[PATCH 3/6] libstdc++: port bitwise relocatable away from is_trivial

[Giuseppe D'Angelo]

Hello,




Thanks,
--
Giuseppe D'Angelo

From 0666e993066818ab0940c61d8d9539e883848b29 Mon Sep 17 00:00:00 2001
From: Giuseppe D'Angelo <giuseppe.dang...@kdab.com>
Date: Mon, 9 Dec 2024 02:11:19 +0100
Subject: [PATCH 3/6] libstdc++: port bitwise relocatable away from is_trivial
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In preparation for the deprecation of is_trivial (P3247R2).
"bitwise relocation" (or "trivial relocation" à la P1144/P2786)
doesn't need the full-fledged notion of triviality, just checking for a
trivial move constructor and a trivial destructor is sufficient.

libstdc++-v3/ChangeLog:

	* include/bits/stl_uninitialized.h: Amended the
	  __is_bitwise_relocatable type trait.

Signed-off-by: Giuseppe D'Angelo <giuseppe.dang...@kdab.com>
---
 libstdc++-v3/include/bits/stl_uninitialized.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/bits/stl_uninitialized.h b/libstdc++-v3/include/bits/stl_uninitialized.h
index 2190261134e..916288352d7 100644
--- a/libstdc++-v3/include/bits/stl_uninitialized.h
+++ b/libstdc++-v3/include/bits/stl_uninitialized.h
@@ -1248,7 +1248,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // Also known as is_trivially_relocatable.
   template<typename _Tp, typename = void>
     struct __is_bitwise_relocatable
-    : is_trivial<_Tp> { };
+    : __and_<is_trivially_move_constructible<_Tp>, is_trivially_destructible<_Tp>> { };
 
   template <typename _InputIterator, typename _ForwardIterator,
 	    typename _Allocator>
-- 
2.34.1

This aligns __is_bitwise_relocatable with its modern meaning, that is, checking for trivial move construction and destruction.

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