diff --git a/include/clang/AST/DeclBase.h b/include/clang/AST/DeclBase.h
index 30628e692c..a9b948eee5 100644
--- a/include/clang/AST/DeclBase.h
+++ b/include/clang/AST/DeclBase.h
@@ -132,7 +132,12 @@ public:
     /// *introduces* a number of other declarations into the current
     /// scope, and those declarations use the IDNS of their targets,
     /// but the actual using declarations go in this namespace.
-    IDNS_Using               = 0x0200
+    IDNS_Using               = 0x0200,
+
+    /// This declaration is a C++ operator declared in a non-class
+    /// context.  All such operators are also in IDNS_Ordinary.
+    /// C++ lexical operator lookup looks for these.
+    IDNS_NonMemberOperator   = 0x0400
   };
 
   /// ObjCDeclQualifier - Qualifier used on types in method declarations
@@ -533,6 +538,14 @@ public:
               FOK_Declared : FOK_Undeclared);
   }
 
+  /// Specifies that this declaration is a C++ overloaded non-member.
+  void setNonMemberOperator() {
+    assert(getKind() == Function || getKind() == FunctionTemplate);
+    assert((IdentifierNamespace & IDNS_Ordinary) &&
+           "visible non-member operators should be in ordinary namespace");
+    IdentifierNamespace |= IDNS_NonMemberOperator;
+  }
+
   // Implement isa/cast/dyncast/etc.
   static bool classof(const Decl *) { return true; }
   static bool classofKind(Kind K) { return true; }
diff --git a/lib/Frontend/PCHReaderDecl.cpp b/lib/Frontend/PCHReaderDecl.cpp
index 45f7e496ba..53647badff 100644
--- a/lib/Frontend/PCHReaderDecl.cpp
+++ b/lib/Frontend/PCHReaderDecl.cpp
@@ -197,6 +197,11 @@ void PCHDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
   for (unsigned I = 0; I != NumParams; ++I)
     Params.push_back(cast<ParmVarDecl>(Reader.GetDecl(Record[Idx++])));
   FD->setParams(Params.data(), NumParams);
+
+  // FIXME: order this properly w.r.t. friendness
+  // FIXME: this same thing needs to happen for function templates
+  if (FD->isOverloadedOperator() && !FD->getDeclContext()->isRecord())
+    FD->setNonMemberOperator();
 }
 
 void PCHDeclReader::VisitObjCMethodDecl(ObjCMethodDecl *MD) {
diff --git a/lib/Sema/Lookup.h b/lib/Sema/Lookup.h
index 97bc4f25a5..0961299587 100644
--- a/lib/Sema/Lookup.h
+++ b/lib/Sema/Lookup.h
@@ -124,7 +124,6 @@ public:
   };
 
   typedef UnresolvedSetImpl::iterator iterator;
-  typedef bool (*ResultFilter)(NamedDecl*, unsigned IDNS);
 
   LookupResult(Sema &SemaRef, DeclarationName Name, SourceLocation NameLoc,
                Sema::LookupNameKind LookupKind,
@@ -136,7 +135,6 @@ public:
       Name(Name),
       NameLoc(NameLoc),
       LookupKind(LookupKind),
-      IsAcceptableFn(0),
       IDNS(0),
       Redecl(Redecl != Sema::NotForRedeclaration),
       HideTags(true),
@@ -156,7 +154,6 @@ public:
       Name(Other.Name),
       NameLoc(Other.NameLoc),
       LookupKind(Other.LookupKind),
-      IsAcceptableFn(Other.IsAcceptableFn),
       IDNS(Other.IDNS),
       Redecl(Other.Redecl),
       HideTags(Other.HideTags),
@@ -242,8 +239,7 @@ public:
 
   /// \brief Tests whether the given declaration is acceptable.
   bool isAcceptableDecl(NamedDecl *D) const {
-    assert(IsAcceptableFn);
-    return IsAcceptableFn(D, IDNS);
+    return D->isInIdentifierNamespace(IDNS);
   }
 
