re PR libstdc++/48760 (std::complex constructor buggy in the face of NaN's)
[gcc.git] / libstdc++-v3 / include / parallel / losertree.h
index f83333bcb2f86498819aa345b5f53259d7321e3e..306fcd8856fa941252c5f374598e2a79e6657bd9 100644 (file)
@@ -1,6 +1,6 @@
 // -*- C++ -*-
 
-// Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
+// Copyright (C) 2007, 2008, 2009, 2010, 2011 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
 #ifndef _GLIBCXX_PARALLEL_LOSERTREE_H
 #define _GLIBCXX_PARALLEL_LOSERTREE_H 1
 
-#include <functional>
-
 #include <bits/stl_algobase.h>
+#include <bits/stl_function.h>
 #include <parallel/features.h>
 #include <parallel/base.h>
 
 namespace __gnu_parallel
 {
-/**
- * @brief Guarded loser/tournament tree.
- *
- * The smallest element is at the top.
- *
- * Guarding is done explicitly through one flag _M_sup per element,
- * inf is not needed due to a better initialization routine.  This
- * is a well-performing variant.
- *
- * @param _Tp the element type
- * @param _Compare the comparator to use, defaults to std::less<_Tp>
- */
-template<typename _Tp, typename _Compare>
-  class _LoserTreeBase
-  {
-  protected:
-    /** @brief Internal representation of a _LoserTree element. */
-    struct _Loser
+  /**
+   * @brief Guarded loser/tournament tree.
+   *
+   * The smallest element is at the top.
+   *
+   * Guarding is done explicitly through one flag _M_sup per element,
+   * inf is not needed due to a better initialization routine.  This
+   * is a well-performing variant.
+   *
+   * @param _Tp the element type
+   * @param _Compare the comparator to use, defaults to std::less<_Tp>
+   */
+  template<typename _Tp, typename _Compare>
+    class _LoserTreeBase
     {
-      /** @brief flag, true iff this is a "maximum" __sentinel. */
-      bool _M_sup;
-      /** @brief __index of the __source __sequence. */
-      int _M_source;
-      /** @brief _M_key of the element in the _LoserTree. */
-      _Tp _M_key;
+    protected:
+      /** @brief Internal representation of a _LoserTree element. */
+      struct _Loser
+      {
+       /** @brief flag, true iff this is a "maximum" __sentinel. */
+       bool _M_sup;
+       /** @brief __index of the __source __sequence. */
+       int _M_source;
+       /** @brief _M_key of the element in the _LoserTree. */
+       _Tp _M_key;
+      };
+
+      unsigned int _M_ik, _M_k, _M_offset;
+
+      /** log_2{_M_k} */
+      unsigned int _M_log_k;
+
+      /** @brief _LoserTree __elements. */
+      _Loser* _M_losers;
+
+      /** @brief _Compare to use. */
+      _Compare _M_comp;
+
+      /**
+       * @brief State flag that determines whether the _LoserTree is empty.
+       *
+       * Only used for building the _LoserTree.
+       */
+      bool _M_first_insert;
+
+    public:
+      /**
+       * @brief The constructor.
+       *
+       * @param __k The number of sequences to merge.
+       * @param __comp The comparator to use.
+       */
+      _LoserTreeBase(unsigned int __k, _Compare __comp)
+      : _M_comp(__comp)
+      {
+       _M_ik = __k;
+
+       // Compute log_2{_M_k} for the _Loser Tree
+       _M_log_k = __rd_log2(_M_ik - 1) + 1;
+
+       // Next greater power of 2.
+       _M_k = 1 << _M_log_k;
+       _M_offset = _M_k;
+
+       // Avoid default-constructing _M_losers[]._M_key
+       _M_losers = static_cast<_Loser*>(::operator new(2 * _M_k
+                                                       * sizeof(_Loser)));
+       for (unsigned int __i = _M_ik - 1; __i < _M_k; ++__i)
+         _M_losers[__i + _M_k]._M_sup = true;
+
+       _M_first_insert = true;
+      }
+
+      /**
+       * @brief The destructor.
+       */
+      ~_LoserTreeBase()
+      {
+       for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
+         _M_losers[__i].~_Loser();
+       ::operator delete(_M_losers);
+      }
+
+      /**
+       * @brief Initializes the sequence "_M_source" with the element "__key".
+       *
+       * @param __key the element to insert
+       * @param __source __index of the __source __sequence
+       * @param __sup flag that determines whether the value to insert is an
+       *   explicit __supremum.
+       */
+      void
+      __insert_start(const _Tp& __key, int __source, bool __sup)
+      {
+       unsigned int __pos = _M_k + __source;
+
+       if (_M_first_insert)
+         {
+           // Construct all keys, so we can easily destruct them.
+           for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
+             new(&(_M_losers[__i]._M_key)) _Tp(__key);
+           _M_first_insert = false;
+         }
+       else
+         _M_losers[__pos]._M_key = __key;
+
+       _M_losers[__pos]._M_sup = __sup;
+       _M_losers[__pos]._M_source = __source;
+      }
+
+      /**
+       * @return the index of the sequence with the smallest element.
+       */
+      int __get_min_source()
+      { return _M_losers[0]._M_source; }
     };
 
