Index: llvm/lib/Support/CommandLine.cpp
===================================================================
--- llvm/lib/Support/CommandLine.cpp
+++ llvm/lib/Support/CommandLine.cpp
@@ -592,6 +592,10 @@
                                            ie = OptionsMap.end();
        it != ie; ++it) {
     Option *O = it->second;
+    // Do not suggest really hidden options (not shown in any help).
+    if (O->getOptionHiddenFlag() == ReallyHidden)
+      continue;
+
     SmallVector<StringRef, 16> OptionNames;
     O->getExtraOptionNames(OptionNames);
     if (O->hasArgStr())
Index: llvm/unittests/Support/CommandLineTest.cpp
===================================================================
--- llvm/unittests/Support/CommandLineTest.cpp
+++ llvm/unittests/Support/CommandLineTest.cpp
@@ -1735,6 +1735,29 @@
   cl::ResetAllOptionOccurrences();
 }
 
+TEST(CommandLineTest, OptionErrorMessageSuggestNoHidden) {
+  // We expect that 'really hidden' option do not show up in option
+  // suggestions.
+  cl::ResetCommandLineParser();
+
+  StackOption<bool> OptLong("aluminium", cl::desc("Some long option"));
+  StackOption<bool> OptLong2("aluminum", cl::desc("Bad option"),
+                             cl::ReallyHidden);
+
+  const char *args[] = {"prog", "--alumnum"};
+
+  std::string Errs;
+  raw_string_ostream OS(Errs);
+
+  EXPECT_FALSE(cl::ParseCommandLineOptions(2, args, StringRef(), &OS));
+  OS.flush();
+  EXPECT_FALSE(Errs.find("prog: Did you mean '--aluminium'?\n") ==
+               std::string::npos);
+  Errs.clear();
+
+  cl::ResetAllOptionOccurrences();
+}
+
 TEST(CommandLineTest, Callback) {
   cl::ResetCommandLineParser();