Document non-conformance of parallel mode to recent C++ standards

	* doc/xml/manual/parallel_mode.xml: Add caveat about support for
	recent standards.
	* doc/html/*: Regenerate.

From-SVN: r276463

3 files changed, 37 insertions, 7 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 9cf1c9a..9b534cb 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2019-10-02  Jonathan Wakely  <jwakely@redhat.com>
+
+	* doc/xml/manual/parallel_mode.xml: Add caveat about support for
+	recent standards.
+	* doc/html/*: Regenerate.
+
 2019-10-01  Jonathan Wakely  <jwakely@redhat.com>
 
 	* include/experimental/algorithm (experimental::sample): Qualify call
diff --git a/libstdc++-v3/doc/html/manual/parallel_mode.html b/libstdc++-v3/doc/html/manual/parallel_mode.html
index db64389..7ffa8bb 100644
--- a/libstdc++-v3/doc/html/manual/parallel_mode.html
+++ b/libstdc++-v3/doc/html/manual/parallel_mode.html
@@ -3,20 +3,30 @@
   Extensions
   
 </th><td width="20%" align="right"> <a accesskey="n" href="parallel_mode_semantics.html">Next</a></td></tr></table><hr /></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.parallel_mode"></a>Chapter 18. Parallel Mode</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="parallel_mode.html#manual.ext.parallel_mode.intro">Intro</a></span></dt><dt><span class="section"><a href="parallel_mode_semantics.html">Semantics</a></span></dt><dt><span class="section"><a href="parallel_mode_using.html">Using</a></span></dt><dd><dl><dt><span class="section"><a href="parallel_mode_using.html#parallel_mode.using.prereq_flags">Prerequisite Compiler Flags</a></span></dt><dt><span class="section"><a href="parallel_mode_using.html#parallel_mode.using.parallel_mode">Using Parallel Mode</a></span></dt><dt><span class="section"><a href="parallel_mode_using.html#parallel_mode.using.specific">Using Specific Parallel Components</a></span></dt></dl></dd><dt><span class="section"><a href="parallel_mode_design.html">Design</a></span></dt><dd><dl><dt><span class="section"><a href="parallel_mode_design.html#parallel_mode.design.intro">Interface Basics</a></span></dt><dt><span class="section"><a href="parallel_mode_design.html#parallel_mode.design.tuning">Configuration and Tuning</a></span></dt><dd><dl><dt><span class="section"><a href="parallel_mode_design.html#parallel_mode.design.tuning.omp">Setting up the OpenMP Environment</a></span></dt><dt><span class="section"><a href="parallel_mode_design.html#parallel_mode.design.tuning.compile">Compile Time Switches</a></span></dt><dt><span class="section"><a href="parallel_mode_design.html#parallel_mode.design.tuning.settings">Run Time Settings and Defaults</a></span></dt></dl></dd><dt><span class="section"><a href="parallel_mode_design.html#parallel_mode.design.impl">Implementation Namespaces</a></span></dt></dl></dd><dt><span class="section"><a href="parallel_mode_test.html">Testing</a></span></dt><dt><span class="bibliography"><a href="parallel_mode.html#parallel_mode.biblio">Bibliography</a></span></dt></dl></div><p> The libstdc++ parallel mode is an experimental parallel
-implementation of many algorithms the C++ Standard Library.
+implementation of many algorithms of the C++ Standard Library.
 </p><p>
 Several of the standard algorithms, for instance
 <code class="function">std::sort</code>, are made parallel using OpenMP
-annotations. These parallel mode constructs and can be invoked by
+annotations. These parallel mode constructs can be invoked by
 explicit source declaration or by compiling existing sources with a
 specific compiler flag.
-</p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.ext.parallel_mode.intro"></a>Intro</h2></div></div></div><p>The following library components in the include
+</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
+    The parallel mode has not been kept up to date with recent C++ standards
+    and so it only conforms to the C++03 requirements.
+    That means that move-only predicates may not work with parallel mode
+    algorithms, and for C++20 most of the algorithms cannot be used in
+    <code class="code">constexpr</code> functions.
+  </p><p>
+    For C++17 and above there are new overloads of the standard algorithms
+    which take an execution policy argument. You should consider using those
+    instead of the non-standard parallel mode extensions.
+  </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.ext.parallel_mode.intro"></a>Intro</h2></div></div></div><p>The following library components in the include
