merge(3p/absl): subtree merge of Abseil up to e19260f r/1889

... notably, this includes Abseil's own StatusOr type, which
conflicted with our implementation (that was taken from TensorFlow).

Change-Id: Ie7d6764b64055caaeb8dc7b6b9d066291e6b538f

1 files changed, 1 insertions, 19 deletions

diff --git a/third_party/abseil_cpp/absl/hash/internal/city.h b/third_party/abseil_cpp/absl/hash/internal/city.h
index 161c7748ec..393da0b95d 100644
--- a/third_party/abseil_cpp/absl/hash/internal/city.h
+++ b/third_party/abseil_cpp/absl/hash/internal/city.h
@@ -56,11 +56,6 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace hash_internal {
 
-typedef std::pair<uint64_t, uint64_t> uint128;
-
-inline uint64_t Uint128Low64(const uint128 &x) { return x.first; }
-inline uint64_t Uint128High64(const uint128 &x) { return x.second; }
-
 // Hash function for a byte array.
 uint64_t CityHash64(const char *s, size_t len);
 
@@ -71,24 +66,11 @@ uint64_t CityHash64WithSeed(const char *s, size_t len, uint64_t seed);
 // Hash function for a byte array.  For convenience, two seeds are also
 // hashed into the result.
 uint64_t CityHash64WithSeeds(const char *s, size_t len, uint64_t seed0,
-                           uint64_t seed1);
+                             uint64_t seed1);
 
 // Hash function for a byte array.  Most useful in 32-bit binaries.
 uint32_t CityHash32(const char *s, size_t len);
 
-// Hash 128 input bits down to 64 bits of output.
-// This is intended to be a reasonably good hash function.
-inline uint64_t Hash128to64(const uint128 &x) {
-  // Murmur-inspired hashing.
-  const uint64_t kMul = 0x9ddfea08eb382d69ULL;
-  uint64_t a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul;
-  a ^= (a >> 47);
-  uint64_t b = (Uint128High64(x) ^ a) * kMul;
-  b ^= (b >> 47);
-  b *= kMul;
-  return b;
-}
-
 }  // namespace hash_internal
 ABSL_NAMESPACE_END
 }  // namespace absl