* [committed] libstdc++: Strip cv-qualifiers in std::atomic<FP> (PR 95282)
@ 2020-06-16 21:35 Jonathan Wakely
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From: Jonathan Wakely @ 2020-06-16 21:35 UTC (permalink / raw)
To: libstdc++, gcc-patches
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This improves the previous fix for PR 95282, and extends it to also
apply to the exchange function (which has a similar problem and would
become ill-formed with my proposed fix for PR 95378).
PR libstdc++/95282
* include/bits/atomic_base.h (__atomic_impl::load): Use the _Val
alias instead of deducing _Tp as an unqualified type.
(__atomic_impl::exchange): Use the _Val alias to remove volatile
from the reinterpret_cast result type.
Tested powerpc64le-linux, committed to master.
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commit e40b11a91cb345db1324c3cb8f75b01e28056693
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Tue Jun 16 22:34:55 2020 +0100
libstdc++: Strip cv-qualifiers in std::atomic<FP> (PR 95282)
This improves the previous fix for PR 95282, and extends it to also
apply to the exchange function (which has a similar problem and would
become ill-formed with my proposed fix for PR 95378).
PR libstdc++/95282
* include/bits/atomic_base.h (__atomic_impl::load): Use the _Val
alias instead of deducing _Tp as an unqualified type.
(__atomic_impl::exchange): Use the _Val alias to remove volatile
from the reinterpret_cast result type.
diff --git a/libstdc++-v3/include/bits/atomic_base.h b/libstdc++-v3/include/bits/atomic_base.h
index ebcfeb4d51a..015acef83c4 100644
--- a/libstdc++-v3/include/bits/atomic_base.h
+++ b/libstdc++-v3/include/bits/atomic_base.h
@@ -870,21 +870,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ __atomic_store(__ptr, std::__addressof(__t), int(__m)); }
template<typename _Tp>
- _GLIBCXX_ALWAYS_INLINE _Tp
- load(const volatile _Tp* __ptr, memory_order __m) noexcept
+ _GLIBCXX_ALWAYS_INLINE _Val<_Tp>
+ load(const _Tp* __ptr, memory_order __m) noexcept
{
alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
- _Tp* __dest = reinterpret_cast<_Tp*>(__buf);
+ auto* __dest = reinterpret_cast<_Val<_Tp>*>(__buf);
__atomic_load(__ptr, __dest, int(__m));
return *__dest;
}
template<typename _Tp>
- _GLIBCXX_ALWAYS_INLINE _Tp
+ _GLIBCXX_ALWAYS_INLINE _Val<_Tp>
exchange(_Tp* __ptr, _Val<_Tp> __desired, memory_order __m) noexcept
{
alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
- _Tp* __dest = reinterpret_cast<_Tp*>(__buf);
+ auto* __dest = reinterpret_cast<_Val<_Tp>*>(__buf);
__atomic_exchange(__ptr, std::__addressof(__desired), __dest, int(__m));
return *__dest;
}
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2020-06-16 21:35 [committed] libstdc++: Strip cv-qualifiers in std::atomic<FP> (PR 95282) Jonathan Wakely
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