Speculatively revert r124236

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124247 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 29 insertions, 70 deletions

diff --git a/include/clang/Sema/Overload.h b/include/clang/Sema/Overload.h
index 4a7cb20e61..fa3c94b0ac 100644
--- a/include/clang/Sema/Overload.h
+++ b/include/clang/Sema/Overload.h
@@ -133,30 +133,24 @@ namespace clang {
     /// Deprecated - Whether this the deprecated conversion of a
     /// string literal to a pointer to non-const character data
     /// (C++ 4.2p2).
-    unsigned DeprecatedStringLiteralToCharPtr : 1;
+    bool DeprecatedStringLiteralToCharPtr : 1;
 
     /// IncompatibleObjC - Whether this is an Objective-C conversion
     /// that we should warn about (if we actually use it).
-    unsigned IncompatibleObjC : 1;
+    bool IncompatibleObjC : 1;
 
     /// ReferenceBinding - True when this is a reference binding
     /// (C++ [over.ics.ref]).
-    unsigned ReferenceBinding : 1;
+    bool ReferenceBinding : 1;
 
     /// DirectBinding - True when this is a reference binding that is a
     /// direct binding (C++ [dcl.init.ref]).
-    unsigned DirectBinding : 1;
+    bool DirectBinding : 1;
+
+    /// RRefBinding - True when this is a reference binding of an rvalue
+    /// reference to an rvalue (C++0x [over.ics.rank]p3b4).
+    bool RRefBinding : 1;
 
-    /// \brief Whether this is an lvalue reference binding (otherwise, it's
-    /// an rvalue reference binding).
-    unsigned IsLvalueReference : 1;
-    
-    /// \brief Whether we're binding to a function lvalue.
-    unsigned BindsToFunctionLvalue : 1;
-    
-    /// \brief Whether we're binding to an rvalue.
-    unsigned BindsToRvalue : 1;
-    
     /// FromType - The type that this conversion is converting
     /// from. This is an opaque pointer that can be translated into a
     /// QualType.
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 602a118c3b..85ae6f7326 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -170,9 +170,7 @@ void StandardConversionSequence::setAsIdentityConversion() {
   DeprecatedStringLiteralToCharPtr = false;
   ReferenceBinding = false;
   DirectBinding = false;
-  IsLvalueReference = true;
-  BindsToFunctionLvalue = false;
-  BindsToRvalue = false;
+  RRefBinding = false;
   CopyConstructor = 0;
 }
 
@@ -2326,33 +2324,6 @@ compareStandardConversionSubsets(ASTContext &Context,
   return ImplicitConversionSequence::Indistinguishable;
 }
 
-/// \brief Determine whether one of the given reference bindings is better
-/// than the other based on what kind of bindings they are.
-static bool isBetterReferenceBindingKind(const StandardConversionSequence &SCS1,
-                                       const StandardConversionSequence &SCS2) {
-  // C++0x [over.ics.rank]p3b4:
-  //   -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
-  //      implicit object parameter of a non-static member function declared
-  //      without a ref-qualifier, and *either* S1 binds an rvalue reference 
-  //      to an rvalue and S2 binds an lvalue reference *or S1 binds an
-  //      lvalue reference to a function lvalue and S2 binds an rvalue 
-  //      reference*.
-  //
-  // FIXME: Rvalue references. We're going rogue with the above edits,
-  // because the semantics in the current C++0x working paper (N3225 at the
-  // time of this writing) break the standard definition of std::forward
-  // and std::reference_wrapper when dealing with references to functions.
-  // Proposed wording changes submitted to CWG for consideration.
-  //
-  // FIXME: Rvalue references. We don't know if we're dealing with the 
-  // implicit object parameter, or if the member function in this case has a 
-  // ref qualifier. (Of course, we don't have ref qualifiers yet.)
-  return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue &&
-          SCS2.IsLvalueReference) ||
-         (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue &&
-          !SCS2.IsLvalueReference);
-}
-  
 /// CompareStandardConversionSequences - Compare two standard
 /// conversion sequences to determine whether one is better than the
 /// other or if they are indistinguishable (C++ 13.3.3.2p3).
@@ -2458,12 +2429,18 @@ CompareStandardConversionSequences(Sema &S,
     return QualCK;
 
