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

[Jonathan Wakely]

On 09/12/24 13:22 +0100, Giuseppe D'Angelo wrote:
>Hello,
>
>This aligns __is_bitwise_relocatable with its modern meaning, that is, 
>checking for trivial move construction and destruction.

Looks good, thanks.

>Thanks,
>-- 
>Giuseppe D'Angelo

>From 0666e993066818ab0940c61d8d9539e883848b29 Mon Sep 17 00:00:00 2001
>From: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
>Date: Mon, 9 Dec 2024 02:11:19 +0100
>Subject: [PATCH 3/6] libstdc++: port bitwise relocatable away from is_trivial
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>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.dangelo@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
>