diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 37ba39d..7114e65 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2154,7 +2154,16 @@
   Opts.ImplicitModules = !Args.hasArg(OPT_fno_implicit_modules);
   Opts.CharIsSigned = Opts.OpenCL || !Args.hasArg(OPT_fno_signed_char);
   Opts.WChar = Opts.CPlusPlus && !Args.hasArg(OPT_fno_wchar);
-  Opts.ShortWChar = Args.hasFlag(OPT_fshort_wchar, OPT_fno_short_wchar, false);
+  if (const Arg *A = Args.getLastArg(OPT_fwchar_type_EQ)) {
+    Opts.WCharSize = llvm::StringSwitch<unsigned>(A->getValue())
+                         .Case("char", 1)
+                         .Case("short", 2)
+                         .Case("int", 4)
+                         .Default(0);
+    if (Opts.WCharSize == 0)
+      Diags.Report(diag::err_fe_invalid_wchar_type) << A->getValue();
+  }
+  Opts.WCharIsSigned = Args.hasFlag(OPT_fsigned_wchar, OPT_fno_signed_wchar, true);
   Opts.ShortEnums = Args.hasArg(OPT_fshort_enums);
   Opts.Freestanding = Args.hasArg(OPT_ffreestanding);
   Opts.NoBuiltin = Args.hasArg(OPT_fno_builtin) || Opts.Freestanding;