diff --git a/CoreFoundation/Base.subproj/CFBase.h b/CoreFoundation/Base.subproj/CFBase.h
index 0dc06b1e76..34ca2f80e9 100644
--- a/CoreFoundation/Base.subproj/CFBase.h
+++ b/CoreFoundation/Base.subproj/CFBase.h
@@ -683,8 +683,7 @@ CFTypeRef CFMakeCollectable(CFTypeRef cf) CF_AUTOMATED_REFCOUNT_UNAVAILABLE;
 #if DEPLOYMENT_RUNTIME_SWIFT
 
 #define _CF_SWIFT_RC_PINNED_FLAG 0x1
-#define _CF_SWIFT_RC_FLAGS_COUNT 2
-#define _CF_CONSTANT_OBJECT_STRONG_RC ((1 << _CF_SWIFT_RC_FLAGS_COUNT) | _CF_SWIFT_RC_PINNED_FLAG)
+#define _CF_CONSTANT_OBJECT_STRONG_RC (_CF_SWIFT_RC_PINNED_FLAG)
 
 #endif
 
diff --git a/CoreFoundation/Base.subproj/CFInternal.h b/CoreFoundation/Base.subproj/CFInternal.h
index 6cf37b3839..ccc58ee68f 100644
--- a/CoreFoundation/Base.subproj/CFInternal.h
+++ b/CoreFoundation/Base.subproj/CFInternal.h
@@ -412,11 +412,11 @@ CF_EXPORT void *__CFConstantStringClassReference[];
 #endif
 
 #define CONST_STRING_DECL(S, V) \
-const struct __CFConstStr __##S CONST_STRING_SECTION = {{(uintptr_t)&__CFConstantStringClassReference, _CF_CONSTANT_OBJECT_STRONG_RC, 0, 0x000007c8U}, (uint8_t *)(V), sizeof(V) - 1}; \
+const struct __CFConstStr __##S CONST_STRING_SECTION = {{(uintptr_t)&__CFConstantStringClassReference, _CF_CONSTANT_OBJECT_STRONG_RC, 0x000007c8U}, (uint8_t *)(V), sizeof(V) - 1}; \
 const CFStringRef S = (CFStringRef)&__##S;
 
 #define PE_CONST_STRING_DECL(S, V) \
-const static struct __CFConstStr __##S CONST_STRING_SECTION = {{(uintptr_t)&__CFConstantStringClassReference, _CF_CONSTANT_OBJECT_STRONG_RC, 0, 0x000007c8U}, (uint8_t *)(V), sizeof(V) - 1}; \
+const static struct __CFConstStr __##S CONST_STRING_SECTION = {{(uintptr_t)&__CFConstantStringClassReference, _CF_CONSTANT_OBJECT_STRONG_RC, 0x000007c8U}, (uint8_t *)(V), sizeof(V) - 1}; \
 CF_PRIVATE const CFStringRef S = (CFStringRef)&__##S;
 
 
diff --git a/CoreFoundation/Base.subproj/CFRuntime.c b/CoreFoundation/Base.subproj/CFRuntime.c
index da9d2c0d09..386770b241 100644
--- a/CoreFoundation/Base.subproj/CFRuntime.c
+++ b/CoreFoundation/Base.subproj/CFRuntime.c
@@ -387,7 +387,7 @@ CFTypeRef _CFRuntimeCreateInstance(CFAllocatorRef allocator, CFTypeID typeID, CF
     CFRuntimeBase *memory = (CFRuntimeBase *)swift_allocObject(isa, size, align - 1);
     
     // Zero the rest of the memory, starting at cfinfo
-    memset(&memory->_cfinfoa, 0, size - (sizeof(memory->_cfisa) + sizeof(memory->_swift_strong_rc) + sizeof(memory->_swift_weak_rc)));
+    memset(&memory->_cfinfoa, 0, size - (sizeof(memory->_cfisa) + sizeof(memory->_swift_rc)));
     
     // Set up the cfinfo struct
     uint32_t *cfinfop = (uint32_t *)&(memory->_cfinfoa);
diff --git a/CoreFoundation/Base.subproj/CFRuntime.h b/CoreFoundation/Base.subproj/CFRuntime.h
index d7aa26cfc9..84a056505f 100644
--- a/CoreFoundation/Base.subproj/CFRuntime.h
+++ b/CoreFoundation/Base.subproj/CFRuntime.h
@@ -193,13 +193,12 @@ CF_EXPORT void _CFRuntimeUnregisterClassWithTypeID(CFTypeID typeID);
 typedef struct __CFRuntimeBase {
     // This matches the isa and retain count storage in Swift
     uintptr_t _cfisa;
-    uint32_t _swift_strong_rc;
-    uint32_t _swift_weak_rc;
+    uintptr_t _swift_rc;
     // This is for CF's use, and must match _NSCFType layout
     _Atomic(uint64_t) _cfinfoa;
 } CFRuntimeBase;
 
-#define INIT_CFRUNTIME_BASE(...) {0, _CF_CONSTANT_OBJECT_STRONG_RC, 0, 0x0000000000000080ULL}
+#define INIT_CFRUNTIME_BASE(...) {0, _CF_CONSTANT_OBJECT_STRONG_RC, 0x0000000000000080ULL}
 
