diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -1321,12 +1321,20 @@
                                                Errs, LongOptionsUseDoubleDash);
 }
 
+/// Reset all options at least once, so that we can parse different options.
 void CommandLineParser::ResetAllOptionOccurrences() {
-  // So that we can parse different command lines multiple times in succession
-  // we reset all option values to look like they have never been seen before.
+  // Reset all option values to look like they have never been seen before.
+  // Options might be reset twice (they can be reference in both OptionsMap
+  // and one of the other members), but that does not harm.
   for (auto *SC : RegisteredSubCommands) {
     for (auto &O : SC->OptionsMap)
       O.second->reset();
+    for (Option *O : SC->PositionalOpts)
+      O->reset();
+    for (Option *O : SC->SinkOpts)
+      O->reset();
+    if (SC->ConsumeAfterOpt)
+      SC->ConsumeAfterOpt->reset();
   }
 }
 
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
@@ -1894,4 +1894,34 @@
   EXPECT_TRUE(Errs.empty());
 }
 
+TEST(CommandLineTest, ResetAllOptionOccurrences) {
+  cl::ResetCommandLineParser();
+
+  // -option [sink] input [args]
+  StackOption<bool> Option("option");
+  StackOption<std::string, cl::list<std::string>> Sink(cl::Sink);
+  StackOption<std::string> Input(cl::Positional);
+  StackOption<std::string, cl::list<std::string>> ExtraArgs(cl::ConsumeAfter);
+
+  const char *Args[] = {"prog", "-option", "-unknown", "input", "-arg"};
+
+  std::string Errs;
+  raw_string_ostream OS(Errs);
+  EXPECT_TRUE(cl::ParseCommandLineOptions(5, Args, StringRef(), &OS));
+  EXPECT_TRUE(OS.str().empty());
+
+  EXPECT_TRUE(Option);
+  EXPECT_EQ(1, (int)Sink.size());
+  EXPECT_EQ("-unknown", Sink[0]);
+  EXPECT_EQ("input", Input);
+  EXPECT_EQ(1, (int)ExtraArgs.size());
+  EXPECT_EQ("-arg", ExtraArgs[0]);
+
+  cl::ResetAllOptionOccurrences();
+  EXPECT_FALSE(Option);
+  EXPECT_EQ(0, (int)Sink.size());
+  EXPECT_EQ(0, Input.getNumOccurrences());
+  EXPECT_EQ(0, (int)ExtraArgs.size());
+}
+
 } // anonymous namespace