1diff --git a/base/third_party/cityhash/city.cc b/base/third_party/cityhash/city.cc 2index b0d2294aabb3..2ab3db20f4fa 100644 3--- a/base/third_party/cityhash/city.cc 4+++ b/base/third_party/cityhash/city.cc 5@@ -35,7 +35,14 @@ 6 using std::make_pair; 7 using std::pair; 8 9-#ifdef _MSC_VER 10+#if defined(__clang__) 11+ 12+// Use builtins where possible. On Windows for instance, this may prevent a 13+// function call instead of emitting a single instruction. 14+#define bswap_32(x) __builtin_bswap32(x) 15+#define bswap_64(x) __builtin_bswap64(x) 16+ 17+#elif _MSC_VER 18 19 #include <stdlib.h> 20 #define bswap_32(x) _byteswap_ulong(x) 21