diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@@ -879,6 +879,10 @@
   process_llvm_pass_plugins()
 endif()
 
+if (LLVM_INCLUDE_BENCHMARKS)
+  add_subdirectory(benchmarks)
+endif()
+
 configure_file(
   ${CLANG_SOURCE_DIR}/include/clang/Config/config.h.cmake
   ${CLANG_BINARY_DIR}/include/clang/Config/config.h)
diff --git a/clang/benchmarks/CMakeLists.txt b/clang/benchmarks/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/clang/benchmarks/CMakeLists.txt
@@ -0,0 +1,7 @@
+add_benchmark(CompilerInvocationBench CompilerInvocationBench.cpp)
+
+target_link_libraries(CompilerInvocationBench
+  PRIVATE
+  clangFrontend
+  LLVMSupport
+  )
diff --git a/clang/benchmarks/CompilerInvocationBench.cpp b/clang/benchmarks/CompilerInvocationBench.cpp
new file mode 100644
--- /dev/null
+++ b/clang/benchmarks/CompilerInvocationBench.cpp
@@ -0,0 +1,77 @@
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/CompilerInvocation.h"
+#include "clang/Frontend/TextDiagnosticBuffer.h"
+
+#include "benchmark/benchmark.h"
+
+using namespace llvm;
+using namespace clang;
+
+// Pointer to '--' in Argv that got replaced by '-round-trip-args'.
+static const char **Begin;
+
+// Pointer to the end of Argv.
+static const char **End;
+
+// Returns a dummy DiagnosticsEngine.
+static DiagnosticsEngine &Diags() {
+  static IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
+      CompilerInstance::createDiagnostics(new DiagnosticOptions,
+                                          new TextDiagnosticBuffer);
+  return *Diags;
+}
+
+// Parses the command line arguments starting **after** the injected
+// '-round-trip-args', resulting in a parse **without** round-trip.
+static void BM_CompilerInvocationNoRoundTrip(benchmark::State &State) {
+  for (auto _ : State) {
+    CompilerInvocation Invocation;
+    CompilerInvocation::CreateFromArgs(Invocation, {Begin + 1, End}, Diags());
+  }
+}
+
+// Parses the command line arguments starting **at** the injected
+// '-round-trip-args', resulting in a parse **with** round-trip.
+static void BM_CompilerInvocationDoRoundTrip(benchmark::State &State) {
+  for (auto _ : State) {
+    CompilerInvocation Invocation;
+    CompilerInvocation::CreateFromArgs(Invocation, {Begin, End}, Diags());
+  }
+}
+
+BENCHMARK(BM_CompilerInvocationNoRoundTrip);
+BENCHMARK(BM_CompilerInvocationDoRoundTrip);
+
+// USAGE:
+// ./CompilerInvocationBench [ Google Benchmark options ... ] \
+//    -- [ CompilerInvocation::CreateFromArgs arguments ... ]
+int main(int Argc, const char *Argv[]) {
+  // Find the '--' argument.
+  int DashDashIndex = 0;
+  for (int i = 0; i < Argc; ++i)
+    if (StringRef(Argv[i]) == "--")
+      DashDashIndex = i;
+
+  if (DashDashIndex == 0) {
+    llvm::errs() << "USAGE:\n"
+                 << "  " << Argv[0] << " [ Google Benchmark options ... ] -- "
+                 << "[ CompilerInvocation::CreateFromArgs arguments ... ]\n";
+    return 1;
+  }
+
+  // Remove all '-round-trip-args' occurrences.
+  for (int i = DashDashIndex + 1; i < Argc; ++i)
+    if (StringRef(Argv[i]) == "-round-trip-args")
+      Argv[i] = "";
+
+  // Inject '-round-trip-args' in place of '--'.
+  Argv[DashDashIndex] = "-round-trip-args";
+
+  Begin = Argv + DashDashIndex;
+  End = Argv + Argc;
+
+  int BenchmarkArgc = DashDashIndex - Argc;
+
+  ::benchmark::Initialize(&BenchmarkArgc, const_cast<char **>(Argv));
+  ::benchmark::RunSpecifiedBenchmarks();
+}