[gcc r12-1212] libstdc++: Add feature test macro for heterogeneous lookup in unordered containers

[gcc r12-1212] libstdc++: Add feature test macro for heterogeneous lookup in unordered containers

[Jonathan Wakely]

https://gcc.gnu.org/g:f78f25f43864f38ae5a6a9fcce8f26c94fe45bcd

commit r12-1212-gf78f25f43864f38ae5a6a9fcce8f26c94fe45bcd
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Jun 4 15:59:37 2021 +0100

    libstdc++: Add feature test macro for heterogeneous lookup in unordered containers
    
    Also update the C++20 status docs.
    
    Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
    
    libstdc++-v3/ChangeLog:
    
            * doc/xml/manual/status_cxx2020.xml:
            * doc/html/*: Regenerate.
            * include/bits/hashtable.h (__cpp_lib_generic_unordered_lookup):
            Define.
            * include/std/version (__cpp_lib_generic_unordered_lookup):
            Define.
            * testsuite/23_containers/unordered_map/operations/1.cc: Check
            feature test macro.
            * testsuite/23_containers/unordered_set/operations/1.cc:
            Likewise.

Diff:
---
 libstdc++-v3/doc/html/manual/status.html                 | 11 +++++++----
 libstdc++-v3/doc/xml/manual/status_cxx2020.xml           | 16 ++++++++++++----
 libstdc++-v3/include/bits/hashtable.h                    |  6 ++++--
 libstdc++-v3/include/std/version                         |  3 ++-
 .../23_containers/unordered_map/operations/1.cc          |  7 +++++++
 .../23_containers/unordered_set/operations/1.cc          |  7 +++++++
 6 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/libstdc++-v3/doc/html/manual/status.html b/libstdc++-v3/doc/html/manual/status.html
index dee6c3a56e7..75ac9e7d9b0 100644
--- a/libstdc++-v3/doc/html/manual/status.html
+++ b/libstdc++-v3/doc/html/manual/status.html
@@ -1364,10 +1364,10 @@ or any notes about the implementation.
       </td><td align="center"> 10.1 </td><td align="left"> <code class="code">__cpp_lib_jthread &gt;= 201907L</code> </td></tr><tr><td align="left"> Rename <code class="code">condition_variable_any</code> interruptible wait methods </td><td align="left">
         <a class="link" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1869r1.html" target="_top">
         P1869R1 </a>
-      </td><td align="center"> 10.1 </td><td align="left"> <code class="code">__cpp_lib_jthread &gt;= 201911L</code> </td></tr><tr bgcolor="#C8B0B0"><td align="left"> Atomic waiting and notifying, std::semaphore, std::latch and std::barrier </td><td align="left">
+      </td><td align="center"> 10.1 </td><td align="left"> <code class="code">__cpp_lib_jthread &gt;= 201911L</code> </td></tr><tr><td align="left"> Atomic waiting and notifying, std::semaphore, std::latch and std::barrier </td><td align="left">
         <a class="link" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1135r6.html" target="_top">
         P1135R6 </a>
-      </td><td align="center"> </td><td align="left">
+      </td><td align="center"> 11.1 </td><td align="left">
         <div class="informaltable"><table class="informaltable" border="0"><colgroup><col /></colgroup><tbody><tr><td> <code class="code">__cpp_lib_atomic_lock_free_type_aliases &gt;= 201907L</code> </td></tr><tr><td> <code class="code">__cpp_lib_atomic_flag_test &gt;= 201907L</code> </td></tr><tr><td> <code class="code">__cpp_lib_atomic_wait &gt;= 201907L</code> </td></tr><tr><td> <code class="code">__cpp_lib_semaphore &gt;= 201907L</code> </td></tr><tr><td> <code class="code">__cpp_lib_latch &gt;= 201907L</code> </td></tr><tr><td> <code class="code">__cpp_lib_barrier &gt;= 201907L</code> </td></tr></tbody></table></div>
       </td></tr><tr><td align="left"> Fixing Atomic Initialization </td><td align="left">
         <a class="link" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p0883r2.pdf" target="_top">
@@ -1479,10 +1479,13 @@ or any notes about the implementation.
       </td><td align="center"> 9.1 </td><td align="left"> </td></tr><tr bgcolor="#C8B0B0"><td align="left">  Comparing Unordered Containers </td><td align="left">
         <a class="link" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0809r0.pdf" target="_top">
         P0809R0 </a>
-      </td><td align="center"> </td><td align="left"> </td></tr><tr bgcolor="#C8B0B0"><td align="left">  Heterogeneous lookup for unordered containers </td><td align="left">
+      </td><td align="center"> </td><td align="left"> </td></tr><tr><td align="left">  Heterogeneous lookup for unordered containers </td><td align="left">
         <a class="link" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0919r3.html" target="_top">
         P0919R3 </a>
-      </td><td align="center"> </td><td align="left"> <code class="code">__cpp_lib_generic_unordered_lookup &gt;= 201811</code> </td></tr><tr><td align="left">  Adopt Consistent Container Erasure from Library Fundamentals 2 for C++20 </td><td align="left">
+      </td><td align="center"> 11.1 </td><td align="left"> <code class="code">__cpp_lib_generic_unordered_lookup &gt;= 201811</code> </td></tr><tr><td align="left"> Refinement Proposal for P0919 </td><td align="left">
+        <a class="link" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1690r1.html" target="_top">
+        P1690R1 </a>
+      </td><td align="center"> 11.1 </td><td align="left"> </td></tr><tr><td align="left">  Adopt Consistent Container Erasure from Library Fundamentals 2 for C++20 </td><td align="left">
         <a class="link" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1209r0.html" target="_top">
         P1209R0 </a>
       </td><td align="center"> 9.1 </td><td align="left"> <code class="code">__cpp_lib_erase_if &gt;= 201811L</code> </td></tr><tr><td align="left">  Improving the Return Value of Erase-Like Algorithms </td><td align="left">
diff --git a/libstdc++-v3/doc/xml/manual/status_cxx2020.xml b/libstdc++-v3/doc/xml/manual/status_cxx2020.xml
index b62a432eed1..ca12d8023f1 100644
--- a/libstdc++-v3/doc/xml/manual/status_cxx2020.xml
+++ b/libstdc++-v3/doc/xml/manual/status_cxx2020.xml
@@ -429,13 +429,12 @@ or any notes about the implementation.
     </row>
 