-    unsigned int _M_ik, _M_k, _M_offset;
-
-    /** log_2{_M_k} */
-    unsigned int _M_log_k;
-
-    /** @brief _LoserTree __elements. */
-    _Loser* _M_losers;
-
-    /** @brief _Compare to use. */
-    _Compare _M_comp;
-
     /**
-     * @brief State flag that determines whether the _LoserTree is empty.
+     * @brief Stable _LoserTree variant.
      *
-     * Only used for building the _LoserTree.
-     */
-    bool _M_first_insert;
-
-  public:
-    /**
-     * @brief The constructor.
+     * Provides the stable implementations of insert_start, __init_winner,
+     * __init and __delete_min_insert.
      *
-     * @param __k The number of sequences to merge.
-     * @param __comp The comparator to use.
+     * Unstable variant is done using partial specialisation below.
      */
-    _LoserTreeBase(unsigned int __k, _Compare __comp)
-    : _M_comp(__comp)
+  template<bool __stable/* default == true */, typename _Tp,
+          typename _Compare>
+    class _LoserTree
+    : public _LoserTreeBase<_Tp, _Compare>
     {
-      _M_ik = __k;
-
-      // Compute log_2{_M_k} for the _Loser Tree
-      _M_log_k = __rd_log2(_M_ik - 1) + 1;
-
-      // Next greater power of 2.
-      _M_k = 1 << _M_log_k;
-      _M_offset = _M_k;
-
-      // Avoid default-constructing _M_losers[]._M_key
-      _M_losers
-        = static_cast<_Loser*>(::operator new(2 * _M_k * sizeof(_Loser)));
-      for (unsigned int __i = _M_ik - 1; __i < _M_k; ++__i)
-       _M_losers[__i + _M_k]._M_sup = true;
-
-      _M_first_insert = true;
-    }
+      typedef _LoserTreeBase<_Tp, _Compare> _Base;
+      using _Base::_M_k;
+      using _Base::_M_losers;
+      using _Base::_M_first_insert;
+
+    public:
+      _LoserTree(unsigned int __k, _Compare __comp)
+      : _Base::_LoserTreeBase(__k, __comp)
+      { }
+
+      unsigned int
+      __init_winner(unsigned int __root)
+      {
+       if (__root >= _M_k)
+         return __root;
+       else
+         {
+           unsigned int __left = __init_winner(2 * __root);
+           unsigned int __right = __init_winner(2 * __root + 1);
+           if (_M_losers[__right]._M_sup
+               || (!_M_losers[__left]._M_sup
+                   && !_M_comp(_M_losers[__right]._M_key,
+                               _M_losers[__left]._M_key)))
+             {
+               // Left one is less or equal.
+               _M_losers[__root] = _M_losers[__right];
+               return __left;
+             }
+           else
+             {
+               // Right one is less.
+               _M_losers[__root] = _M_losers[__left];
+               return __right;
+             }
+         }
+      }
+
+      void __init()
+      { _M_losers[0] = _M_losers[__init_winner(1)]; }
+
+      /**
+       * @brief Delete the smallest element and insert a new element from
+       *   the previously smallest element's sequence.
+       *
+       * This implementation is stable.
+       */
+      // Do not pass a const reference since __key will be used as
+      // local variable.
+      void
+      __delete_min_insert(_Tp __key, bool __sup)
+      {
+        using std::swap;
+#if _GLIBCXX_ASSERTIONS
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
 
-    /**
-     * @brief The destructor.
-     */
-    ~_LoserTreeBase()
-    { ::operator delete(_M_losers); }
+       int __source = _M_losers[0]._M_source;
+       for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+            __pos /= 2)
+         {
+           // The smaller one gets promoted, ties are broken by _M_source.
+           if ((__sup && (!_M_losers[__pos]._M_sup
+                          || _M_losers[__pos]._M_source < __source))
+               || (!__sup && !_M_losers[__pos]._M_sup
+                   && ((_M_comp(_M_losers[__pos]._M_key, __key))
+                       || (!_M_comp(__key, _M_losers[__pos]._M_key)
+                           && _M_losers[__pos]._M_source < __source))))
+             {
+               // The other one is smaller.
+               std::swap(_M_losers[__pos]._M_sup, __sup);
+               std::swap(_M_losers[__pos]._M_source, __source);
+               swap(_M_losers[__pos]._M_key, __key);
+             }
+         }
+
+       _M_losers[0]._M_sup = __sup;
+       _M_losers[0]._M_source = __source;
+       _M_losers[0]._M_key = __key;
+      }
+    };
 
     /**
-     * @brief Initializes the sequence "_M_source" with the element "_M_key".
+     * @brief Unstable _LoserTree variant.
      *
-     * @param _M_key the element to insert
-     * @param _M_source __index of the __source __sequence
-     * @param _M_sup flag that determines whether the value to insert is an
-     *   explicit __supremum.
+     * Stability (non-stable here) is selected with partial specialization.
      */
-    void
-    __insert_start(const _Tp& _M_key, int _M_source, bool _M_sup)
+  template<typename _Tp, typename _Compare>
+    class _LoserTree</* __stable == */false, _Tp, _Compare>
+    : public _LoserTreeBase<_Tp, _Compare>
     {
-      unsigned int __pos = _M_k + _M_source;
-
-      if(_M_first_insert)
-       {
-         // Construct all keys, so we can easily deconstruct them.
-         for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
-           new(&(_M_losers[__i]._M_key)) _Tp(_M_key);
-         _M_first_insert = false;
-       }
-      else
-       new(&(_M_losers[__pos]._M_key)) _Tp(_M_key);
-
-      _M_losers[__pos]._M_sup = _M_sup;
-      _M_losers[__pos]._M_source = _M_source;
-    }
+      typedef _LoserTreeBase<_Tp, _Compare> _Base;
+      using _Base::_M_log_k;
+      using _Base::_M_k;
+      using _Base::_M_losers;
+      using _Base::_M_first_insert;
+
+    public:
+      _LoserTree(unsigned int __k, _Compare __comp)
+      : _Base::_LoserTreeBase(__k, __comp)
+      { }
+
+      /**
+       * Computes the winner of the competition at position "__root".
+       *
+       * Called recursively (starting at 0) to build the initial tree.
+       *
+       * @param __root __index of the "game" to start.
+       */
+      unsigned int
+      __init_winner(unsigned int __root)
+      {
+       if (__root >= _M_k)
+         return __root;
+       else
+         {
+           unsigned int __left = __init_winner(2 * __root);
+           unsigned int __right = __init_winner(2 * __root + 1);
+           if (_M_losers[__right]._M_sup
+               || (!_M_losers[__left]._M_sup
+                   && !_M_comp(_M_losers[__right]._M_key,
+                               _M_losers[__left]._M_key)))
+             {
+               // Left one is less or equal.
+               _M_losers[__root] = _M_losers[__right];
+               return __left;
+             }
+           else
+             {
+               // Right one is less.
+               _M_losers[__root] = _M_losers[__left];
+               return __right;
+             }
+         }
+      }
+
+      void
+      __init()
+      { _M_losers[0] = _M_losers[__init_winner(1)]; }
+
+      /**
+       * Delete the _M_key smallest element and insert the element __key
+       * instead.
+       *
+       * @param __key the _M_key to insert
+       * @param __sup true iff __key is an explicitly marked supremum
+       */
+      // Do not pass a const reference since __key will be used as local
+      // variable.
+      void
+      __delete_min_insert(_Tp __key, bool __sup)
+      {
+        using std::swap;
+#if _GLIBCXX_ASSERTIONS
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
 
