diff --git a/libcxx/benchmarks/CartesianBenchmarks.hpp b/libcxx/benchmarks/CartesianBenchmarks.h
similarity index 100%
rename from libcxx/benchmarks/CartesianBenchmarks.hpp
rename to libcxx/benchmarks/CartesianBenchmarks.h
diff --git a/libcxx/benchmarks/ContainerBenchmarks.hpp b/libcxx/benchmarks/ContainerBenchmarks.h
similarity index 96%
rename from libcxx/benchmarks/ContainerBenchmarks.hpp
rename to libcxx/benchmarks/ContainerBenchmarks.h
index 581d3c53e603..d2061f288536 100644
--- a/libcxx/benchmarks/ContainerBenchmarks.hpp
+++ b/libcxx/benchmarks/ContainerBenchmarks.h
@@ -7,12 +7,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef BENCHMARK_CONTAINER_BENCHMARKS_HPP
-#define BENCHMARK_CONTAINER_BENCHMARKS_HPP
+#ifndef BENCHMARK_CONTAINER_BENCHMARKS_H
+#define BENCHMARK_CONTAINER_BENCHMARKS_H
 
 #include <cassert>
 
-#include "Utilities.hpp"
+#include "Utilities.h"
 #include "benchmark/benchmark.h"
 
 namespace ContainerBenchmarks {
@@ -137,4 +137,4 @@ static void BM_FindRehash(benchmark::State& st, Container c, GenInputs gen) {
 
 } // end namespace ContainerBenchmarks
 
-#endif // BENCHMARK_CONTAINER_BENCHMARKS_HPP
+#endif // BENCHMARK_CONTAINER_BENCHMARKS_H
diff --git a/libcxx/benchmarks/GenerateInput.hpp b/libcxx/benchmarks/GenerateInput.h
similarity index 97%
rename from libcxx/benchmarks/GenerateInput.hpp
rename to libcxx/benchmarks/GenerateInput.h
index 8c97f5881f1e..e4f131c628f1 100644
--- a/libcxx/benchmarks/GenerateInput.hpp
+++ b/libcxx/benchmarks/GenerateInput.h
@@ -1,5 +1,5 @@
-#ifndef BENCHMARK_GENERATE_INPUT_HPP
-#define BENCHMARK_GENERATE_INPUT_HPP
+#ifndef BENCHMARK_GENERATE_INPUT_H
+#define BENCHMARK_GENERATE_INPUT_H
 
 #include <algorithm>
 #include <random>
@@ -141,4 +141,4 @@ inline std::vector<const char*> getRandomCStringInputs(size_t N) {
 }
 
 
-#endif // BENCHMARK_GENERATE_INPUT_HPP
+#endif // BENCHMARK_GENERATE_INPUT_H
diff --git a/libcxx/benchmarks/Utilities.hpp b/libcxx/benchmarks/Utilities.h
similarity index 92%
rename from libcxx/benchmarks/Utilities.hpp
rename to libcxx/benchmarks/Utilities.h
index 1b25f746ddaf..9ad2a58796ea 100644
--- a/libcxx/benchmarks/Utilities.hpp
+++ b/libcxx/benchmarks/Utilities.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef BENCHMARK_UTILITIES_HPP
-#define BENCHMARK_UTILITIES_HPP
+#ifndef BENCHMARK_UTILITIES_H
+#define BENCHMARK_UTILITIES_H
 
 #include <cassert>
 #include <type_traits>
@@ -30,4 +30,4 @@ template <class Container, std::enable_if_t<!UtilitiesInternal::HasData<Containe
 void DoNotOptimizeData(Container &c) { benchmark::DoNotOptimize(&c); }
 
 
-#endif // BENCHMARK_UTILITIES_HPP
+#endif // BENCHMARK_UTILITIES_H
diff --git a/libcxx/benchmarks/algorithms.bench.cpp b/libcxx/benchmarks/algorithms.bench.cpp
index f5f0a02a9a25..b259d476457b 100644
--- a/libcxx/benchmarks/algorithms.bench.cpp
+++ b/libcxx/benchmarks/algorithms.bench.cpp
@@ -7,8 +7,8 @@
 #include <utility>
 #include <vector>
 
-#include "CartesianBenchmarks.hpp"
-#include "GenerateInput.hpp"
+#include "CartesianBenchmarks.h"
+#include "GenerateInput.h"
 #include "benchmark/benchmark.h"
 #include "test_macros.h"
 
diff --git a/libcxx/benchmarks/algorithms.partition_point.bench.cpp b/libcxx/benchmarks/algorithms.partition_point.bench.cpp
index 00a3bb272672..840cf0391ee1 100644
--- a/libcxx/benchmarks/algorithms.partition_point.bench.cpp
+++ b/libcxx/benchmarks/algorithms.partition_point.bench.cpp
@@ -7,8 +7,8 @@
 
