType();
+  if (const PointerType *PT = TargetQT->getAs<PointerType>())
+    TargetQT = PT->getPointeeType();
+
+  // Check this cast lands within the final derived-to-base subobject path.
+  if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
+    Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
+      << D.MostDerivedType << TargetQT;
+    return false;
+  }
+
+  // Check the type of the final cast. We don't need to check the path,
+  // since a cast can only be formed if the path is unique.
+  unsigned NewEntriesSize = D.Entries.size() - E->path_size();
+  const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
+  const CXXRecordDecl *FinalType;
+  if (NewEntriesSize == D.MostDerivedPathLength)
+    FinalType = D.MostDerivedType->getAsCXXRecordDecl();
+  else
+    FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
+  if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
+    Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
+      << D.MostDerivedType << TargetQT;
+    return false;
+  }
+
+  // Truncate the lvalue to the appropriate derived class.
+  return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
+}
+
+namespace {
+enum EvalStmtResult {
+  /// Evaluation failed.
+  ESR_Failed,
+  /// Hit a 'return' statement.
+  ESR_Returned,
+  /// Evaluation succeeded.
+  ESR_Succeeded
+};
+}
+
+// Evaluate a statement.
+static EvalStmtResult EvaluateStmt(APValue &Result, EvalInfo &Info,
+                                   const Stmt *S) {
+  switch (S->getStmtClass()) {
+  default:
+    return ESR_Failed;
+
+  case Stmt::NullStmtClass:
+  case Stmt::DeclStmtClass:
+    return ESR_Succeeded;
+
+  case Stmt::ReturnStmtClass: {
+    const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
+    if (!Evaluate(Result, Info, RetExpr))
+      return ESR_Failed;
+    return ESR_Returned;
+  }
+
+  case Stmt::CompoundStmtClass: {
+    const CompoundStmt *CS = cast<CompoundStmt>(S);
+    for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
+           BE = CS->body_end(); BI != BE; ++BI) {
+      EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
+      if (ESR != ESR_Succeeded)
+        return ESR;
+    }
+    return ESR_Succeeded;
+  }
+  }
+}
+
+/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
+/// default constructor. If so, we'll fold it whether or not it's marked as
+/// constexpr. If it is marked as constexpr, we will never implicitly define it,
+/// so we need special handling.
+static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
+                                           const CXXConstructorDecl *CD,
+                                           bool IsValueInitialization) {
+  if (!CD->isTrivial() || !CD->isDefaultConstructor())
+    return false;
+
+  // Value-initialization does not call a trivial default constructor, so such a
+  // call is a core constant expression whether or not the constructor is
+  // constexpr.
+  if (!CD->isConstexpr() && !IsValueInitialization) {
+    if (Info.getLangOpts().CPlusPlus0x) {
+      // FIXME: If DiagDecl is an implicitly-declared special member function,
+      // we should be much more explicit about why it's not constexpr.
+      Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
+        << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
+      Info.Note(CD->getLocation(), diag::note_declared_at);
+    } else {
+      Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
+    }
+  }
+  return true;
+}
+
+/// CheckConstexprFunction - Check that a function can be called in a constant
+/// expression.
+static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
+                                   const FunctionDecl *Declaration,
+                                   const FunctionDecl *Definition) {
+  // Potential constant expressions can contain calls to declared, but not yet
+  // defined, constexpr functions.
+  if (Info.CheckingPotentialConstantExpression && !Definition &&
+      Declaration->isConstexpr())
+    return false;
+
+  // Can we evaluate this function call?
+  if (Definition && Definition->isConstexpr() && !Definition->isInvalidDecl())
+    return true;
+
+  if (Info.getLangOpts().CPlusPlus0x) {
+    const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
+    // FIXME: If DiagDecl is an implicitly-declared special member function, we
+    // should be much more explicit about why it's not constexpr.
+    Info.Diag(CallLoc, diag::note_constexpr_invalid_function, 1)
+      << DiagDecl->isConstexpr() << isa<CXXConstructorDecl>(DiagDecl)
+      << DiagDecl;
+    Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
+  } else {
+    Info.Diag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
+  }
+  return false;
+}
+
+namespace {
+typedef SmallVector<APValue, 8> ArgVector;
+}
+
+/// EvaluateArgs - Evaluate the arguments to a function call.
+static bool EvaluateArgs(ArrayRef<const Expr*> Args, ArgVector &ArgValues,
+                         EvalInfo &Info) {
+  bool Success = true;
+  for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
+       I != E; ++I) {
+    if (!Evaluate(ArgValues[I - Args.begin()], Info, *I)) {
+      // If we're checking for a potential constant expression, evaluate all
+      // initializers even if some of them fail.
+      if (!Info.keepEvaluatingAfterFailure())
+        return false;
+      Success = false;
+    }
+  }
+  return Success;
+}
+
+/// Evaluate a function call.
+static bool HandleFunctionCall(SourceLocation CallLoc,
+                               const FunctionDecl *Callee, const LValue *This,
+                               ArrayRef<const Expr*> Args, const Stmt *Body,
+                               EvalInfo &Info, APValue &Result) {
+  ArgVector ArgValues(Args.size());
+  if (!EvaluateArgs(Args, ArgValues, Info))
+    return false;
+
+  if (!Info.CheckCallLimit(CallLoc))
+    return false;
+
+  CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data());
+  return EvaluateStmt(Result, Info, Body) == ESR_Returned;
+}
+
+/// Evaluate a constructor call.
+static bool HandleConstructorCall(SourceLocation CallLoc, const LValue &This,
+                                  ArrayRef<const Expr*> Args,
+                                  const CXXConstructorDecl *Definition,
+                                  EvalInfo &Info, APValue &Result) {
+  ArgVector ArgValues(Args.size());
+  if (!EvaluateArgs(Args, ArgValues, Info))
+    return false;
+
+  if (!Info.CheckCallLimit(CallLoc))
+    return false;
+
+  const CXXRecordDecl *RD = Definition->getParent();
+  if (RD->getNumVBases()) {
+    Info.Diag(CallLoc, diag::note_constexpr_virtual_base) << RD;
+    return false;
+  }
+
+  CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues.data());
+
+  // If it's a delegating constructor, just delegate.
+  if (Definition->isDelegatingConstructor()) {
+    CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
+    return EvaluateInPlace(Result, Info, This, (*I)->getInit());
+  }
+
+  // For a trivial copy or move constructor, perform an APValue copy. This is
+  // essential for unions, where the operations performed by the constructor
+  // cannot be represented by ctor-initializers.
+  if (Definition->isDefaulted() &&
+      ((Definition->isCopyConstructor() && Definition->isTrivial()) ||
+       (Definition->isMoveConstructor() && Definition->isTrivial()))) {
+    LValue RHS;
+    RHS.setFrom(Info.Ctx, ArgValues[0]);
+    return HandleLValueToRValueConversion(Info, Args[0], Args[0]->getType(),
+                                          RHS, Result);
+  }
+
+  // Reserve space for the struct members.
+  if (!RD->isUnion() && Result.isUninit())
+    Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
+                     std::distance(RD->field_begin(), RD->field_end()));
+
+  const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
+
+  bool Success = true;
+  unsigned BasesSeen = 0;
+#ifndef NDEBUG
+  CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
+#endif
+  for (CXXConstructorDecl::init_const_iterator I = Definition->init_begin(),
+       E = Definition->init_end(); I != E; ++I) {
+    LValue Subobject = This;
+    APValue *Value = &Result;
+
+    // Determine the subobject to initialize.
+    if ((*I)->isBaseInitializer()) {
+      QualType BaseType((*I)->getBaseClass(), 0);
+#ifndef NDEBUG
+      // Non-virtual base classes are initialized in the order in the class
+      // definition. We have already checked for virtual base classes.
+      assert(!BaseIt->isVirtual() && "virtual base for literal type");
+      assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
+             "base class initializers not in expected order");
+      ++BaseIt;
+#endif
+      HandleLValueDirectBase(Info, (*I)->getInit(), Subobject, RD,
+                             BaseType->getAsCXXRecordDecl(), &Layout);
+      Value = &Result.getStructBase(BasesSeen++);
+    } else if (FieldDecl *FD = (*I)->getMember()) {
+      HandleLValueMember(Info, (*I)->getInit(), Subobject, FD, &Layout);
+      if (RD->isUnion()) {
+        Result = APValue(FD);
+        Value = &Result.getUnionValue();
+      } else {
+        Value = &Result.getStructField(FD->getFieldIndex());
+      }
+    } else if (IndirectFieldDecl *IFD = (*I)->getIndirectMember()) {
+      // Walk the indirect field decl's chain to find the object to initialize,
+      // and make sure we've initialized every step along it.
+      for (IndirectFieldDecl::chain_iterator C = IFD->chain_begin(),
+                                             CE = IFD->chain_end();
+           C != CE; ++C) {
+        FieldDecl *FD = cast<FieldDecl>(*C);
+        CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
+        // Switch the union field if it differs. This happens if we had
+        // preceding zero-initialization, and we're now initializing a union
+        // subobject other than the first.
+        // FIXME: In this case, the values of the other subobjects are
+        // specified, since zero-initialization sets all padding bits to zero.
+        if (Value->isUninit() ||
+            (Value->isUnion() && Value->getUnionField() != FD)) {
+          if (CD->isUnion())
+            *Value = APValue(FD);
+          else
+            *Value = APValue(APValue::UninitStruct(), CD->getNumBases(),
+                             std::distance(CD->field_begin(), CD->field_end()));
+        }
+        HandleLValueMember(Info, (*I)->getInit(), Subobject, FD);
+        if (CD->isUnion())
+          Value = &Value->getUnionValue();
+        else
+          Value = &Value->getStructField(FD->getFieldIndex());
+      }
+    } else {
+      llvm_unreachable("unknown base initializer kind");
+    }
+
+    if (!EvaluateInPlace(*Value, Info, Subobject, (*I)->getInit(),
+                         (*I)->isBaseInitializer()
+                                      ? CCEK_Constant : CCEK_MemberInit)) {
+      // If we're checking for a potential constant expression, evaluate all
+      // initializers even if some of them fail.
+      if (!Info.keepEvaluatingAfterFailure())
+        return false;
+      Success = false;
+    }
+  }
+
+  return Success;
+}
+
+namespace {
+class HasSideEffect
+  : public ConstStmtVisitor<HasSideEffect, bool> {
+  const ASTContext &Ctx;
+public:
+
+  HasSideEffect(const ASTContext &C) : Ctx(C) {}
+
+  // Unhandled nodes conservatively default to having side effects.
+  bool VisitStmt(const Stmt *S) {
+    return true;
+  }
+
+  bool VisitParenExpr(const ParenExpr *E) { return Visit(E->getSubExpr()); }
+  bool VisitGenericSelectionExpr(const GenericSelectionExpr *E) {
+    return Visit(E->getResultExpr());
+  }
+  bool VisitDeclRefExpr(const DeclRefExpr *E) {
+    if (Ctx.getCanonicalType(E->getType()).isVolatileQualified())
+      return true;
+    return false;
+  }
+  bool VisitObjCIvarRefExpr(const ObjCIvarRefExpr *E) {
+    if (Ctx.getCanonicalType(E->getType()).isVolatileQualified())
+      return true;
+    return false;
+  }
+
+  // We don't want to evaluate BlockExprs multiple times, as they generate
+  // a ton of code.
+  bool VisitBlockExpr(const BlockExpr *E) { return true; }
+  bool VisitPredefinedExpr(const PredefinedExpr *E) { return false; }
+  bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E)
+    { return Visit(E->getInitializer()); }
+  bool VisitMemberExpr(const MemberExpr *E) { return Visit(E->getBase()); }
+  bool VisitIntegerLiteral(const IntegerLiteral *E) { return false; }
+  bool VisitFloatingLiteral(const FloatingLiteral *E) { return false; }
+  bool VisitStringLiteral(const StringLiteral *E) { return false; }
+  bool VisitCharacterLiteral(const CharacterLiteral *E) { return false; }
+  bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E)
+    { return false; }
+  bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E)
+    { return Visit(E->getLHS()) || Visit(E->getRHS()); }
+  bool VisitChooseExpr(const ChooseExpr *E)
+    { return Visit(E->getChosenSubExpr(Ctx)); }
+  bool VisitCastExpr(const CastExpr *E) { return Visit(E->getSubExpr()); }
+  bool VisitBinAssign(const BinaryOperator *E) { return true; }
+  bool VisitCompoundAssignOperator(const BinaryOperator *E) { return true; }
+  bool VisitBinaryOperator(const BinaryOperator *E)
+  { return Visit(E->getLHS()) || Visit(E->getRHS()); }
+  bool VisitUnaryPreInc(const UnaryOperator *E) { return true; }
+  bool VisitUnaryPostInc(const UnaryOperator *E) { return true; }
+  bool VisitUnaryPreDec(const UnaryOperator *E) { return true; }
+  bool VisitUnaryPostDec(const UnaryOperator *E) { return true; }
+  bool VisitUnaryDeref(const UnaryOperator *E) {
+    if (Ctx.getCanonicalType(E->getType()).isVolatileQualified())
+      return true;
+    return Visit(E->getSubExpr());
+  }
+  bool VisitUnaryOperator(const UnaryOperator *E) { return Visit(E->getSubExpr()); }
+    
+  // Has side effects if any element does.
+  bool VisitInitListExpr(const InitListExpr *E) {
+    for (unsigned i = 0, e = E->getNumInits(); i != e; ++i)
+      if (Visit(E->getInit(i))) return true;
+    if (const Expr *filler = E->getArrayFiller())
+      return Visit(filler);
+    return false;
+  }
+    
+  bool VisitSizeOfPackExpr(const SizeOfPackExpr *) { return false; }
+};
+
+class OpaqueValueEvaluation {
+  EvalInfo &info;
+  OpaqueValueExpr *opaqueValue;
+
+public:
+  OpaqueValueEvaluation(EvalInfo &info, OpaqueValueExpr *opaqueValue,
+                        Expr *value)
+    : info(info), opaqueValue(opaqueValue) {
+
+    // If evaluation fails, fail immediately.
+    if (!Evaluate(info.OpaqueValues[opaqueValue], info, value)) {
+      this->opaqueValue = 0;
+      return;
+    }
+  }
+
+  bool hasError() const { return opaqueValue == 0; }
+
+  ~OpaqueValueEvaluation() {
+    // FIXME: For a recursive constexpr call, an outer stack frame might have
+    // been using this opaque value too, and will now have to re-evaluate the
+    // source expression.
+    if (opaqueValue) info.OpaqueValues.erase(opaqueValue);
+  }
+};
+  
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// Generic Evaluation
+//===----------------------------------------------------------------------===//
+namespace {
+
+// FIXME: RetTy is always bool. Remove it.
+template <class Derived, typename RetTy=bool>
+class ExprEvaluatorBase
+  : public ConstStmtVisitor<Derived, RetTy> {
+private:
+  RetTy DerivedSuccess(const APValue &V, const Expr *E) {
+    return static_cast<Derived*>(this)->Success(V, E);
+  }
+  RetTy DerivedZeroInitialization(const Expr *E) {
+    return static_cast<Derived*>(this)->ZeroInitialization(E);
+  }
+
+  // Check whether a conditional operator with a non-constant condition is a
+  // potential constant expression. If neither arm is a potential constant
+  // expression, then the conditional operator is not either.
+  template<typename ConditionalOperator>
+  void CheckPotentialConstantConditional(const ConditionalOperator *E) {
+    assert(Info.CheckingPotentialConstantExpression);
+
+    // Speculatively evaluate both arms.
+    {
+      llvm::SmallVector<PartialDiagnosticAt, 8> Diag;
+      SpeculativeEvaluationRAII Speculate(Info, &Diag);
+
+      StmtVisitorTy::Visit(E->getFalseExpr());
+      if (Diag.empty())
+        return;
+
+      Diag.clear();
+      StmtVisitorTy::Visit(E->getTrueExpr());
+      if (Diag.empty())
+        return;
+    }
+
+    Error(E, diag::note_constexpr_conditional_never_const);
+  }
+
+
+  template<typename ConditionalOperator>
+  bool HandleConditionalOperator(const ConditionalOperator *E) {
+    bool BoolResult;
+    if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
+      if (Info.CheckingPotentialConstantExpression)
+        CheckPotentialConstantConditional(E);
+      return false;
+    }
+
+    Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
+    return StmtVisitorTy::Visit(EvalExpr);
+  }
+
+protected:
+  EvalInfo &Info;
+  typedef ConstStmtVisitor<Derived, RetTy> StmtVisitorTy;
+  typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
+
+  OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
+    return Info.CCEDiag(E, D);
+  }
+
+  RetTy ZeroInitialization(const Expr *E) { return Error(E); }
+
+public:
+  ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
+
+  EvalInfo &getEvalInfo() { return Info; }
+
+  /// Report an evaluation error. This should only be called when an error is
+  /// first discovered. When propagating an error, just return false.
+  bool Error(const Expr *E, diag::kind D) {
+    Info.Diag(E, D);
+    return false;
+  }
+  bool Error(const Expr *E) {
+    return Error(E, diag::note_invalid_subexpr_in_const_expr);
+  }
+
+  RetTy VisitStmt(const Stmt *) {
+    llvm_unreachable("Expression evaluator should not be called on stmts");
+  }
+  RetTy VisitExpr(const Expr *E) {
+    return Error(E);
+  }
+
+  RetTy VisitParenExpr(const ParenExpr *E)
+    { return StmtVisitorTy::Visit(E->getSubExpr()); }
+  RetTy VisitUnaryExtension(const UnaryOperator *E)
+    { return StmtVisitorTy::Visit(E->getSubExpr()); }
+  RetTy VisitUnaryPlus(const UnaryOperator *E)
+    { return StmtVisitorTy::Visit(E->getSubExpr()); }
+  RetTy VisitChooseExpr(const ChooseExpr *E)
+    { return StmtVisitorTy::Visit(E->getChosenSubExpr(Info.Ctx)); }
+  RetTy VisitGenericSelectionExpr(const GenericSelectionExpr *E)
+    { return StmtVisitorTy::Visit(E->getResultExpr()); }
+  RetTy VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
+    { return StmtVisitorTy::Visit(E->getReplacement()); }
+  RetTy VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E)
+    { return StmtVisitorTy::Visit(E->getExpr()); }
+  // We cannot create any objects for which cleanups are required, so there is
+  // nothing to do here; all cleanups must come from unevaluated subexpressions.
+  RetTy VisitExprWithCleanups(const ExprWithCleanups *E)
+    { return StmtVisitorTy::Visit(E->getSubExpr()); }
+
+  RetTy VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
+    CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
+    return static_cast<Derived*>(this)->VisitCastExpr(E);
+  }
+  RetTy VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
+    CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
+    return static_cast<Derived*>(this)->VisitCastExpr(E);
+  }
+
+  RetTy VisitBinaryOperator(const BinaryOperator *E) {
+    switch (E->getOpcode()) {
+    default:
+      return Error(E);
+
+    case BO_Comma:
+      VisitIgnoredValue(E->getLHS());
+      return StmtVisitorTy::Visit(E->getRHS());
+
+    case BO_PtrMemD:
+    case BO_PtrMemI: {
+      LValue Obj;
+      if (!HandleMemberPointerAccess(Info, E, Obj))
+        return false;
+      APValue Result;
+      if (!HandleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
+        return false;
+      return DerivedSuccess(Result, E);
+    }
+    }
+  }
+
+  RetTy VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
+    // Cache the value of the common expression.
+    OpaqueValueEvaluation opaque(Info, E->getOpaqueValue(), E->getCommon());
+    if (opaque.hasError())
+      return false;
+
+    return HandleConditionalOperator(E);
+  }
+
+  RetTy VisitConditionalOperator(const ConditionalOperator *E) {
+    bool IsBcpCall = false;
+    // If the condition (ignoring parens) is a __builtin_constant_p call,
+    // the result is a constant expression if it can be folded without
+    // side-effects. This is an important GNU extension. See GCC PR38377
+    // for discussion.
+    if (const CallExpr *CallCE =
+          dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
+      if (CallCE->isBuiltinCall() == Builtin::BI__builtin_constant_p)
+        IsBcpCall = true;
+
+    // Always assume __builtin_constant_p(...) ? ... : ... is a potential
+    // constant expression; we can't check whether it's potentially foldable.
+    if (Info.CheckingPotentialConstantExpression && IsBcpCall)
+      return false;
+
+    FoldConstant Fold(Info);
+
+    if (!HandleConditionalOperator(E))
+      return false;
+
+    if (IsBcpCall)
+      Fold.Fold(Info);
+
+    return true;
+  }
+
+  RetTy VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
+    const APValue *Value = Info.getOpaqueValue(E);
+    if (!Value) {
+      const Expr *Source = E->getSourceExpr();
+      if (!Source)
+        return Error(E);
+      if (Source == E) { // sanity checking.
