[v3] libstdc++/58437

Hi,

thus the below are the patches which I'm applying to mainline and 
4_7/4_8, respectively. Tested x86_64-linux.

Thanks,
Paolo.

/////////////////////////
2013-09-30  Chris Jefferson  <chris@bubblescope.net>

	PR libstdc++/58437
	* include/bits/stl_algo.h (__move_median_first): Rename to
	__move_median_to_first, change to take an addition argument.
	(__unguarded_partition_pivot): Adjust.
	* testsuite/performance/25_algorithms/sort.cc: New.
	* testsuite/performance/25_algorithms/sort_heap.cc: Likewise.
	* testsuite/performance/25_algorithms/stable_sort.cc: Likewise.

Index: include/bits/stl_algo.h
===================================================================
--- include/bits/stl_algo.h	(revision 202752)
+++ include/bits/stl_algo.h	(working copy)
@@ -72,10 +72,11 @@
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
-  /// Swaps the median value of *__a, *__b and *__c to *__a
+  /// Swaps the median value of *__a, *__b and *__c to *__result
   template<typename _Iterator>
     void
-    __move_median_first(_Iterator __a, _Iterator __b, _Iterator __c)
+    __move_median_to_first(_Iterator __result, _Iterator __a,
+			   _Iterator __b, _Iterator __c)
     {
       // concept requirements
       __glibcxx_function_requires(_LessThanComparableConcept<
@@ -84,23 +85,26 @@
       if (*__a < *__b)
 	{
 	  if (*__b < *__c)
-	    std::iter_swap(__a, __b);
+	    std::iter_swap(__result, __b);
 	  else if (*__a < *__c)
-	    std::iter_swap(__a, __c);
+	    std::iter_swap(__result, __c);
+	  else
+	    std::iter_swap(__result, __a);
 	}
       else if (*__a < *__c)
-	return;
+      	std::iter_swap(__result, __a);
       else if (*__b < *__c)
-	std::iter_swap(__a, __c);
+	std::iter_swap(__result, __c);
       else
-	std::iter_swap(__a, __b);
+	std::iter_swap(__result, __b);
     }
 
-  /// Swaps the median value of *__a, *__b and *__c under __comp to *__a
+  /// Swaps the median value of *__a, *__b and *__c under __comp to *__result
   template<typename _Iterator, typename _Compare>
     void
-    __move_median_first(_Iterator __a, _Iterator __b, _Iterator __c,
-			_Compare __comp)
+    __move_median_to_first(_Iterator __result, _Iterator __a,
+			   _Iterator __b, _Iterator __c,
+			   _Compare __comp)
     {
       // concept requirements
       __glibcxx_function_requires(_BinaryFunctionConcept<_Compare, bool,
@@ -110,16 +114,18 @@
       if (__comp(*__a, *__b))
 	{
 	  if (__comp(*__b, *__c))
-	    std::iter_swap(__a, __b);
+	    std::iter_swap(__result, __b);
 	  else if (__comp(*__a, *__c))
-	    std::iter_swap(__a, __c);
+	    std::iter_swap(__result, __c);
+	  else
+	    std::iter_swap(__result, __a);
 	}
       else if (__comp(*__a, *__c))
-	return;
+	std::iter_swap(__result, __a);
       else if (__comp(*__b, *__c))
-	std::iter_swap(__a, __c);
+	std::iter_swap(__result, __c);
       else
-	std::iter_swap(__a, __b);
+	std::iter_swap(__result, __b);
     }
 
   // for_each
@@ -2273,7 +2279,7 @@
 				_RandomAccessIterator __last)
     {
       _RandomAccessIterator __mid = __first + (__last - __first) / 2;
-      std::__move_median_first(__first, __mid, (__last - 1));
+      std::__move_median_to_first(__first, __first + 1, __mid, (__last - 2));
       return std::__unguarded_partition(__first + 1, __last, *__first);
     }
 
@@ -2285,7 +2291,8 @@
 				_RandomAccessIterator __last, _Compare __comp)
     {
       _RandomAccessIterator __mid = __first + (__last - __first) / 2;
-      std::__move_median_first(__first, __mid, (__last - 1), __comp);
+      std::__move_median_to_first(__first, __first + 1, __mid, (__last - 2),
+				  __comp);
       return std::__unguarded_partition(__first + 1, __last, *__first, __comp);
     }
 