 <code class="filename">numeric</code> are included in the parallel mode:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><code class="function">std::accumulate</code></p></li><li class="listitem"><p><code class="function">std::adjacent_difference</code></p></li><li class="listitem"><p><code class="function">std::inner_product</code></p></li><li class="listitem"><p><code class="function">std::partial_sum</code></p></li></ul></div><p>The following library components in the include
-<code class="filename">algorithm</code> are included in the parallel mode:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><code class="function">std::adjacent_find</code></p></li><li class="listitem"><p><code class="function">std::count</code></p></li><li class="listitem"><p><code class="function">std::count_if</code></p></li><li class="listitem"><p><code class="function">std::equal</code></p></li><li class="listitem"><p><code class="function">std::find</code></p></li><li class="listitem"><p><code class="function">std::find_if</code></p></li><li class="listitem"><p><code class="function">std::find_first_of</code></p></li><li class="listitem"><p><code class="function">std::for_each</code></p></li><li class="listitem"><p><code class="function">std::generate</code></p></li><li class="listitem"><p><code class="function">std::generate_n</code></p></li><li class="listitem"><p><code class="function">std::lexicographical_compare</code></p></li><li class="listitem"><p><code class="function">std::mismatch</code></p></li><li class="listitem"><p><code class="function">std::search</code></p></li><li class="listitem"><p><code class="function">std::search_n</code></p></li><li class="listitem"><p><code class="function">std::transform</code></p></li><li class="listitem"><p><code class="function">std::replace</code></p></li><li class="listitem"><p><code class="function">std::replace_if</code></p></li><li class="listitem"><p><code class="function">std::max_element</code></p></li><li class="listitem"><p><code class="function">std::merge</code></p></li><li class="listitem"><p><code class="function">std::min_element</code></p></li><li class="listitem"><p><code class="function">std::nth_element</code></p></li><li class="listitem"><p><code class="function">std::partial_sort</code></p></li><li class="listitem"><p><code class="function">std::partition</code></p></li><li class="listitem"><p><code class="function">std::random_shuffle</code></p></li><li class="listitem"><p><code class="function">std::set_union</code></p></li><li class="listitem"><p><code class="function">std::set_intersection</code></p></li><li class="listitem"><p><code class="function">std::set_symmetric_difference</code></p></li><li class="listitem"><p><code class="function">std::set_difference</code></p></li><li class="listitem"><p><code class="function">std::sort</code></p></li><li class="listitem"><p><code class="function">std::stable_sort</code></p></li><li class="listitem"><p><code class="function">std::unique_copy</code></p></li></ul></div></div><div class="bibliography"><div class="titlepage"><div><div><h2 class="title"><a id="parallel_mode.biblio"></a>Bibliography</h2></div></div></div><div class="biblioentry"><a id="id-1.3.5.5.9.2"></a><p><span class="citetitle"><em class="citetitle">
+<code class="filename">algorithm</code> are included in the parallel mode:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><code class="function">std::adjacent_find</code></p></li><li class="listitem"><p><code class="function">std::count</code></p></li><li class="listitem"><p><code class="function">std::count_if</code></p></li><li class="listitem"><p><code class="function">std::equal</code></p></li><li class="listitem"><p><code class="function">std::find</code></p></li><li class="listitem"><p><code class="function">std::find_if</code></p></li><li class="listitem"><p><code class="function">std::find_first_of</code></p></li><li class="listitem"><p><code class="function">std::for_each</code></p></li><li class="listitem"><p><code class="function">std::generate</code></p></li><li class="listitem"><p><code class="function">std::generate_n</code></p></li><li class="listitem"><p><code class="function">std::lexicographical_compare</code></p></li><li class="listitem"><p><code class="function">std::mismatch</code></p></li><li class="listitem"><p><code class="function">std::search</code></p></li><li