+        assert(0 && "OpaqueValueExpr recursively refers to itself");
+        return Error(E);
+      }
+      return StmtVisitorTy::Visit(Source);
+    }
+    return DerivedSuccess(*Value, E);
+  }
+
+  RetTy VisitCallExpr(const CallExpr *E) {
+    const Expr *Callee = E->getCallee()->IgnoreParens();
+    QualType CalleeType = Callee->getType();
+
+    const FunctionDecl *FD = 0;
+    LValue *This = 0, ThisVal;
+    llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs());
+    bool HasQualifier = false;
+
+    // Extract function decl and 'this' pointer from the callee.
+    if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
+      const ValueDecl *Member = 0;
+      if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
+        // Explicit bound member calls, such as x.f() or p->g();
+        if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
+          return false;
+        Member = ME->getMemberDecl();
+        This = &ThisVal;
+        HasQualifier = ME->hasQualifier();
+      } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
+        // Indirect bound member calls ('.*' or '->*').
+        Member = HandleMemberPointerAccess(Info, BE, ThisVal, false);
+        if (!Member) return false;
+        This = &ThisVal;
+      } else
+        return Error(Callee);
+
+      FD = dyn_cast<FunctionDecl>(Member);
+      if (!FD)
+        return Error(Callee);
+    } else if (CalleeType->isFunctionPointerType()) {
+      LValue Call;
+      if (!EvaluatePointer(Callee, Call, Info))
+        return false;
+
+      if (!Call.getLValueOffset().isZero())
+        return Error(Callee);
+      FD = dyn_cast_or_null<FunctionDecl>(
+                             Call.getLValueBase().dyn_cast<const ValueDecl*>());
+      if (!FD)
+        return Error(Callee);
+
+      // Overloaded operator calls to member functions are represented as normal
+      // calls with '*this' as the first argument.
+      const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
+      if (MD && !MD->isStatic()) {
+        // FIXME: When selecting an implicit conversion for an overloaded
+        // operator delete, we sometimes try to evaluate calls to conversion
+        // operators without a 'this' parameter!
+        if (Args.empty())
+          return Error(E);
+
+        if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
+          return false;
+        This = &ThisVal;
+        Args = Args.slice(1);
+      }
+
+      // Don't call function pointers which have been cast to some other type.
+      if (!Info.Ctx.hasSameType(CalleeType->getPointeeType(), FD->getType()))
+        return Error(E);
+    } else
+      return Error(E);
+
+    if (This && !This->checkSubobject(Info, E, CSK_This))
+      return false;
+
+    // DR1358 allows virtual constexpr functions in some cases. Don't allow
+    // calls to such functions in constant expressions.
+    if (This && !HasQualifier &&
+        isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isVirtual())
+      return Error(E, diag::note_constexpr_virtual_call);
+
+    const FunctionDecl *Definition = 0;
+    Stmt *Body = FD->getBody(Definition);
+    APValue Result;
+
+    if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition) ||
+        !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body,
+                            Info, Result))
+      return false;
+
+    return DerivedSuccess(Result, E);
+  }
+
+  RetTy VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
+    return StmtVisitorTy::Visit(E->getInitializer());
+  }
+  RetTy VisitInitListExpr(const InitListExpr *E) {
+    if (E->getNumInits() == 0)
+      return DerivedZeroInitialization(E);
+    if (E->getNumInits() == 1)
+      return StmtVisitorTy::Visit(E->getInit(0));
+    return Error(E);
+  }
+  RetTy VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
+    return DerivedZeroInitialization(E);
+  }
+  RetTy VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
+    return DerivedZeroInitialization(E);
+  }
+  RetTy VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
+    return DerivedZeroInitialization(E);
+  }
+
+  /// A member expression where the object is a prvalue is itself a prvalue.
+  RetTy VisitMemberExpr(const MemberExpr *E) {
+    assert(!E->isArrow() && "missing call to bound member function?");
+
+    APValue Val;
+    if (!Evaluate(Val, Info, E->getBase()))
+      return false;
+
+    QualType BaseTy = E->getBase()->getType();
+
+    const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
+    if (!FD) return Error(E);
+    assert(!FD->getType()->isReferenceType() && "prvalue reference?");
+    assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() ==
+           FD->getParent()->getCanonicalDecl() && "record / field mismatch");
+
+    SubobjectDesignator Designator(BaseTy);
+    Designator.addDeclUnchecked(FD);
+
+    return ExtractSubobject(Info, E, Val, BaseTy, Designator, E->getType()) &&
+           DerivedSuccess(Val, E);
+  }
+
+  RetTy VisitCastExpr(const CastExpr *E) {
+    switch (E->getCastKind()) {
+    default:
+      break;
+
+    case CK_AtomicToNonAtomic:
+    case CK_NonAtomicToAtomic:
+    case CK_NoOp:
+    case CK_UserDefinedConversion:
+      return StmtVisitorTy::Visit(E->getSubExpr());
+
+    case CK_LValueToRValue: {
+      LValue LVal;
+      if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
+        return false;
+      APValue RVal;
+      // Note, we use the subexpression's type in order to retain cv-qualifiers.
+      if (!HandleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
+                                          LVal, RVal))
+        return false;
+      return DerivedSuccess(RVal, E);
+    }
+    }
+
+    return Error(E);
+  }
+
+  /// Visit a value which is evaluated, but whose value is ignored.
+  void VisitIgnoredValue(const Expr *E) {
+    APValue Scratch;
+    if (!Evaluate(Scratch, Info, E))
+      Info.EvalStatus.HasSideEffects = true;
+  }
+};
+
+}
+
+//===----------------------------------------------------------------------===//
+// Common base class for lvalue and temporary evaluation.
+//===----------------------------------------------------------------------===//
+namespace {
+template<class Derived>
+class LValueExprEvaluatorBase
+  : public ExprEvaluatorBase<Derived, bool> {
+protected:
+  LValue &Result;
+  typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
+  typedef ExprEvaluatorBase<Derived, bool> ExprEvaluatorBaseTy;
+
+  bool Success(APValue::LValueBase B) {
+    Result.set(B);
+    return true;
+  }
+
+public:
+  LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result) :
+    ExprEvaluatorBaseTy(Info), Result(Result) {}
+
+  bool Success(const APValue &V, const Expr *E) {
+    Result.setFrom(this->Info.Ctx, V);
+    return true;
+  }
+
+  bool VisitMemberExpr(const MemberExpr *E) {
+    // Handle non-static data members.
+    QualType BaseTy;
+    if (E->isArrow()) {
+      if (!EvaluatePointer(E->getBase(), Result, this->Info))
+        return false;
+      BaseTy = E->getBase()->getType()->getAs<PointerType>()->getPointeeType();
+    } else if (E->getBase()->isRValue()) {
+      assert(E->getBase()->getType()->isRecordType());
+      if (!EvaluateTemporary(E->getBase(), Result, this->Info))
+        return false;
+      BaseTy = E->getBase()->getType();
+    } else {
+      if (!this->Visit(E->getBase()))
+        return false;
+      BaseTy = E->getBase()->getType();
+    }
+
+    const ValueDecl *MD = E->getMemberDecl();
+    if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
+      assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() ==
+             FD->getParent()->getCanonicalDecl() && "record / field mismatch");
+      (void)BaseTy;
+      HandleLValueMember(this->Info, E, Result, FD);
+    } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
+      HandleLValueIndirectMember(this->Info, E, Result, IFD);
+    } else
+      return this->Error(E);
+
+    if (MD->getType()->isReferenceType()) {
+      APValue RefValue;
+      if (!HandleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
+                                          RefValue))
+        return false;
+      return Success(RefValue, E);
+    }
+    return true;
+  }
+
+  bool VisitBinaryOperator(const BinaryOperator *E) {
+    switch (E->getOpcode()) {
+    default:
+      return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
+
+    case BO_PtrMemD:
+    case BO_PtrMemI:
+      return HandleMemberPointerAccess(this->Info, E, Result);
+    }
+  }
+
+  bool VisitCastExpr(const CastExpr *E) {
+    switch (E->getCastKind()) {
+    default:
+      return ExprEvaluatorBaseTy::VisitCastExpr(E);
+
+    case CK_DerivedToBase:
+    case CK_UncheckedDerivedToBase: {
+      if (!this->Visit(E->getSubExpr()))
+        return false;
+
+      // Now figure out the necessary offset to add to the base LV to get from
+      // the derived class to the base class.
+      QualType Type = E->getSubExpr()->getType();
+
+      for (CastExpr::path_const_iterator PathI = E->path_begin(),
+           PathE = E->path_end(); PathI != PathE; ++PathI) {
+        if (!HandleLValueBase(this->Info, E, Result, Type->getAsCXXRecordDecl(),
+                              *PathI))
+          return false;
+        Type = (*PathI)->getType();
+      }
+
+      return true;
+    }
+    }
+  }
+};
+}
+
+//===----------------------------------------------------------------------===//
+// LValue Evaluation
+//
+// This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
+// function designators (in C), decl references to void objects (in C), and
+// temporaries (if building with -Wno-address-of-temporary).
+//
+// LValue evaluation produces values comprising a base expression of one of the
+// following types:
+// - Declarations
+//  * VarDecl
+//  * FunctionDecl
+// - Literals
+//  * CompoundLiteralExpr in C
+//  * StringLiteral
+//  * CXXTypeidExpr
+//  * PredefinedExpr
+//  * ObjCStringLiteralExpr
+//  * ObjCEncodeExpr
+//  * AddrLabelExpr
+//  * BlockExpr
+//  * CallExpr for a MakeStringConstant builtin
+// - Locals and temporaries
+//  * Any Expr, with a CallIndex indicating the function in which the temporary
+//    was evaluated.
+// plus an offset in bytes.
+//===----------------------------------------------------------------------===//
+namespace {
+class LValueExprEvaluator
+  : public LValueExprEvaluatorBase<LValueExprEvaluator> {
+public:
+  LValueExprEvaluator(EvalInfo &Info, LValue &Result) :
+    LValueExprEvaluatorBaseTy(Info, Result) {}
+
+  bool VisitVarDecl(const Expr *E, const VarDecl *VD);
+
+  bool VisitDeclRefExpr(const DeclRefExpr *E);
+  bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
+  bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
+  bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
+  bool VisitMemberExpr(const MemberExpr *E);
+  bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
+  bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
+  bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
+  bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
+  bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
+  bool VisitUnaryDeref(const UnaryOperator *E);
+  bool VisitUnaryReal(const UnaryOperator *E);
+  bool VisitUnaryImag(const UnaryOperator *E);
+
+  bool VisitCastExpr(const CastExpr *E) {
+    switch (E->getCastKind()) {
+    default:
+      return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
+
+    case CK_LValueBitCast:
+      this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
+      if (!Visit(E->getSubExpr()))
+        return false;
+      Result.Designator.setInvalid();
+      return true;
+
+    case CK_BaseToDerived:
+      if (!Visit(E->getSubExpr()))
+        return false;
+      return HandleBaseToDerivedCast(Info, E, Result);
+    }
+  }
+};
+} // end anonymous namespace
+
+/// Evaluate an expression as an lvalue. This can be legitimately called on
+/// expressions which are not glvalues, in a few cases:
+///  * function designators in C,
+///  * "extern void" objects,
+///  * temporaries, if building with -Wno-address-of-temporary.
+static bool EvaluateLValue(const Expr* E, LValue& Result, EvalInfo &Info) {
+  assert((E->isGLValue() || E->getType()->isFunctionType() ||
+          E->getType()->isVoidType() || isa<CXXTemporaryObjectExpr>(E)) &&
+         "can't evaluate expression as an lvalue");
+  return LValueExprEvaluator(Info, Result).Visit(E);
+}
+
+bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
+  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl()))
+    return Success(FD);
+  if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
+    return VisitVarDecl(E, VD);
+  return Error(E);
+}
+
+bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
+  if (!VD->getType()->isReferenceType()) {
+    if (isa<ParmVarDecl>(VD)) {
+      Result.set(VD, Info.CurrentCall->Index);
+      return true;
+    }
+    return Success(VD);
+  }
+
+  APValue V;
+  if (!EvaluateVarDeclInit(Info, E, VD, Info.CurrentCall, V))
+    return false;
+  return Success(V, E);
+}
+
+bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
+    const MaterializeTemporaryExpr *E) {
+  if (E->GetTemporaryExpr()->isRValue()) {
+    if (E->getType()->isRecordType())
+      return EvaluateTemporary(E->GetTemporaryExpr(), Result, Info);
+
+    Result.set(E, Info.CurrentCall->Index);
+    return EvaluateInPlace(Info.CurrentCall->Temporaries[E], Info,
+                           Result, E->GetTemporaryExpr());
+  }
+
+  // Materialization of an lvalue temporary occurs when we need to force a copy
+  // (for instance, if it's a bitfield).
+  // FIXME: The AST should contain an lvalue-to-rvalue node for such cases.
+  if (!Visit(E->GetTemporaryExpr()))
+    return false;
+  if (!HandleLValueToRValueConversion(Info, E, E->getType(), Result,
+                                      Info.CurrentCall->Temporaries[E]))
+    return false;
+  Result.set(E, Info.CurrentCall->Index);
+  return true;
+}
+
+bool
+LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
+  assert(!Info.getLangOpts().CPlusPlus && "lvalue compound literal in c++?");
+  // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
+  // only see this when folding in C, so there's no standard to follow here.
+  return Success(E);
+}
+
+bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
+  if (E->isTypeOperand())
+    return Success(E);
+  CXXRecordDecl *RD = E->getExprOperand()->getType()->getAsCXXRecordDecl();
+  if (RD && RD->isPolymorphic()) {
+    Info.Diag(E, diag::note_constexpr_typeid_polymorphic)
+      << E->getExprOperand()->getType()
+      << E->getExprOperand()->getSourceRange();
+    return false;
+  }
+  return Success(E);
+}
+
+bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
+  return Success(E);
+} 
+
+bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
+  // Handle static data members.
+  if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
+    VisitIgnoredValue(E->getBase());
+    return VisitVarDecl(E, VD);
+  }
+
+  // Handle static member functions.
+  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
+    if (MD->isStatic()) {
+      VisitIgnoredValue(E->getBase());
+      return Success(MD);
+    }
+  }
+
+  // Handle non-static data members.
+  return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
+}
+
+bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
+  // FIXME: Deal with vectors as array subscript bases.
+  if (E->getBase()->getType()->isVectorType())
+    return Error(E);
+
+  if (!EvaluatePointer(E->getBase(), Result, Info))
+    return false;
+
+  APSInt Index;
+  if (!EvaluateInteger(E->getIdx(), Index, Info))
+    return false;
+  int64_t IndexValue
+    = Index.isSigned() ? Index.getSExtValue()
+                       : static_cast<int64_t>(Index.getZExtValue());
+
+  return HandleLValueArrayAdjustment(Info, E, Result, E->getType(), IndexValue);
+}
+
+bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
+  return EvaluatePointer(E->getSubExpr(), Result, Info);
+}
+
+bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
+  if (!Visit(E->getSubExpr()))
+    return false;
+  // __real is a no-op on scalar lvalues.
+  if (E->getSubExpr()->getType()->isAnyComplexType())
+    HandleLValueComplexElement(Info, E, Result, E->getType(), false);
+  return true;
+}
+
+bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
+  assert(E->getSubExpr()->getType()->isAnyComplexType() &&
+         "lvalue __imag__ on scalar?");
+  if (!Visit(E->getSubExpr()))
+    return false;
+  HandleLValueComplexElement(Info, E, Result, E->getType(), true);
+  return true;
+}
+
+//===----------------------------------------------------------------------===//
+// Pointer Evaluation
+//===----------------------------------------------------------------------===//
+
+namespace {
+class PointerExprEvaluator
+  : public ExprEvaluatorBase<PointerExprEvaluator, bool> {
+  LValue &Result;
+
+  bool Success(const Expr *E) {
+    Result.set(E);
+    return true;
+  }
+public:
+
+  PointerExprEvaluator(EvalInfo &info, LValue &Result)
+    : ExprEvaluatorBaseTy(info), Result(Result) {}
+
+  bool Success(const APValue &V, const Expr *E) {
+    Result.setFrom(Info.Ctx, V);
+    return true;
+  }
+  bool ZeroInitialization(const Expr *E) {
+    return Success((Expr*)0);
+  }
+
+  bool VisitBinaryOperator(const BinaryOperator *E);
+  bool VisitCastExpr(const CastExpr* E);
+  bool VisitUnaryAddrOf(const UnaryOperator *E);
+  bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
+      { return Success(E); }
+  bool VisitObjCNumericLiteral(const ObjCNumericLiteral *E)
+      { return Success(E); }    
+  bool VisitAddrLabelExpr(const AddrLabelExpr *E)
+      { return Success(E); }
+  bool VisitCallExpr(const CallExpr *E);
+  bool VisitBlockExpr(const BlockExpr *E) {
+    if (!E->getBlockDecl()->hasCaptures())
+      return Success(E);
+    return Error(E);
+  }
+  bool VisitCXXThisExpr(const CXXThisExpr *E) {
+    if (!Info.CurrentCall->This)
+      return Error(E);
+    Result = *Info.CurrentCall->This;
+    return true;
+  }
+
+  // FIXME: Missing: @protocol, @selector
+};
+} // end anonymous namespace
+
+static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->hasPointerRepresentation());
+  return PointerExprEvaluator(Info, Result).Visit(E);
+}
+
+bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
+  if (E->getOpcode() != BO_Add &&
+      E->getOpcode() != BO_Sub)
+    return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
+
+  const Expr *PExp = E->getLHS();
+  const Expr *IExp = E->getRHS();
+  if (IExp->getType()->isPointerType())
+    std::swap(PExp, IExp);
+
+  bool EvalPtrOK = EvaluatePointer(PExp, Result, Info);
+  if (!EvalPtrOK && !Info.keepEvaluatingAfterFailure())
+    return false;
+
+  llvm::APSInt Offset;
+  if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
+    return false;
+  int64_t AdditionalOffset
+    = Offset.isSigned() ? Offset.getSExtValue()
+                        : static_cast<int64_t>(Offset.getZExtValue());
+  if (E->getOpcode() == BO_Sub)
+    AdditionalOffset = -AdditionalOffset;
+
+  QualType Pointee = PExp->getType()->getAs<PointerType>()->getPointeeType();
+  return HandleLValueArrayAdjustment(Info, E, Result, Pointee,
+                                     AdditionalOffset);
+}
+
+bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
+  return EvaluateLValue(E->getSubExpr(), Result, Info);
+}
+
+bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
+  const Expr* SubExpr = E->getSubExpr();
+
+  switch (E->getCastKind()) {
+  default:
+    break;
+
+  case CK_BitCast:
+  case CK_CPointerToObjCPointerCast:
+  case CK_BlockPointerToObjCPointerCast:
+  case CK_AnyPointerToBlockPointerCast:
+    if (!Visit(SubExpr))
+      return false;
+    // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
+    // permitted in constant expressions in C++11. Bitcasts from cv void* are
+    // also static_casts, but we disallow them as a resolution to DR1312.
+    if (!E->getType()->isVoidPointerType()) {
+      Result.Designator.setInvalid();
+      if (SubExpr->getType()->isVoidPointerType())
+        CCEDiag(E, diag::note_constexpr_invalid_cast)
+          << 3 << SubExpr->getType();
+      else
+        CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
+    }
+    return true;
+
+  case CK_DerivedToBase:
+  case CK_UncheckedDerivedToBase: {
+    if (!EvaluatePointer(E->getSubExpr(), Result, Info))
+      return false;
+    if (!Result.Base && Result.Offset.isZero())
+      return true;
+
+    // Now figure out the necessary offset to add to the base LV to get from
+    // the derived class to the base class.
+    QualType Type =
+        E->getSubExpr()->getType()->castAs<PointerType>()->getPointeeType();
+
+    for (CastExpr::path_const_iterator PathI = E->path_begin(),
+         PathE = E->path_end(); PathI != PathE; ++PathI) {
+      if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
+                            *PathI))
+        return false;
+      Type = (*PathI)->getType();
+    }
+
+    return true;
+  }
+
+  case CK_BaseToDerived:
+    if (!Visit(E->getSubExpr()))
+      return false;
+    if (!Result.Base && Result.Offset.isZero())
+      return true;
+    return HandleBaseToDerivedCast(Info, E, Result);
+
+  case CK_NullToPointer:
+    VisitIgnoredValue(E->getSubExpr());
+    return ZeroInitialization(E);
+
+  case CK_IntegralToPointer: {
+    CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
+
+    APValue Value;
+    if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
+      break;
+
+    if (Value.isInt()) {
+      unsigned Size = Info.Ctx.getTypeSize(E->getType());
+      uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
+      Result.Base = (Expr*)0;
+      Result.Offset = CharUnits::fromQuantity(N);
+      Result.CallIndex = 0;
+      Result.Designator.setInvalid();
+      return true;
+    } else {
+      // Cast is of an lvalue, no need to change value.
