diff --git a/llvm/include/llvm/Support/CommandLine.h b/llvm/include/llvm/Support/CommandLine.h
--- a/llvm/include/llvm/Support/CommandLine.h
+++ b/llvm/include/llvm/Support/CommandLine.h
@@ -286,6 +286,7 @@
   SmallVector<OptionCategory *, 1>
       Categories;                    // The Categories this option belongs to
   SmallPtrSet<SubCommand *, 1> Subs; // The subcommands this option belongs to.
+  Option *ImpliedOption = nullptr;
 
   inline enum NumOccurrencesFlag getNumOccurrencesFlag() const {
     return (enum NumOccurrencesFlag)Occurrences;
@@ -337,6 +338,8 @@
   void setPosition(unsigned pos) { Position = pos; }
   void addCategory(OptionCategory &C);
   void addSubCommand(SubCommand &S) { Subs.insert(&S); }
+  void addImpliedOption(Option &O) { ImpliedOption = &O; }
+  virtual void setImplied() {}
 
 protected:
   explicit Option(enum NumOccurrencesFlag OccurrencesFlag,
@@ -399,6 +402,14 @@
 // command line option parsers...
 //
 
+struct implies {
+  Option &ImpliedOpt;
+
+  implies(Option &Opt) : ImpliedOpt(Opt) {}
+
+  void apply(Option &O) const { O.addImpliedOption(ImpliedOpt); }
+};
+
 // desc - Modifier to set the description shown in the -help output...
 struct desc {
   StringRef Desc;
@@ -1339,11 +1350,32 @@
         typename ParserClass::parser_data_type();
     if (Parser.parse(*this, ArgName, Arg, Val))
       return true; // Parse error!
-    this->setValue(Val);
+    this->setOptionValue(Val);
     this->setPosition(pos);
     return false;
   }
 
+  template <class T> void setOptionValue(const T &Val) {
+    this->setValue(Val);
+    if (ImpliedOption)
+      ImpliedOption->setImplied();
+  }
+
+  // setImplied is only supported for enabling boolean options.
+  template <typename T, typename std::enable_if<std::is_same<T, bool>::value,
+                                                int>::type = 0>
+  void setImpliedValue() {
+    this->setOptionValue(true);
+  }
+
+  template <typename T, typename std::enable_if<!std::is_same<T, bool>::value,
+                                                int>::type = 0>
+  void setImpliedValue() {}
+
+  void setImplied() override {
+    setImpliedValue<typename ParserClass::parser_data_type>();
+  }
+
   enum ValueExpected getValueExpectedFlagDefault() const override {
     return Parser.getValueExpectedFlagDefault();
   }
@@ -1544,12 +1576,18 @@
         typename ParserClass::parser_data_type();
     if (Parser.parse(*this, ArgName, Arg, Val))
       return true; // Parse Error!
-    list_storage<DataType, StorageClass>::addValue(Val);
+    setOptionValue(Val);
     setPosition(pos);
     Positions.push_back(pos);
     return false;
   }
 
+  template <class T> void setOptionValue(const T &Val) {
+    list_storage<DataType, StorageClass>::addValue(Val);
+    if(ImpliedOption)
+      ImpliedOption->setImplied();
+  }
+
   // Forward printing stuff to the parser...
   size_t getOptionWidth() const override {
     return Parser.getOptionWidth(*this);
diff --git a/llvm/unittests/Support/CommandLineTest.cpp b/llvm/unittests/Support/CommandLineTest.cpp
--- a/llvm/unittests/Support/CommandLineTest.cpp
+++ b/llvm/unittests/Support/CommandLineTest.cpp
@@ -1703,4 +1703,42 @@
 
   cl::ResetAllOptionOccurrences();
 }
+
+TEST(CommandLineTest, ImpliedOptions) {
+  cl::ResetCommandLineParser();
+
+  StackOption<bool> OptA("a");
+  StackOption<bool> OptB("b", cl::implies(OptA));
+  StackOption<bool> OptC("c", cl::implies(OptB));
+  StackOption<std::string, cl::list<std::string>> List("list", cl::implies(OptC));
+
+  const char *args1[] = {"prog", "-a"};
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args1));
+  EXPECT_TRUE(OptA);
+  EXPECT_FALSE(OptB);
+  EXPECT_FALSE(OptC);
+  cl::ResetAllOptionOccurrences();
+
+  const char *args2[] = {"prog", "-b"};
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args2));
+  EXPECT_TRUE(OptA);
+  EXPECT_TRUE(OptB);
+  EXPECT_FALSE(OptC);
+  cl::ResetAllOptionOccurrences();
+
+  const char *args3[] = {"prog", "-c"};
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args3));
+  EXPECT_TRUE(OptA);
+  EXPECT_TRUE(OptB);
+  EXPECT_TRUE(OptC);
+  cl::ResetAllOptionOccurrences();
+
+  const char *args4[] = {"prog", "--list=one,two,three"};
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args4));
+  EXPECT_TRUE(OptA);
+  EXPECT_TRUE(OptB);
+  EXPECT_TRUE(OptC);
+
+  cl::ResetAllOptionOccurrences();
+}
 }  // anonymous namespace