Index: llvm/include/llvm/Support/CommandLine.h
===================================================================
--- llvm/include/llvm/Support/CommandLine.h
+++ llvm/include/llvm/Support/CommandLine.h
@@ -1968,24 +1968,28 @@
                          SmallVectorImpl<const char *> &Argv,
                          bool MarkEOLs = false, bool RelativeNames = false);
 
-/// Mark all options not part of this category as cl::ReallyHidden.
+/// Mark all options not part of this category with the given cl::OptionHidden
 ///
-/// \param Category the category of options to keep displaying
+/// \param Category the category of options to keep displaying.
+/// \param Opt the flag to apply to all other categories.
 ///
 /// Some tools (like clang-format) like to be able to hide all options that are
 /// not specific to the tool. This function allows a tool to specify a single
 /// option category to display in the -help output.
 void HideUnrelatedOptions(cl::OptionCategory &Category,
+                          cl::OptionHidden Opt = cl::ReallyHidden,
                           SubCommand &Sub = *TopLevelSubCommand);
 
-/// Mark all options not part of the categories as cl::ReallyHidden.
+/// Mark all options not part of the categories with the given cl::OptionHidden
 ///
 /// \param Categories the categories of options to keep displaying.
+/// \param Opt the flag to apply to all other categories.
 ///
 /// Some tools (like clang-format) like to be able to hide all options that are
 /// not specific to the tool. This function allows a tool to specify a single
 /// option category to display in the -help output.
 void HideUnrelatedOptions(ArrayRef<const cl::OptionCategory *> Categories,
+                          OptionHidden Opt = cl::ReallyHidden,
                           SubCommand &Sub = *TopLevelSubCommand);
 
 /// Reset all command line options to a state that looks as if they have
Index: llvm/lib/Support/CommandLine.cpp
===================================================================
--- llvm/lib/Support/CommandLine.cpp
+++ llvm/lib/Support/CommandLine.cpp
@@ -2422,22 +2422,23 @@
   return GlobalParser->getRegisteredSubcommands();
 }
 
-void cl::HideUnrelatedOptions(cl::OptionCategory &Category, SubCommand &Sub) {
+void cl::HideUnrelatedOptions(cl::OptionCategory &Category, OptionHidden Opt,
+                              SubCommand &Sub) {
   for (auto &I : Sub.OptionsMap) {
     for (auto &Cat : I.second->Categories) {
       if (Cat != &Category &&
           Cat != &GenericCategory)
-        I.second->setHiddenFlag(cl::ReallyHidden);
+        I.second->setHiddenFlag(Opt);
     }
   }
 }
 
 void cl::HideUnrelatedOptions(ArrayRef<const cl::OptionCategory *> Categories,
-                              SubCommand &Sub) {
+                              OptionHidden Opt, SubCommand &Sub) {
   for (auto &I : Sub.OptionsMap) {
     for (auto &Cat : I.second->Categories) {
       if (find(Categories, Cat) == Categories.end() && Cat != &GenericCategory)
-        I.second->setHiddenFlag(cl::ReallyHidden);
+        I.second->setHiddenFlag(Opt);
     }
   }
 }
Index: llvm/unittests/Support/CommandLineTest.cpp
===================================================================
--- llvm/unittests/Support/CommandLineTest.cpp
+++ llvm/unittests/Support/CommandLineTest.cpp
@@ -378,17 +378,34 @@
   StackOption<int> TestOption1("hide-option-1");
   StackOption<int> TestOption2("hide-option-2", cl::cat(TestCategory));
 
+  cl::HideUnrelatedOptions(TestCategory, cl::Hidden);
+
+  ASSERT_EQ(cl::Hidden, TestOption1.getOptionHiddenFlag())
+      << "Failed to hide extra option.";
+  ASSERT_EQ(cl::NotHidden, TestOption2.getOptionHiddenFlag())
+      << "Hid extra option that should be visible.";
+
+  StringMap<cl::Option *> &Map =
+      cl::getRegisteredOptions(*cl::TopLevelSubCommand);
+  ASSERT_EQ(cl::NotHidden, Map["help"]->getOptionHiddenFlag())
+      << "Hid default option that should be visible.";
+}
+
+TEST(CommandLineTest, ReallyHideUnrelatedOptions) {
+  StackOption<int> TestOption1("hide-option-1");
+  StackOption<int> TestOption2("hide-option-2", cl::cat(TestCategory));
+
   cl::HideUnrelatedOptions(TestCategory);
 
   ASSERT_EQ(cl::ReallyHidden, TestOption1.getOptionHiddenFlag())
       << "Failed to hide extra option.";
   ASSERT_EQ(cl::NotHidden, TestOption2.getOptionHiddenFlag())
-      << "Hid extra option that should be visable.";
+      << "Hid extra option that should be visible.";
 
   StringMap<cl::Option *> &Map =
       cl::getRegisteredOptions(*cl::TopLevelSubCommand);
   ASSERT_EQ(cl::NotHidden, Map["help"]->getOptionHiddenFlag())
-      << "Hid default option that should be visable.";
+      << "Hid default option that should be visible.";
 }
 
 cl::OptionCategory TestCategory2("Test Options set 2", "Description");
@@ -401,19 +418,42 @@
   const cl::OptionCategory *VisibleCategories[] = {&TestCategory,
                                                    &TestCategory2};
 
+  cl::HideUnrelatedOptions(makeArrayRef(VisibleCategories), cl::Hidden);
+
+  ASSERT_EQ(cl::Hidden, TestOption1.getOptionHiddenFlag())
+      << "Failed to hide extra option.";
+  ASSERT_EQ(cl::NotHidden, TestOption2.getOptionHiddenFlag())
+      << "Hid extra option that should be visible.";
+  ASSERT_EQ(cl::NotHidden, TestOption3.getOptionHiddenFlag())
+      << "Hid extra option that should be visible.";
+
+  StringMap<cl::Option *> &Map =
+      cl::getRegisteredOptions(*cl::TopLevelSubCommand);
+  ASSERT_EQ(cl::NotHidden, Map["help"]->getOptionHiddenFlag())
+      << "Hid default option that should be visible.";
+}
+
+TEST(CommandLineTest, ReallyHideUnrelatedOptionsMulti) {
+  StackOption<int> TestOption1("multi-hide-option-1");
+  StackOption<int> TestOption2("multi-hide-option-2", cl::cat(TestCategory));
+  StackOption<int> TestOption3("multi-hide-option-3", cl::cat(TestCategory2));
+
+  const cl::OptionCategory *VisibleCategories[] = {&TestCategory,
+                                                   &TestCategory2};
+
   cl::HideUnrelatedOptions(makeArrayRef(VisibleCategories));
 
   ASSERT_EQ(cl::ReallyHidden, TestOption1.getOptionHiddenFlag())
       << "Failed to hide extra option.";
   ASSERT_EQ(cl::NotHidden, TestOption2.getOptionHiddenFlag())
-      << "Hid extra option that should be visable.";
+      << "Hid extra option that should be visible.";
   ASSERT_EQ(cl::NotHidden, TestOption3.getOptionHiddenFlag())
-      << "Hid extra option that should be visable.";
+      << "Hid extra option that should be visible.";
 
   StringMap<cl::Option *> &Map =
       cl::getRegisteredOptions(*cl::TopLevelSubCommand);
   ASSERT_EQ(cl::NotHidden, Map["help"]->getOptionHiddenFlag())
-      << "Hid default option that should be visable.";
+      << "Hid default option that should be visible.";
 }
 
 TEST(CommandLineTest, SetValueInSubcategories) {