+      Result.setFrom(Info.Ctx, Value);
+      return true;
+    }
+  }
+  case CK_ArrayToPointerDecay:
+    if (SubExpr->isGLValue()) {
+      if (!EvaluateLValue(SubExpr, Result, Info))
+        return false;
+    } else {
+      Result.set(SubExpr, Info.CurrentCall->Index);
+      if (!EvaluateInPlace(Info.CurrentCall->Temporaries[SubExpr],
+                           Info, Result, SubExpr))
+        return false;
+    }
+    // The result is a pointer to the first element of the array.
+    if (const ConstantArrayType *CAT
+          = Info.Ctx.getAsConstantArrayType(SubExpr->getType()))
+      Result.addArray(Info, E, CAT);
+    else
+      Result.Designator.setInvalid();
+    return true;
+
+  case CK_FunctionToPointerDecay:
+    return EvaluateLValue(SubExpr, Result, Info);
+  }
+
+  return ExprEvaluatorBaseTy::VisitCastExpr(E);
+}
+
+bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
+  if (IsStringLiteralCall(E))
+    return Success(E);
+
+  return ExprEvaluatorBaseTy::VisitCallExpr(E);
+}
+
+//===----------------------------------------------------------------------===//
+// Member Pointer Evaluation
+//===----------------------------------------------------------------------===//
+
+namespace {
+class MemberPointerExprEvaluator
+  : public ExprEvaluatorBase<MemberPointerExprEvaluator, bool> {
+  MemberPtr &Result;
+
+  bool Success(const ValueDecl *D) {
+    Result = MemberPtr(D);
+    return true;
+  }
+public:
+
+  MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
+    : ExprEvaluatorBaseTy(Info), Result(Result) {}
+
+  bool Success(const APValue &V, const Expr *E) {
+    Result.setFrom(V);
+    return true;
+  }
+  bool ZeroInitialization(const Expr *E) {
+    return Success((const ValueDecl*)0);
+  }
+
+  bool VisitCastExpr(const CastExpr *E);
+  bool VisitUnaryAddrOf(const UnaryOperator *E);
+};
+} // end anonymous namespace
+
+static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
+                                  EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isMemberPointerType());
+  return MemberPointerExprEvaluator(Info, Result).Visit(E);
+}
+
+bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
+  switch (E->getCastKind()) {
+  default:
+    return ExprEvaluatorBaseTy::VisitCastExpr(E);
+
+  case CK_NullToMemberPointer:
+    VisitIgnoredValue(E->getSubExpr());
+    return ZeroInitialization(E);
+
+  case CK_BaseToDerivedMemberPointer: {
+    if (!Visit(E->getSubExpr()))
+      return false;
+    if (E->path_empty())
+      return true;
+    // Base-to-derived member pointer casts store the path in derived-to-base
+    // order, so iterate backwards. The CXXBaseSpecifier also provides us with
+    // the wrong end of the derived->base arc, so stagger the path by one class.
+    typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
+    for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
+         PathI != PathE; ++PathI) {
+      assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
+      const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
+      if (!Result.castToDerived(Derived))
+        return Error(E);
+    }
+    const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
+    if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
+      return Error(E);
+    return true;
+  }
+
+  case CK_DerivedToBaseMemberPointer:
+    if (!Visit(E->getSubExpr()))
+      return false;
+    for (CastExpr::path_const_iterator PathI = E->path_begin(),
+         PathE = E->path_end(); PathI != PathE; ++PathI) {
+      assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
+      const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
+      if (!Result.castToBase(Base))
+        return Error(E);
+    }
+    return true;
+  }
+}
+
+bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
+  // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
+  // member can be formed.
+  return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
+}
+
+//===----------------------------------------------------------------------===//
+// Record Evaluation
+//===----------------------------------------------------------------------===//
+
+namespace {
+  class RecordExprEvaluator
+  : public ExprEvaluatorBase<RecordExprEvaluator, bool> {
+    const LValue &This;
+    APValue &Result;
+  public:
+
+    RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
+      : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
+
+    bool Success(const APValue &V, const Expr *E) {
+      Result = V;
+      return true;
+    }
+    bool ZeroInitialization(const Expr *E);
+
+    bool VisitCastExpr(const CastExpr *E);
+    bool VisitInitListExpr(const InitListExpr *E);
+    bool VisitCXXConstructExpr(const CXXConstructExpr *E);
+  };
+}
+
+/// Perform zero-initialization on an object of non-union class type.
+/// C++11 [dcl.init]p5:
+///  To zero-initialize an object or reference of type T means:
+///    [...]
+///    -- if T is a (possibly cv-qualified) non-union class type,
+///       each non-static data member and each base-class subobject is
+///       zero-initialized
+static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
+                                          const RecordDecl *RD,
+                                          const LValue &This, APValue &Result) {
+  assert(!RD->isUnion() && "Expected non-union class type");
+  const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
+  Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
+                   std::distance(RD->field_begin(), RD->field_end()));
+
+  const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
+
+  if (CD) {
+    unsigned Index = 0;
+    for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
+           End = CD->bases_end(); I != End; ++I, ++Index) {
+      const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
+      LValue Subobject = This;
+      HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout);
+      if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
+                                         Result.getStructBase(Index)))
+        return false;
+    }
+  }
+
+  for (RecordDecl::field_iterator I = RD->field_begin(), End = RD->field_end();
+       I != End; ++I) {
+    // -- if T is a reference type, no initialization is performed.
+    if ((*I)->getType()->isReferenceType())
+      continue;
+
+    LValue Subobject = This;
+    HandleLValueMember(Info, E, Subobject, *I, &Layout);
+
+    ImplicitValueInitExpr VIE((*I)->getType());
+    if (!EvaluateInPlace(
+          Result.getStructField((*I)->getFieldIndex()), Info, Subobject, &VIE))
+      return false;
+  }
+
+  return true;
+}
+
+bool RecordExprEvaluator::ZeroInitialization(const Expr *E) {
+  const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
+  if (RD->isUnion()) {
+    // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
+    // object's first non-static named data member is zero-initialized
+    RecordDecl::field_iterator I = RD->field_begin();
+    if (I == RD->field_end()) {
+      Result = APValue((const FieldDecl*)0);
+      return true;
+    }
+
+    LValue Subobject = This;
+    HandleLValueMember(Info, E, Subobject, *I);
+    Result = APValue(*I);
+    ImplicitValueInitExpr VIE((*I)->getType());
+    return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
+  }
+
+  if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
+    Info.Diag(E, diag::note_constexpr_virtual_base) << RD;
+    return false;
+  }
+
+  return HandleClassZeroInitialization(Info, E, RD, This, Result);
+}
+
+bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
+  switch (E->getCastKind()) {
+  default:
+    return ExprEvaluatorBaseTy::VisitCastExpr(E);
+
+  case CK_ConstructorConversion:
+    return Visit(E->getSubExpr());
+
+  case CK_DerivedToBase:
+  case CK_UncheckedDerivedToBase: {
+    APValue DerivedObject;
+    if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
+      return false;
+    if (!DerivedObject.isStruct())
+      return Error(E->getSubExpr());
+
+    // Derived-to-base rvalue conversion: just slice off the derived part.
+    APValue *Value = &DerivedObject;
+    const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
+    for (CastExpr::path_const_iterator PathI = E->path_begin(),
+         PathE = E->path_end(); PathI != PathE; ++PathI) {
+      assert(!(*PathI)->isVirtual() && "record rvalue with virtual base");
+      const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
+      Value = &Value->getStructBase(getBaseIndex(RD, Base));
+      RD = Base;
+    }
+    Result = *Value;
+    return true;
+  }
+  }
+}
+
+bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
+  // Cannot constant-evaluate std::initializer_list inits.
+  if (E->initializesStdInitializerList())
+    return false;
+
+  const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
+  const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
+
+  if (RD->isUnion()) {
+    const FieldDecl *Field = E->getInitializedFieldInUnion();
+    Result = APValue(Field);
+    if (!Field)
+      return true;
+
+    // If the initializer list for a union does not contain any elements, the
+    // first element of the union is value-initialized.
+    ImplicitValueInitExpr VIE(Field->getType());
+    const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;
+
+    LValue Subobject = This;
+    HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout);
+    return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr);
+  }
+
+  assert((!isa<CXXRecordDecl>(RD) || !cast<CXXRecordDecl>(RD)->getNumBases()) &&
+         "initializer list for class with base classes");
+  Result = APValue(APValue::UninitStruct(), 0,
+                   std::distance(RD->field_begin(), RD->field_end()));
+  unsigned ElementNo = 0;
+  bool Success = true;
+  for (RecordDecl::field_iterator Field = RD->field_begin(),
+       FieldEnd = RD->field_end(); Field != FieldEnd; ++Field) {
+    // Anonymous bit-fields are not considered members of the class for
+    // purposes of aggregate initialization.
+    if (Field->isUnnamedBitfield())
+      continue;
+
+    LValue Subobject = This;
+
+    bool HaveInit = ElementNo < E->getNumInits();
+
+    // FIXME: Diagnostics here should point to the end of the initializer
+    // list, not the start.
+    HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E, Subobject,
+                       *Field, &Layout);
+
+    // Perform an implicit value-initialization for members beyond the end of
+    // the initializer list.
+    ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
+
+    if (!EvaluateInPlace(
+          Result.getStructField((*Field)->getFieldIndex()),
+          Info, Subobject, HaveInit ? E->getInit(ElementNo++) : &VIE)) {
+      if (!Info.keepEvaluatingAfterFailure())
+        return false;
+      Success = false;
+    }
+  }
+
+  return Success;
+}
+
+bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
+  const CXXConstructorDecl *FD = E->getConstructor();
+  bool ZeroInit = E->requiresZeroInitialization();
+  if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
+    // If we've already performed zero-initialization, we're already done.
+    if (!Result.isUninit())
+      return true;
+
+    if (ZeroInit)
+      return ZeroInitialization(E);
+
+    const CXXRecordDecl *RD = FD->getParent();
+    if (RD->isUnion())
+      Result = APValue((FieldDecl*)0);
+    else
+      Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
+                       std::distance(RD->field_begin(), RD->field_end()));
+    return true;
+  }
+
+  const FunctionDecl *Definition = 0;
+  FD->getBody(Definition);
+
+  if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition))
+    return false;
+
+  // Avoid materializing a temporary for an elidable copy/move constructor.
+  if (E->isElidable() && !ZeroInit)
+    if (const MaterializeTemporaryExpr *ME
+          = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0)))
+      return Visit(ME->GetTemporaryExpr());
+
+  if (ZeroInit && !ZeroInitialization(E))
+    return false;
+
+  llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs());
+  return HandleConstructorCall(E->getExprLoc(), This, Args,
+                               cast<CXXConstructorDecl>(Definition), Info,
+                               Result);
+}
+
+static bool EvaluateRecord(const Expr *E, const LValue &This,
+                           APValue &Result, EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isRecordType() &&
+         "can't evaluate expression as a record rvalue");
+  return RecordExprEvaluator(Info, This, Result).Visit(E);
+}
+
+//===----------------------------------------------------------------------===//
+// Temporary Evaluation
+//
+// Temporaries are represented in the AST as rvalues, but generally behave like
+// lvalues. The full-object of which the temporary is a subobject is implicitly
+// materialized so that a reference can bind to it.
+//===----------------------------------------------------------------------===//
+namespace {
+class TemporaryExprEvaluator
+  : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
+public:
+  TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
+    LValueExprEvaluatorBaseTy(Info, Result) {}
+
+  /// Visit an expression which constructs the value of this temporary.
+  bool VisitConstructExpr(const Expr *E) {
+    Result.set(E, Info.CurrentCall->Index);
+    return EvaluateInPlace(Info.CurrentCall->Temporaries[E], Info, Result, E);
+  }
+
+  bool VisitCastExpr(const CastExpr *E) {
+    switch (E->getCastKind()) {
+    default:
+      return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
+
+    case CK_ConstructorConversion:
+      return VisitConstructExpr(E->getSubExpr());
+    }
+  }
+  bool VisitInitListExpr(const InitListExpr *E) {
+    return VisitConstructExpr(E);
+  }
+  bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
+    return VisitConstructExpr(E);
+  }
+  bool VisitCallExpr(const CallExpr *E) {
+    return VisitConstructExpr(E);
+  }
+};
+} // end anonymous namespace
+
+/// Evaluate an expression of record type as a temporary.
+static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isRecordType());
+  return TemporaryExprEvaluator(Info, Result).Visit(E);
+}
+
+//===----------------------------------------------------------------------===//
+// Vector Evaluation
+//===----------------------------------------------------------------------===//
+
+namespace {
+  class VectorExprEvaluator
+  : public ExprEvaluatorBase<VectorExprEvaluator, bool> {
+    APValue &Result;
+  public:
+
+    VectorExprEvaluator(EvalInfo &info, APValue &Result)
+      : ExprEvaluatorBaseTy(info), Result(Result) {}
+
+    bool Success(const ArrayRef<APValue> &V, const Expr *E) {
+      assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements());
+      // FIXME: remove this APValue copy.
+      Result = APValue(V.data(), V.size());
+      return true;
+    }
+    bool Success(const APValue &V, const Expr *E) {
+      assert(V.isVector());
+      Result = V;
+      return true;
+    }
+    bool ZeroInitialization(const Expr *E);
+
+    bool VisitUnaryReal(const UnaryOperator *E)
+      { return Visit(E->getSubExpr()); }
+    bool VisitCastExpr(const CastExpr* E);
+    bool VisitInitListExpr(const InitListExpr *E);
+    bool VisitUnaryImag(const UnaryOperator *E);
+    // FIXME: Missing: unary -, unary ~, binary add/sub/mul/div,
+    //                 binary comparisons, binary and/or/xor,
+    //                 shufflevector, ExtVectorElementExpr
+  };
+} // end anonymous namespace
+
+static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue");
+  return VectorExprEvaluator(Info, Result).Visit(E);
+}
+
+bool VectorExprEvaluator::VisitCastExpr(const CastExpr* E) {
+  const VectorType *VTy = E->getType()->castAs<VectorType>();
+  unsigned NElts = VTy->getNumElements();
+
+  const Expr *SE = E->getSubExpr();
+  QualType SETy = SE->getType();
+
+  switch (E->getCastKind()) {
+  case CK_VectorSplat: {
+    APValue Val = APValue();
+    if (SETy->isIntegerType()) {
+      APSInt IntResult;
+      if (!EvaluateInteger(SE, IntResult, Info))
+         return false;
+      Val = APValue(IntResult);
+    } else if (SETy->isRealFloatingType()) {
+       APFloat F(0.0);
+       if (!EvaluateFloat(SE, F, Info))
+         return false;
+       Val = APValue(F);
+    } else {
+      return Error(E);
+    }
+
+    // Splat and create vector APValue.
+    SmallVector<APValue, 4> Elts(NElts, Val);
+    return Success(Elts, E);
+  }
+  case CK_BitCast: {
+    // Evaluate the operand into an APInt we can extract from.
+    llvm::APInt SValInt;
+    if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
+      return false;
+    // Extract the elements
+    QualType EltTy = VTy->getElementType();
+    unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
+    bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
+    SmallVector<APValue, 4> Elts;
+    if (EltTy->isRealFloatingType()) {
+      const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
+      bool isIEESem = &Sem != &APFloat::PPCDoubleDouble;
+      unsigned FloatEltSize = EltSize;
+      if (&Sem == &APFloat::x87DoubleExtended)
+        FloatEltSize = 80;
+      for (unsigned i = 0; i < NElts; i++) {
+        llvm::APInt Elt;
+        if (BigEndian)
+          Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
+        else
+          Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
+        Elts.push_back(APValue(APFloat(Elt, isIEESem)));
+      }
+    } else if (EltTy->isIntegerType()) {
+      for (unsigned i = 0; i < NElts; i++) {
+        llvm::APInt Elt;
+        if (BigEndian)
+          Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
+        else
+          Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
+        Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType())));
+      }
+    } else {
+      return Error(E);
+    }
+    return Success(Elts, E);
+  }
+  default:
+    return ExprEvaluatorBaseTy::VisitCastExpr(E);
+  }
+}
+
+bool
+VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
+  const VectorType *VT = E->getType()->castAs<VectorType>();
+  unsigned NumInits = E->getNumInits();
+  unsigned NumElements = VT->getNumElements();
+
+  QualType EltTy = VT->getElementType();
+  SmallVector<APValue, 4> Elements;
+
+  // The number of initializers can be less than the number of
+  // vector elements. For OpenCL, this can be due to nested vector
+  // initialization. For GCC compatibility, missing trailing elements 
+  // should be initialized with zeroes.
+  unsigned CountInits = 0, CountElts = 0;
+  while (CountElts < NumElements) {
+    // Handle nested vector initialization.
+    if (CountInits < NumInits 
+        && E->getInit(CountInits)->getType()->isExtVectorType()) {
+      APValue v;
+      if (!EvaluateVector(E->getInit(CountInits), v, Info))
+        return Error(E);
+      unsigned vlen = v.getVectorLength();
+      for (unsigned j = 0; j < vlen; j++) 
+        Elements.push_back(v.getVectorElt(j));
+      CountElts += vlen;
+    } else if (EltTy->isIntegerType()) {
+      llvm::APSInt sInt(32);
+      if (CountInits < NumInits) {
+        if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
+          return false;
+      } else // trailing integer zero.
+        sInt = Info.Ctx.MakeIntValue(0, EltTy);
+      Elements.push_back(APValue(sInt));
+      CountElts++;
+    } else {
+      llvm::APFloat f(0.0);
+      if (CountInits < NumInits) {
+        if (!EvaluateFloat(E->getInit(CountInits), f, Info))
+          return false;
+      } else // trailing float zero.
+        f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
+      Elements.push_back(APValue(f));
+      CountElts++;
+    }
+    CountInits++;
+  }
+  return Success(Elements, E);
+}
+
+bool
+VectorExprEvaluator::ZeroInitialization(const Expr *E) {
+  const VectorType *VT = E->getType()->getAs<VectorType>();
+  QualType EltTy = VT->getElementType();
+  APValue ZeroElement;
+  if (EltTy->isIntegerType())
+    ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
+  else
+    ZeroElement =
+        APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
+
+  SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
+  return Success(Elements, E);
+}
+
+bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
+  VisitIgnoredValue(E->getSubExpr());
+  return ZeroInitialization(E);
+}
+
+//===----------------------------------------------------------------------===//
+// Array Evaluation
+//===----------------------------------------------------------------------===//
+
+namespace {
+  class ArrayExprEvaluator
+  : public ExprEvaluatorBase<ArrayExprEvaluator, bool> {
+    const LValue &This;
+    APValue &Result;
+  public:
+
+    ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
+      : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
+
+    bool Success(const APValue &V, const Expr *E) {
+      assert((V.isArray() || V.isLValue()) &&
+             "expected array or string literal");
+      Result = V;
+      return true;
+    }
+
+    bool ZeroInitialization(const Expr *E) {
+      const ConstantArrayType *CAT =
+          Info.Ctx.getAsConstantArrayType(E->getType());
+      if (!CAT)
+        return Error(E);
+
+      Result = APValue(APValue::UninitArray(), 0,
+                       CAT->getSize().getZExtValue());
+      if (!Result.hasArrayFiller()) return true;
+
+      // Zero-initialize all elements.
+      LValue Subobject = This;
+      Subobject.addArray(Info, E, CAT);
+      ImplicitValueInitExpr VIE(CAT->getElementType());
+      return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
+    }
+
+    bool VisitInitListExpr(const InitListExpr *E);
+    bool VisitCXXConstructExpr(const CXXConstructExpr *E);
+  };
+} // end anonymous namespace
+
+static bool EvaluateArray(const Expr *E, const LValue &This,
+                          APValue &Result, EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue");
+  return ArrayExprEvaluator(Info, This, Result).Visit(E);
+}
+
+bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
+  const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType());
+  if (!CAT)
+    return Error(E);
+
+  // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
+  // an appropriately-typed string literal enclosed in braces.
