From fffac1157dbab582b431c8f8ab1021096dd5df2a Mon Sep 17 00:00:00 2001
From: Dertosh <Dertosh7@gmail.com>
Date: Fri, 13 Dec 2024 10:58:56 -0800
Subject: [PATCH] PR #1794: Update cpu_detect.cc fix hw crc32 and AES
 capability check, fix undefined

Imported from GitHub PR https://github.com/abseil/abseil-cpp/pull/1794

Source and explanation
https://github.com/JuliaLang/julia/issues/26458
https://github.com/memcached/memcached/pull/744

For build for aarch64 on v22_clang-16.0.6-centos7
`
abseil-cpp/absl/crc/internal/cpu_detect.cc:273:20: error: use of undeclared identifier 'HWCAP_CRC32'
  return (hwcaps & HWCAP_CRC32) && (hwcaps & HWCAP_PMULL);
                   ^
abseil-cpp/absl/crc/internal/cpu_detect.cc:273:46: error: use of undeclared identifier 'HWCAP_PMULL'
  return (hwcaps & HWCAP_CRC32) && (hwcaps & HWCAP_PMULL);
`

Merge 3ee325b7a4141fbf31891c08f0184822c4706274 into 940e0ec36afbc7acf5de31167d4820d274d28c92

Merging this change closes #1794

COPYBARA_INTEGRATE_REVIEW=https://github.com/abseil/abseil-cpp/pull/1794 from Dertosh:patch-1 3ee325b7a4141fbf31891c08f0184822c4706274
PiperOrigin-RevId: 705936372
Change-Id: Ifebd6d1a854e17acf6cc00bab92053bc0d4c2349
---
 absl/crc/internal/cpu_detect.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/absl/crc/internal/cpu_detect.cc b/absl/crc/internal/cpu_detect.cc
index d7eedd1c..e27719cf 100644
--- a/absl/crc/internal/cpu_detect.cc
+++ b/absl/crc/internal/cpu_detect.cc
@@ -269,8 +269,12 @@ CpuType GetCpuType() {
 }
 
 bool SupportsArmCRC32PMULL() {
+#if defined(HWCAP_CRC32) && defined(HWCAP_PMULL)
   uint64_t hwcaps = getauxval(AT_HWCAP);
   return (hwcaps & HWCAP_CRC32) && (hwcaps & HWCAP_PMULL);
+#else
+  return false;
+#endif
 }
 
 #else