diff options
Diffstat (limited to 'absl/flags/config.h')
| -rw-r--r-- | absl/flags/config.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/absl/flags/config.h b/absl/flags/config.h index a9fd97ad0f37..fbe349611f54 100644 --- a/absl/flags/config.h +++ b/absl/flags/config.h @@ -45,4 +45,15 @@ #define ABSL_FLAGS_STRIP_HELP ABSL_FLAGS_STRIP_NAMES #endif +// ABSL_FLAGS_INTERNAL_ATOMIC_DOUBLE_WORD macro is used for using atomics with +// double words, e.g. absl::Duration. +// For reasons in bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80878, modern +// versions of GCC do not support cmpxchg16b instruction in standard atomics. +#ifdef ABSL_FLAGS_INTERNAL_ATOMIC_DOUBLE_WORD +#error "ABSL_FLAGS_INTERNAL_ATOMIC_DOUBLE_WORD should not be defined." +#elif defined(__clang__) && defined(__x86_64__) && \ + defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_16) +#define ABSL_FLAGS_INTERNAL_ATOMIC_DOUBLE_WORD 1 +#endif + #endif // ABSL_FLAGS_CONFIG_H_ |