+  if (E->isStringLiteralInit()) {
+    LValue LV;
+    if (!EvaluateLValue(E->getInit(0), LV, Info))
+      return false;
+    APValue Val;
+    LV.moveInto(Val);
+    return Success(Val, E);
+  }
+
+  bool Success = true;
+
+  Result = APValue(APValue::UninitArray(), E->getNumInits(),
+                   CAT->getSize().getZExtValue());
+  LValue Subobject = This;
+  Subobject.addArray(Info, E, CAT);
+  unsigned Index = 0;
+  for (InitListExpr::const_iterator I = E->begin(), End = E->end();
+       I != End; ++I, ++Index) {
+    if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
+                         Info, Subobject, cast<Expr>(*I)) ||
+        !HandleLValueArrayAdjustment(Info, cast<Expr>(*I), Subobject,
+                                     CAT->getElementType(), 1)) {
+      if (!Info.keepEvaluatingAfterFailure())
+        return false;
+      Success = false;
+    }
+  }
+
+  if (!Result.hasArrayFiller()) return Success;
+  assert(E->hasArrayFiller() && "no array filler for incomplete init list");
+  // FIXME: The Subobject here isn't necessarily right. This rarely matters,
+  // but sometimes does:
+  //   struct S { constexpr S() : p(&p) {} void *p; };
+  //   S s[10] = {};
+  return EvaluateInPlace(Result.getArrayFiller(), Info,
+                         Subobject, E->getArrayFiller()) && Success;
+}
+
+bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
+  const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType());
+  if (!CAT)
+    return Error(E);
+
+  bool HadZeroInit = !Result.isUninit();
+  if (!HadZeroInit)
+    Result = APValue(APValue::UninitArray(), 0, CAT->getSize().getZExtValue());
+  if (!Result.hasArrayFiller())
+    return true;
+
+  const CXXConstructorDecl *FD = E->getConstructor();
+
+  bool ZeroInit = E->requiresZeroInitialization();
+  if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
+    if (HadZeroInit)
+      return true;
+
+    if (ZeroInit) {
+      LValue Subobject = This;
+      Subobject.addArray(Info, E, CAT);
+      ImplicitValueInitExpr VIE(CAT->getElementType());
+      return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
+    }
+
+    const CXXRecordDecl *RD = FD->getParent();
+    if (RD->isUnion())
+      Result.getArrayFiller() = APValue((FieldDecl*)0);
+    else
+      Result.getArrayFiller() =
+          APValue(APValue::UninitStruct(), RD->getNumBases(),
+                  std::distance(RD->field_begin(), RD->field_end()));
+    return true;
+  }
+
+  const FunctionDecl *Definition = 0;
+  FD->getBody(Definition);
+
+  if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition))
+    return false;
+
+  // FIXME: The Subobject here isn't necessarily right. This rarely matters,
+  // but sometimes does:
+  //   struct S { constexpr S() : p(&p) {} void *p; };
+  //   S s[10];
+  LValue Subobject = This;
+  Subobject.addArray(Info, E, CAT);
+
+  if (ZeroInit && !HadZeroInit) {
+    ImplicitValueInitExpr VIE(CAT->getElementType());
+    if (!EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE))
+      return false;
+  }
+
+  llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs());
+  return HandleConstructorCall(E->getExprLoc(), Subobject, Args,
+                               cast<CXXConstructorDecl>(Definition),
+                               Info, Result.getArrayFiller());
+}
+
+//===----------------------------------------------------------------------===//
+// Integer Evaluation
+//
+// As a GNU extension, we support casting pointers to sufficiently-wide integer
+// types and back in constant folding. Integer values are thus represented
+// either as an integer-valued APValue, or as an lvalue-valued APValue.
+//===----------------------------------------------------------------------===//
+
+namespace {
+class IntExprEvaluator
+  : public ExprEvaluatorBase<IntExprEvaluator, bool> {
+  APValue &Result;
+public:
+  IntExprEvaluator(EvalInfo &info, APValue &result)
+    : ExprEvaluatorBaseTy(info), Result(result) {}
+
+  bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
+    assert(E->getType()->isIntegralOrEnumerationType() &&
+           "Invalid evaluation result.");
+    assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
+           "Invalid evaluation result.");
+    assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
+           "Invalid evaluation result.");
+    Result = APValue(SI);
+    return true;
+  }
+  bool Success(const llvm::APSInt &SI, const Expr *E) {
+    return Success(SI, E, Result);
+  }
+
+  bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
+    assert(E->getType()->isIntegralOrEnumerationType() && 
+           "Invalid evaluation result.");
+    assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
+           "Invalid evaluation result.");
+    Result = APValue(APSInt(I));
+    Result.getInt().setIsUnsigned(
+                            E->getType()->isUnsignedIntegerOrEnumerationType());
+    return true;
+  }
+  bool Success(const llvm::APInt &I, const Expr *E) {
+    return Success(I, E, Result);
+  }
+
+  bool Success(uint64_t Value, const Expr *E, APValue &Result) {
+    assert(E->getType()->isIntegralOrEnumerationType() && 
+           "Invalid evaluation result.");
+    Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
+    return true;
+  }
+  bool Success(uint64_t Value, const Expr *E) {
+    return Success(Value, E, Result);
+  }
+
+  bool Success(CharUnits Size, const Expr *E) {
+    return Success(Size.getQuantity(), E);
+  }
+
+  bool Success(const APValue &V, const Expr *E) {
+    if (V.isLValue() || V.isAddrLabelDiff()) {
+      Result = V;
+      return true;
+    }
+    return Success(V.getInt(), E);
+  }
+
+  bool ZeroInitialization(const Expr *E) { return Success(0, E); }
+
+  //===--------------------------------------------------------------------===//
+  //                            Visitor Methods
+  //===--------------------------------------------------------------------===//
+
+  bool VisitIntegerLiteral(const IntegerLiteral *E) {
+    return Success(E->getValue(), E);
+  }
+  bool VisitCharacterLiteral(const CharacterLiteral *E) {
+    return Success(E->getValue(), E);
+  }
+
+  bool CheckReferencedDecl(const Expr *E, const Decl *D);
+  bool VisitDeclRefExpr(const DeclRefExpr *E) {
+    if (CheckReferencedDecl(E, E->getDecl()))
+      return true;
+
+    return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
+  }
+  bool VisitMemberExpr(const MemberExpr *E) {
+    if (CheckReferencedDecl(E, E->getMemberDecl())) {
+      VisitIgnoredValue(E->getBase());
+      return true;
+    }
+
+    return ExprEvaluatorBaseTy::VisitMemberExpr(E);
+  }
+
+  bool VisitCallExpr(const CallExpr *E);
+  bool VisitBinaryOperator(const BinaryOperator *E);
+  bool VisitOffsetOfExpr(const OffsetOfExpr *E);
+  bool VisitUnaryOperator(const UnaryOperator *E);
+
+  bool VisitCastExpr(const CastExpr* E);
+  bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
+
+  bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
+    return Success(E->getValue(), E);
+  }
+
+  bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
+    return Success(E->getValue(), E);
+  }
+    
+  // Note, GNU defines __null as an integer, not a pointer.
+  bool VisitGNUNullExpr(const GNUNullExpr *E) {
+    return ZeroInitialization(E);
+  }
+
+  bool VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr *E) {
+    return Success(E->getValue(), E);
+  }
+
+  bool VisitBinaryTypeTraitExpr(const BinaryTypeTraitExpr *E) {
+    return Success(E->getValue(), E);
+  }
+
+  bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
+    return Success(E->getValue(), E);
+  }
+
+  bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
+    return Success(E->getValue(), E);
+  }
+
+  bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
+    return Success(E->getValue(), E);
+  }
+
+  bool VisitUnaryReal(const UnaryOperator *E);
+  bool VisitUnaryImag(const UnaryOperator *E);
+
+  bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
+  bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
+
+private:
+  CharUnits GetAlignOfExpr(const Expr *E);
+  CharUnits GetAlignOfType(QualType T);
+  static QualType GetObjectType(APValue::LValueBase B);
+  bool TryEvaluateBuiltinObjectSize(const CallExpr *E);
+  // FIXME: Missing: array subscript of vector, member of vector
+};
+} // end anonymous namespace
+
+/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
+/// produce either the integer value or a pointer.
+///
+/// GCC has a heinous extension which folds casts between pointer types and
+/// pointer-sized integral types. We support this by allowing the evaluation of
+/// an integer rvalue to produce a pointer (represented as an lvalue) instead.
+/// Some simple arithmetic on such values is supported (they are treated much
+/// like char*).
+static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
+                                    EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType());
+  return IntExprEvaluator(Info, Result).Visit(E);
+}
+
+static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
+  APValue Val;
+  if (!EvaluateIntegerOrLValue(E, Val, Info))
+    return false;
+  if (!Val.isInt()) {
+    // FIXME: It would be better to produce the diagnostic for casting
+    //        a pointer to an integer.
+    Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+    return false;
+  }
+  Result = Val.getInt();
+  return true;
+}
+
+/// Check whether the given declaration can be directly converted to an integral
+/// rvalue. If not, no diagnostic is produced; there are other things we can
+/// try.
+bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
+  // Enums are integer constant exprs.
+  if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
+    // Check for signedness/width mismatches between E type and ECD value.
+    bool SameSign = (ECD->getInitVal().isSigned()
+                     == E->getType()->isSignedIntegerOrEnumerationType());
+    bool SameWidth = (ECD->getInitVal().getBitWidth()
+                      == Info.Ctx.getIntWidth(E->getType()));
+    if (SameSign && SameWidth)
+      return Success(ECD->getInitVal(), E);
+    else {
+      // Get rid of mismatch (otherwise Success assertions will fail)
+      // by computing a new value matching the type of E.
+      llvm::APSInt Val = ECD->getInitVal();
+      if (!SameSign)
+        Val.setIsSigned(!ECD->getInitVal().isSigned());
+      if (!SameWidth)
+        Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
+      return Success(Val, E);
+    }
+  }
+  return false;
+}
+
+/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
+/// as GCC.
+static int EvaluateBuiltinClassifyType(const CallExpr *E) {
+  // The following enum mimics the values returned by GCC.
+  // FIXME: Does GCC differ between lvalue and rvalue references here?
+  enum gcc_type_class {
+    no_type_class = -1,
+    void_type_class, integer_type_class, char_type_class,
+    enumeral_type_class, boolean_type_class,
+    pointer_type_class, reference_type_class, offset_type_class,
+    real_type_class, complex_type_class,
+    function_type_class, method_type_class,
+    record_type_class, union_type_class,
+    array_type_class, string_type_class,
+    lang_type_class
+  };
+
+  // If no argument was supplied, default to "no_type_class". This isn't
+  // ideal, however it is what gcc does.
+  if (E->getNumArgs() == 0)
+    return no_type_class;
+
+  QualType ArgTy = E->getArg(0)->getType();
+  if (ArgTy->isVoidType())
+    return void_type_class;
+  else if (ArgTy->isEnumeralType())
+    return enumeral_type_class;
+  else if (ArgTy->isBooleanType())
+    return boolean_type_class;
+  else if (ArgTy->isCharType())
+    return string_type_class; // gcc doesn't appear to use char_type_class
+  else if (ArgTy->isIntegerType())
+    return integer_type_class;
+  else if (ArgTy->isPointerType())
+    return pointer_type_class;
+  else if (ArgTy->isReferenceType())
+    return reference_type_class;
+  else if (ArgTy->isRealType())
+    return real_type_class;
+  else if (ArgTy->isComplexType())
+    return complex_type_class;
+  else if (ArgTy->isFunctionType())
+    return function_type_class;
+  else if (ArgTy->isStructureOrClassType())
+    return record_type_class;
+  else if (ArgTy->isUnionType())
+    return union_type_class;
+  else if (ArgTy->isArrayType())
+    return array_type_class;
+  else if (ArgTy->isUnionType())
+    return union_type_class;
+  else  // FIXME: offset_type_class, method_type_class, & lang_type_class?
+    llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
+}
+
+/// EvaluateBuiltinConstantPForLValue - Determine the result of
+/// __builtin_constant_p when applied to the given lvalue.
+///
+/// An lvalue is only "constant" if it is a pointer or reference to the first
+/// character of a string literal.
+template<typename LValue>
+static bool EvaluateBuiltinConstantPForLValue(const LValue &LV) {
+  const Expr *E = LV.getLValueBase().template dyn_cast<const Expr*>();
+  return E && isa<StringLiteral>(E) && LV.getLValueOffset().isZero();
+}
+
+/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
+/// GCC as we can manage.
+static bool EvaluateBuiltinConstantP(ASTContext &Ctx, const Expr *Arg) {
+  QualType ArgType = Arg->getType();
+
+  // __builtin_constant_p always has one operand. The rules which gcc follows
+  // are not precisely documented, but are as follows:
+  //
+  //  - If the operand is of integral, floating, complex or enumeration type,
+  //    and can be folded to a known value of that type, it returns 1.
+  //  - If the operand and can be folded to a pointer to the first character
+  //    of a string literal (or such a pointer cast to an integral type), it
+  //    returns 1.
+  //
+  // Otherwise, it returns 0.
+  //
+  // FIXME: GCC also intends to return 1 for literals of aggregate types, but
+  // its support for this does not currently work.
+  if (ArgType->isIntegralOrEnumerationType()) {
+    Expr::EvalResult Result;
+    if (!Arg->EvaluateAsRValue(Result, Ctx) || Result.HasSideEffects)
+      return false;
+
+    APValue &V = Result.Val;
+    if (V.getKind() == APValue::Int)
+      return true;
+
+    return EvaluateBuiltinConstantPForLValue(V);
+  } else if (ArgType->isFloatingType() || ArgType->isAnyComplexType()) {
+    return Arg->isEvaluatable(Ctx);
+  } else if (ArgType->isPointerType() || Arg->isGLValue()) {
+    LValue LV;
+    Expr::EvalStatus Status;
+    EvalInfo Info(Ctx, Status);
+    if ((Arg->isGLValue() ? EvaluateLValue(Arg, LV, Info)
+                          : EvaluatePointer(Arg, LV, Info)) &&
+        !Status.HasSideEffects)
+      return EvaluateBuiltinConstantPForLValue(LV);
+  }
+
+  // Anything else isn't considered to be sufficiently constant.
+  return false;
+}
+
+/// Retrieves the "underlying object type" of the given expression,
+/// as used by __builtin_object_size.
+QualType IntExprEvaluator::GetObjectType(APValue::LValueBase B) {
+  if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
+    if (const VarDecl *VD = dyn_cast<VarDecl>(D))
+      return VD->getType();
+  } else if (const Expr *E = B.get<const Expr*>()) {
+    if (isa<CompoundLiteralExpr>(E))
+      return E->getType();
+  }
+
+  return QualType();
+}
+
+bool IntExprEvaluator::TryEvaluateBuiltinObjectSize(const CallExpr *E) {
+  // TODO: Perhaps we should let LLVM lower this?
+  LValue Base;
+  if (!EvaluatePointer(E->getArg(0), Base, Info))
+    return false;
+
+  // If we can prove the base is null, lower to zero now.
+  if (!Base.getLValueBase()) return Success(0, E);
+
+  QualType T = GetObjectType(Base.getLValueBase());
+  if (T.isNull() ||
+      T->isIncompleteType() ||
+      T->isFunctionType() ||
+      T->isVariablyModifiedType() ||
+      T->isDependentType())
+    return Error(E);
+
+  CharUnits Size = Info.Ctx.getTypeSizeInChars(T);
+  CharUnits Offset = Base.getLValueOffset();
+
+  if (!Offset.isNegative() && Offset <= Size)
+    Size -= Offset;
+  else
+    Size = CharUnits::Zero();
+  return Success(Size, E);
+}
+
+bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
+  switch (unsigned BuiltinOp = E->isBuiltinCall()) {
+  default:
+    return ExprEvaluatorBaseTy::VisitCallExpr(E);
+
+  case Builtin::BI__builtin_object_size: {
+    if (TryEvaluateBuiltinObjectSize(E))
+      return true;
+
+    // If evaluating the argument has side-effects we can't determine
+    // the size of the object and lower it to unknown now.
+    if (E->getArg(0)->HasSideEffects(Info.Ctx)) {
+      if (E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue() <= 1)
+        return Success(-1ULL, E);
+      return Success(0, E);
+    }
+
+    return Error(E);
+  }
+
+  case Builtin::BI__builtin_classify_type:
+    return Success(EvaluateBuiltinClassifyType(E), E);
+
+  case Builtin::BI__builtin_constant_p:
+    return Success(EvaluateBuiltinConstantP(Info.Ctx, E->getArg(0)), E);
+
+  case Builtin::BI__builtin_eh_return_data_regno: {
+    int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
+    Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
+    return Success(Operand, E);
+  }
+
+  case Builtin::BI__builtin_expect:
+    return Visit(E->getArg(0));
+
+  case Builtin::BIstrlen:
+    // A call to strlen is not a constant expression.
+    if (Info.getLangOpts().CPlusPlus0x)
+      Info.CCEDiag(E, diag::note_constexpr_invalid_function)
+        << /*isConstexpr*/0 << /*isConstructor*/0 << "'strlen'";
+    else
+      Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
+    // Fall through.
+  case Builtin::BI__builtin_strlen:
+    // As an extension, we support strlen() and __builtin_strlen() as constant
+    // expressions when the argument is a string literal.
+    if (const StringLiteral *S
+               = dyn_cast<StringLiteral>(E->getArg(0)->IgnoreParenImpCasts())) {
+      // The string literal may have embedded null characters. Find the first
+      // one and truncate there.
+      StringRef Str = S->getString();
+      StringRef::size_type Pos = Str.find(0);
+      if (Pos != StringRef::npos)
+        Str = Str.substr(0, Pos);
+      
+      return Success(Str.size(), E);
+    }
+      
+    return Error(E);
+
+  case Builtin::BI__atomic_always_lock_free:
+  case Builtin::BI__atomic_is_lock_free:
+  case Builtin::BI__c11_atomic_is_lock_free: {
+    APSInt SizeVal;
+    if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
+      return false;
+
+    // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
+    // of two less than the maximum inline atomic width, we know it is
+    // lock-free.  If the size isn't a power of two, or greater than the
+    // maximum alignment where we promote atomics, we know it is not lock-free
+    // (at least not in the sense of atomic_is_lock_free).  Otherwise,
+    // the answer can only be determined at runtime; for example, 16-byte
+    // atomics have lock-free implementations on some, but not all,
+    // x86-64 processors.
+
+    // Check power-of-two.
+    CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
+    if (Size.isPowerOfTwo()) {
+      // Check against inlining width.
+      unsigned InlineWidthBits =
+          Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
+      if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
+        if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
+            Size == CharUnits::One() ||
+            E->getArg(1)->isNullPointerConstant(Info.Ctx,
+                                                Expr::NPC_NeverValueDependent))
+          // OK, we will inline appropriately-aligned operations of this size,
+          // and _Atomic(T) is appropriately-aligned.
+          return Success(1, E);
+
+        QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
+          castAs<PointerType>()->getPointeeType();
+        if (!PointeeType->isIncompleteType() &&
+            Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
+          // OK, we will inline operations on this object.
+          return Success(1, E);
+        }
+      }
+    }
+
+    return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
+        Success(0, E) : Error(E);
+  }
+  }
+}
+
+static bool HasSameBase(const LValue &A, const LValue &B) {
+  if (!A.getLValueBase())
+    return !B.getLValueBase();
+  if (!B.getLValueBase())
+    return false;
+
+  if (A.getLValueBase().getOpaqueValue() !=
+      B.getLValueBase().getOpaqueValue()) {
+    const Decl *ADecl = GetLValueBaseDecl(A);
+    if (!ADecl)
+      return false;
+    const Decl *BDecl = GetLValueBaseDecl(B);
+    if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl())
+      return false;
+  }
+
+  return IsGlobalLValue(A.getLValueBase()) ||
+         A.getLValueCallIndex() == B.getLValueCallIndex();
+}
+
+/// Perform the given integer operation, which is known to need at most BitWidth
+/// bits, and check for overflow in the original type (if that type was not an
+/// unsigned type).
+template<typename Operation>
+static APSInt CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
+                                   const APSInt &LHS, const APSInt &RHS,
+                                   unsigned BitWidth, Operation Op) {
+  if (LHS.isUnsigned())
+    return Op(LHS, RHS);
+
+  APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
+  APSInt Result = Value.trunc(LHS.getBitWidth());
+  if (Result.extend(BitWidth) != Value)
+    HandleOverflow(Info, E, Value, E->getType());
+  return Result;
+}
+
+namespace {
+
+/// \brief Data recursive integer evaluator of certain binary operators.