-    /**
-     * @return the index of the sequence with the smallest element.
-     */
-    int __get_min_source()
-    { return _M_losers[0]._M_source; }
-  };
+       int __source = _M_losers[0]._M_source;
+       for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+            __pos /= 2)
+         {
+           // The smaller one gets promoted.
+           if (__sup || (!_M_losers[__pos]._M_sup
+                         && _M_comp(_M_losers[__pos]._M_key, __key)))
+             {
+               // The other one is smaller.
+               std::swap(_M_losers[__pos]._M_sup, __sup);
+               std::swap(_M_losers[__pos]._M_source, __source);
+               swap(_M_losers[__pos]._M_key, __key);
+             }
+         }
+
+       _M_losers[0]._M_sup = __sup;
+       _M_losers[0]._M_source = __source;
+       _M_losers[0]._M_key = __key;
+      }
+    };
 
   /**
-   * @brief Stable _LoserTree variant.
-   *
-   * Provides the stable implementations of insert_start, __init_winner,
-   * __init and __delete_min_insert.
-   *
-   * Unstable variant is done using partial specialisation below.
+   * @brief Base class of _Loser Tree implementation using pointers.
    */
-template<bool __stable/* default == true */, typename _Tp,
-        typename _Compare>
-  class _LoserTree : public _LoserTreeBase<_Tp, _Compare>
-  {
-    typedef _LoserTreeBase<_Tp, _Compare> _Base;
-    using _Base::_M_k;
-    using _Base::_M_losers;
-    using _Base::_M_first_insert;
-
-  public:
-    _LoserTree(unsigned int __k, _Compare __comp)
-    : _Base::_LoserTreeBase(__k, __comp)
-    { }
-
-    unsigned int
-    __init_winner(unsigned int __root)
+  template<typename _Tp, typename _Compare>
+    class _LoserTreePointerBase
     {
-      if (__root >= _M_k)
-       return __root;
-      else
-       {
-         unsigned int __left = __init_winner (2 * __root);
-         unsigned int __right = __init_winner (2 * __root + 1);
-         if (_M_losers[__right]._M_sup
-             || (!_M_losers[__left]._M_sup
-                 && !_M_comp(_M_losers[__right]._M_key,
-                             _M_losers[__left]._M_key)))
-           {
-             // Left one is less or equal.
-             _M_losers[__root] = _M_losers[__right];
-             return __left;
-           }
-         else
-           {
-             // Right one is less.
-             _M_losers[__root] = _M_losers[__left];
-             return __right;
-           }
-       }
-    }
-
-    void __init()
-    { _M_losers[0] = _M_losers[__init_winner(1)]; }
+    protected:
+      /** @brief Internal representation of _LoserTree __elements. */
+      struct _Loser
+      {
+       bool _M_sup;
+       int _M_source;
+       const _Tp* _M_keyp;
+      };
+
+      unsigned int _M_ik, _M_k, _M_offset;
+      _Loser* _M_losers;
+      _Compare _M_comp;
+
+    public:
+      _LoserTreePointerBase(unsigned int __k,
+                           _Compare __comp = std::less<_Tp>())
+      : _M_comp(__comp)
+      {
+       _M_ik = __k;
+
+       // Next greater power of 2.
+       _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
+       _M_offset = _M_k;
+       _M_losers = new _Loser[_M_k * 2];
+       for (unsigned int __i = _M_ik - 1; __i < _M_k; __i++)
+         _M_losers[__i + _M_k]._M_sup = true;
+      }
+
+      ~_LoserTreePointerBase()
+      { delete[] _M_losers; }
+
+      int __get_min_source()
+      { return _M_losers[0]._M_source; }
+
+      void __insert_start(const _Tp& __key, int __source, bool __sup)
+      {
+       unsigned int __pos = _M_k + __source;
+
+       _M_losers[__pos]._M_sup = __sup;
+       _M_losers[__pos]._M_source = __source;
+       _M_losers[__pos]._M_keyp = &__key;
+      }
+    };
 
