Re: [PATCH] Define std::atomic_ref and std::atomic for C++20

[Jonathan Wakely]

On 11/07/19 20:45 +0100, Jonathan Wakely wrote:

This adds the new atomic types from C++2a, as proposed by P0019 and
P0020. To reduce duplication the calls to the compiler's atomic
built-ins are wrapped in new functions in the __atomic_impl namespace.
These functions are currently only used by std::atomic<floating-point>
and std::atomic_ref but could also be used for all other specializations
of std::atomic.

        * include/bits/atomic_base.h (__atomic_impl): New namespace for
        wrappers around atomic built-ins.
        (__atomic_float, __atomic_ref): New class templates for use as base
        classes.
        * include/std/atomic (atomic<float>, atomic<double>)
        (atomic<long double>): New explicit specializations.
        (atomic_ref): New class template.
        (__cpp_lib_atomic_ref): Define.
        * include/std/version (__cpp_lib_atomic_ref): Define.
        * testsuite/29_atomics/atomic/60695.cc: Adjust dg-error.
        * testsuite/29_atomics/atomic_float/1.cc: New test.
        * testsuite/29_atomics/atomic_float/requirements.cc: New test.
        * testsuite/29_atomics/atomic_ref/deduction.cc: New test.
        * testsuite/29_atomics/atomic_ref/float.cc: New test.
        * testsuite/29_atomics/atomic_ref/generic.cc: New test.
        * testsuite/29_atomics/atomic_ref/integral.cc: New test.
        * testsuite/29_atomics/atomic_ref/pointer.cc: New test.
        * testsuite/29_atomics/atomic_ref/requirements.cc: New test.

Here's the doc update for these features. Committed to trunk.



commit 6e6ad5a7338f902cfa1f8296eb11f6e0e6993a92
Author: redi <redi@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Fri Jul 12 11:43:17 2019 +0000

    Update C++2a library status table
    
            * doc/xml/manual/status_cxx2020.xml: Update status for atomic_ref
            and floating point atomics.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@273441 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/libstdc++-v3/doc/xml/manual/status_cxx2020.xml b/libstdc++-v3/doc/xml/manual/status_cxx2020.xml
index 029c5bc9b8e..3a5de38ad22 100644
--- a/libstdc++-v3/doc/xml/manual/status_cxx2020.xml
+++ b/libstdc++-v3/doc/xml/manual/status_cxx2020.xml
@@ -78,14 +78,13 @@ Feature-testing recommendations for C++</link>.
     </row>
 
     <row>
-      <?dbhtml bgcolor="#C8B0B0" ?>
       <entry>  Floating Point Atomic </entry>
       <entry>
         <link xmlns:xlink="http://www.w3.org/1999/xlink"; xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0020r6.html";>
 	P0020R6
 	</link>
       </entry>
-      <entry align="center"> </entry>
+      <entry align="center"> 10.1 </entry>
       <entry />
     </row>
 
@@ -345,15 +344,14 @@ Feature-testing recommendations for C++</link>.
     </row>
 
     <row>
-      <?dbhtml bgcolor="#C8B0B0" ?>
       <entry>  Atomic Ref </entry>
       <entry>
         <link xmlns:xlink="http://www.w3.org/1999/xlink"; xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0019r8.html";>
 	P0019R8
 	</link>
       </entry>
-      <entry align="center"> </entry>
-      <entry />
+      <entry align="center"> 10.1 </entry>
+      <entry> <code>__cpp_lib_atomic_ref &gt;= 201806L</code> </entry>
     </row>
 
     <row>