Index: lib/CodeGen/CGObjCMac.cpp
===================================================================
--- lib/CodeGen/CGObjCMac.cpp
+++ lib/CodeGen/CGObjCMac.cpp
@@ -2517,7 +2517,8 @@
         printf(", BL_WEAK:%d", (int) numWeak);
       printf(", BL_OPERATOR:0\n");
     }
-    return llvm::ConstantInt::get(CGM.IntPtrTy, Result);
+    return llvm::ConstantExpr::getIntToPtr(
+        llvm::ConstantInt::get(CGM.IntPtrTy, Result), CGM.Int8PtrTy);
   }
   
   unsigned char inst = (BLOCK_LAYOUT_OPERATOR << 4) | 0;
Index: lib/CodeGen/CGObjCRuntime.h
===================================================================
--- lib/CodeGen/CGObjCRuntime.h
+++ lib/CodeGen/CGObjCRuntime.h
@@ -275,8 +275,11 @@
                                   const CodeGen::CGBlockInfo &blockInfo) = 0;
   virtual llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM,
                                   const CodeGen::CGBlockInfo &blockInfo) = 0;
+
+  /// Returns an i8* which points to the byref layout information.
   virtual llvm::Constant *BuildByrefLayout(CodeGen::CodeGenModule &CGM,
                                            QualType T) = 0;
+
   virtual llvm::GlobalVariable *GetClassGlobal(const std::string &Name,
                                                bool Weak = false) = 0;
 
Index: test/CodeGenObjCXX/blocks.mm
===================================================================
--- test/CodeGenObjCXX/blocks.mm
+++ test/CodeGenObjCXX/blocks.mm
@@ -68,3 +68,18 @@
     takeBlock(^{ useValues(ptr, this); });
   }
 };
+
+// rdar://problem/23713871
+// Check that we don't crash when using BLOCK_LAYOUT_STRONG.
+#pragma clang assume_nonnull begin
+@interface NSUUID @end
+#pragma clang assume_nonnull end
+
+struct Wrapper1 { NSUUID *Ref; };
+struct Wrapper2 { Wrapper1 W1; };
+
+@implementation B
+- (void) captureStrongRef {
+  __block Wrapper2 W2;
+}
+@end