-    /**
-     * @brief Delete the smallest element and insert a new element from
-     *   the previously smallest element's sequence.
-     *
-     * This implementation is stable.
-     */
-    // Do not pass a const reference since _M_key will be used as
-    // local variable.
-    void
-    __delete_min_insert(_Tp _M_key, bool _M_sup)
+  /**
+   * @brief Stable _LoserTree implementation.
+   *
+   * The unstable variant is implemented using partial instantiation below.
+   */
+  template<bool __stable/* default == true */, typename _Tp, typename _Compare>
+    class _LoserTreePointer
+    : public _LoserTreePointerBase<_Tp, _Compare>
     {
+      typedef _LoserTreePointerBase<_Tp, _Compare> _Base;
+      using _Base::_M_k;
+      using _Base::_M_losers;
+
+    public:
+      _LoserTreePointer(unsigned int __k, _Compare __comp = std::less<_Tp>())
+      : _Base::_LoserTreePointerBase(__k, __comp)
+      { }
+
+      unsigned int
+      __init_winner(unsigned int __root)
+      {
+       if (__root >= _M_k)
+         return __root;
+       else
+         {
+           unsigned int __left = __init_winner(2 * __root);
+           unsigned int __right = __init_winner(2 * __root + 1);
+           if (_M_losers[__right]._M_sup
+               || (!_M_losers[__left]._M_sup
+                   && !_M_comp(*_M_losers[__right]._M_keyp,
+                               *_M_losers[__left]._M_keyp)))
+             {
+               // Left one is less or equal.
+               _M_losers[__root] = _M_losers[__right];
+               return __left;
+             }
+           else
+             {
+               // Right one is less.
+               _M_losers[__root] = _M_losers[__left];
+               return __right;
+             }
+         }
+      }
+
+      void __init()
+      { _M_losers[0] = _M_losers[__init_winner(1)]; }
+
+      void __delete_min_insert(const _Tp& __key, bool __sup)
+      {
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
 
-      int _M_source = _M_losers[0]._M_source;
-      for (unsigned int __pos = (_M_k + _M_source) / 2; __pos > 0;
-          __pos /= 2)
-       {
-         // The smaller one gets promoted, ties are broken by _M_source.
-         if ((_M_sup && (!_M_losers[__pos]._M_sup
-                         || _M_losers[__pos]._M_source < _M_source))
-             || (!_M_sup && !_M_losers[__pos]._M_sup
-                 && ((_M_comp(_M_losers[__pos]._M_key, _M_key))
-                     || (!_M_comp(_M_key, _M_losers[__pos]._M_key)
-                         && _M_losers[__pos]._M_source < _M_source))))
-           {
-             // The other one is smaller.
-             std::swap(_M_losers[__pos]._M_sup, _M_sup);
-             std::swap(_M_losers[__pos]._M_source, _M_source);
-             std::swap(_M_losers[__pos]._M_key, _M_key);
-           }
-       }
-
-      _M_losers[0]._M_sup = _M_sup;
-      _M_losers[0]._M_source = _M_source;
-      _M_losers[0]._M_key = _M_key;
-    }
-  };
+       const _Tp* __keyp = &__key;
+       int __source = _M_losers[0]._M_source;
+       for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+            __pos /= 2)
+         {
+           // The smaller one gets promoted, ties are broken by __source.
+           if ((__sup && (!_M_losers[__pos]._M_sup
+                          || _M_losers[__pos]._M_source < __source))
+               || (!__sup && !_M_losers[__pos]._M_sup &&
+                   ((_M_comp(*_M_losers[__pos]._M_keyp, *__keyp))
+                    || (!_M_comp(*__keyp, *_M_losers[__pos]._M_keyp)
+                        && _M_losers[__pos]._M_source < __source))))
+             {
+               // The other one is smaller.
+               std::swap(_M_losers[__pos]._M_sup, __sup);
+               std::swap(_M_losers[__pos]._M_source, __source);
+               std::swap(_M_losers[__pos]._M_keyp, __keyp);
+             }
+         }
+
+       _M_losers[0]._M_sup = __sup;
+       _M_losers[0]._M_source = __source;
+       _M_losers[0]._M_keyp = __keyp;
+      }
+    };
 
   /**
-   * @brief Unstable _LoserTree variant.
+   * @brief Unstable _LoserTree implementation.
    *
-   * Stability (non-stable here) is selected with partial specialization.
+   * The stable variant is above.
    */
-template<typename _Tp, typename _Compare>
-  class _LoserTree</* __stable == */false, _Tp, _Compare>
-  : public _LoserTreeBase<_Tp, _Compare>
-  {
-    typedef _LoserTreeBase<_Tp, _Compare> _Base;
-    using _Base::_M_log_k;
-    using _Base::_M_k;
-    using _Base::_M_losers;
-    using _Base::_M_first_insert;
-
-  public:
-    _LoserTree(unsigned int __k, _Compare __comp)
-    : _Base::_LoserTreeBase(__k, __comp)
-    { }
-
-    /**
-     * Computes the winner of the competition at position "__root".
-     *
-     * Called recursively (starting at 0) to build the initial tree.
-     *
-     * @param __root __index of the "game" to start.
-     */
-    unsigned int
-    __init_winner(unsigned int __root)
-    {
-      if (__root >= _M_k)
-       return __root;
-      else
-       {
-         unsigned int __left = __init_winner (2 * __root);
-         unsigned int __right = __init_winner (2 * __root + 1);
-         if (_M_losers[__right]._M_sup
-             || (!_M_losers[__left]._M_sup
-                 && !_M_comp(_M_losers[__right]._M_key,
-                             _M_losers[__left]._M_key)))
-           {
-             // Left one is less or equal.
-             _M_losers[__root] = _M_losers[__right];
-             return __left;
-           }
-         else
-           {
-             // Right one is less.
-             _M_losers[__root] = _M_losers[__left];
-             return __right;
-           }
-       }
-    }
-
-    void
-    __init()
-    { _M_losers[0] = _M_losers[__init_winner(1)]; }
-
-    /**
-     * Delete the _M_key smallest element and insert the element _M_key
-     * instead.
-     *
-     * @param _M_key the _M_key to insert
-     * @param _M_sup true iff _M_key is an explicitly marked supremum
-     */
-    // Do not pass a const reference since _M_key will be used as local
-    // variable.
-    void
-    __delete_min_insert(_Tp _M_key, bool _M_sup)
+  template<typename _Tp, typename _Compare>
+    class _LoserTreePointer</* __stable == */false, _Tp, _Compare>
+    : public _LoserTreePointerBase<_Tp, _Compare>
     {
+      typedef _LoserTreePointerBase<_Tp, _Compare> _Base;
+      using _Base::_M_k;
+      using _Base::_M_losers;
+
+    public:
+      _LoserTreePointer(unsigned int __k, _Compare __comp = std::less<_Tp>())
+      : _Base::_LoserTreePointerBase(__k, __comp)
+      { }
+
+      unsigned int
+      __init_winner(unsigned int __root)
+      {
+       if (__root >= _M_k)
+         return __root;
+       else
+         {
+           unsigned int __left = __init_winner(2 * __root);
+           unsigned int __right = __init_winner(2 * __root + 1);
+           if (_M_losers[__right]._M_sup
+               || (!_M_losers[__left]._M_sup
+                   && !_M_comp(*_M_losers[__right]._M_keyp,
+                               *_M_losers[__left]._M_keyp)))
+             {
+               // Left one is less or equal.
+               _M_losers[__root] = _M_losers[__right];
+               return __left;
+             }
+           else
+             {
+               // Right one is less.
+               _M_losers[__root] = _M_losers[__left];
+               return __right;
+             }
+         }
+      }
+
+      void __init()
+      { _M_losers[0] = _M_losers[__init_winner(1)]; }
+
+      void __delete_min_insert(const _Tp& __key, bool __sup)
+      {
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
 