 #else
 
diff --git a/CoreFoundation/String.subproj/CFString.c b/CoreFoundation/String.subproj/CFString.c
index b1f4fa3633..a71d96ca3a 100644
--- a/CoreFoundation/String.subproj/CFString.c
+++ b/CoreFoundation/String.subproj/CFString.c
@@ -245,7 +245,7 @@ CF_INLINE void __CFStrClearHasLengthAndNullBytes(CFMutableStringRef str) {
 
 CF_INLINE Boolean __CFStrIsConstant(CFStringRef str) {
 #if DEPLOYMENT_RUNTIME_SWIFT
-    return str->base._swift_strong_rc & _CF_SWIFT_RC_PINNED_FLAG;
+    return str->base._swift_rc & _CF_SWIFT_RC_PINNED_FLAG;
 #else
     return __CFRuntimeIsConstant(str);
 #endif
diff --git a/CoreFoundation/String.subproj/CFString.h b/CoreFoundation/String.subproj/CFString.h
index 2793bfbe24..d818f2ae27 100644
--- a/CoreFoundation/String.subproj/CFString.h
+++ b/CoreFoundation/String.subproj/CFString.h
@@ -155,8 +155,7 @@ since it is the default choice with Mac OS X developer tools.
 struct __CFConstStr {
     struct {
         uintptr_t _cfisa;
-        uint32_t _swift_strong_rc;
-        uint32_t _swift_weak_rc;
+        uintptr_t _swift_rc;
         uint64_t _cfinfoa;
     } _base;
     uint8_t *_ptr;
@@ -175,12 +174,12 @@ struct __CFConstStr {
 
 #if __BIG_ENDIAN__
 #define CFSTR(cStr)  ({ \
-    static struct __CFConstStr str CONST_STRING_LITERAL_SECTION = {{(uintptr_t)&__CFConstantStringClassReference, _CF_CONSTANT_OBJECT_STRONG_RC, 0, 0x00000000C8070000}, (uint8_t *)(cStr), sizeof(cStr) - 1}; \
+    static struct __CFConstStr str CONST_STRING_LITERAL_SECTION = {{(uintptr_t)&__CFConstantStringClassReference, _CF_CONSTANT_OBJECT_STRONG_RC, 0x00000000C8070000}, (uint8_t *)(cStr), sizeof(cStr) - 1}; \
     (CFStringRef)&str; \
 })
 #else
 #define CFSTR(cStr)  ({ \
-    static struct __CFConstStr str CONST_STRING_LITERAL_SECTION = {{(uintptr_t)&__CFConstantStringClassReference, _CF_CONSTANT_OBJECT_STRONG_RC, 0, 0x07C8}, (uint8_t *)(cStr), sizeof(cStr) - 1}; \
+    static struct __CFConstStr str CONST_STRING_LITERAL_SECTION = {{(uintptr_t)&__CFConstantStringClassReference, _CF_CONSTANT_OBJECT_STRONG_RC, 0x07C8}, (uint8_t *)(cStr), sizeof(cStr) - 1}; \
     (CFStringRef)&str; \
 })
 #endif
diff --git a/Foundation/NSCFString.swift b/Foundation/NSCFString.swift
index 92177ca9e5..638de7e449 100644
--- a/Foundation/NSCFString.swift
+++ b/Foundation/NSCFString.swift
@@ -61,9 +61,8 @@ internal final class _NSCFConstantString : _NSCFString {
     internal var _ptr : UnsafePointer<UInt8> {
         // FIXME: Split expression as a work-around for slow type
         //        checking (tracked by SR-5322).
-        let offTemp1 = MemoryLayout<OpaquePointer>.size + MemoryLayout<Int32>.size
-        let offTemp2 = MemoryLayout<Int32>.size + MemoryLayout<_CFInfo>.size
-        let offset = offTemp1 + offTemp2
+        let offTemp1 = MemoryLayout<OpaquePointer>.size + MemoryLayout<uintptr_t>.size
+        let offset = offTemp1 + MemoryLayout<_CFInfo>.size
         let ptr = Unmanaged.passUnretained(self).toOpaque()
         return ptr.load(fromByteOffset: offset, as: UnsafePointer<UInt8>.self)
     }
@@ -71,8 +70,8 @@ internal final class _NSCFConstantString : _NSCFString {
     private var _lenOffset : Int {
         // FIXME: Split expression as a work-around for slow type
         //        checking (tracked by SR-5322).
-        let offTemp1 = MemoryLayout<OpaquePointer>.size + MemoryLayout<Int32>.size
-        let offTemp2 = MemoryLayout<Int32>.size + MemoryLayout<_CFInfo>.size
+        let offTemp1 = MemoryLayout<OpaquePointer>.size + MemoryLayout<uintptr_t>.size
+        let offTemp2 = MemoryLayout<_CFInfo>.size
         return offTemp1 + offTemp2 + MemoryLayout<UnsafePointer<UInt8>>.size
     }