diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index 587a68beb225..82c72288d918 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -465,7 +465,7 @@ static void EmitMemberInitializer(CodeGenFunction &CGF,
                                          /*IsInitializer=*/true);
     CGF.EmitStoreThroughLValue(RHS, LHS, FieldType);
   } else if (FieldType->isArrayType() && !MemberInit->getInit()) {
-    CGF.EmitNullInitialization(LHS.getAddress(), Field->getType());
+    CGF.EmitMemSetToZero(LHS.getAddress(), Field->getType());
   } else if (!CGF.hasAggregateLLVMType(Field->getType())) {
     RHS = RValue::get(CGF.EmitScalarExpr(MemberInit->getInit(), true));
     CGF.EmitStoreThroughLValue(RHS, LHS, FieldType);
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index a4a4bda723d8..74e64e59a5a8 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1844,7 +1844,7 @@ LValue CodeGenFunction::EmitNullInitializationLValue(
                                               const CXXZeroInitValueExpr *E) {
   QualType Ty = E->getType();
   LValue LV = LValue::MakeAddr(CreateMemTemp(Ty), MakeQualifiers(Ty));
-  EmitNullInitialization(LV.getAddress(), Ty);
+  EmitMemSetToZero(LV.getAddress(), Ty);
   return LV;
 }
 
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 4a7e6ecc42d9..3bf2f8a52025 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -573,10 +573,14 @@ void AggExprEmitter::EmitNullInitializationToLValue(LValue LV, QualType T) {
     llvm::Value *Null = llvm::Constant::getNullValue(CGF.ConvertType(T));
     CGF.EmitStoreThroughLValue(RValue::get(Null), LV, T);
   } else {
+    // Otherwise, just memset the whole thing to zero.  This is legal
+    // because in LLVM, all default initializers are guaranteed to have a
+    // bit pattern of all zeros.
+    // FIXME: That isn't true for member pointers!
     // There's a potential optimization opportunity in combining
     // memsets; that would be easy for arrays, but relatively
     // difficult for structures with the current code.
-    CGF.EmitNullInitialization(LV.getAddress(), T);
+    CGF.EmitMemSetToZero(LV.getAddress(), T);
   }
 }
 
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index b07a02b5b3c7..2f70969e9490 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -123,10 +123,10 @@ public:
     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
   }
   Value *VisitCXXZeroInitValueExpr(const CXXZeroInitValueExpr *E) {
-    return CGF.CGM.EmitNullConstant(E->getType());
+    return llvm::Constant::getNullValue(ConvertType(E->getType()));
   }
   Value *VisitGNUNullExpr(const GNUNullExpr *E) {
-    return CGF.CGM.EmitNullConstant(E->getType());
+    return llvm::Constant::getNullValue(ConvertType(E->getType()));
   }
   Value *VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) {
     return llvm::ConstantInt::get(ConvertType(E->getType()),
diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index d44c56fcf68d..674f50234e55 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -632,7 +632,7 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
   // Fast enumeration state.
   QualType StateTy = getContext().getObjCFastEnumerationStateType();
   llvm::Value *StatePtr = CreateMemTemp(StateTy, "state.ptr");
-  EmitNullInitialization(StatePtr, StateTy);
+  EmitMemSetToZero(StatePtr, StateTy);
 
   // Number of elements in the items array.
   static const unsigned NumItems = 16;
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 222dcc4b8f5e..d3bf1645a026 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -472,23 +472,7 @@ void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type,
   CGM.ErrorUnsupported(S, Type, OmitOnError);
 }
 
-void
-CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) {
-  // If the type contains a pointer to data member we can't memset it to zero.
-  // Instead, create a null constant and copy it to the destination.
-  if (CGM.getTypes().ContainsPointerToDataMember(Ty)) {
-    llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty);
-    
-    llvm::GlobalVariable *NullVariable = 
-      new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(),
-                               /*isConstant=*/true, 
-                               llvm::GlobalVariable::PrivateLinkage,
-                               NullConstant, llvm::Twine());
-    EmitAggregateCopy(DestPtr, NullVariable, Ty, /*isVolatile=*/false);
-    return;
-  } 
-  
-
+void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty) {
   // Ignore empty classes in C++.
   if (getContext().getLangOptions().CPlusPlus) {
     if (const RecordType *RT = Ty->getAs<RecordType>()) {
@@ -497,9 +481,6 @@ CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) {
     }
   }
   
-  // Otherwise, just memset the whole thing to zero.  This is legal
-  // because in LLVM, all default initializers (other than the ones we just
-  // handled above) are guaranteed to have a bit pattern of all zeros.
   const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext);
   if (DestPtr->getType() != BP)
     DestPtr = Builder.CreateBitCast(DestPtr, BP, "tmp");
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 8e68949f3023..bac05ba70512 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -747,10 +747,8 @@ public:
   llvm::BlockAddress *GetAddrOfLabel(const LabelStmt *L);
   llvm::BasicBlock *GetIndirectGotoBlock();
 
-  /// EmitNullInitialization - Generate code to set a value of the given type to
-  /// null, If the type contains data member pointers, they will be initialized
-  /// to -1 in accordance with the Itanium C++ ABI.
-  void EmitNullInitialization(llvm::Value *DestPtr, QualType Ty);
+  /// EmitMemSetToZero - Generate code to memset a value of the given type to 0.
+  void EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty);
 
   // EmitVAArg - Generate code to get an argument from the passed in pointer
   // and update it accordingly. The return value is a pointer to the argument.
diff --git a/clang/test/CodeGenCXX/pointers-to-data-members.cpp b/clang/test/CodeGenCXX/pointers-to-data-members.cpp
index ac238fb8fc6c..cab06dbd3d37 100644
--- a/clang/test/CodeGenCXX/pointers-to-data-members.cpp
+++ b/clang/test/CodeGenCXX/pointers-to-data-members.cpp
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin10 | FileCheck %s
-// RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin10 -O3 | FileCheck --check-prefix=CHECK-O3 %s
+
 struct A { int a; int b; };
 struct B { int b; };
 struct C : B, A { };
@@ -118,30 +118,3 @@ A::A() : a() {}
 
 }
 
-namespace PR7139 {
-
-struct pair {
-  int first;
-  int second;
-};
-
-typedef int pair::*ptr_to_member_type;
-
-struct ptr_to_member_struct { 
-  ptr_to_member_type data;
-  int i;
-};
-
-struct A {
-  ptr_to_member_struct a;
-
-  A() : a() {}
-};
-
-// CHECK-O3: define zeroext i1 @_ZN6PR71395checkEv() nounwind readnone
-bool check() {
-  // CHECK-O3: ret i1 true
-  return A().a.data == 0;
-}
-
-}