-      int _M_source = _M_losers[0]._M_source;
-      for (unsigned int __pos = (_M_k + _M_source) / 2; __pos > 0;
-          __pos /= 2)
-       {
-         // The smaller one gets promoted.
-         if (_M_sup || (!_M_losers[__pos]._M_sup
-                        && _M_comp(_M_losers[__pos]._M_key, _M_key)))
-           {
-             // The other one is smaller.
-             std::swap(_M_losers[__pos]._M_sup, _M_sup);
-             std::swap(_M_losers[__pos]._M_source, _M_source);
-             std::swap(_M_losers[__pos]._M_key, _M_key);
-           }
-       }
-
-      _M_losers[0]._M_sup = _M_sup;
-      _M_losers[0]._M_source = _M_source;
-      _M_losers[0]._M_key = _M_key;
-    }
-  };
-
-/**
- * @brief Base class of _Loser Tree implementation using pointers.
- */
-template<typename _Tp, typename _Compare>
-  class _LoserTreePointerBase
-  {
-  protected:
-    /** @brief Internal representation of _LoserTree __elements. */
-    struct _Loser
-    {
-      bool _M_sup;
-      int _M_source;
-      const _Tp* _M_keyp;
+       const _Tp* __keyp = &__key;
+       int __source = _M_losers[0]._M_source;
+       for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+            __pos /= 2)
+         {
+           // The smaller one gets promoted.
+           if (__sup || (!_M_losers[__pos]._M_sup
+                         && _M_comp(*_M_losers[__pos]._M_keyp, *__keyp)))
+             {
+               // The other one is smaller.
+               std::swap(_M_losers[__pos]._M_sup, __sup);
+               std::swap(_M_losers[__pos]._M_source, __source);
+               std::swap(_M_losers[__pos]._M_keyp, __keyp);
+             }
+         }
+
+       _M_losers[0]._M_sup = __sup;
+       _M_losers[0]._M_source = __source;
+       _M_losers[0]._M_keyp = __keyp;
+      }
     };
 
-    unsigned int _M_ik, _M_k, _M_offset;
-    _Loser* _M_losers;
-    _Compare _M_comp;
-
-  public:
-    _LoserTreePointerBase(unsigned int __k,
-                         _Compare __comp = std::less<_Tp>())
-    : _M_comp(__comp)
+  /** @brief Base class for unguarded _LoserTree implementation.
+   * 
+   * The whole element is copied into the tree structure.
+   *
+   * No guarding is done, therefore not a single input sequence must
+   * run empty.  Unused __sequence heads are marked with a sentinel which
+   * is &gt; all elements that are to be merged.
+   *
+   * This is a very fast variant.
+   */
+  template<typename _Tp, typename _Compare>
+    class _LoserTreeUnguardedBase
     {
-      _M_ik = __k;
-
-      // Next greater power of 2.
-      _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
-      _M_offset = _M_k;
-      _M_losers = new _Loser[_M_k * 2];
-      for (unsigned int __i = _M_ik - 1; __i < _M_k; __i++)
-       _M_losers[__i + _M_k]._M_sup = true;
-    }
+    protected:
+      struct _Loser
+      {
+       int _M_source;
+       _Tp _M_key;
+      };
+
+      unsigned int _M_ik, _M_k, _M_offset;
+      _Loser* _M_losers;
+      _Compare _M_comp;
+
+    public:
+      _LoserTreeUnguardedBase(unsigned int __k, const _Tp __sentinel,
+                             _Compare __comp = std::less<_Tp>())
+      : _M_comp(__comp)
+      {
+       _M_ik = __k;
+
+       // Next greater power of 2.
+       _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
+       _M_offset = _M_k;
+       // Avoid default-constructing _M_losers[]._M_key
+       _M_losers = static_cast<_Loser*>(::operator new(2 * _M_k
+                                                       * sizeof(_Loser)));
+
+       for (unsigned int __i = _M_k + _M_ik - 1; __i < (2 * _M_k); ++__i)
+         {
+           ::new(&(_M_losers[__i]._M_key)) _Tp(__sentinel);
+           _M_losers[__i]._M_source = -1;
+         }
+      }
+
+      ~_LoserTreeUnguardedBase()
+      {
+       for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
+         _M_losers[__i].~_Loser();
+       ::operator delete(_M_losers);
+      }
+
+      int
+      __get_min_source()
+      {
+#if _GLIBCXX_ASSERTIONS
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+#endif
+       return _M_losers[0]._M_source;
+      }
 
