[gcc r12-5180] libstdc++: Make pmr::memory_resource::allocate implicitly create objects

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:083fd73202fb7387c16b6c9beab9841939a62acb

commit r12-5180-g083fd73202fb7387c16b6c9beab9841939a62acb
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Nov 10 16:59:29 2021 +0000

    libstdc++: Make pmr::memory_resource::allocate implicitly create objects
    
    Calling the placement version of ::operator new "implicitly creates
    objects in the returned region of storage" as per [intro.object]. This
    allows the returned memory to be used as storage for implicit-lifetime
    types (including arrays) without additional action by the caller. This
    is required by the proposed resolution of LWG 3147.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/memory_resource (memory_resource::allocate):
            Implicitly create objects in the returned storage.

Diff:
---
 libstdc++-v3/include/std/memory_resource | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/std/memory_resource b/libstdc++-v3/include/std/memory_resource
index 6bca0afa018..97d37f18512 100644
--- a/libstdc++-v3/include/std/memory_resource
+++ b/libstdc++-v3/include/std/memory_resource
@@ -33,6 +33,7 @@
 
 #if __cplusplus >= 201703L
 
+#include <new>
 #include <vector>			// vector
 #include <cstddef>			// size_t, max_align_t, byte
 #include <shared_mutex>			// shared_mutex
@@ -103,7 +104,7 @@ namespace pmr
     void*
     allocate(size_t __bytes, size_t __alignment = _S_max_align)
     __attribute__((__returns_nonnull__,__alloc_size__(2),__alloc_align__(3)))
-    { return do_allocate(__bytes, __alignment); }
+    { return ::operator new(__bytes, do_allocate(__bytes, __alignment)); }
 
     void
     deallocate(void* __p, size_t __bytes, size_t __alignment = _S_max_align)