1 files changed, 52 insertions, 0 deletions
diff --git a/third-party/benchmark/test/donotoptimize_test.cc b/third-party/benchmark/test/donotoptimize_test.cc
new file mode 100644
index 000000000000..2ce92d1c72be
--- /dev/null
+++ b/third-party/benchmark/test/donotoptimize_test.cc
@@ -0,0 +1,52 @@
+#include "benchmark/benchmark.h"
+
+#include <cstdint>
+
+namespace {
+#if defined(__GNUC__)
+std::uint64_t double_up(const std::uint64_t x) __attribute__((const));
+#endif
+std::uint64_t double_up(const std::uint64_t x) { return x * 2; }
+}
+
+// Using DoNotOptimize on types like BitRef seem to cause a lot of problems
+// with the inline assembly on both GCC and Clang.
+struct BitRef {
+  int index;
+  unsigned char &byte;
+
+public:
+  static BitRef Make() {
+    static unsigned char arr[2] = {};
+    BitRef b(1, arr[0]);
+    return b;
+  }
+private:
+  BitRef(int i, unsigned char& b) : index(i), byte(b) {}
+};
+
+int main(int, char*[]) {
+  // this test verifies compilation of DoNotOptimize() for some types
+
+  char buffer8[8] = "";
+  benchmark::DoNotOptimize(buffer8);
+
+  char buffer20[20] = "";
+  benchmark::DoNotOptimize(buffer20);
+
+  char buffer1024[1024] = "";
+  benchmark::DoNotOptimize(buffer1024);
+  benchmark::DoNotOptimize(&buffer1024[0]);
+
+  int x = 123;
+  benchmark::DoNotOptimize(x);
+  benchmark::DoNotOptimize(&x);
+  benchmark::DoNotOptimize(x += 42);
+
+  benchmark::DoNotOptimize(double_up(x));
+
+  // These tests are to e
+  benchmark::DoNotOptimize(BitRef::Make());
+  BitRef lval = BitRef::Make();
+  benchmark::DoNotOptimize(lval);
+}