Revert "Revert r229082 for a bit, it caused PR22577."

This reverts commit r229123.  It was a red herring, the bug was present
without r229082.

llvm-svn: 229205

clang/lib/Frontend/CompilerInvocation.cpp

@@ -477,6 +477,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
                                    OPT_fno_data_sections, false);
   Opts.MergeFunctions = Args.hasArg(OPT_fmerge_functions);
 
+  Opts.MSVolatile = Args.hasArg(OPT_fms_volatile);
+
   Opts.VectorizeBB = Args.hasArg(OPT_vectorize_slp_aggressive);
   Opts.VectorizeLoop = Args.hasArg(OPT_vectorize_loops);
   Opts.VectorizeSLP = Args.hasArg(OPT_vectorize_slp);