diff --git a/lib/ARCMigrate/TransProperties.cpp b/lib/ARCMigrate/TransProperties.cpp
index 050512f..7e890ef 100644
--- a/lib/ARCMigrate/TransProperties.cpp
+++ b/lib/ARCMigrate/TransProperties.cpp
@@ -287,8 +287,10 @@
   void maybeAddStrongAttr(PropsTy &props, SourceLocation atLoc) const {
     ObjCPropertyDecl::PropertyAttributeKind propAttrs = getPropertyAttrs(props);
 
-    if (!(propAttrs & ObjCPropertyDecl::OBJC_PR_readonly) ||
-        !hasAllIvarsBacked(props)) {
+    if (!(propAttrs & ObjCPropertyDecl::OBJC_PR_readonly))
+      return; // 'strong' by default.
+
+    if (!hasAllIvarsBacked(props)) {
       addAttribute("strong", atLoc);
     }
 
diff --git a/test/ARCMT/GC.m b/test/ARCMT/GC.m
index 2884679..d657387 100644
--- a/test/ARCMT/GC.m
+++ b/test/ARCMT/GC.m
@@ -57,15 +57,17 @@
 
 @interface I4Impl {
   I4Impl *pds2;
+  I4Impl *pds3;
 }
 @property (assign) I4Impl *__weak pw1, *__weak pw2;
 @property (assign) I4Impl *__strong ps;
 @property (assign) I4Impl * pds;
 @property (assign) I4Impl * pds2;
+@property (readwrite) I4Impl * pds3;
 @end
 
 @implementation I4Impl
-@synthesize pw1, pw2, ps, pds, pds2;
+@synthesize pw1, pw2, ps, pds, pds2, pds3;
 
 -(void)test1:(CFTypeRef *)cft {
   id x = NSMakeCollectable(cft);
diff --git a/test/ARCMT/GC.m.result b/test/ARCMT/GC.m.result
index aaa5ee5..96437b8 100644
--- a/test/ARCMT/GC.m.result
+++ b/test/ARCMT/GC.m.result
@@ -52,15 +52,17 @@
 
 @interface I4Impl {
   I4Impl *pds2;
+  I4Impl *pds3;
 }
 @property (weak) I4Impl * pw1, * pw2;
 @property  I4Impl * ps;
 @property  I4Impl * pds;
 @property  I4Impl * pds2;
+@property (readwrite) I4Impl * pds3;
 @end
 
 @implementation I4Impl
-@synthesize pw1, pw2, ps, pds, pds2;
+@synthesize pw1, pw2, ps, pds, pds2, pds3;
 
 -(void)test1:(CFTypeRef *)cft {
   id x = CFBridgingRelease(cft);