 #include "benchmark/benchmark.h"
 
-#include "CartesianBenchmarks.hpp"
-#include "GenerateInput.hpp"
+#include "CartesianBenchmarks.h"
+#include "GenerateInput.h"
 
 namespace {
 
diff --git a/libcxx/benchmarks/deque.bench.cpp b/libcxx/benchmarks/deque.bench.cpp
index 44a492b7b3d1..0025a335ccf2 100644
--- a/libcxx/benchmarks/deque.bench.cpp
+++ b/libcxx/benchmarks/deque.bench.cpp
@@ -11,8 +11,8 @@
 
 #include "benchmark/benchmark.h"
 
-#include "ContainerBenchmarks.hpp"
-#include "GenerateInput.hpp"
+#include "ContainerBenchmarks.h"
+#include "GenerateInput.h"
 
 using namespace ContainerBenchmarks;
 
diff --git a/libcxx/benchmarks/filesystem.bench.cpp b/libcxx/benchmarks/filesystem.bench.cpp
index 4c464442d91a..64314ac5ab04 100644
--- a/libcxx/benchmarks/filesystem.bench.cpp
+++ b/libcxx/benchmarks/filesystem.bench.cpp
@@ -1,5 +1,5 @@
 #include "benchmark/benchmark.h"
-#include "GenerateInput.hpp"
+#include "GenerateInput.h"
 #include "test_iterators.h"
 #include "filesystem_include.h"
 
diff --git a/libcxx/benchmarks/function.bench.cpp b/libcxx/benchmarks/function.bench.cpp
index 5cc3e7105e42..7fabc937dd93 100644
--- a/libcxx/benchmarks/function.bench.cpp
+++ b/libcxx/benchmarks/function.bench.cpp
@@ -11,7 +11,7 @@
 #include <memory>
 #include <string>
 
-#include "CartesianBenchmarks.hpp"
+#include "CartesianBenchmarks.h"
 #include "benchmark/benchmark.h"
 #include "test_macros.h"
 
diff --git a/libcxx/benchmarks/ordered_set.bench.cpp b/libcxx/benchmarks/ordered_set.bench.cpp
index e179aac4562a..a9d9c929ac64 100644
--- a/libcxx/benchmarks/ordered_set.bench.cpp
+++ b/libcxx/benchmarks/ordered_set.bench.cpp
@@ -14,7 +14,7 @@
 #include <string>
 #include <vector>
 
-#include "CartesianBenchmarks.hpp"
+#include "CartesianBenchmarks.h"
 #include "benchmark/benchmark.h"
 #include "test_macros.h"
 
diff --git a/libcxx/benchmarks/string.bench.cpp b/libcxx/benchmarks/string.bench.cpp
index 22d84afe14ad..c4f209039c81 100644
--- a/libcxx/benchmarks/string.bench.cpp
+++ b/libcxx/benchmarks/string.bench.cpp
@@ -3,8 +3,8 @@
 #include <new>
 #include <vector>
 
-#include "CartesianBenchmarks.hpp"
-#include "GenerateInput.hpp"
+#include "CartesianBenchmarks.h"
+#include "GenerateInput.h"
 #include "benchmark/benchmark.h"
 #include "test_macros.h"
 
diff --git a/libcxx/benchmarks/unordered_set_operations.bench.cpp b/libcxx/benchmarks/unordered_set_operations.bench.cpp
index 1fee6d362c41..3824386e7e2b 100644
--- a/libcxx/benchmarks/unordered_set_operations.bench.cpp
+++ b/libcxx/benchmarks/unordered_set_operations.bench.cpp
@@ -7,8 +7,8 @@
 
 #include "benchmark/benchmark.h"
 
-#include "ContainerBenchmarks.hpp"
-#include "GenerateInput.hpp"
+#include "ContainerBenchmarks.h"
+#include "GenerateInput.h"
 #include "test_macros.h"
 
 using namespace ContainerBenchmarks;
diff --git a/libcxx/benchmarks/vector_operations.bench.cpp b/libcxx/benchmarks/vector_operations.bench.cpp
index c41259eaac31..70a317df9fb8 100644
--- a/libcxx/benchmarks/vector_operations.bench.cpp
+++ b/libcxx/benchmarks/vector_operations.bench.cpp
@@ -6,8 +6,8 @@
 
 #include "benchmark/benchmark.h"
 
-#include "ContainerBenchmarks.hpp"
-#include "GenerateInput.hpp"
+#include "ContainerBenchmarks.h"
+#include "GenerateInput.h"
 
 using namespace ContainerBenchmarks;