--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/CodeGen/cfstring.c	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,25 @@
+// REQUIRES: x86-registered-target
+
+// RUN: %clang_cc1 -triple x86_64-macho -emit-llvm %s -o %t
+
+// <rdar://problem/10657500>: Check that the backing store of CFStrings are
+// constant with the -fwritable-strings flag.
+//
+// RUN: %clang_cc1 -triple x86_64-macho -fwritable-strings -emit-llvm %s -o - | FileCheck %s
+//
+// CHECK: @.str = private unnamed_addr constant [14 x i8] c"Hello, World!\00", section "__TEXT,__cstring,cstring_literals", align 1
+// CHECK: @.str.1 = private unnamed_addr constant [7 x i8] c"yo joe\00", section "__TEXT,__cstring,cstring_literals", align 1
+// CHECK: @.str.3 = private unnamed_addr constant [16 x i8] c"Goodbye, World!\00", section "__TEXT,__cstring,cstring_literals", align 1
+
+#define CFSTR __builtin___CFStringMakeConstantString
+
+void f() {
+  CFSTR("Hello, World!");
+}
+
+// rdar://6248329
+void *G = CFSTR("yo joe");
+
+void h() {
+  static void* h = CFSTR("Goodbye, World!");
+}