   /// \brief Returns the identifier namespace mask for this lookup.
@@ -575,7 +571,6 @@ private:
   SourceLocation NameLoc;
   SourceRange NameContextRange;
   Sema::LookupNameKind LookupKind;
-  ResultFilter IsAcceptableFn; // set by configure()
   unsigned IDNS; // set by configure()
 
   bool Redecl;
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index cc57bdd5f8..7d2d866828 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -3269,6 +3269,12 @@ Sema::ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
     NewFD->setAccess(Access);
   }
 
+  if (NewFD->isOverloadedOperator() && !DC->isRecord() &&
+      NewFD->isInIdentifierNamespace(Decl::IDNS_Ordinary)) {
+    NewFD->setNonMemberOperator();
+    if (FunctionTemplate) FunctionTemplate->setNonMemberOperator();
+  }
+
   // If we have a function template, check the template parameter
   // list. This will check and merge default template arguments.
   if (FunctionTemplate) {
diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index a7a1084d31..0609eef3c9 100644
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -193,37 +193,6 @@ namespace {
   };
 }
 
-static bool IsAcceptableIDNS(NamedDecl *D, unsigned IDNS) {
-  return D->isInIdentifierNamespace(IDNS);
-}
-
-static bool IsAcceptableOperatorName(NamedDecl *D, unsigned IDNS) {
-  return D->isInIdentifierNamespace(IDNS) &&
-    !D->getDeclContext()->isRecord();
-}
-
-/// Gets the default result filter for the given lookup.
-static inline
-LookupResult::ResultFilter getResultFilter(Sema::LookupNameKind NameKind) {
-  switch (NameKind) {
-  case Sema::LookupOrdinaryName:
-  case Sema::LookupTagName:
-  case Sema::LookupMemberName:
-  case Sema::LookupRedeclarationWithLinkage: // FIXME: check linkage, scoping
-  case Sema::LookupUsingDeclName:
-  case Sema::LookupObjCProtocolName:
-  case Sema::LookupNestedNameSpecifierName:
-  case Sema::LookupNamespaceName:
-    return &IsAcceptableIDNS;
-
-  case Sema::LookupOperatorName:
-    return &IsAcceptableOperatorName;
-  }
-
-  llvm_unreachable("unkknown lookup kind");
-  return 0;
-}
-
 // Retrieve the set of identifier namespaces that correspond to a
 // specific kind of name lookup.
 static inline unsigned getIDNS(Sema::LookupNameKind NameKind,
@@ -232,7 +201,6 @@ static inline unsigned getIDNS(Sema::LookupNameKind NameKind,
   unsigned IDNS = 0;
   switch (NameKind) {
   case Sema::LookupOrdinaryName:
-  case Sema::LookupOperatorName:
   case Sema::LookupRedeclarationWithLinkage:
     IDNS = Decl::IDNS_Ordinary;
     if (CPlusPlus) {
@@ -241,6 +209,13 @@ static inline unsigned getIDNS(Sema::LookupNameKind NameKind,
     }
     break;
 
+  case Sema::LookupOperatorName:
+    // Operator lookup is its own crazy thing;  it is not the same
+    // as (e.g.) looking up an operator name for redeclaration.
+    assert(!Redeclaration && "cannot do redeclaration operator lookup");
+    IDNS = Decl::IDNS_NonMemberOperator;
+    break;
+
   case Sema::LookupTagName:
     if (CPlusPlus) {
       IDNS = Decl::IDNS_Type;
@@ -287,7 +262,6 @@ void LookupResult::configure() {
   IDNS = getIDNS(LookupKind,
                  SemaRef.getLangOptions().CPlusPlus,
                  isForRedeclaration());
-  IsAcceptableFn = getResultFilter(LookupKind);
 
   // If we're looking for one of the allocation or deallocation
   // operators, make sure that the implicitly-declared new and delete
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index fe60be062c..8924c7876a 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1140,6 +1140,12 @@ Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
     DC->makeDeclVisibleInContext(ToFriendD, /*Recoverable=*/ false);
   }
 
+  if (Function->isOverloadedOperator() && !DC->isRecord() &&
+      Function->isInIdentifierNamespace(Decl::IDNS_Ordinary)) {
+    Function->setNonMemberOperator();
+    if (FunctionTemplate) FunctionTemplate->setNonMemberOperator();
+  }
+
   return Function;
 }