class="listitem"><p><code class="function">std::search_n</code></p></li><li class="listitem"><p><code class="function">std::transform</code></p></li><li class="listitem"><p><code class="function">std::replace</code></p></li><li class="listitem"><p><code class="function">std::replace_if</code></p></li><li class="listitem"><p><code class="function">std::max_element</code></p></li><li class="listitem"><p><code class="function">std::merge</code></p></li><li class="listitem"><p><code class="function">std::min_element</code></p></li><li class="listitem"><p><code class="function">std::nth_element</code></p></li><li class="listitem"><p><code class="function">std::partial_sort</code></p></li><li class="listitem"><p><code class="function">std::partition</code></p></li><li class="listitem"><p><code class="function">std::random_shuffle</code></p></li><li class="listitem"><p><code class="function">std::set_union</code></p></li><li class="listitem"><p><code class="function">std::set_intersection</code></p></li><li class="listitem"><p><code class="function">std::set_symmetric_difference</code></p></li><li class="listitem"><p><code class="function">std::set_difference</code></p></li><li class="listitem"><p><code class="function">std::sort</code></p></li><li class="listitem"><p><code class="function">std::stable_sort</code></p></li><li class="listitem"><p><code class="function">std::unique_copy</code></p></li></ul></div></div><div class="bibliography"><div class="titlepage"><div><div><h2 class="title"><a id="parallel_mode.biblio"></a>Bibliography</h2></div></div></div><div class="biblioentry"><a id="id-1.3.5.5.10.2"></a><p><span class="citetitle"><em class="citetitle">
       Parallelization of Bulk Operations for STL Dictionaries
     </em>. </span><span class="author"><span class="firstname">Johannes</span> <span class="surname">Singler</span>. </span><span class="author"><span class="firstname">Leonor</span> <span class="surname">Frias</span>. </span><span class="copyright">Copyright © 2007 . </span><span class="publisher"><span class="publishername">
 	Workshop on Highly Parallel Processing on a Chip (HPPC) 2007. (LNCS)
-      . </span></span></p></div><div class="biblioentry"><a id="id-1.3.5.5.9.3"></a><p><span class="citetitle"><em class="citetitle">
+      . </span></span></p></div><div class="biblioentry"><a id="id-1.3.5.5.10.3"></a><p><span class="citetitle"><em class="citetitle">
       The Multi-Core Standard Template Library
     </em>. </span><span class="author"><span class="firstname">Johannes</span> <span class="surname">Singler</span>. </span><span class="author"><span class="firstname">Peter</span> <span class="surname">Sanders</span>. </span><span class="author"><span class="firstname">Felix</span> <span class="surname">Putze</span>. </span><span class="copyright">Copyright © 2007 . </span><span class="publisher"><span class="publishername">
 	 Euro-Par 2007: Parallel Processing. (LNCS 4641)
diff --git a/libstdc++-v3/doc/xml/manual/parallel_mode.xml b/libstdc++-v3/doc/xml/manual/parallel_mode.xml
index 60e2088..ab7d2f2 100644
--- a/libstdc++-v3/doc/xml/manual/parallel_mode.xml
+++ b/libstdc++-v3/doc/xml/manual/parallel_mode.xml
@@ -13,17 +13,31 @@
 
 
 <para> The libstdc++ parallel mode is an experimental parallel
-implementation of many algorithms the C++ Standard Library.
+implementation of many algorithms of the C++ Standard Library.
 </para>
 
 <para>
 Several of the standard algorithms, for instance
 <function>std::sort</function>, are made parallel using OpenMP
-annotations. These parallel mode constructs and can be invoked by
+annotations. These parallel mode constructs can be invoked by
 explicit source declaration or by compiling existing sources with a
 specific compiler flag.
 </para>
 
+<note>
+  <para>
+    The parallel mode has not been kept up to date with recent C++ standards
+    and so it only conforms to the C++03 requirements.
+    That means that move-only predicates may not work with parallel mode
+    algorithms, and for C++20 most of the algorithms cannot be used in
+    <code>constexpr</code> functions.
+  </para>
+  <para>
+    For C++17 and above there are new overloads of the standard algorithms
+    which take an execution policy argument. You should consider using those
+    instead of the non-standard parallel mode extensions.
+  </para>
+</note>
 
 <section xml:id="manual.ext.parallel_mode.intro" xreflabel="Intro"><info><title>Intro</title></info>