+///
+/// We use a data recursive algorithm for binary operators so that we are able
+/// to handle extreme cases of chained binary operators without causing stack
+/// overflow.
+class DataRecursiveIntBinOpEvaluator {
+  struct EvalResult {
+    APValue Val;
+    bool Failed;
+
+    EvalResult() : Failed(false) { }
+
+    void swap(EvalResult &RHS) {
+      Val.swap(RHS.Val);
+      Failed = RHS.Failed;
+      RHS.Failed = false;
+    }
+  };
+
+  struct Job {
+    const Expr *E;
+    EvalResult LHSResult; // meaningful only for binary operator expression.
+    enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
+    
+    Job() : StoredInfo(0) { }
+    void startSpeculativeEval(EvalInfo &Info) {
+      OldEvalStatus = Info.EvalStatus;
+      Info.EvalStatus.Diag = 0;
+      StoredInfo = &Info;
+    }
+    ~Job() {
+      if (StoredInfo) {
+        StoredInfo->EvalStatus = OldEvalStatus;
+      }
+    }
+  private:
+    EvalInfo *StoredInfo; // non-null if status changed.
+    Expr::EvalStatus OldEvalStatus;
+  };
+
+  SmallVector<Job, 16> Queue;
+
+  IntExprEvaluator &IntEval;
+  EvalInfo &Info;
+  APValue &FinalResult;
+
+public:
+  DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
+    : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
+
+  /// \brief True if \param E is a binary operator that we are going to handle
+  /// data recursively.
+  /// We handle binary operators that are comma, logical, or that have operands
+  /// with integral or enumeration type.
+  static bool shouldEnqueue(const BinaryOperator *E) {
+    return E->getOpcode() == BO_Comma ||
+           E->isLogicalOp() ||
+           (E->getLHS()->getType()->isIntegralOrEnumerationType() &&
+            E->getRHS()->getType()->isIntegralOrEnumerationType());
+  }
+
+  bool Traverse(const BinaryOperator *E) {
+    enqueue(E);
+    EvalResult PrevResult;
+    while (!Queue.empty())
+      process(PrevResult);
+
+    if (PrevResult.Failed) return false;
+
+    FinalResult.swap(PrevResult.Val);
+    return true;
+  }
+
+private:
+  bool Success(uint64_t Value, const Expr *E, APValue &Result) {
+    return IntEval.Success(Value, E, Result);
+  }
+  bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
+    return IntEval.Success(Value, E, Result);
+  }
+  bool Error(const Expr *E) {
+    return IntEval.Error(E);
+  }
+  bool Error(const Expr *E, diag::kind D) {
+    return IntEval.Error(E, D);
+  }
+
+  OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
+    return Info.CCEDiag(E, D);
+  }
+
+  // \brief Returns true if visiting the RHS is necessary, false otherwise.
+  bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
+                         bool &SuppressRHSDiags);
+
+  bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
+                  const BinaryOperator *E, APValue &Result);
+
+  void EvaluateExpr(const Expr *E, EvalResult &Result) {
+    Result.Failed = !Evaluate(Result.Val, Info, E);
+    if (Result.Failed)
+      Result.Val = APValue();
+  }
+
+  void process(EvalResult &Result);
+
+  void enqueue(const Expr *E) {
+    E = E->IgnoreParens();
+    Queue.resize(Queue.size()+1);
+    Queue.back().E = E;
+    Queue.back().Kind = Job::AnyExprKind;
+  }
+};
+
+}
+
+bool DataRecursiveIntBinOpEvaluator::
+       VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
+                         bool &SuppressRHSDiags) {
+  if (E->getOpcode() == BO_Comma) {
+    // Ignore LHS but note if we could not evaluate it.
+    if (LHSResult.Failed)
+      Info.EvalStatus.HasSideEffects = true;
+    return true;
+  }
+  
+  if (E->isLogicalOp()) {
+    bool lhsResult;
+    if (HandleConversionToBool(LHSResult.Val, lhsResult)) {
+      // We were able to evaluate the LHS, see if we can get away with not
+      // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
+      if (lhsResult == (E->getOpcode() == BO_LOr)) {
+        Success(lhsResult, E, LHSResult.Val);
+        return false; // Ignore RHS
+      }
+    } else {
+      // Since we weren't able to evaluate the left hand side, it
+      // must have had side effects.
+      Info.EvalStatus.HasSideEffects = true;
+      
+      // We can't evaluate the LHS; however, sometimes the result
+      // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
+      // Don't ignore RHS and suppress diagnostics from this arm.
+      SuppressRHSDiags = true;
+    }
+    
+    return true;
+  }
+  
+  assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
+         E->getRHS()->getType()->isIntegralOrEnumerationType());
+  
+  if (LHSResult.Failed && !Info.keepEvaluatingAfterFailure())
+    return false; // Ignore RHS;
+
+  return true;
+}
+
+bool DataRecursiveIntBinOpEvaluator::
+       VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
+                  const BinaryOperator *E, APValue &Result) {
+  if (E->getOpcode() == BO_Comma) {
+    if (RHSResult.Failed)
+      return false;
+    Result = RHSResult.Val;
+    return true;
+  }
+  
+  if (E->isLogicalOp()) {
+    bool lhsResult, rhsResult;
+    bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
+    bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);
+    
+    if (LHSIsOK) {
+      if (RHSIsOK) {
+        if (E->getOpcode() == BO_LOr)
+          return Success(lhsResult || rhsResult, E, Result);
+        else
+          return Success(lhsResult && rhsResult, E, Result);
+      }
+    } else {
+      if (RHSIsOK) {
+        // We can't evaluate the LHS; however, sometimes the result
+        // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
+        if (rhsResult == (E->getOpcode() == BO_LOr))
+          return Success(rhsResult, E, Result);
+      }
+    }
+    
+    return false;
+  }
+  
+  assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
+         E->getRHS()->getType()->isIntegralOrEnumerationType());
+  
+  if (LHSResult.Failed || RHSResult.Failed)
+    return false;
+  
+  const APValue &LHSVal = LHSResult.Val;
+  const APValue &RHSVal = RHSResult.Val;
+  
+  // Handle cases like (unsigned long)&a + 4.
+  if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
+    Result = LHSVal;
+    CharUnits AdditionalOffset = CharUnits::fromQuantity(
+                                                         RHSVal.getInt().getZExtValue());
+    if (E->getOpcode() == BO_Add)
+      Result.getLValueOffset() += AdditionalOffset;
+    else
+      Result.getLValueOffset() -= AdditionalOffset;
+    return true;
+  }
+  
+  // Handle cases like 4 + (unsigned long)&a
+  if (E->getOpcode() == BO_Add &&
+      RHSVal.isLValue() && LHSVal.isInt()) {
+    Result = RHSVal;
+    Result.getLValueOffset() += CharUnits::fromQuantity(
+                                                        LHSVal.getInt().getZExtValue());
+    return true;
+  }
+  
+  if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
+    // Handle (intptr_t)&&A - (intptr_t)&&B.
+    if (!LHSVal.getLValueOffset().isZero() ||
+        !RHSVal.getLValueOffset().isZero())
+      return false;
+    const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
+    const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
+    if (!LHSExpr || !RHSExpr)
+      return false;
+    const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
+    const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
+    if (!LHSAddrExpr || !RHSAddrExpr)
+      return false;
+    // Make sure both labels come from the same function.
+    if (LHSAddrExpr->getLabel()->getDeclContext() !=
+        RHSAddrExpr->getLabel()->getDeclContext())
+      return false;
+    Result = APValue(LHSAddrExpr, RHSAddrExpr);
+    return true;
+  }
+  
+  // All the following cases expect both operands to be an integer
+  if (!LHSVal.isInt() || !RHSVal.isInt())
+    return Error(E);
+  
+  const APSInt &LHS = LHSVal.getInt();
+  APSInt RHS = RHSVal.getInt();
+  
+  switch (E->getOpcode()) {
+    default:
+      return Error(E);
+    case BO_Mul:
+      return Success(CheckedIntArithmetic(Info, E, LHS, RHS,
+                                          LHS.getBitWidth() * 2,
+                                          std::multiplies<APSInt>()), E,
+                     Result);
+    case BO_Add:
+      return Success(CheckedIntArithmetic(Info, E, LHS, RHS,
+                                          LHS.getBitWidth() + 1,
+                                          std::plus<APSInt>()), E, Result);
+    case BO_Sub:
+      return Success(CheckedIntArithmetic(Info, E, LHS, RHS,
+                                          LHS.getBitWidth() + 1,
+                                          std::minus<APSInt>()), E, Result);
+    case BO_And: return Success(LHS & RHS, E, Result);
+    case BO_Xor: return Success(LHS ^ RHS, E, Result);
+    case BO_Or:  return Success(LHS | RHS, E, Result);
+    case BO_Div:
+    case BO_Rem:
+      if (RHS == 0)
+        return Error(E, diag::note_expr_divide_by_zero);
+      // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. The latter is
+      // not actually undefined behavior in C++11 due to a language defect.
+      if (RHS.isNegative() && RHS.isAllOnesValue() &&
+          LHS.isSigned() && LHS.isMinSignedValue())
+        HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1), E->getType());
+      return Success(E->getOpcode() == BO_Rem ? LHS % RHS : LHS / RHS, E,
+                     Result);
+    case BO_Shl: {
+      // During constant-folding, a negative shift is an opposite shift. Such
+      // a shift is not a constant expression.
+      if (RHS.isSigned() && RHS.isNegative()) {
+        CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
+        RHS = -RHS;
+        goto shift_right;
+      }
+      
+    shift_left:
+      // C++11 [expr.shift]p1: Shift width must be less than the bit width of
+      // the shifted type.
+      unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
+      if (SA != RHS) {
+        CCEDiag(E, diag::note_constexpr_large_shift)
+        << RHS << E->getType() << LHS.getBitWidth();
+      } else if (LHS.isSigned()) {
+        // C++11 [expr.shift]p2: A signed left shift must have a non-negative
+        // operand, and must not overflow the corresponding unsigned type.
+        if (LHS.isNegative())
+          CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
+        else if (LHS.countLeadingZeros() < SA)
+          CCEDiag(E, diag::note_constexpr_lshift_discards);
+      }
+      
+      return Success(LHS << SA, E, Result);
+    }
+    case BO_Shr: {
+      // During constant-folding, a negative shift is an opposite shift. Such a
+      // shift is not a constant expression.
+      if (RHS.isSigned() && RHS.isNegative()) {
+        CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
+        RHS = -RHS;
+        goto shift_left;
+      }
+      
+    shift_right:
+      // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
+      // shifted type.
+      unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
+      if (SA != RHS)
+        CCEDiag(E, diag::note_constexpr_large_shift)
+        << RHS << E->getType() << LHS.getBitWidth();
+      
+      return Success(LHS >> SA, E, Result);
+    }
+      
+    case BO_LT: return Success(LHS < RHS, E, Result);
+    case BO_GT: return Success(LHS > RHS, E, Result);
+    case BO_LE: return Success(LHS <= RHS, E, Result);
+    case BO_GE: return Success(LHS >= RHS, E, Result);
+    case BO_EQ: return Success(LHS == RHS, E, Result);
+    case BO_NE: return Success(LHS != RHS, E, Result);
+  }
+}
+
+void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
+  Job &job = Queue.back();
+  
+  switch (job.Kind) {
+    case Job::AnyExprKind: {
+      if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
+        if (shouldEnqueue(Bop)) {
+          job.Kind = Job::BinOpKind;
+          enqueue(Bop->getLHS());
+          return;
+        }
+      }
+      
+      EvaluateExpr(job.E, Result);
+      Queue.pop_back();
+      return;
+    }
+      
+    case Job::BinOpKind: {
+      const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
+      bool SuppressRHSDiags = false;
+      if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) {
+        Queue.pop_back();
+        return;
+      }
+      if (SuppressRHSDiags)
+        job.startSpeculativeEval(Info);
+      job.LHSResult.swap(Result);
+      job.Kind = Job::BinOpVisitedLHSKind;
+      enqueue(Bop->getRHS());
+      return;
+    }
+      
+    case Job::BinOpVisitedLHSKind: {
+      const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
+      EvalResult RHS;
+      RHS.swap(Result);
+      Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val);
+      Queue.pop_back();
+      return;
+    }
+  }
+  
+  llvm_unreachable("Invalid Job::Kind!");
+}
+
+bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
+  if (E->isAssignmentOp())
+    return Error(E);
+
+  if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
+    return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
+
+  QualType LHSTy = E->getLHS()->getType();
+  QualType RHSTy = E->getRHS()->getType();
+
+  if (LHSTy->isAnyComplexType()) {
+    assert(RHSTy->isAnyComplexType() && "Invalid comparison");
+    ComplexValue LHS, RHS;
+
+    bool LHSOK = EvaluateComplex(E->getLHS(), LHS, Info);
+    if (!LHSOK && !Info.keepEvaluatingAfterFailure())
+      return false;
+
+    if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
+      return false;
+
+    if (LHS.isComplexFloat()) {
+      APFloat::cmpResult CR_r =
+        LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
+      APFloat::cmpResult CR_i =
+        LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
+
+      if (E->getOpcode() == BO_EQ)
+        return Success((CR_r == APFloat::cmpEqual &&
+                        CR_i == APFloat::cmpEqual), E);
+      else {
+        assert(E->getOpcode() == BO_NE &&
+               "Invalid complex comparison.");
+        return Success(((CR_r == APFloat::cmpGreaterThan ||
+                         CR_r == APFloat::cmpLessThan ||
+                         CR_r == APFloat::cmpUnordered) ||
+                        (CR_i == APFloat::cmpGreaterThan ||
+                         CR_i == APFloat::cmpLessThan ||
+                         CR_i == APFloat::cmpUnordered)), E);
+      }
+    } else {
+      if (E->getOpcode() == BO_EQ)
+        return Success((LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
+                        LHS.getComplexIntImag() == RHS.getComplexIntImag()), E);
+      else {
+        assert(E->getOpcode() == BO_NE &&
+               "Invalid compex comparison.");
+        return Success((LHS.getComplexIntReal() != RHS.getComplexIntReal() ||
+                        LHS.getComplexIntImag() != RHS.getComplexIntImag()), E);
+      }
+    }
+  }
+
+  if (LHSTy->isRealFloatingType() &&
+      RHSTy->isRealFloatingType()) {
+    APFloat RHS(0.0), LHS(0.0);
+
+    bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info);
+    if (!LHSOK && !Info.keepEvaluatingAfterFailure())
+      return false;
+
+    if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK)
+      return false;
+
+    APFloat::cmpResult CR = LHS.compare(RHS);
+
+    switch (E->getOpcode()) {
+    default:
+      llvm_unreachable("Invalid binary operator!");
+    case BO_LT:
+      return Success(CR == APFloat::cmpLessThan, E);
+    case BO_GT:
+      return Success(CR == APFloat::cmpGreaterThan, E);
+    case BO_LE:
+      return Success(CR == APFloat::cmpLessThan || CR == APFloat::cmpEqual, E);
+    case BO_GE:
+      return Success(CR == APFloat::cmpGreaterThan || CR == APFloat::cmpEqual,
+                     E);
+    case BO_EQ:
+      return Success(CR == APFloat::cmpEqual, E);
+    case BO_NE:
+      return Success(CR == APFloat::cmpGreaterThan
+                     || CR == APFloat::cmpLessThan
+                     || CR == APFloat::cmpUnordered, E);
+    }
+  }
+
+  if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
+    if (E->getOpcode() == BO_Sub || E->isComparisonOp()) {
+      LValue LHSValue, RHSValue;
+
+      bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
+      if (!LHSOK && Info.keepEvaluatingAfterFailure())
+        return false;
+
+      if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
+        return false;
+
+      // Reject differing bases from the normal codepath; we special-case
+      // comparisons to null.
+      if (!HasSameBase(LHSValue, RHSValue)) {
+        if (E->getOpcode() == BO_Sub) {
+          // Handle &&A - &&B.
+          if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
+            return false;
+          const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr*>();
+          const Expr *RHSExpr = LHSValue.Base.dyn_cast<const Expr*>();
+          if (!LHSExpr || !RHSExpr)
+            return false;
+          const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
+          const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
+          if (!LHSAddrExpr || !RHSAddrExpr)
+            return false;
+          // Make sure both labels come from the same function.
+          if (LHSAddrExpr->getLabel()->getDeclContext() !=
+              RHSAddrExpr->getLabel()->getDeclContext())
+            return false;
+          Result = APValue(LHSAddrExpr, RHSAddrExpr);
+          return true;
+        }
+        // Inequalities and subtractions between unrelated pointers have
+        // unspecified or undefined behavior.
+        if (!E->isEqualityOp())
+          return Error(E);
+        // A constant address may compare equal to the address of a symbol.
+        // The one exception is that address of an object cannot compare equal
+        // to a null pointer constant.
+        if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
+            (!RHSValue.Base && !RHSValue.Offset.isZero()))
+          return Error(E);
+        // It's implementation-defined whether distinct literals will have
+        // distinct addresses. In clang, the result of such a comparison is
+        // unspecified, so it is not a constant expression. However, we do know
+        // that the address of a literal will be non-null.
+        if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
+            LHSValue.Base && RHSValue.Base)
+          return Error(E);
+        // We can't tell whether weak symbols will end up pointing to the same
+        // object.
+        if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
+          return Error(E);
+        // Pointers with different bases cannot represent the same object.
+        // (Note that clang defaults to -fmerge-all-constants, which can
+        // lead to inconsistent results for comparisons involving the address
+        // of a constant; this generally doesn't matter in practice.)
+        return Success(E->getOpcode() == BO_NE, E);
+      }
+
+      const CharUnits &LHSOffset = LHSValue.getLValueOffset();
+      const CharUnits &RHSOffset = RHSValue.getLValueOffset();
+
+      SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
+      SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
+
+      if (E->getOpcode() == BO_Sub) {
+        // C++11 [expr.add]p6:
+        //   Unless both pointers point to elements of the same array object, or
+        //   one past the last element of the array object, the behavior is
+        //   undefined.
+        if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
+            !AreElementsOfSameArray(getType(LHSValue.Base),
+                                    LHSDesignator, RHSDesignator))
+          CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);
+
+        QualType Type = E->getLHS()->getType();
+        QualType ElementType = Type->getAs<PointerType>()->getPointeeType();
+
+        CharUnits ElementSize;
+        if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize))
+          return false;
+
+        // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
+        // and produce incorrect results when it overflows. Such behavior
+        // appears to be non-conforming, but is common, so perhaps we should
+        // assume the standard intended for such cases to be undefined behavior
+        // and check for them.
+
+        // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
+        // overflow in the final conversion to ptrdiff_t.
+        APSInt LHS(
+          llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
+        APSInt RHS(
+          llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
+        APSInt ElemSize(
+          llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true), false);
+        APSInt TrueResult = (LHS - RHS) / ElemSize;
+        APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType()));
+
+        if (Result.extend(65) != TrueResult)
+          HandleOverflow(Info, E, TrueResult, E->getType());
+        return Success(Result, E);
+      }
+
+      // C++11 [expr.rel]p3:
+      //   Pointers to void (after pointer conversions) can be compared, with a
+      //   result defined as follows: If both pointers represent the same
+      //   address or are both the null pointer value, the result is true if the
+      //   operator is <= or >= and false otherwise; otherwise the result is
+      //   unspecified.
+      // We interpret this as applying to pointers to *cv* void.
+      if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset &&
+          E->isRelationalOp())
+        CCEDiag(E, diag::note_constexpr_void_comparison);
+
+      // C++11 [expr.rel]p2:
+      // - If two pointers point to non-static data members of the same object,
+      //   or to subobjects or array elements fo such members, recursively, the
+      //   pointer to the later declared member compares greater provided the
+      //   two members have the same access control and provided their class is
+      //   not a union.
+      //   [...]
+      // - Otherwise pointer comparisons are unspecified.
+      if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
+          E->isRelationalOp()) {
+        bool WasArrayIndex;
+        unsigned Mismatch =
+          FindDesignatorMismatch(getType(LHSValue.Base), LHSDesignator,
+                                 RHSDesignator, WasArrayIndex);
+        // At the point where the designators diverge, the comparison has a
+        // specified value if:
+        //  - we are comparing array indices
+        //  - we are comparing fields of a union, or fields with the same access
+        // Otherwise, the result is unspecified and thus the comparison is not a
+        // constant expression.