     <row>
-      <?dbhtml bgcolor="#C8B0B0" ?>
       <entry> Atomic waiting and notifying, std::semaphore, std::latch and std::barrier </entry>
       <entry>
         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1135r6.html">
         P1135R6 </link>
       </entry>
-      <entry align="center"> </entry>
+      <entry align="center"> 11.1 </entry>
       <entry>
         <informaltable colsep="0" rowsep="0" rowheader="norowheader" frame="none"><tgroup cols="1"><tbody>
         <row><entry> <code>__cpp_lib_atomic_lock_free_type_aliases &gt;= 201907L</code> </entry></row>
@@ -803,16 +802,25 @@ or any notes about the implementation.
     </row>
 
     <row>
-      <?dbhtml bgcolor="#C8B0B0" ?>
       <entry>  Heterogeneous lookup for unordered containers </entry>
       <entry>
         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0919r3.html">
         P0919R3 </link>
       </entry>
-      <entry align="center"> </entry>
+      <entry align="center"> 11.1 </entry>
       <entry> <code>__cpp_lib_generic_unordered_lookup &gt;= 201811</code> </entry>
     </row>
 
+    <row>
+      <entry> Refinement Proposal for P0919 </entry>
+      <entry>
+        <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1690r1.html">
+        P1690R1 </link>
+      </entry>
+      <entry align="center"> 11.1 </entry>
+      <entry/>
+    </row>
+
     <row>
       <entry>  Adopt Consistent Container Erasure from Library Fundamentals 2 for C++20 </entry>
       <entry>
diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index 4bdbe7dd9cc..dfc2a2a7800 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -735,7 +735,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       std::pair<const_iterator, const_iterator>
       equal_range(const key_type& __k) const;
 
-#if __cplusplus > 201702L
+#if __cplusplus >= 202002L
+#define __cpp_lib_generic_unordered_lookup 201811L
+
       template<typename _Kt,
 	       typename = __has_is_transparent_t<_Hash, _Kt>,
 	       typename = __has_is_transparent_t<_Equal, _Kt>>
@@ -765,7 +767,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	       typename = __has_is_transparent_t<_Equal, _Kt>>
 	pair<const_iterator, const_iterator>
 	_M_equal_range_tr(const _Kt& __k) const;
-#endif
+#endif // C++20
 
     private:
       // Bucket index computation helpers.
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index ea0e18a3f9d..8d0b2b95f34 100644
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -169,7 +169,7 @@
 #define __cpp_lib_variant 201606L
 #endif
 
-#if __cplusplus > 201703L
+#if __cplusplus >= 202002L
 // c++20
 #define __cpp_lib_atomic_flag_test 201907L
 #define __cpp_lib_atomic_float 201711L
@@ -225,6 +225,7 @@
 #define __cpp_lib_constexpr_tuple 201811L
 #define __cpp_lib_constexpr_utility 201811L
 #define __cpp_lib_erase_if 202002L
+#define __cpp_lib_generic_unordered_lookup 201811L
 #define __cpp_lib_interpolate 201902L
 #ifdef _GLIBCXX_HAS_GTHREADS
 # define __cpp_lib_jthread 201911L
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_map/operations/1.cc b/libstdc++-v3/testsuite/23_containers/unordered_map/operations/1.cc
index 4f2df728ebb..f310a8a55ed 100644
--- a/libstdc++-v3/testsuite/23_containers/unordered_map/operations/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_map/operations/1.cc
@@ -18,6 +18,13 @@
 // { dg-do run { target c++20 } }
 
 #include <unordered_map>
+
+#ifndef __cpp_lib_generic_unordered_lookup
+# error "Feature-test macro for generic lookup missing in <unordered_map>"
+#elif __cpp_lib_generic_unordered_lookup < 201811L
+# error "Feature-test macro for generic lookup has wrong value in <unordered_map>"
+#endif
+
 #include <testsuite_hooks.h>
 
 struct Equal
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/operations/1.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/operations/1.cc
index 34414d2434a..66826dc33ec 100644
--- a/libstdc++-v3/testsuite/23_containers/unordered_set/operations/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/operations/1.cc
@@ -18,6 +18,13 @@
 // { dg-do run { target c++20 } }
 
 #include <unordered_set>
+
+#ifndef __cpp_lib_generic_unordered_lookup
+# error "Feature-test macro for generic lookup missing in <unordered_set>"
+#elif __cpp_lib_generic_unordered_lookup < 201811L
+# error "Feature-test macro for generic lookup has wrong value in <unordered_set>"
+#endif
+
 #include <testsuite_hooks.h>
 
 struct Equal