-    ~_LoserTreePointerBase()
-    { ::operator delete[](_M_losers); }
+      void
+      __insert_start(const _Tp& __key, int __source, bool)
+      {
+       unsigned int __pos = _M_k + __source;
 
-    int __get_min_source()
-    { return _M_losers[0]._M_source; }
+       ::new(&(_M_losers[__pos]._M_key)) _Tp(__key);
+       _M_losers[__pos]._M_source = __source;
+      }
+    };
 
-    void __insert_start(const _Tp& _M_key, int _M_source, bool _M_sup)
+  /**
+   * @brief Stable implementation of unguarded _LoserTree.
+   *
+   * Unstable variant is selected below with partial specialization.
+   */
+  template<bool __stable/* default == true */, typename _Tp, typename _Compare>
+    class _LoserTreeUnguarded
+    : public _LoserTreeUnguardedBase<_Tp, _Compare>
     {
-      unsigned int __pos = _M_k + _M_source;
-
-      _M_losers[__pos]._M_sup = _M_sup;
-      _M_losers[__pos]._M_source = _M_source;
-      _M_losers[__pos]._M_keyp = &_M_key;
-    }
-  };
-
-/**
- * @brief Stable _LoserTree implementation.
- *
- * The unstable variant is implemented using partial instantiation below.
- */
-template<bool __stable/* default == true */, typename _Tp, typename _Compare>
-  class _LoserTreePointer
-  : public _LoserTreePointerBase<_Tp, _Compare>
-  {
-    typedef _LoserTreePointerBase<_Tp, _Compare> _Base;
-    using _Base::_M_k;
-    using _Base::_M_losers;
+      typedef _LoserTreeUnguardedBase<_Tp, _Compare> _Base;
+      using _Base::_M_k;
+      using _Base::_M_losers;
 
   public:
-    _LoserTreePointer(unsigned int __k, _Compare __comp = std::less<_Tp>())
-    : _Base::_LoserTreePointerBase(__k, __comp)
-    { }
+      _LoserTreeUnguarded(unsigned int __k, const _Tp __sentinel,
+                         _Compare __comp = std::less<_Tp>())
+      : _Base::_LoserTreeUnguardedBase(__k, __sentinel, __comp)
+      { }
+
+      unsigned int
+      __init_winner(unsigned int __root)
+      {
+       if (__root >= _M_k)
+         return __root;
+       else
+         {
+           unsigned int __left = __init_winner(2 * __root);
+           unsigned int __right = __init_winner(2 * __root + 1);
+           if (!_M_comp(_M_losers[__right]._M_key,
+                        _M_losers[__left]._M_key))
+             {
+               // Left one is less or equal.
+               _M_losers[__root] = _M_losers[__right];
+               return __left;
+             }
+           else
+             {
+               // Right one is less.
+               _M_losers[__root] = _M_losers[__left];
+               return __right;
+             }
+         }
+      }
+
+      void
+      __init()
+      {
+       _M_losers[0] = _M_losers[__init_winner(1)];
 
-    unsigned int
-    __init_winner(unsigned int __root)
-    {
-      if (__root >= _M_k)
-       return __root;
-      else
-       {
-         unsigned int __left = __init_winner (2 * __root);
-         unsigned int __right = __init_winner (2 * __root + 1);
-         if (_M_losers[__right]._M_sup
-             || (!_M_losers[__left]._M_sup
-                 && !_M_comp(*_M_losers[__right]._M_keyp,
-                             *_M_losers[__left]._M_keyp)))
-           {
-             // Left one is less or equal.
-             _M_losers[__root] = _M_losers[__right];
-             return __left;
-           }
-         else
-           {
-             // Right one is less.
-             _M_losers[__root] = _M_losers[__left];
-             return __right;
-           }
-       }
-    }
-
-    void __init()
-    { _M_losers[0] = _M_losers[__init_winner(1)]; }
-
-    void __delete_min_insert(const _Tp& _M_key, bool _M_sup)
-    {
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top at the beginning
+       // (0 sequences!)
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
-
-      const _Tp* _M_keyp = &_M_key;
-      int _M_source = _M_losers[0]._M_source;
-      for (unsigned int __pos = (_M_k + _M_source) / 2; __pos > 0; __pos /= 2)
-       {
-         // The smaller one gets promoted, ties are broken by _M_source.
-         if ((_M_sup && (!_M_losers[__pos]._M_sup ||
-                         _M_losers[__pos]._M_source < _M_source)) ||
-              (!_M_sup && !_M_losers[__pos]._M_sup &&
-              ((_M_comp(*_M_losers[__pos]._M_keyp, *_M_keyp)) ||
-                (!_M_comp(*_M_keyp, *_M_losers[__pos]._M_keyp)
-                && _M_losers[__pos]._M_source < _M_source))))
-           {
-             // The other one is smaller.
-             std::swap(_M_losers[__pos]._M_sup, _M_sup);
-             std::swap(_M_losers[__pos]._M_source, _M_source);
-             std::swap(_M_losers[__pos]._M_keyp, _M_keyp);
-           }
-       }
-
-      _M_losers[0]._M_sup = _M_sup;
-      _M_losers[0]._M_source = _M_source;
-      _M_losers[0]._M_keyp = _M_keyp;
-    }
-  };
-
-/**
- * @brief Unstable _LoserTree implementation.
- *
- * The stable variant is above.
- */
-template<typename _Tp, typename _Compare>
-  class _LoserTreePointer</* __stable == */false, _Tp, _Compare>
-  : public _LoserTreePointerBase<_Tp, _Compare>
-  {
-    typedef _LoserTreePointerBase<_Tp, _Compare> _Base;
-    using _Base::_M_k;
-    using _Base::_M_losers;
-
-  public:
-    _LoserTreePointer(unsigned int __k, _Compare __comp = std::less<_Tp>())
-    : _Base::_LoserTreePointerBase(__k, __comp)
-    { }
-
-    unsigned int
-    __init_winner(unsigned int __root)
-    {
-      if (__root >= _M_k)
-       return __root;
-      else
-       {
-         unsigned int __left = __init_winner (2 * __root);
-         unsigned int __right = __init_winner (2 * __root + 1);
-         if (_M_losers[__right]._M_sup
-              || (!_M_losers[__left]._M_sup
-                 && !_M_comp(*_M_losers[__right]._M_keyp,
-                             *_M_losers[__left]._M_keyp)))
-           {
-             // Left one is less or equal.
-             _M_losers[__root] = _M_losers[__right];
-             return __left;
-           }
-         else
-           {
-             // Right one is less.
-             _M_losers[__root] = _M_losers[__left];
-             return __right;
-           }
-       }
-    }
-
-    void __init()
-    { _M_losers[0] = _M_losers[__init_winner(1)]; }
-
-    void __delete_min_insert(const _Tp& _M_key, bool _M_sup)
-    {
+      }
+
+      // Do not pass a const reference since __key will be used as
+      // local variable.
+      void
+      __delete_min_insert(_Tp __key, bool)
+      {
+        using std::swap;
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
 
