3 files changed, 8 insertions, 0 deletions
diff --git a/absl/numeric/BUILD.bazel b/absl/numeric/BUILD.bazel
index f49571e..324ce66 100644
--- a/absl/numeric/BUILD.bazel
+++ b/absl/numeric/BUILD.bazel
@@ -49,6 +49,7 @@ cc_test(
         ":int128",
         "//absl/base",
         "//absl/base:core_headers",
+        "//absl/hash:hash_testing",
         "//absl/meta:type_traits",
         "@com_google_googletest//:gtest_main",
     ],
diff --git a/absl/numeric/int128.h b/absl/numeric/int128.h
index 2d131b8..79b62a7 100644
--- a/absl/numeric/int128.h
+++ b/absl/numeric/int128.h
@@ -192,6 +192,12 @@ class
   // Returns the highest value for a 128-bit unsigned integer.
   friend constexpr uint128 Uint128Max();
 
+  // Support for absl::Hash.
+  template <typename H>
+  friend H AbslHashValue(H h, uint128 v) {
+    return H::combine(std::move(h), Uint128High64(v), Uint128Low64(v));
+  }
+
  private:
   constexpr uint128(uint64_t high, uint64_t low);
 
diff --git a/absl/numeric/int128_test.cc b/absl/numeric/int128_test.cc
index 1eb3e0e..dfe3475 100644
--- a/absl/numeric/int128_test.cc
+++ b/absl/numeric/int128_test.cc
@@ -23,6 +23,7 @@
 
 #include "gtest/gtest.h"
 #include "absl/base/internal/cycleclock.h"
+#include "absl/hash/hash_testing.h"
 #include "absl/meta/type_traits.h"
 
 #if defined(_MSC_VER) && _MSC_VER == 1900