+        if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
+            Mismatch < RHSDesignator.Entries.size()) {
+          const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]);
+          const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]);
+          if (!LF && !RF)
+            CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
+          else if (!LF)
+            CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
+              << getAsBaseClass(LHSDesignator.Entries[Mismatch])
+              << RF->getParent() << RF;
+          else if (!RF)
+            CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
+              << getAsBaseClass(RHSDesignator.Entries[Mismatch])
+              << LF->getParent() << LF;
+          else if (!LF->getParent()->isUnion() &&
+                   LF->getAccess() != RF->getAccess())
+            CCEDiag(E, diag::note_constexpr_pointer_comparison_differing_access)
+              << LF << LF->getAccess() << RF << RF->getAccess()
+              << LF->getParent();
+        }
+      }
+
+      // The comparison here must be unsigned, and performed with the same
+      // width as the pointer.
+      unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy);
+      uint64_t CompareLHS = LHSOffset.getQuantity();
+      uint64_t CompareRHS = RHSOffset.getQuantity();
+      assert(PtrSize <= 64 && "Unexpected pointer width");
+      uint64_t Mask = ~0ULL >> (64 - PtrSize);
+      CompareLHS &= Mask;
+      CompareRHS &= Mask;
+
+      // If there is a base and this is a relational operator, we can only
+      // compare pointers within the object in question; otherwise, the result
+      // depends on where the object is located in memory.
+      if (!LHSValue.Base.isNull() && E->isRelationalOp()) {
+        QualType BaseTy = getType(LHSValue.Base);
+        if (BaseTy->isIncompleteType())
+          return Error(E);
+        CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy);
+        uint64_t OffsetLimit = Size.getQuantity();
+        if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
+          return Error(E);
+      }
+
+      switch (E->getOpcode()) {
+      default: llvm_unreachable("missing comparison operator");
+      case BO_LT: return Success(CompareLHS < CompareRHS, E);
+      case BO_GT: return Success(CompareLHS > CompareRHS, E);
+      case BO_LE: return Success(CompareLHS <= CompareRHS, E);
+      case BO_GE: return Success(CompareLHS >= CompareRHS, E);
+      case BO_EQ: return Success(CompareLHS == CompareRHS, E);
+      case BO_NE: return Success(CompareLHS != CompareRHS, E);
+      }
+    }
+  }
+
+  if (LHSTy->isMemberPointerType()) {
+    assert(E->isEqualityOp() && "unexpected member pointer operation");
+    assert(RHSTy->isMemberPointerType() && "invalid comparison");
+
+    MemberPtr LHSValue, RHSValue;
+
+    bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info);
+    if (!LHSOK && Info.keepEvaluatingAfterFailure())
+      return false;
+
+    if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK)
+      return false;
+
+    // C++11 [expr.eq]p2:
+    //   If both operands are null, they compare equal. Otherwise if only one is
+    //   null, they compare unequal.
+    if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
+      bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
+      return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E);
+    }
+
+    //   Otherwise if either is a pointer to a virtual member function, the
+    //   result is unspecified.
+    if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
+      if (MD->isVirtual())
+        CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
+    if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
+      if (MD->isVirtual())
+        CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
+
+    //   Otherwise they compare equal if and only if they would refer to the
+    //   same member of the same most derived object or the same subobject if
+    //   they were dereferenced with a hypothetical object of the associated
+    //   class type.
+    bool Equal = LHSValue == RHSValue;
+    return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E);
+  }
+
+  if (LHSTy->isNullPtrType()) {
+    assert(E->isComparisonOp() && "unexpected nullptr operation");
+    assert(RHSTy->isNullPtrType() && "missing pointer conversion");
+    // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
+    // are compared, the result is true of the operator is <=, >= or ==, and
+    // false otherwise.
+    BinaryOperator::Opcode Opcode = E->getOpcode();
+    return Success(Opcode == BO_EQ || Opcode == BO_LE || Opcode == BO_GE, E);
+  }
+
+  assert((!LHSTy->isIntegralOrEnumerationType() ||
+          !RHSTy->isIntegralOrEnumerationType()) &&
+         "DataRecursiveIntBinOpEvaluator should have handled integral types");
+  // We can't continue from here for non-integral types.
+  return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
+}
+
+CharUnits IntExprEvaluator::GetAlignOfType(QualType T) {
+  // C++ [expr.alignof]p3: "When alignof is applied to a reference type, the
+  //   result shall be the alignment of the referenced type."
+  if (const ReferenceType *Ref = T->getAs<ReferenceType>())
+    T = Ref->getPointeeType();
+
+  // __alignof is defined to return the preferred alignment.
+  return Info.Ctx.toCharUnitsFromBits(
+    Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
+}
+
+CharUnits IntExprEvaluator::GetAlignOfExpr(const Expr *E) {
+  E = E->IgnoreParens();
+
+  // alignof decl is always accepted, even if it doesn't make sense: we default
+  // to 1 in those cases.
+  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
+    return Info.Ctx.getDeclAlign(DRE->getDecl(), 
+                                 /*RefAsPointee*/true);
+
+  if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
+    return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
+                                 /*RefAsPointee*/true);
+
+  return GetAlignOfType(E->getType());
+}
+
+
+/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
+/// a result as the expression's type.
+bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
+                                    const UnaryExprOrTypeTraitExpr *E) {
+  switch(E->getKind()) {
+  case UETT_AlignOf: {
+    if (E->isArgumentType())
+      return Success(GetAlignOfType(E->getArgumentType()), E);
+    else
+      return Success(GetAlignOfExpr(E->getArgumentExpr()), E);
+  }
+
+  case UETT_VecStep: {
+    QualType Ty = E->getTypeOfArgument();
+
+    if (Ty->isVectorType()) {
+      unsigned n = Ty->getAs<VectorType>()->getNumElements();
+
+      // The vec_step built-in functions that take a 3-component
+      // vector return 4. (OpenCL 1.1 spec 6.11.12)
+      if (n == 3)
+        n = 4;
+
+      return Success(n, E);
+    } else
+      return Success(1, E);
+  }
+
+  case UETT_SizeOf: {
+    QualType SrcTy = E->getTypeOfArgument();
+    // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
+    //   the result is the size of the referenced type."
+    if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
+      SrcTy = Ref->getPointeeType();
+
+    CharUnits Sizeof;
+    if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof))
+      return false;
+    return Success(Sizeof, E);
+  }
+  }
+
+  llvm_unreachable("unknown expr/type trait");
+}
+
+bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
+  CharUnits Result;
+  unsigned n = OOE->getNumComponents();
+  if (n == 0)
+    return Error(OOE);
+  QualType CurrentType = OOE->getTypeSourceInfo()->getType();
+  for (unsigned i = 0; i != n; ++i) {
+    OffsetOfExpr::OffsetOfNode ON = OOE->getComponent(i);
+    switch (ON.getKind()) {
+    case OffsetOfExpr::OffsetOfNode::Array: {
+      const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
+      APSInt IdxResult;
+      if (!EvaluateInteger(Idx, IdxResult, Info))
+        return false;
+      const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
+      if (!AT)
+        return Error(OOE);
+      CurrentType = AT->getElementType();
+      CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
+      Result += IdxResult.getSExtValue() * ElementSize;
+        break;
+    }
+
+    case OffsetOfExpr::OffsetOfNode::Field: {
+      FieldDecl *MemberDecl = ON.getField();
+      const RecordType *RT = CurrentType->getAs<RecordType>();
+      if (!RT)
+        return Error(OOE);
+      RecordDecl *RD = RT->getDecl();
+      const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
+      unsigned i = MemberDecl->getFieldIndex();
+      assert(i < RL.getFieldCount() && "offsetof field in wrong type");
+      Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
+      CurrentType = MemberDecl->getType().getNonReferenceType();
+      break;
+    }
+
+    case OffsetOfExpr::OffsetOfNode::Identifier:
+      llvm_unreachable("dependent __builtin_offsetof");
+
+    case OffsetOfExpr::OffsetOfNode::Base: {
+      CXXBaseSpecifier *BaseSpec = ON.getBase();
+      if (BaseSpec->isVirtual())
+        return Error(OOE);
+
+      // Find the layout of the class whose base we are looking into.
+      const RecordType *RT = CurrentType->getAs<RecordType>();
+      if (!RT)
+        return Error(OOE);
+      RecordDecl *RD = RT->getDecl();
+      const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
+
+      // Find the base class itself.
+      CurrentType = BaseSpec->getType();
+      const RecordType *BaseRT = CurrentType->getAs<RecordType>();
+      if (!BaseRT)
+        return Error(OOE);
+      
+      // Add the offset to the base.
+      Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
+      break;
+    }
+    }
+  }
+  return Success(Result, OOE);
+}
+
+bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
+  switch (E->getOpcode()) {
+  default:
+    // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
+    // See C99 6.6p3.
+    return Error(E);
+  case UO_Extension:
+    // FIXME: Should extension allow i-c-e extension expressions in its scope?
+    // If so, we could clear the diagnostic ID.
+    return Visit(E->getSubExpr());
+  case UO_Plus:
+    // The result is just the value.
+    return Visit(E->getSubExpr());
+  case UO_Minus: {
+    if (!Visit(E->getSubExpr()))
+      return false;
+    if (!Result.isInt()) return Error(E);
+    const APSInt &Value = Result.getInt();
+    if (Value.isSigned() && Value.isMinSignedValue())
+      HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
+                     E->getType());
+    return Success(-Value, E);
+  }
+  case UO_Not: {
+    if (!Visit(E->getSubExpr()))
+      return false;
+    if (!Result.isInt()) return Error(E);
+    return Success(~Result.getInt(), E);
+  }
+  case UO_LNot: {
+    bool bres;
+    if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
+      return false;
+    return Success(!bres, E);
+  }
+  }
+}
+
+/// HandleCast - This is used to evaluate implicit or explicit casts where the
+/// result type is integer.
+bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
+  const Expr *SubExpr = E->getSubExpr();
+  QualType DestType = E->getType();
+  QualType SrcType = SubExpr->getType();
+
+  switch (E->getCastKind()) {
+  case CK_BaseToDerived:
+  case CK_DerivedToBase:
+  case CK_UncheckedDerivedToBase:
+  case CK_Dynamic:
+  case CK_ToUnion:
+  case CK_ArrayToPointerDecay:
+  case CK_FunctionToPointerDecay:
+  case CK_NullToPointer:
+  case CK_NullToMemberPointer:
+  case CK_BaseToDerivedMemberPointer:
+  case CK_DerivedToBaseMemberPointer:
+  case CK_ReinterpretMemberPointer:
+  case CK_ConstructorConversion:
+  case CK_IntegralToPointer:
+  case CK_ToVoid:
+  case CK_VectorSplat:
+  case CK_IntegralToFloating:
+  case CK_FloatingCast:
+  case CK_CPointerToObjCPointerCast:
+  case CK_BlockPointerToObjCPointerCast:
+  case CK_AnyPointerToBlockPointerCast:
+  case CK_ObjCObjectLValueCast:
+  case CK_FloatingRealToComplex:
+  case CK_FloatingComplexToReal:
+  case CK_FloatingComplexCast:
+  case CK_FloatingComplexToIntegralComplex:
+  case CK_IntegralRealToComplex:
+  case CK_IntegralComplexCast:
+  case CK_IntegralComplexToFloatingComplex:
+    llvm_unreachable("invalid cast kind for integral value");
+
+  case CK_BitCast:
+  case CK_Dependent:
+  case CK_LValueBitCast:
+  case CK_ARCProduceObject:
+  case CK_ARCConsumeObject:
+  case CK_ARCReclaimReturnedObject:
+  case CK_ARCExtendBlockObject:
+  case CK_CopyAndAutoreleaseBlockObject:
+    return Error(E);
+
+  case CK_UserDefinedConversion:
+  case CK_LValueToRValue:
+  case CK_AtomicToNonAtomic:
+  case CK_NonAtomicToAtomic:
+  case CK_NoOp:
+    return ExprEvaluatorBaseTy::VisitCastExpr(E);
+
+  case CK_MemberPointerToBoolean:
+  case CK_PointerToBoolean:
+  case CK_IntegralToBoolean:
+  case CK_FloatingToBoolean:
+  case CK_FloatingComplexToBoolean:
+  case CK_IntegralComplexToBoolean: {
+    bool BoolResult;
+    if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info))
+      return false;
+    return Success(BoolResult, E);
+  }
+
+  case CK_IntegralCast: {
+    if (!Visit(SubExpr))
+      return false;
+
+    if (!Result.isInt()) {
+      // Allow casts of address-of-label differences if they are no-ops
+      // or narrowing.  (The narrowing case isn't actually guaranteed to
+      // be constant-evaluatable except in some narrow cases which are hard
+      // to detect here.  We let it through on the assumption the user knows
+      // what they are doing.)
+      if (Result.isAddrLabelDiff())
+        return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
+      // Only allow casts of lvalues if they are lossless.
+      return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
+    }
+
+    return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
+                                      Result.getInt()), E);
+  }
+
+  case CK_PointerToIntegral: {
+    CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
+
+    LValue LV;
+    if (!EvaluatePointer(SubExpr, LV, Info))
+      return false;
+
+    if (LV.getLValueBase()) {
+      // Only allow based lvalue casts if they are lossless.
+      // FIXME: Allow a larger integer size than the pointer size, and allow
+      // narrowing back down to pointer width in subsequent integral casts.
+      // FIXME: Check integer type's active bits, not its type size.
+      if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
+        return Error(E);
+
+      LV.Designator.setInvalid();
+      LV.moveInto(Result);
+      return true;
+    }
+
+    APSInt AsInt = Info.Ctx.MakeIntValue(LV.getLValueOffset().getQuantity(), 
+                                         SrcType);
+    return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
+  }
+
+  case CK_IntegralComplexToReal: {
+    ComplexValue C;
+    if (!EvaluateComplex(SubExpr, C, Info))
+      return false;
+    return Success(C.getComplexIntReal(), E);
+  }
+
+  case CK_FloatingToIntegral: {
+    APFloat F(0.0);
+    if (!EvaluateFloat(SubExpr, F, Info))
+      return false;
+
+    APSInt Value;
+    if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
+      return false;
+    return Success(Value, E);
+  }
+  }
+
+  llvm_unreachable("unknown cast resulting in integral value");
+}
+
+bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
+  if (E->getSubExpr()->getType()->isAnyComplexType()) {
+    ComplexValue LV;
+    if (!EvaluateComplex(E->getSubExpr(), LV, Info))
+      return false;
+    if (!LV.isComplexInt())
+      return Error(E);
+    return Success(LV.getComplexIntReal(), E);
+  }
+
+  return Visit(E->getSubExpr());
+}
+
+bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
+  if (E->getSubExpr()->getType()->isComplexIntegerType()) {
+    ComplexValue LV;
+    if (!EvaluateComplex(E->getSubExpr(), LV, Info))
+      return false;
+    if (!LV.isComplexInt())
+      return Error(E);
+    return Success(LV.getComplexIntImag(), E);
+  }
+
+  VisitIgnoredValue(E->getSubExpr());
+  return Success(0, E);
+}
+
+bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
+  return Success(E->getPackLength(), E);
+}
+
+bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
+  return Success(E->getValue(), E);
+}
+
+//===----------------------------------------------------------------------===//
+// Float Evaluation
+//===----------------------------------------------------------------------===//
+
+namespace {
+class FloatExprEvaluator
+  : public ExprEvaluatorBase<FloatExprEvaluator, bool> {
+  APFloat &Result;
+public:
+  FloatExprEvaluator(EvalInfo &info, APFloat &result)
+    : ExprEvaluatorBaseTy(info), Result(result) {}
+
+  bool Success(const APValue &V, const Expr *e) {
+    Result = V.getFloat();
+    return true;
+  }
+
+  bool ZeroInitialization(const Expr *E) {
+    Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
+    return true;
+  }
+
+  bool VisitCallExpr(const CallExpr *E);
+
+  bool VisitUnaryOperator(const UnaryOperator *E);
+  bool VisitBinaryOperator(const BinaryOperator *E);
+  bool VisitFloatingLiteral(const FloatingLiteral *E);
+  bool VisitCastExpr(const CastExpr *E);
+
+  bool VisitUnaryReal(const UnaryOperator *E);
+  bool VisitUnaryImag(const UnaryOperator *E);
+
+  // FIXME: Missing: array subscript of vector, member of vector
+};
+} // end anonymous namespace
+
+static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isRealFloatingType());
+  return FloatExprEvaluator(Info, Result).Visit(E);
+}
+
+static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
+                                  QualType ResultTy,
+                                  const Expr *Arg,
+                                  bool SNaN,
+                                  llvm::APFloat &Result) {
+  const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
+  if (!S) return false;
+
+  const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);
+
+  llvm::APInt fill;
+
+  // Treat empty strings as if they were zero.
+  if (S->getString().empty())
+    fill = llvm::APInt(32, 0);
+  else if (S->getString().getAsInteger(0, fill))
+    return false;
+
+  if (SNaN)
+    Result = llvm::APFloat::getSNaN(Sem, false, &fill);
+  else
+    Result = llvm::APFloat::getQNaN(Sem, false, &fill);
+  return true;
+}
+
+bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
+  switch (E->isBuiltinCall()) {
+  default:
+    return ExprEvaluatorBaseTy::VisitCallExpr(E);
+
+  case Builtin::BI__builtin_huge_val:
+  case Builtin::BI__builtin_huge_valf:
+  case Builtin::BI__builtin_huge_vall:
+  case Builtin::BI__builtin_inf:
+  case Builtin::BI__builtin_inff:
+  case Builtin::BI__builtin_infl: {
+    const llvm::fltSemantics &Sem =
+      Info.Ctx.getFloatTypeSemantics(E->getType());
+    Result = llvm::APFloat::getInf(Sem);
+    return true;
+  }
+
+  case Builtin::BI__builtin_nans:
+  case Builtin::BI__builtin_nansf:
+  case Builtin::BI__builtin_nansl:
+    if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
+                               true, Result))
+      return Error(E);
+    return true;
+
+  case Builtin::BI__builtin_nan:
+  case Builtin::BI__builtin_nanf:
+  case Builtin::BI__builtin_nanl:
+    // If this is __builtin_nan() turn this into a nan, otherwise we
+    // can't constant fold it.
