diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 386b1d3bd2..45ba699652 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -10978,6 +10978,14 @@ std::unique_ptr<Command> visualstudio::Compiler::GetCommand(
                                options::OPT__SLASH_MT, options::OPT__SLASH_MTd))
     A->render(Args, CmdArgs);
 
+  // Use MSVC's default threadsafe statics behaviour unless there was a flag.
+  if (Arg *A = Args.getLastArg(options::OPT_fthreadsafe_statics,
+                               options::OPT_fno_threadsafe_statics)) {
+    CmdArgs.push_back(A->getOption().getID() == options::OPT_fthreadsafe_statics
+                          ? "/Zc:threadSafeInit"
+                          : "/Zc:threadSafeInit-");
+  }
+
   // Pass through all unknown arguments so that the fallback command can see
   // them too.
   Args.AddAllArgs(CmdArgs, options::OPT_UNKNOWN);
diff --git a/test/Driver/cl-fallback.c b/test/Driver/cl-fallback.c
index e73f7c03c2..2e5698ce9f 100644
--- a/test/Driver/cl-fallback.c
+++ b/test/Driver/cl-fallback.c
@@ -46,6 +46,12 @@
 // GS: cl.exe
 // GS: "/GS-"
 
+// RUN: %clang_cl /fallback /Zc:threadSafeInit -### -- %s 2>&1 | FileCheck -check-prefix=ThreadSafe %s
+// ThreadSafe: /Zc:threadSafeInit
+
+// RUN: %clang_cl /fallback /Zc:threadSafeInit- -### -- %s 2>&1 | FileCheck -check-prefix=NonThreadSafe %s
+// NonThreadSafe: /Zc:threadSafeInit-
+
 // RUN: %clang_cl /fallback /Od -### -- %s 2>&1 | FileCheck -check-prefix=O0 %s
 // O0: cl.exe
 // O0: "/Od"