-      const _Tp* _M_keyp = &_M_key;
-      int _M_source = _M_losers[0]._M_source;
-      for (unsigned int __pos = (_M_k + _M_source) / 2; __pos > 0;
-          __pos /= 2)
-       {
-         // The smaller one gets promoted.
-         if (_M_sup || (!_M_losers[__pos]._M_sup
-                        && _M_comp(*_M_losers[__pos]._M_keyp, *_M_keyp)))
-           {
-             // The other one is smaller.
-             std::swap(_M_losers[__pos]._M_sup, _M_sup);
-             std::swap(_M_losers[__pos]._M_source, _M_source);
-             std::swap(_M_losers[__pos]._M_keyp, _M_keyp);
-           }
-       }
-
-      _M_losers[0]._M_sup = _M_sup;
-      _M_losers[0]._M_source = _M_source;
-      _M_losers[0]._M_keyp = _M_keyp;
-    }
-  };
-
-/** @brief Base class for unguarded _LoserTree implementation.
- * 
- * The whole element is copied into the tree structure.
- *
- * No guarding is done, therefore not a single input sequence must
- * run empty.  Unused __sequence heads are marked with a sentinel which
- * is &gt; all elements that are to be merged.
- *
- * This is a very fast variant.
- */
-template<typename _Tp, typename _Compare>
-  class _LoserTreeUnguardedBase
-  {
-  protected:
-    struct _Loser
-    {
-      int _M_source;
-      _Tp _M_key;
+       int __source = _M_losers[0]._M_source;
+       for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+            __pos /= 2)
+         {
+           // The smaller one gets promoted, ties are broken by _M_source.
+           if (_M_comp(_M_losers[__pos]._M_key, __key)
+               || (!_M_comp(__key, _M_losers[__pos]._M_key)
+                    && _M_losers[__pos]._M_source < __source))
+             {
+               // The other one is smaller.
+               std::swap(_M_losers[__pos]._M_source, __source);
+               swap(_M_losers[__pos]._M_key, __key);
+             }
+         }
+
+       _M_losers[0]._M_source = __source;
+       _M_losers[0]._M_key = __key;
+      }
     };
 
-    unsigned int _M_ik, _M_k, _M_offset;
-    _Loser* _M_losers;
-    _Compare _M_comp;
-
-  public:
-    _LoserTreeUnguardedBase(unsigned int __k, const _Tp _sentinel,
-                           _Compare __comp = std::less<_Tp>())
-    : _M_comp(__comp)
-    {
-      _M_ik = __k;
-
-      // Next greater power of 2.
-      _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
-      _M_offset = _M_k;
-      // Avoid default-constructing _M_losers[]._M_key
-      _M_losers
-        = static_cast<_Loser*>(::operator new(2 * _M_k * sizeof(_Loser)));
-
-      for (unsigned int __i = _M_k + _M_ik - 1; __i < (2 * _M_k); ++__i)
-       {
-         _M_losers[__i]._M_key = _sentinel;
-         _M_losers[__i]._M_source = -1;
-       }
-    }
-
-    ~_LoserTreeUnguardedBase()
-    { ::operator delete(_M_losers); }
-
-    int
-    __get_min_source()
-    {
-#if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
-#endif
-      return _M_losers[0]._M_source;
-    }
-
-    void
-    __insert_start(const _Tp& _M_key, int _M_source, bool)
-    {
-      unsigned int __pos = _M_k + _M_source;
-
-      new(&(_M_losers[__pos]._M_key)) _Tp(_M_key);
-      _M_losers[__pos]._M_source = _M_source;
-    }
-  };
-
-/**
- * @brief Stable implementation of unguarded _LoserTree.
- *
- * Unstable variant is selected below with partial specialization.
- */
-template<bool __stable/* default == true */, typename _Tp, typename _Compare>
-  class _LoserTreeUnguarded
-  : public _LoserTreeUnguardedBase<_Tp, _Compare>
-  {
-    typedef _LoserTreeUnguardedBase<_Tp, _Compare> _Base;
-    using _Base::_M_k;
-    using _Base::_M_losers;
-
-public:
-    _LoserTreeUnguarded(unsigned int __k, const _Tp _sentinel,
-                       _Compare __comp = std::less<_Tp>())
-    : _Base::_LoserTreeUnguardedBase(__k, _sentinel, __comp)
-    { }
-
-    unsigned int
-    __init_winner(unsigned int __root)
-    {
-      if (__root >= _M_k)
-       return __root;
-      else
-       {
-         unsigned int __left = __init_winner (2 * __root);
-         unsigned int __right = __init_winner (2 * __root + 1);
-         if (!_M_comp(_M_losers[__right]._M_key, _M_losers[__left]._M_key))
-           {
-             // Left one is less or equal.
-             _M_losers[__root] = _M_losers[__right];
-             return __left;
-           }
-         else
-           {
-             // Right one is less.
-             _M_losers[__root] = _M_losers[__left];
-             return __right;
-           }
-       }
-    }
-
-    void
-    __init()
+  /**
+   * @brief Non-Stable implementation of unguarded _LoserTree.
+   *
+   * Stable implementation is above.
+   */
+  template<typename _Tp, typename _Compare>
+    class _LoserTreeUnguarded</* __stable == */false, _Tp, _Compare>
+    : public _LoserTreeUnguardedBase<_Tp, _Compare>
     {
-      _M_losers[0] = _M_losers[__init_winner(1)];
-      
-#if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top at the beginning
-      // (0 sequences!)
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
-#endif
-    }
+      typedef _LoserTreeUnguardedBase<_Tp, _Compare> _Base;
+      using _Base::_M_k;
+      using _Base::_M_losers;
 