+    if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
+                               false, Result))
+      return Error(E);
+    return true;
+
+  case Builtin::BI__builtin_fabs:
+  case Builtin::BI__builtin_fabsf:
+  case Builtin::BI__builtin_fabsl:
+    if (!EvaluateFloat(E->getArg(0), Result, Info))
+      return false;
+
+    if (Result.isNegative())
+      Result.changeSign();
+    return true;
+
+  case Builtin::BI__builtin_copysign:
+  case Builtin::BI__builtin_copysignf:
+  case Builtin::BI__builtin_copysignl: {
+    APFloat RHS(0.);
+    if (!EvaluateFloat(E->getArg(0), Result, Info) ||
+        !EvaluateFloat(E->getArg(1), RHS, Info))
+      return false;
+    Result.copySign(RHS);
+    return true;
+  }
+  }
+}
+
+bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
+  if (E->getSubExpr()->getType()->isAnyComplexType()) {
+    ComplexValue CV;
+    if (!EvaluateComplex(E->getSubExpr(), CV, Info))
+      return false;
+    Result = CV.FloatReal;
+    return true;
+  }
+
+  return Visit(E->getSubExpr());
+}
+
+bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
+  if (E->getSubExpr()->getType()->isAnyComplexType()) {
+    ComplexValue CV;
+    if (!EvaluateComplex(E->getSubExpr(), CV, Info))
+      return false;
+    Result = CV.FloatImag;
+    return true;
+  }
+
+  VisitIgnoredValue(E->getSubExpr());
+  const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
+  Result = llvm::APFloat::getZero(Sem);
+  return true;
+}
+
+bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
+  switch (E->getOpcode()) {
+  default: return Error(E);
+  case UO_Plus:
+    return EvaluateFloat(E->getSubExpr(), Result, Info);
+  case UO_Minus:
+    if (!EvaluateFloat(E->getSubExpr(), Result, Info))
+      return false;
+    Result.changeSign();
+    return true;
+  }
+}
+
+bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
+  if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
+    return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
+
+  APFloat RHS(0.0);
+  bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info);
+  if (!LHSOK && !Info.keepEvaluatingAfterFailure())
+    return false;
+  if (!EvaluateFloat(E->getRHS(), RHS, Info) || !LHSOK)
+    return false;
+
+  switch (E->getOpcode()) {
+  default: return Error(E);
+  case BO_Mul:
+    Result.multiply(RHS, APFloat::rmNearestTiesToEven);
+    break;
+  case BO_Add:
+    Result.add(RHS, APFloat::rmNearestTiesToEven);
+    break;
+  case BO_Sub:
+    Result.subtract(RHS, APFloat::rmNearestTiesToEven);
+    break;
+  case BO_Div:
+    Result.divide(RHS, APFloat::rmNearestTiesToEven);
+    break;
+  }
+
+  if (Result.isInfinity() || Result.isNaN())
+    CCEDiag(E, diag::note_constexpr_float_arithmetic) << Result.isNaN();
+  return true;
+}
+
+bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
+  Result = E->getValue();
+  return true;
+}
+
+bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
+  const Expr* SubExpr = E->getSubExpr();
+
+  switch (E->getCastKind()) {
+  default:
+    return ExprEvaluatorBaseTy::VisitCastExpr(E);
+
+  case CK_IntegralToFloating: {
+    APSInt IntResult;
+    return EvaluateInteger(SubExpr, IntResult, Info) &&
+           HandleIntToFloatCast(Info, E, SubExpr->getType(), IntResult,
+                                E->getType(), Result);
+  }
+
+  case CK_FloatingCast: {
+    if (!Visit(SubExpr))
+      return false;
+    return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
+                                  Result);
+  }
+
+  case CK_FloatingComplexToReal: {
+    ComplexValue V;
+    if (!EvaluateComplex(SubExpr, V, Info))
+      return false;
+    Result = V.getComplexFloatReal();
+    return true;
+  }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Complex Evaluation (for float and integer)
+//===----------------------------------------------------------------------===//
+
+namespace {
+class ComplexExprEvaluator
+  : public ExprEvaluatorBase<ComplexExprEvaluator, bool> {
+  ComplexValue &Result;
+
+public:
+  ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
+    : ExprEvaluatorBaseTy(info), Result(Result) {}
+
+  bool Success(const APValue &V, const Expr *e) {
+    Result.setFrom(V);
+    return true;
+  }
+
+  bool ZeroInitialization(const Expr *E);
+
+  //===--------------------------------------------------------------------===//
+  //                            Visitor Methods
+  //===--------------------------------------------------------------------===//
+
+  bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
+  bool VisitCastExpr(const CastExpr *E);
+  bool VisitBinaryOperator(const BinaryOperator *E);
+  bool VisitUnaryOperator(const UnaryOperator *E);
+  bool VisitInitListExpr(const InitListExpr *E);
+};
+} // end anonymous namespace
+
+static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
+                            EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isAnyComplexType());
+  return ComplexExprEvaluator(Info, Result).Visit(E);
+}
+
+bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
+  QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
+  if (ElemTy->isRealFloatingType()) {
+    Result.makeComplexFloat();
+    APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy));
+    Result.FloatReal = Zero;
+    Result.FloatImag = Zero;
+  } else {
+    Result.makeComplexInt();
+    APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy);
+    Result.IntReal = Zero;
+    Result.IntImag = Zero;
+  }
+  return true;
+}
+
+bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
+  const Expr* SubExpr = E->getSubExpr();
+
+  if (SubExpr->getType()->isRealFloatingType()) {
+    Result.makeComplexFloat();
+    APFloat &Imag = Result.FloatImag;
+    if (!EvaluateFloat(SubExpr, Imag, Info))
+      return false;
+
+    Result.FloatReal = APFloat(Imag.getSemantics());
+    return true;
+  } else {
+    assert(SubExpr->getType()->isIntegerType() &&
+           "Unexpected imaginary literal.");
+
+    Result.makeComplexInt();
+    APSInt &Imag = Result.IntImag;
+    if (!EvaluateInteger(SubExpr, Imag, Info))
+      return false;
+
+    Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
+    return true;
+  }
+}
+
+bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
+
+  switch (E->getCastKind()) {
+  case CK_BitCast:
+  case CK_BaseToDerived:
+  case CK_DerivedToBase:
+  case CK_UncheckedDerivedToBase:
+  case CK_Dynamic:
+  case CK_ToUnion:
+  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_ConstructorConversion:
+  case CK_IntegralToPointer:
+  case CK_PointerToIntegral:
+  case CK_PointerToBoolean:
+  case CK_ToVoid:
+  case CK_VectorSplat:
+  case CK_IntegralCast:
+  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_FloatingComplexToReal:
+  case CK_FloatingComplexToBoolean:
+  case CK_IntegralComplexToReal:
+  case CK_IntegralComplexToBoolean:
+  case CK_ARCProduceObject:
+  case CK_ARCConsumeObject:
+  case CK_ARCReclaimReturnedObject:
+  case CK_ARCExtendBlockObject:
+  case CK_CopyAndAutoreleaseBlockObject:
+    llvm_unreachable("invalid cast kind for complex value");
+
+  case CK_LValueToRValue:
+  case CK_AtomicToNonAtomic:
+  case CK_NonAtomicToAtomic:
+  case CK_NoOp:
+    return ExprEvaluatorBaseTy::VisitCastExpr(E);
+
+  case CK_Dependent:
+  case CK_LValueBitCast:
+  case CK_UserDefinedConversion:
+    return Error(E);
+
+  case CK_FloatingRealToComplex: {
+    APFloat &Real = Result.FloatReal;
+    if (!EvaluateFloat(E->getSubExpr(), Real, Info))
+      return false;
+
+    Result.makeComplexFloat();
+    Result.FloatImag = APFloat(Real.getSemantics());
+    return true;
+  }
+
+  case CK_FloatingComplexCast: {
+    if (!Visit(E->getSubExpr()))
+      return false;
+
+    QualType To = E->getType()->getAs<ComplexType>()->getElementType();
+    QualType From
+      = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
+
+    return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
+           HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
+  }
+
+  case CK_FloatingComplexToIntegralComplex: {
+    if (!Visit(E->getSubExpr()))
+      return false;
+
+    QualType To = E->getType()->getAs<ComplexType>()->getElementType();
+    QualType From
+      = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
+    Result.makeComplexInt();
+    return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
+                                To, Result.IntReal) &&
+           HandleFloatToIntCast(Info, E, From, Result.FloatImag,
+                                To, Result.IntImag);
+  }
+
+  case CK_IntegralRealToComplex: {
+    APSInt &Real = Result.IntReal;
+    if (!EvaluateInteger(E->getSubExpr(), Real, Info))
+      return false;
+
+    Result.makeComplexInt();
+    Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
+    return true;
+  }
+
+  case CK_IntegralComplexCast: {
+    if (!Visit(E->getSubExpr()))
+      return false;
+
+    QualType To = E->getType()->getAs<ComplexType>()->getElementType();
+    QualType From
+      = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
+
+    Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
+    Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
+    return true;
+  }
+
+  case CK_IntegralComplexToFloatingComplex: {
+    if (!Visit(E->getSubExpr()))
+      return false;
+
+    QualType To = E->getType()->getAs<ComplexType>()->getElementType();
+    QualType From
+      = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
+    Result.makeComplexFloat();
+    return HandleIntToFloatCast(Info, E, From, Result.IntReal,
+                                To, Result.FloatReal) &&
+           HandleIntToFloatCast(Info, E, From, Result.IntImag,
+                                To, Result.FloatImag);
+  }
+  }
+
+  llvm_unreachable("unknown cast resulting in complex value");
+}
+
+bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
+  if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
+    return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
+
+  bool LHSOK = Visit(E->getLHS());
+  if (!LHSOK && !Info.keepEvaluatingAfterFailure())
+    return false;
+
+  ComplexValue RHS;
+  if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
+    return false;
+
+  assert(Result.isComplexFloat() == RHS.isComplexFloat() &&
+         "Invalid operands to binary operator.");
+  switch (E->getOpcode()) {
+  default: return Error(E);
+  case BO_Add:
+    if (Result.isComplexFloat()) {
+      Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
+                                       APFloat::rmNearestTiesToEven);
+      Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
+                                       APFloat::rmNearestTiesToEven);
+    } else {
+      Result.getComplexIntReal() += RHS.getComplexIntReal();
+      Result.getComplexIntImag() += RHS.getComplexIntImag();
+    }
+    break;
+  case BO_Sub:
+    if (Result.isComplexFloat()) {
+      Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
+                                            APFloat::rmNearestTiesToEven);
+      Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
+                                            APFloat::rmNearestTiesToEven);
+    } else {
+      Result.getComplexIntReal() -= RHS.getComplexIntReal();
+      Result.getComplexIntImag() -= RHS.getComplexIntImag();
+    }
+    break;
+  case BO_Mul:
+    if (Result.isComplexFloat()) {
+      ComplexValue LHS = Result;
+      APFloat &LHS_r = LHS.getComplexFloatReal();
+      APFloat &LHS_i = LHS.getComplexFloatImag();
+      APFloat &RHS_r = RHS.getComplexFloatReal();
+      APFloat &RHS_i = RHS.getComplexFloatImag();
+
+      APFloat Tmp = LHS_r;
+      Tmp.multiply(RHS_r, APFloat::rmNearestTiesToEven);
+      Result.getComplexFloatReal() = Tmp;
+      Tmp = LHS_i;
+      Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
+      Result.getComplexFloatReal().subtract(Tmp, APFloat::rmNearestTiesToEven);
+
+      Tmp = LHS_r;
+      Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
+      Result.getComplexFloatImag() = Tmp;
+      Tmp = LHS_i;
+      Tmp.multiply(RHS_r, APFloat::rmNearestTiesToEven);
+      Result.getComplexFloatImag().add(Tmp, APFloat::rmNearestTiesToEven);
+    } else {
+      ComplexValue LHS = Result;
+      Result.getComplexIntReal() =
+        (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
+         LHS.getComplexIntImag() * RHS.getComplexIntImag());
+      Result.getComplexIntImag() =
+        (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
+         LHS.getComplexIntImag() * RHS.getComplexIntReal());
+    }
+    break;
+  case BO_Div:
+    if (Result.isComplexFloat()) {
+      ComplexValue LHS = Result;
+      APFloat &LHS_r = LHS.getComplexFloatReal();
+      APFloat &LHS_i = LHS.getComplexFloatImag();
+      APFloat &RHS_r = RHS.getComplexFloatReal();
+      APFloat &RHS_i = RHS.getComplexFloatImag();
+      APFloat &Res_r = Result.getComplexFloatReal();
+      APFloat &Res_i = Result.getComplexFloatImag();
+
+      APFloat Den = RHS_r;
+      Den.multiply(RHS_r, APFloat::rmNearestTiesToEven);
+      APFloat Tmp = RHS_i;
+      Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
+      Den.add(Tmp, APFloat::rmNearestTiesToEven);
+
+      Res_r = LHS_r;
+      Res_r.multiply(RHS_r, APFloat::rmNearestTiesToEven);
+      Tmp = LHS_i;
+      Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
+      Res_r.add(Tmp, APFloat::rmNearestTiesToEven);
+      Res_r.divide(Den, APFloat::rmNearestTiesToEven);
+
+      Res_i = LHS_i;
+      Res_i.multiply(RHS_r, APFloat::rmNearestTiesToEven);
+      Tmp = LHS_r;
+      Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
+      Res_i.subtract(Tmp, APFloat::rmNearestTiesToEven);
+      Res_i.divide(Den, APFloat::rmNearestTiesToEven);
+    } else {
+      if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
+        return Error(E, diag::note_expr_divide_by_zero);
+
+      ComplexValue LHS = Result;
+      APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
+        RHS.getComplexIntImag() * RHS.getComplexIntImag();
+      Result.getComplexIntReal() =
+        (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
+         LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
+      Result.getComplexIntImag() =
+        (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
+         LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
+    }
+    break;
+  }
+
+  return true;
+}
+
+bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
+  // Get the operand value into 'Result'.
+  if (!Visit(E->getSubExpr()))
+    return false;
+
+  switch (E->getOpcode()) {
+  default:
+    return Error(E);
+  case UO_Extension:
+    return true;
+  case UO_Plus:
+    // The result is always just the subexpr.
+    return true;
+  case UO_Minus:
+    if (Result.isComplexFloat()) {
+      Result.getComplexFloatReal().changeSign();
+      Result.getComplexFloatImag().changeSign();
+    }
+    else {
+      Result.getComplexIntReal() = -Result.getComplexIntReal();
+      Result.getComplexIntImag() = -Result.getComplexIntImag();
+    }
+    return true;
+  case UO_Not:
+    if (Result.isComplexFloat())
+      Result.getComplexFloatImag().changeSign();
+    else
+      Result.getComplexIntImag() = -Result.getComplexIntImag();
+    return true;
+  }
+}
+
+bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
+  if (E->getNumInits() == 2) {
+    if (E->getType()->isComplexType()) {
+      Result.makeComplexFloat();
+      if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info))
+        return false;
+      if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info))
+        return false;
+    } else {
+      Result.makeComplexInt();
+      if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info))
+        return false;
+      if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info))
+        return false;
+    }
+    return true;
+  }
+  return ExprEvaluatorBaseTy::VisitInitListExpr(E);
+}
+
+//===----------------------------------------------------------------------===//
+// Void expression evaluation, primarily for a cast to void on the LHS of a
+// comma operator
+//===----------------------------------------------------------------------===//
+
+namespace {
+class VoidExprEvaluator
+  : public ExprEvaluatorBase<VoidExprEvaluator, bool> {
+public:
+  VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
+
+  bool Success(const APValue &V, const Expr *e) { return true; }
+
+  bool VisitCastExpr(const CastExpr *E) {
+    switch (E->getCastKind()) {
+    default:
+      return ExprEvaluatorBaseTy::VisitCastExpr(E);
+    case CK_ToVoid:
+      VisitIgnoredValue(E->getSubExpr());
+      return true;
+    }
+  }
+};
+} // end anonymous namespace
+
+static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
+  assert(E->isRValue() && E->getType()->isVoidType());
+  return VoidExprEvaluator(Info).Visit(E);
+}
+
+//===----------------------------------------------------------------------===//
+// Top level Expr::EvaluateAsRValue method.
+//===----------------------------------------------------------------------===//
+
+static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
+  // In C, function designators are not lvalues, but we evaluate them as if they
+  // are.
+  if (E->isGLValue() || E->getType()->isFunctionType()) {
+    LValue LV;
+    if (!EvaluateLValue(E, LV, Info))
+      return false;
+    LV.moveInto(Result);
+  } else if (E->getType()->isVectorType()) {
+    if (!EvaluateVector(E, Result, Info))
+      return false;
+  } else if (E->getType()->isIntegralOrEnumerationType()) {
+    if (!IntExprEvaluator(Info, Result).Visit(E))
+      return false;
+  } else if (E->getType()->hasPointerRepresentation()) {
+    LValue LV;
+    if (!EvaluatePointer(E, LV, Info))
+      return false;
+    LV.moveInto(Result);
+  } else if (E->getType()->isRealFloatingType()) {
+    llvm::APFloat F(0.0);
+    if (!EvaluateFloat(E, F, Info))
+      return false;
+    Result = APValue(F);
+  } else if (E->getType()->isAnyComplexType()) {
+    ComplexValue C;
+    if (!EvaluateComplex(E, C, Info))
+      return false;
+    C.moveInto(Result);
+  } else if (E->getType()->isMemberPointerType()) {
+    MemberPtr P;
+    if (!EvaluateMemberPointer(E, P, Info))
+      return false;
+    P.moveInto(Result);
+    return true;
+  } else if (E->getType()->isArrayType()) {
+    LValue LV;
+    LV.set(E, Info.CurrentCall->Index);
+    if (!EvaluateArray(E, LV, Info.CurrentCall->Temporaries[E], Info))
+      return false;
+    Result = Info.CurrentCall->Temporaries[E];
+  } else if (E->getType()->isRecordType()) {
+    LValue LV;
+    LV.set(E, Info.CurrentCall->Index);
+    if (!EvaluateRecord(E, LV, Info.CurrentCall->Temporaries[E], Info))
+      return false;
+    Result = Info.CurrentCall->Temporaries[E];
+  } else if (E->getType()->isVoidType()) {
+    if (Info.getLangOpts().CPlusPlus0x)
+      Info.CCEDiag(E, diag::note_constexpr_nonliteral)
+        << E->getType();
+    else
+      Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
+    if (!EvaluateVoid(E, Info))
+      return false;
+  } else if (Info.getLangOpts().CPlusPlus0x) {
+    Info.Diag(E, diag::note_constexpr_nonliteral) << E->getType();
+    return false;
+  } else {
+    Info.Diag(E, diag::note_invalid_subexpr_in_const_expr);
+    return false;
+  }
+
+  return true;
+}
+
+/// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
+/// cases, the in-place evaluation is essential, since later initializers for
+/// an object can indirectly refer to subobjects which were initialized earlier.
+static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
+                            const Expr *E, CheckConstantExpressionKind CCEK,
+                            bool AllowNonLiteralTypes) {
+  if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E))
+    return false;
+
+  if (E->isRValue()) {
+    // Evaluate arrays and record types in-place, so that later initializers can
+    // refer to earlier-initialized members of the object.
+    if (E->getType()->isArrayType())
+      return EvaluateArray(E, This, Result, Info);
+    else if (E->getType()->isRecordType())
+      return EvaluateRecord(E, This, Result, Info);
+  }
+
+  // For any other type, in-place evaluation is unimportant.
+  return Evaluate(Result, Info, E);
+}
+
+/// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
+/// lvalue-to-rvalue cast if it is an lvalue.
+static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
+  if (!CheckLiteralType(Info, E))
+    return false;
+
+  if (!::Evaluate(Result, Info, E))
+    return false;
+
+  if (E->isGLValue()) {
+    LValue LV;
+    LV.setFrom(Info.Ctx, Result);
+    if (!HandleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
+      return false;
+  }
+
+  // Check this core constant expression is a constant expression.
+  return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result);
+}
+
+/// EvaluateAsRValue - Return true if this is a constant which we can fold using
+/// any crazy technique (that has nothing to do with language standards) that
+/// we want to.  If this function returns true, it returns the folded constant
+/// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
+/// will be applied to the result.
+bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const {
+  // Fast-path evaluations of integer literals, since we sometimes see files
+  // containing vast quantities of these.
+  if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(this)) {
+    Result.Val = APValue(APSInt(L->getValue(),
+                                L->getType()->isUnsignedIntegerType()));
+    return true;
+  }
+
+  // FIXME: Evaluating values of large array and record types can cause
+  // performance problems. Only do so in C++11 for now.
+  if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
+      !Ctx.getLangOpts().CPlusPlus0x)
+    return false;
+
+  EvalInfo Info(Ctx, Result);
+  return ::EvaluateAsRValue(Info, this, Result.Val);
+}
+
+bool Expr::EvaluateAsBooleanCondition(bool &Result,
+                                      const ASTContext &Ctx) const {
+  EvalResult Scratch;
+  return EvaluateAsRValue(Scratch, Ctx) &&
+         HandleConversionToBool(Scratch.Val, Result);
+}
+
+bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx,
+                         SideEffectsKind AllowSideEffects) const {
+  if (!getType()->isIntegralOrEnumerationType())
+    return false;
+
+  EvalResult ExprResult;
+  if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isInt() ||
+      (!AllowSideEffects && ExprResult.HasSideEffects))
+    return false;
+
+  Result = ExprResult.Val.getInt();
+  return true;
+}
+
+bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const {
+  EvalInfo Info(Ctx, Result);
+
+  LValue LV;
+  if (!EvaluateLValue(this, LV, Info) || Result.HasSideEffects ||
+      !CheckLValueConstantExpression(Info, getExprLoc(),
+                                     Ctx.getLValueReferenceType(getType()), LV))
+    return false;
+
+  LV.moveInto(Result.Val);
+  return true;
+}
+
+bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
+                                 const VarDecl *VD,
+                      llvm::SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
+  // FIXME: Evaluating initializers for large array and record types can cause
+  // performance problems. Only do so in C++11 for now.
+  if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
+      !Ctx.getLangOpts().CPlusPlus0x)
+    return false;
+
+  Expr::EvalStatus EStatus;
+  EStatus.Diag = &Notes;
+
+  EvalInfo InitInfo(Ctx, EStatus);
+  InitInfo.setEvaluatingDecl(VD, Value);
+
+  LValue LVal;
+  LVal.set(VD);
+
+  // C++11 [basic.start.init]p2:
+  //  Variables with static storage duration or thread storage duration shall be
+  //  zero-initialized before any other initialization takes place.
+  // This behavior is not present in C.
+  if (Ctx.getLangOpts().CPlusPlus && !VD->hasLocalStorage() &&
+      !VD->getType()->isReferenceType()) {
+    ImplicitValueInitExpr VIE(VD->getType());
+    if (!EvaluateInPlace(Value, InitInfo, LVal, &VIE, CCEK_Constant,
+                         /*AllowNonLiteralTypes=*/true))
+      return false;
+  }
+
+  if (!EvaluateInPlace(Value, InitInfo, LVal, this, CCEK_Constant,
+                         /*AllowNonLiteralTypes=*/true) ||
+      EStatus.HasSideEffects)
+    return false;
+
+  return CheckConstantExpression(InitInfo, VD->getLocation(), VD->getType(),
+                                 Value);
+}
+
+/// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
+/// constant folded, but discard the result.