   if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
-    // Check for a better reference binding based on the kind of bindings.
-    if (isBetterReferenceBindingKind(SCS1, SCS2))
-      return ImplicitConversionSequence::Better;
-    else if (isBetterReferenceBindingKind(SCS2, SCS1))
-      return ImplicitConversionSequence::Worse;
-    
+    // C++0x [over.ics.rank]p3b4:
+    //   -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
+    //      implicit object parameter of a non-static member function declared
+    //      without a ref-qualifier, and S1 binds an rvalue reference to an
+    //      rvalue and S2 binds an lvalue reference.
+    // FIXME: Rvalue references. We don't know if we're dealing with the 
+    // implicit object parameter, or if the member function in this case has a 
+    // ref qualifier. (Of course, we don't have ref qualifiers yet.)
+    if (SCS1.RRefBinding != SCS2.RRefBinding)
+      return SCS1.RRefBinding ? ImplicitConversionSequence::Better
+                              : ImplicitConversionSequence::Worse;
+
     // C++ [over.ics.rank]p3b4:
     //   -- S1 and S2 are reference bindings (8.5.3), and the types to
     //      which the references refer are the same type except for
@@ -2989,9 +2966,7 @@ TryReferenceInit(Sema &S, Expr *&Init, QualType DeclType,
       ICS.Standard.setToType(2, T1);
       ICS.Standard.ReferenceBinding = true;
       ICS.Standard.DirectBinding = true;
-      ICS.Standard.IsLvalueReference = !isRValRef;
-      ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
-      ICS.Standard.BindsToRvalue = false;
+      ICS.Standard.RRefBinding = isRValRef && InitCategory.isRValue();
       ICS.Standard.CopyConstructor = 0;
 
       // Nothing more to do: the inaccessibility/ambiguity check for
@@ -3061,9 +3036,7 @@ TryReferenceInit(Sema &S, Expr *&Init, QualType DeclType,
     ICS.Standard.DirectBinding = 
       S.getLangOptions().CPlusPlus0x || 
       (InitCategory.isPRValue() && !T2->isRecordType());
-    ICS.Standard.IsLvalueReference = !isRValRef;
-    ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
-    ICS.Standard.BindsToRvalue = InitCategory.isRValue();        
+    ICS.Standard.RRefBinding = isRValRef && InitCategory.isRValue();
     ICS.Standard.CopyConstructor = 0;
     return ICS; 
   }
@@ -3141,14 +3114,10 @@ TryReferenceInit(Sema &S, Expr *&Init, QualType DeclType,
   // Of course, that's still a reference binding.
   if (ICS.isStandard()) {
     ICS.Standard.ReferenceBinding = true;
-    ICS.Standard.IsLvalueReference = !isRValRef;
-    ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
-    ICS.Standard.BindsToRvalue = true;
+    ICS.Standard.RRefBinding = isRValRef;
   } else if (ICS.isUserDefined()) {
     ICS.UserDefined.After.ReferenceBinding = true;
-    ICS.Standard.IsLvalueReference = !isRValRef;
-    ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
-    ICS.Standard.BindsToRvalue = true;
+    ICS.UserDefined.After.RRefBinding = isRValRef;
   }
 
   return ICS;
@@ -3243,11 +3212,7 @@ TryObjectArgumentInitialization(Sema &S, QualType OrigFromType,
   ICS.Standard.setAllToTypes(ImplicitParamType);
   ICS.Standard.ReferenceBinding = true;
   ICS.Standard.DirectBinding = true;
-  
-  // FIXME: Rvalue references.
-  ICS.Standard.IsLvalueReference = true; 
-  ICS.Standard.BindsToFunctionLvalue = false;
-  ICS.Standard.BindsToRvalue = false;
+  ICS.Standard.RRefBinding = false;
   return ICS;
 }
 
diff --git a/test/CXX/over/over.match/over.match.best/over.ics.rank/p3-0x.cpp b/test/CXX/over/over.match/over.match.best/over.ics.rank/p3-0x.cpp
index ab171bc3f6..faff058a50 100644
--- a/test/CXX/over/over.match/over.match.best/over.ics.rank/p3-0x.cpp
+++ b/test/CXX/over/over.match/over.match.best/over.ics.rank/p3-0x.cpp
@@ -50,10 +50,10 @@ struct remove_reference<T&&> {
 };
 
 namespace FunctionReferencesOverloading {
-  template<typename T> int &f(typename remove_reference<T>::type&);
-  template<typename T> float &f(typename remove_reference<T>::type&&);
+  template<typename T> int &f(typename remove_reference<T>::type&); // expected-note{{candidate function [with T = int (&)(int)]}}
+  template<typename T> float &f(typename remove_reference<T>::type&&); // expected-note{{candidate function [with T = int (&)(int)]}}
 
   void test_f(int (&func_ref)(int)) {
-    int &ir = f<int (&)(int)>(func_ref);
+    f<int (&)(int)>(func_ref); // expected-error{{call to 'f' is ambiguous}}
   }
 }