Eliminate AArch64-specific code paths from LowLevelHash

After internal investigation, it’s no longer clear that the alternative
LowLevelHash mixer committed in a05366d851c5cb88065272f951e03955197e7c11
unequivocally improves performance on AArch64. It unnecessarily reduces
performance on Apple Silicon and the AWS Graviton. It also lowers hash
quality, which offsets much of the performance gain it provides on the
Arm Neoverse N1 (see https://github.com/abseil/abseil-cpp/issues/1093).
Switch back to the original mixer.

Closes: https://github.com/abseil/abseil-cpp/issues/1093
PiperOrigin-RevId: 493941913
Change-Id: I84c789b2f88c91dec22f6f0f6e8c5129d2939a6f

1 files changed, 0 insertions, 48 deletions

diff --git a/absl/hash/internal/low_level_hash_test.cc b/absl/hash/internal/low_level_hash_test.cc
index ae930b34..589a3d8f 100644
--- a/absl/hash/internal/low_level_hash_test.cc
+++ b/absl/hash/internal/low_level_hash_test.cc
@@ -452,54 +452,6 @@ TEST(LowLevelHashTest, VerifyGolden) {
       0xdd497891465a2cc1, 0x6f1fe8c57a33072e, 0x2c9f4ec078c460c0,
       0x9a725bde8f6a1437, 0x6ce545fa3ef61e4d,
   };
-#elif defined(__aarch64__)
-  constexpr uint64_t kGolden[kNumGoldenOutputs] = {
-      0x45c0aadee165dcbe, 0x25ed8587f6f20d06, 0x5f23ae668ce7926d,
-      0xfef74d1da0846719, 0x54478408e68cb7d4, 0xee27ddaf88c6fe68,
-      0xb7ac7031e81867ca, 0xf1168f818ec6c36d, 0x1dd0b734a83b019a,
-      0xd6ae30d4142b54fe, 0xcd860c721ccb80fb, 0x068acf8493794756,
-      0xd4ada0be58681307, 0x13ffe0f64ca540ed, 0xffc1d7a3401aec02,
-      0xd81c4d865cf95fb9, 0x1dd0793acede62e0, 0xa6722abbca8fe4cf,
-      0x5453d3e4111a7e40, 0xf29b3e3204c9dcd2, 0x23be2980e43117f7,
-      0x74e2ccbc286f08eb, 0x19ef7c0f9496003a, 0xbfbf1c3e49b27987,
-      0x6e6c179eb4a82c70, 0x07f4e184216bc4fc, 0xf17fbc4254927554,
-      0xe57696b70a45b1b6, 0x6d3b144631b320e8, 0xccf8729792c75a2d,
-      0xe832495b41fa980b, 0x5c96cfdc7b227d34, 0xc4dca234ef4e43f4,
-      0x5fc801abf9abe307, 0xe41e3c5076d88f4d, 0x522346200ddec3c3,
-      0x72bed1946fd7aaa4, 0x0ac1f84dcc335f96, 0x3af78db5e0a47670,
-      0x6100ebf1481f1caf, 0xf5fd10037fc651a3, 0xa01227d8944665f3,
-      0x7217681c4bbc9420, 0x4adee538e3eb10d1, 0x35e1761ad96de9a7,
-      0x8b370aef9613bfba, 0x824506f749eeaf59, 0x85e805fa04423991,
-      0xb61e9c33283c3de7, 0xc79721bbcb039ed6, 0x04e1c19a3a1e6639,
-      0x6aaf6346b68dd638, 0x601a4b496be6d0c4, 0x3ece355f91c41787,
-      0xd2fc8998448d7888, 0xd7529804f843efa9, 0xabdcc38a288536aa,
-      0xdd323e48a9718648, 0x2090279c0030a52a, 0xe2f90faca88a3cd1,
-      0x3e0c4e92fc50e4aa, 0xa26d308798e801dd, 0x432eefeedee8c02e,
-      0xca4ce494614b77df, 0xbba82911e838066d, 0x4b00821016adee4b,
-      0x4cf6e526dfb5a20f, 0x5b8466495142cba2, 0xe28ac1406e88a68c,
-      0x8511e5f9d3100999, 0x05acbfe02798890b, 0x74c249c7ce4a8425,
-      0xdbe7468d09bc34bc, 0x11079ab10e3b9b58, 0xb7788dec9032035a,
-      0xb7e8daa786513f80, 0x34c3288831f46b45, 0x014cce5f0c21ecc6,
-      0xc6a8f7b024551a28, 0x49784e902e207fd8, 0x4720d32af0b55158,
-      0x8df3ec5de0c1da00, 0xf4db677b2c9e6853, 0xaa419abea78d312d,
-      0x181e0f91bd757443, 0xa8c45136fada083b, 0x91303b93f5f0582c,
-      0x883b95c6ddc62a08, 0x93186a8875fe952b, 0xd94f533928e957e2,
-      0x6ba343003e10c172, 0xc8623b620c715d6a, 0x8ca0c512e180e244,
-      0xdc9b74c2536b6216, 0x8eb5fdc61b295d96, 0x2ad83966b37c95ba,
-      0xb90bf154ac5edec9, 0x902cf847b326cfb3, 0x7b02d0c0ca7808ca,
-      0x492f310d003ea15f, 0x3eb6497a47c95990, 0x5d46b0ced31428b7,
-      0x081afa67d1986157, 0x043482ec286b20eb, 0xc103c8f18c1a2a53,
-      0xe8e9995a81481e83, 0x6bb3295822bc90b5, 0xeec75297a3fa5672,
-      0x591c8440c4857412, 0x74947f455aaf24ad, 0xcf0e571586ec77a9,
-      0x0c2553ea8c0400ad, 0x380219118066255f, 0x7595adb88b15ebe2,
-      0xb33c00696c64ae23, 0xa143516ddd7c9857, 0x39179af229248d26,
-      0x65d387a6f2ee2079, 0x89f8a9b21cd2f195, 0xbfef032d25df92e6,
-      0x6b7e18a36c69da71, 0x4b3b15f6c28974e6, 0x032a75917f6c544c,
-      0xe3b97ecca6d287cd, 0xa4a563110d3cda81, 0x35e09e8134f4e7f1,
-      0xc9419dd03a9a390e, 0x7b86fae9000fd329, 0x1e044f8d54fe74c3,
-      0x9c4991d7a47e9666, 0xfb485f3a1df4fdb6, 0xb11519969eeb94ff,
-      0x3224ea1c44caeb8d, 0x86570bbd7cc6b80d,
-  };
 #else
   constexpr uint64_t kGolden[kNumGoldenOutputs] = {
       0xe5a40d39ab796423, 0x1766974bf7527d81, 0x5c3bbbe230db17a8,