+bool Expr::isEvaluatable(const ASTContext &Ctx) const {
+  EvalResult Result;
+  return EvaluateAsRValue(Result, Ctx) && !Result.HasSideEffects;
+}
+
+bool Expr::HasSideEffects(const ASTContext &Ctx) const {
+  return HasSideEffect(Ctx).Visit(this);
+}
+
+APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx) const {
+  EvalResult EvalResult;
+  bool Result = EvaluateAsRValue(EvalResult, Ctx);
+  (void)Result;
+  assert(Result && "Could not evaluate expression");
+  assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer");
+
+  return EvalResult.Val.getInt();
+}
+
+ bool Expr::EvalResult::isGlobalLValue() const {
+   assert(Val.isLValue());
+   return IsGlobalLValue(Val.getLValueBase());
+ }
+
+
+/// isIntegerConstantExpr - this recursive routine will test if an expression is
+/// an integer constant expression.
+
+/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
+/// comma, etc
+///
+/// FIXME: Handle offsetof.  Two things to do:  Handle GCC's __builtin_offsetof
+/// to support gcc 4.0+  and handle the idiom GCC recognizes with a null pointer
+/// cast+dereference.
+
+// CheckICE - This function does the fundamental ICE checking: the returned
+// ICEDiag contains a Val of 0, 1, or 2, and a possibly null SourceLocation.
+// Note that to reduce code duplication, this helper does no evaluation
+// itself; the caller checks whether the expression is evaluatable, and
+// in the rare cases where CheckICE actually cares about the evaluated
+// value, it calls into Evalute.
+//
+// Meanings of Val:
+// 0: This expression is an ICE.
+// 1: This expression is not an ICE, but if it isn't evaluated, it's
+//    a legal subexpression for an ICE. This return value is used to handle
+//    the comma operator in C99 mode.
+// 2: This expression is not an ICE, and is not a legal subexpression for one.
+
+namespace {
+
+struct ICEDiag {
+  unsigned Val;
+  SourceLocation Loc;
+
+  public:
+  ICEDiag(unsigned v, SourceLocation l) : Val(v), Loc(l) {}
+  ICEDiag() : Val(0) {}
+};
+
+}
+
+static ICEDiag NoDiag() { return ICEDiag(); }
+
+static ICEDiag CheckEvalInICE(const Expr* E, ASTContext &Ctx) {
+  Expr::EvalResult EVResult;
+  if (!E->EvaluateAsRValue(EVResult, Ctx) || EVResult.HasSideEffects ||
+      !EVResult.Val.isInt()) {
+    return ICEDiag(2, E->getLocStart());
+  }
+  return NoDiag();
+}
+
+static ICEDiag CheckICE(const Expr* E, ASTContext &Ctx) {
+  assert(!E->isValueDependent() && "Should not see value dependent exprs!");
+  if (!E->getType()->isIntegralOrEnumerationType()) {
+    return ICEDiag(2, E->getLocStart());
+  }
+
+  switch (E->getStmtClass()) {
+#define ABSTRACT_STMT(Node)
+#define STMT(Node, Base) case Expr::Node##Class:
+#define EXPR(Node, Base)
+#include "clang/AST/StmtNodes.inc"
+  case Expr::PredefinedExprClass:
+  case Expr::FloatingLiteralClass:
+  case Expr::ImaginaryLiteralClass:
+  case Expr::StringLiteralClass:
+  case Expr::ArraySubscriptExprClass:
+  case Expr::MemberExprClass:
+  case Expr::CompoundAssignOperatorClass:
+  case Expr::CompoundLiteralExprClass:
+  case Expr::ExtVectorElementExprClass:
+  case Expr::DesignatedInitExprClass:
+  case Expr::ImplicitValueInitExprClass:
+  case Expr::ParenListExprClass:
+  case Expr::VAArgExprClass:
+  case Expr::AddrLabelExprClass:
+  case Expr::StmtExprClass:
+  case Expr::CXXMemberCallExprClass:
+  case Expr::CUDAKernelCallExprClass:
+  case Expr::CXXDynamicCastExprClass:
+  case Expr::CXXTypeidExprClass:
+  case Expr::CXXUuidofExprClass:
+  case Expr::CXXNullPtrLiteralExprClass:
+  case Expr::UserDefinedLiteralClass:
+  case Expr::CXXThisExprClass:
+  case Expr::CXXThrowExprClass:
+  case Expr::CXXNewExprClass:
+  case Expr::CXXDeleteExprClass:
+  case Expr::CXXPseudoDestructorExprClass:
+  case Expr::UnresolvedLookupExprClass:
+  case Expr::DependentScopeDeclRefExprClass:
+  case Expr::CXXConstructExprClass:
+  case Expr::CXXBindTemporaryExprClass:
+  case Expr::ExprWithCleanupsClass:
+  case Expr::CXXTemporaryObjectExprClass:
+  case Expr::CXXUnresolvedConstructExprClass:
+  case Expr::CXXDependentScopeMemberExprClass:
+  case Expr::UnresolvedMemberExprClass:
+  case Expr::ObjCStringLiteralClass:
+  case Expr::ObjCNumericLiteralClass:
+  case Expr::ObjCArrayLiteralClass:
+  case Expr::ObjCDictionaryLiteralClass:
+  case Expr::ObjCEncodeExprClass:
+  case Expr::ObjCMessageExprClass:
+  case Expr::ObjCSelectorExprClass:
+  case Expr::ObjCProtocolExprClass:
+  case Expr::ObjCIvarRefExprClass:
+  case Expr::ObjCPropertyRefExprClass:
+  case Expr::ObjCSubscriptRefExprClass:
+  case Expr::ObjCIsaExprClass:
+  case Expr::ShuffleVectorExprClass:
+  case Expr::BlockExprClass:
+  case Expr::NoStmtClass:
+  case Expr::OpaqueValueExprClass:
+  case Expr::PackExpansionExprClass:
+  case Expr::SubstNonTypeTemplateParmPackExprClass:
+  case Expr::AsTypeExprClass:
+  case Expr::ObjCIndirectCopyRestoreExprClass:
+  case Expr::MaterializeTemporaryExprClass:
+  case Expr::PseudoObjectExprClass:
+  case Expr::AtomicExprClass:
+  case Expr::InitListExprClass:
+  case Expr::LambdaExprClass:
+    return ICEDiag(2, E->getLocStart());
+
+  case Expr::SizeOfPackExprClass:
+  case Expr::GNUNullExprClass:
+    // GCC considers the GNU __null value to be an integral constant expression.
+    return NoDiag();
+
+  case Expr::SubstNonTypeTemplateParmExprClass:
+    return
+      CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
+
+  case Expr::ParenExprClass:
+    return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
+  case Expr::GenericSelectionExprClass:
+    return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
+  case Expr::IntegerLiteralClass:
+  case Expr::CharacterLiteralClass:
+  case Expr::ObjCBoolLiteralExprClass:
+  case Expr::CXXBoolLiteralExprClass:
+  case Expr::CXXScalarValueInitExprClass:
+  case Expr::UnaryTypeTraitExprClass:
+  case Expr::BinaryTypeTraitExprClass:
+  case Expr::TypeTraitExprClass:
+  case Expr::ArrayTypeTraitExprClass:
+  case Expr::ExpressionTraitExprClass:
+  case Expr::CXXNoexceptExprClass:
+    return NoDiag();
+  case Expr::CallExprClass:
+  case Expr::CXXOperatorCallExprClass: {
+    // C99 6.6/3 allows function calls within unevaluated subexpressions of
+    // constant expressions, but they can never be ICEs because an ICE cannot
+    // contain an operand of (pointer to) function type.
+    const CallExpr *CE = cast<CallExpr>(E);
+    if (CE->isBuiltinCall())
+      return CheckEvalInICE(E, Ctx);
+    return ICEDiag(2, E->getLocStart());
+  }
+  case Expr::DeclRefExprClass: {
+    if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl()))
+      return NoDiag();
+    const ValueDecl *D = dyn_cast<ValueDecl>(cast<DeclRefExpr>(E)->getDecl());
+    if (Ctx.getLangOpts().CPlusPlus &&
+        D && IsConstNonVolatile(D->getType())) {
+      // Parameter variables are never constants.  Without this check,
+      // getAnyInitializer() can find a default argument, which leads
+      // to chaos.
+      if (isa<ParmVarDecl>(D))
+        return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation());
+
+      // C++ 7.1.5.1p2
+      //   A variable of non-volatile const-qualified integral or enumeration
+      //   type initialized by an ICE can be used in ICEs.
+      if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) {
+        if (!Dcl->getType()->isIntegralOrEnumerationType())
+          return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation());
+
+        const VarDecl *VD;
+        // Look for a declaration of this variable that has an initializer, and
+        // check whether it is an ICE.
+        if (Dcl->getAnyInitializer(VD) && VD->checkInitIsICE())
+          return NoDiag();
+        else
+          return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation());
+      }
+    }
+    return ICEDiag(2, E->getLocStart());
+  }
+  case Expr::UnaryOperatorClass: {
+    const UnaryOperator *Exp = cast<UnaryOperator>(E);
+    switch (Exp->getOpcode()) {
+    case UO_PostInc:
+    case UO_PostDec:
+    case UO_PreInc:
+    case UO_PreDec:
+    case UO_AddrOf:
+    case UO_Deref:
+      // C99 6.6/3 allows increment and decrement within unevaluated
+      // subexpressions of constant expressions, but they can never be ICEs
+      // because an ICE cannot contain an lvalue operand.
+      return ICEDiag(2, E->getLocStart());
+    case UO_Extension:
+    case UO_LNot:
+    case UO_Plus:
+    case UO_Minus:
+    case UO_Not:
+    case UO_Real:
+    case UO_Imag:
+      return CheckICE(Exp->getSubExpr(), Ctx);
+    }
+    
+    // OffsetOf falls through here.
+  }
+  case Expr::OffsetOfExprClass: {
+      // Note that per C99, offsetof must be an ICE. And AFAIK, using
+      // EvaluateAsRValue matches the proposed gcc behavior for cases like
+      // "offsetof(struct s{int x[4];}, x[1.0])".  This doesn't affect
+      // compliance: we should warn earlier for offsetof expressions with
+      // array subscripts that aren't ICEs, and if the array subscripts
+      // are ICEs, the value of the offsetof must be an integer constant.
+      return CheckEvalInICE(E, Ctx);
+  }
+  case Expr::UnaryExprOrTypeTraitExprClass: {
+    const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
+    if ((Exp->getKind() ==  UETT_SizeOf) &&
+        Exp->getTypeOfArgument()->isVariableArrayType())
+      return ICEDiag(2, E->getLocStart());
+    return NoDiag();
+  }
+  case Expr::BinaryOperatorClass: {
+    const BinaryOperator *Exp = cast<BinaryOperator>(E);
+    switch (Exp->getOpcode()) {
+    case BO_PtrMemD:
+    case BO_PtrMemI:
+    case BO_Assign:
+    case BO_MulAssign:
+    case BO_DivAssign:
+    case BO_RemAssign:
+    case BO_AddAssign:
+    case BO_SubAssign:
+    case BO_ShlAssign:
+    case BO_ShrAssign:
+    case BO_AndAssign:
+    case BO_XorAssign:
+    case BO_OrAssign:
+      // C99 6.6/3 allows assignments within unevaluated subexpressions of
+      // constant expressions, but they can never be ICEs because an ICE cannot
+      // contain an lvalue operand.
+      return ICEDiag(2, E->getLocStart());
+
+    case BO_Mul:
+    case BO_Div:
+    case BO_Rem:
+    case BO_Add:
+    case BO_Sub:
+    case BO_Shl:
+    case BO_Shr:
+    case BO_LT:
+    case BO_GT:
+    case BO_LE:
+    case BO_GE:
+    case BO_EQ:
+    case BO_NE:
+    case BO_And:
+    case BO_Xor:
+    case BO_Or:
+    case BO_Comma: {
+      ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
+      ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
+      if (Exp->getOpcode() == BO_Div ||
+          Exp->getOpcode() == BO_Rem) {
+        // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
+        // we don't evaluate one.
+        if (LHSResult.Val == 0 && RHSResult.Val == 0) {
+          llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
+          if (REval == 0)
+            return ICEDiag(1, E->getLocStart());
+          if (REval.isSigned() && REval.isAllOnesValue()) {
+            llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
+            if (LEval.isMinSignedValue())
+              return ICEDiag(1, E->getLocStart());
+          }
+        }
+      }
+      if (Exp->getOpcode() == BO_Comma) {
+        if (Ctx.getLangOpts().C99) {
+          // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
+          // if it isn't evaluated.
+          if (LHSResult.Val == 0 && RHSResult.Val == 0)
+            return ICEDiag(1, E->getLocStart());
+        } else {
+          // In both C89 and C++, commas in ICEs are illegal.
+          return ICEDiag(2, E->getLocStart());
+        }
+      }
+      if (LHSResult.Val >= RHSResult.Val)
+        return LHSResult;
+      return RHSResult;
+    }
+    case BO_LAnd:
+    case BO_LOr: {
+      ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
+      ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
+      if (LHSResult.Val == 0 && RHSResult.Val == 1) {
+        // Rare case where the RHS has a comma "side-effect"; we need
+        // to actually check the condition to see whether the side
+        // with the comma is evaluated.
+        if ((Exp->getOpcode() == BO_LAnd) !=
+            (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
+          return RHSResult;
+        return NoDiag();
+      }
+
+      if (LHSResult.Val >= RHSResult.Val)
+        return LHSResult;
+      return RHSResult;
+    }
+    }
+  }
+  case Expr::ImplicitCastExprClass:
+  case Expr::CStyleCastExprClass:
+  case Expr::CXXFunctionalCastExprClass:
+  case Expr::CXXStaticCastExprClass:
+  case Expr::CXXReinterpretCastExprClass:
+  case Expr::CXXConstCastExprClass:
+  case Expr::ObjCBridgedCastExprClass: {
+    const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
+    if (isa<ExplicitCastExpr>(E)) {
+      if (const FloatingLiteral *FL
+            = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
+        unsigned DestWidth = Ctx.getIntWidth(E->getType());
+        bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
+        APSInt IgnoredVal(DestWidth, !DestSigned);
+        bool Ignored;
+        // If the value does not fit in the destination type, the behavior is
+        // undefined, so we are not required to treat it as a constant
+        // expression.
+        if (FL->getValue().convertToInteger(IgnoredVal,
+                                            llvm::APFloat::rmTowardZero,
+                                            &Ignored) & APFloat::opInvalidOp)
+          return ICEDiag(2, E->getLocStart());
+        return NoDiag();
+      }
+    }
+    switch (cast<CastExpr>(E)->getCastKind()) {
+    case CK_LValueToRValue:
+    case CK_AtomicToNonAtomic:
+    case CK_NonAtomicToAtomic:
+    case CK_NoOp:
+    case CK_IntegralToBoolean:
+    case CK_IntegralCast:
+      return CheckICE(SubExpr, Ctx);
+    default:
+      return ICEDiag(2, E->getLocStart());
+    }
+  }
+  case Expr::BinaryConditionalOperatorClass: {
+    const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
+    ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
+    if (CommonResult.Val == 2) return CommonResult;
+    ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
+    if (FalseResult.Val == 2) return FalseResult;
+    if (CommonResult.Val == 1) return CommonResult;
+    if (FalseResult.Val == 1 &&
+        Exp->getCommon()->EvaluateKnownConstInt(Ctx) == 0) return NoDiag();
+    return FalseResult;
+  }
+  case Expr::ConditionalOperatorClass: {
+    const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
+    // If the condition (ignoring parens) is a __builtin_constant_p call,
+    // then only the true side is actually considered in an integer constant
+    // expression, and it is fully evaluated.  This is an important GNU
+    // extension.  See GCC PR38377 for discussion.
+    if (const CallExpr *CallCE
+        = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
+      if (CallCE->isBuiltinCall() == Builtin::BI__builtin_constant_p)
+        return CheckEvalInICE(E, Ctx);
+    ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
+    if (CondResult.Val == 2)
+      return CondResult;
+
+    ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
+    ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
+
+    if (TrueResult.Val == 2)
+      return TrueResult;
+    if (FalseResult.Val == 2)
+      return FalseResult;
+    if (CondResult.Val == 1)
+      return CondResult;
+    if (TrueResult.Val == 0 && FalseResult.Val == 0)
+      return NoDiag();
+    // Rare case where the diagnostics depend on which side is evaluated
+    // Note that if we get here, CondResult is 0, and at least one of
+    // TrueResult and FalseResult is non-zero.
+    if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0) {
+      return FalseResult;
+    }
+    return TrueResult;
+  }
+  case Expr::CXXDefaultArgExprClass:
+    return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
+  case Expr::ChooseExprClass: {
+    return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(Ctx), Ctx);
+  }
+  }
+
+  llvm_unreachable("Invalid StmtClass!");
+}
+
+/// Evaluate an expression as a C++11 integral constant expression.
+static bool EvaluateCPlusPlus11IntegralConstantExpr(ASTContext &Ctx,
+                                                    const Expr *E,
+                                                    llvm::APSInt *Value,
+                                                    SourceLocation *Loc) {
+  if (!E->getType()->isIntegralOrEnumerationType()) {
+    if (Loc) *Loc = E->getExprLoc();
+    return false;
+  }
+
+  APValue Result;
+  if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc))
+    return false;
+
+  assert(Result.isInt() && "pointer cast to int is not an ICE");
+  if (Value) *Value = Result.getInt();
+  return true;
+}
+
+bool Expr::isIntegerConstantExpr(ASTContext &Ctx, SourceLocation *Loc) const {
+  if (Ctx.getLangOpts().CPlusPlus0x)
+    return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, 0, Loc);
+
+  ICEDiag d = CheckICE(this, Ctx);
+  if (d.Val != 0) {
+    if (Loc) *Loc = d.Loc;
+    return false;
+  }
+  return true;
+}
+
+bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, ASTContext &Ctx,
+                                 SourceLocation *Loc, bool isEvaluated) const {
+  if (Ctx.getLangOpts().CPlusPlus0x)
+    return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc);
+
+  if (!isIntegerConstantExpr(Ctx, Loc))
+    return false;
+  if (!EvaluateAsInt(Value, Ctx))
+    llvm_unreachable("ICE cannot be evaluated!");
+  return true;
+}
+
+bool Expr::isCXX98IntegralConstantExpr(ASTContext &Ctx) const {
+  return CheckICE(this, Ctx).Val == 0;
+}
+
+bool Expr::isCXX11ConstantExpr(ASTContext &Ctx, APValue *Result,
+                               SourceLocation *Loc) const {
+  // We support this checking in C++98 mode in order to diagnose compatibility
+  // issues.
+  assert(Ctx.getLangOpts().CPlusPlus);
+
+  // Build evaluation settings.
+  Expr::EvalStatus Status;
+  llvm::SmallVector<PartialDiagnosticAt, 8> Diags;
+  Status.Diag = &Diags;
+  EvalInfo Info(Ctx, Status);
+
+  APValue Scratch;
+  bool IsConstExpr = ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch);
+
+  if (!Diags.empty()) {
+    IsConstExpr = false;
+    if (Loc) *Loc = Diags[0].first;
+  } else if (!IsConstExpr) {
+    // FIXME: This shouldn't happen.
+    if (Loc) *Loc = getExprLoc();
+  }
+
+  return IsConstExpr;
+}
+
+bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
+                                   llvm::SmallVectorImpl<
+                                     PartialDiagnosticAt> &Diags) {
+  // FIXME: It would be useful to check constexpr function templates, but at the
+  // moment the constant expression evaluator cannot cope with the non-rigorous
+  // ASTs which we build for dependent expressions.
+  if (FD->isDependentContext())
+    return true;
+
+  Expr::EvalStatus Status;
+  Status.Diag = &Diags;
+
+  EvalInfo Info(FD->getASTContext(), Status);
+  Info.CheckingPotentialConstantExpression = true;
+
+  const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
+  const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : 0;
+
+  // FIXME: Fabricate an arbitrary expression on the stack and pretend that it
+  // is a temporary being used as the 'this' pointer.
+  LValue This;
+  ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
+  This.set(&VIE, Info.CurrentCall->Index);
+
+  ArrayRef<const Expr*> Args;
+
+  SourceLocation Loc = FD->getLocation();
+
+  APValue Scratch;
+  if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD))
+    HandleConstructorCall(Loc, This, Args, CD, Info, Scratch);
+  else
+    HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : 0,
+                       Args, FD->getBody(), Info, Scratch);
+
+  return Diags.empty();
+}