Index: testsuite/performance/25_algorithms/sort.cc
===================================================================
--- testsuite/performance/25_algorithms/sort.cc	(revision 0)
+++ testsuite/performance/25_algorithms/sort.cc	(working copy)
@@ -0,0 +1,65 @@
+// Copyright (C) 2013 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <vector>
+#include <algorithm>
+#include <testsuite_performance.h>
+
+int main()
+{
+  using namespace __gnu_test;
+
+  time_counter time;
+  resource_counter resource;
+
+  const int max_size = 10000000;
+
+  std::vector<int> v(max_size);
+
+  for (int i = 0; i < max_size; ++i)
+    v[i] = -i;
+
+  start_counters(time, resource);
+  std::sort(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "reverse", time, resource);
+  clear_counters(time, resource);
+
+  for (int i = 0; i < max_size; ++i)
+    v[i] = i;
+
+  start_counters(time, resource);
+  std::sort(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "forwards", time, resource);
+  clear_counters(time, resource);
+
+  // a simple psuedo-random series which does not rely on rand() and friends
+  v[0] = 0;
+  for (int i = 1; i < max_size; ++i)
+    v[i] = (v[i-1] + 110211473) * 745988807;
+
+  start_counters(time, resource);
+  std::sort(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "random", time, resource);
+
+  return 0;
+}
Index: testsuite/performance/25_algorithms/sort_heap.cc
===================================================================
--- testsuite/performance/25_algorithms/sort_heap.cc	(revision 0)
+++ testsuite/performance/25_algorithms/sort_heap.cc	(working copy)
@@ -0,0 +1,73 @@
+// Copyright (C) 2013 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <vector>
+#include <algorithm>
+#include <testsuite_performance.h>
+
+int main()
+{
+  using namespace __gnu_test;
+
+  time_counter time;
+  resource_counter resource;
+
+  const int max_size = 10000000;
+
+  std::vector<int> v(max_size);
+
+  for (int i = 0; i < max_size; ++i)
+    v[i] = -i;
+
+  start_counters(time, resource);
+  std::make_heap(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "make_heap_reverse", time, resource);
+  clear_counters(time, resource);
+
+  for (int i = 0; i < max_size; ++i)
+    v[i] = i;
+
+  start_counters(time, resource);
+  std::make_heap(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "make_heap_forwards", time, resource);
+  clear_counters(time, resource);
+
+  // a simple psuedo-random series which does not rely on rand() and friends
+  v[0] = 0;
+  for (int i = 1; i < max_size; ++i)
+    v[i] = (v[i-1] + 110211473) * 745988807;
+
+  start_counters(time, resource);
+  std::make_heap(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "make_heap_random", time, resource);
+
+
+  start_counters(time, resource);
+  std::sort_heap(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "sort_heap", time, resource);
+  clear_counters(time, resource);
+
+  return 0;
+}
Index: testsuite/performance/25_algorithms/stable_sort.cc
===================================================================
--- testsuite/performance/25_algorithms/stable_sort.cc	(revision 0)
+++ testsuite/performance/25_algorithms/stable_sort.cc	(working copy)
@@ -0,0 +1,65 @@
+// Copyright (C) 2013 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <vector>
+#include <algorithm>
+#include <testsuite_performance.h>
+
+int main()
+{
+  using namespace __gnu_test;
+
+  time_counter time;
+  resource_counter resource;
+
+  const int max_size = 10000000;
+
+  std::vector<int> v(max_size);
+
+  for (int i = 0; i < max_size; ++i)
+    v[i] = -i;
+
+  start_counters(time, resource);
+  std::stable_sort(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "reverse", time, resource);
+  clear_counters(time, resource);
+
+  for (int i = 0; i < max_size; ++i)
+    v[i] = i;
+
+  start_counters(time, resource);
+  std::stable_sort(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "forwards", time, resource);
+  clear_counters(time, resource);
+
+  // a simple psuedo-random series which does not rely on rand() and friends
+  v[0] = 0;
+  for (int i = 1; i < max_size; ++i)
+    v[i] = (v[i-1] + 110211473) * 745988807;
+
+  start_counters(time, resource);
+  std::stable_sort(v.begin(), v.end());
+  stop_counters(time, resource);
+
+  report_performance(__FILE__, "random", time, resource);
+
+  return 0;
+}