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| author | Jonathan Wakely <jwakely@redhat.com> | 2021-12-01 20:58:58 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2021-12-02 16:46:28 +0000 |
| commit | b5a568683f71b4a8b1e4e45a43484398e9a66ff2 (patch) | |
| tree | 3fcc70af8566481446db259a09d3c451d49b704e | |
| parent | d08236359eb22918ba067489edcec02857109d09 (diff) | |
| download | gcc-b5a568683f71b4a8b1e4e45a43484398e9a66ff2.zip gcc-b5a568683f71b4a8b1e4e45a43484398e9a66ff2.tar.gz gcc-b5a568683f71b4a8b1e4e45a43484398e9a66ff2.tar.bz2 | |
libstdc++: Restore unconditional atomic load in COW std::string
The relaxed load is already optimal, checking the __single_threaded
global before doing a non-atomic load isn't an optimization.
libstdc++-v3/ChangeLog:
* include/bits/cow_string.h (basic_string::_M_is_leaked()):
Revert change to check __is_single_threaded() before using
atomic load.
| -rw-r--r-- | libstdc++-v3/include/bits/cow_string.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/libstdc++-v3/include/bits/cow_string.h b/libstdc++-v3/include/bits/cow_string.h index d6ddf34..389b395 100644 --- a/libstdc++-v3/include/bits/cow_string.h +++ b/libstdc++-v3/include/bits/cow_string.h @@ -207,10 +207,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // so we need to use an atomic load. However, _M_is_leaked // predicate does not change concurrently (i.e. the string is either // leaked or not), so a relaxed load is enough. - if (!__gnu_cxx::__is_single_threaded()) - return __atomic_load_n(&this->_M_refcount, __ATOMIC_RELAXED) < 0; -#endif + return __atomic_load_n(&this->_M_refcount, __ATOMIC_RELAXED) < 0; +#else return this->_M_refcount < 0; +#endif } bool |