diff --git lib/Sema/AnalysisBasedWarnings.cpp lib/Sema/AnalysisBasedWarnings.cpp
index 3f2c41b..eb45315 100644
--- lib/Sema/AnalysisBasedWarnings.cpp
+++ lib/Sema/AnalysisBasedWarnings.cpp
@@ -1334,6 +1334,12 @@ static void diagnoseRepeatedUseOfWeak(Sema &S,
     else
       llvm_unreachable("Unexpected weak object kind!");
 
+    // Do not warn about IBOutlet weak property receivers being set to null
+    // since they are typically only used from the main thread.
+    if (const ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(D))
+      if (Prop->hasAttr<IBOutletAttr>())
+        continue;
+
     // Show the first time the object was read.
     S.Diag(FirstRead->getLocStart(), DiagKind)
       << int(ObjectKind) << D << int(FunctionKind)
diff --git lib/Sema/SemaPseudoObject.cpp lib/Sema/SemaPseudoObject.cpp
index 62c823b..c93d800 100644
--- lib/Sema/SemaPseudoObject.cpp
+++ lib/Sema/SemaPseudoObject.cpp
@@ -578,7 +578,7 @@ bool ObjCPropertyOpBuilder::isWeakProperty() const {
   if (RefExpr->isExplicitProperty()) {
     const ObjCPropertyDecl *Prop = RefExpr->getExplicitProperty();
     if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak)
-      return !Prop->hasAttr<IBOutletAttr>();
+      return true;
 
     T = Prop->getType();
   } else if (Getter) {
diff --git test/SemaObjC/iboutlet.m test/SemaObjC/iboutlet.m
index 2ce4ce1..7bd86d4 100644
--- test/SemaObjC/iboutlet.m
+++ test/SemaObjC/iboutlet.m
@@ -41,6 +41,7 @@ @implementation RKTFHView
 
 // rdar://15885642
 @interface WeakOutlet 
+@property int Number;
 @property IBOutlet __weak WeakOutlet* WeakProp;
 @end
 
@@ -50,3 +51,9 @@ @interface WeakOutlet
   pwi.WeakProp = pwi.WeakProp;
   return pwi.WeakProp;
 }
+
+WeakOutlet* func2(WeakOutlet* pwi) {
+  [[pwi WeakProp] setNumber:0];
+  [[pwi WeakProp] setNumber:1];
+  return [pwi WeakProp];
+}