From 4b9e1db1a14dbfc0b9a3cf9321fda4c041553b3a Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Tue, 10 Dec 2024 09:48:57 +0000
Subject: [PATCH] libstdc++: Revert change to __bitwise_relocatable
This reverts r15-6060-ge4a0157c2397c9 so that __is_bitwise_relocatable
depends only on is_trivial. To avoid the deprecation warnings for C++26,
use the __is_trivial built-in directly instead of std::is_trivial.
We need to be sure that the type is trivially copyable, not just
trivially constructible and trivially assignable. Otherwise we get
-Wclass-memaccess diagnostics for e.g. std::vector<std::pair<A*, B*>>.
We could add is_trivially_copyable to the conditions, but this isn't
really an appropriate change for stage 3 anyway (it affects all modes
from C++11 upwards). Just revert to using is_trivial, and we can revisit
the condition for GCC 16.
libstdc++-v3/ChangeLog:
* include/bits/stl_uninitialized.h (__is_bitwise_relocatable):
Revert to depending on is_trivial.
---
libstdc++-v3/include/bits/stl_uninitialized.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/include/bits/stl_uninitialized.h b/libstdc++-v3/include/bits/stl_uninitialized.h
index 916288352d70..b7e65eb3ca06 100644
--- a/libstdc++-v3/include/bits/stl_uninitialized.h
+++ b/libstdc++-v3/include/bits/stl_uninitialized.h
@@ -1248,7 +1248,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Also known as is_trivially_relocatable.
template<typename _Tp, typename = void>
struct __is_bitwise_relocatable
- : __and_<is_trivially_move_constructible<_Tp>, is_trivially_destructible<_Tp>> { };
+ : __bool_constant<__is_trivial(_Tp)>
+ { };
template <typename _InputIterator, typename _ForwardIterator,
typename _Allocator>
--
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