diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 2ac197f..11d497f 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -4450,6 +4450,8 @@ def ext_array_init_parens : ExtWarn<
   InGroup<DiagGroup<"gnu-array-member-paren-init">>, DefaultError;
 def warn_deprecated_string_literal_conversion : Warning<
   "conversion from string literal to %0 is deprecated">, InGroup<DeprecatedWritableStr>;
+def warn_deprecated_string_literal_conversion_c : Warning<
+  "dummy warning to enable -fconst-strings">, InGroup<DeprecatedWritableStr>, DefaultIgnore;
 def err_realimag_invalid_type : Error<"invalid type %0 to %1 operator">;
 def err_typecheck_sclass_fscope : Error<
   "illegal storage class on file-scoped variable">;
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index d03ec94..147b73d 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -248,8 +248,6 @@ def Wnonportable_cfstrings : Joined<["-"], "Wnonportable-cfstrings">, Group<W_Gr
 def Wp_COMMA : CommaJoined<["-"], "Wp,">,
   HelpText<"Pass the comma separated arguments in <arg> to the preprocessor">,
   MetaVarName<"<arg>">;
-def Wwrite_strings : Flag<["-"], "Wwrite-strings">, Group<W_Group>, Flags<[CC1Option]>;
-def Wno_write_strings : Flag<["-"], "Wno-write-strings">, Group<W_Group>, Flags<[CC1Option]>;
 def W_Joined : Joined<["-"], "W">, Group<W_Group>, Flags<[CC1Option, CoreOption]>,
   MetaVarName<"<warning>">, HelpText<"Enable the specified warning">;
 def Xanalyzer : Separate<["-"], "Xanalyzer">,
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index e5f2681..9d6e6ed 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -21,6 +21,7 @@
 #include "clang/Driver/SanitizerArgs.h"
 #include "clang/Driver/ToolChain.h"
 #include "clang/Driver/Util.h"
+#include "clang/Sema/SemaDiagnostic.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -2702,13 +2703,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // behavior for now. FIXME: Directly diagnose uses of a string literal as
   // a non-const char* in C, rather than using this crude hack.
   if (!types::isCXX(InputType)) {
-    // FIXME: This should behave just like a warning flag, and thus should also
-    // respect -Weverything, -Wno-everything, -Werror=write-strings, and so on.
-    Arg *WriteStrings =
-        Args.getLastArg(options::OPT_Wwrite_strings,
-                        options::OPT_Wno_write_strings, options::OPT_w);
-    if (WriteStrings &&
-        WriteStrings->getOption().matches(options::OPT_Wwrite_strings))
+    DiagnosticsEngine::Level DiagLevel = D.getDiags().getDiagnosticLevel(
+        diag::warn_deprecated_string_literal_conversion_c, SourceLocation());
+    if (DiagLevel > DiagnosticsEngine::Ignored)
       CmdArgs.push_back("-fconst-strings");
   }
 
diff --git a/test/Driver/clang_f_opts.c b/test/Driver/clang_f_opts.c
index 780b727..315c350 100644
--- a/test/Driver/clang_f_opts.c
+++ b/test/Driver/clang_f_opts.c
@@ -15,11 +15,11 @@
 // CHECK-OPTIONS2: -fno-show-source-location
 
 // RUN: %clang -### -S -Wwrite-strings %s 2>&1 | FileCheck -check-prefix=WRITE-STRINGS1 %s
+// RUN: %clang -### -S -Weverything %s 2>&1 | FileCheck -check-prefix=WRITE-STRINGS1 %s
 // WRITE-STRINGS1: -fconst-strings
 // RUN: %clang -### -S -Wwrite-strings -Wno-write-strings %s 2>&1 | FileCheck -check-prefix=WRITE-STRINGS2 %s
+// RUN: %clang -### -S -Wwrite-strings -w %s 2>&1 | FileCheck -check-prefix=WRITE-STRINGS2 %s
 // WRITE-STRINGS2-NOT: -fconst-strings
-// RUN: %clang -### -S -Wwrite-strings -w %s 2>&1 | FileCheck -check-prefix=WRITE-STRINGS3 %s
-// WRITE-STRINGS3-NOT: -fconst-strings
 
 // RUN: %clang -### -x c++ -c %s 2>&1 | FileCheck -check-prefix=DEPRECATED-ON-CHECK %s
 // RUN: %clang -### -x c++ -c -Wdeprecated %s 2>&1 | FileCheck -check-prefix=DEPRECATED-ON-CHECK %s