-    // Do not pass a const reference since _M_key will be used as
-    // local variable.
-    void
-    __delete_min_insert(_Tp _M_key, bool)
-    {
-#if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
-#endif
-
-      int _M_source = _M_losers[0]._M_source;
-      for (unsigned int __pos = (_M_k + _M_source) / 2; __pos > 0; __pos /= 2)
-       {
-         // The smaller one gets promoted, ties are broken by _M_source.
-         if (_M_comp(_M_losers[__pos]._M_key, _M_key)
-              || (!_M_comp(_M_key, _M_losers[__pos]._M_key)
-                  && _M_losers[__pos]._M_source < _M_source))
-           {
-             // The other one is smaller.
-             std::swap(_M_losers[__pos]._M_source, _M_source);
-             std::swap(_M_losers[__pos]._M_key, _M_key);
-           }
-       }
-
-      _M_losers[0]._M_source = _M_source;
-      _M_losers[0]._M_key = _M_key;
-    }
-  };
-
-/**
- * @brief Non-Stable implementation of unguarded _LoserTree.
- *
- * Stable implementation is above.
- */
-template<typename _Tp, typename _Compare>
-  class _LoserTreeUnguarded</* __stable == */false, _Tp, _Compare>
-  : public _LoserTreeUnguardedBase<_Tp, _Compare>
-  {
-    typedef _LoserTreeUnguardedBase<_Tp, _Compare> _Base;
-    using _Base::_M_k;
-    using _Base::_M_losers;
-
-public:
-    _LoserTreeUnguarded(unsigned int __k, const _Tp _sentinel,
-                       _Compare __comp = std::less<_Tp>())
-    : _Base::_LoserTreeUnguardedBase(__k, _sentinel, __comp)
-    { }
-
-    unsigned int
-    __init_winner(unsigned int __root)
-    {
-      if (__root >= _M_k)
-       return __root;
-      else
-       {
-         unsigned int __left = __init_winner (2 * __root);
-         unsigned int __right = __init_winner (2 * __root + 1);
+    public:
+      _LoserTreeUnguarded(unsigned int __k, const _Tp __sentinel,
+                         _Compare __comp = std::less<_Tp>())
+      : _Base::_LoserTreeUnguardedBase(__k, __sentinel, __comp)
+      { }
+
+      unsigned int
+      __init_winner(unsigned int __root)
+      {
+       if (__root >= _M_k)
+         return __root;
+       else
+         {
+           unsigned int __left = __init_winner(2 * __root);
+           unsigned int __right = __init_winner(2 * __root + 1);
 
 #if _GLIBCXX_ASSERTIONS
-         // If __left one is sentinel then __right one must be, too.
-         if (_M_losers[__left]._M_source == -1)
-           _GLIBCXX_PARALLEL_ASSERT(_M_losers[__right]._M_source == -1);
+           // If __left one is sentinel then __right one must be, too.
+           if (_M_losers[__left]._M_source == -1)
+             _GLIBCXX_PARALLEL_ASSERT(_M_losers[__right]._M_source == -1);
 #endif
 
-         if (!_M_comp(_M_losers[__right]._M_key, _M_losers[__left]._M_key))
-           {
-             // Left one is less or equal.
-             _M_losers[__root] = _M_losers[__right];
-             return __left;
-           }
-         else
-           {
-             // Right one is less.
-             _M_losers[__root] = _M_losers[__left];
-             return __right;
-           }
-       }
-    }
-
-    void
-    __init()
-    {
-      _M_losers[0] = _M_losers[__init_winner(1)];
+           if (!_M_comp(_M_losers[__right]._M_key,
+                        _M_losers[__left]._M_key))
+             {
+               // Left one is less or equal.
+               _M_losers[__root] = _M_losers[__right];
+               return __left;
+             }
+           else
+             {
+               // Right one is less.
+               _M_losers[__root] = _M_losers[__left];
+               return __right;
+             }
+         }
+      }
+
+      void
+      __init()
+      {
+       _M_losers[0] = _M_losers[__init_winner(1)];
 
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top at the beginning
-      // (0 sequences!)
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top at the beginning
+       // (0 sequences!)
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
-    }
-
-    // Do not pass a const reference since _M_key will be used as
-    // local variable.
-    void
-    __delete_min_insert(_Tp _M_key, bool)
-    {
+      }
+
+      // Do not pass a const reference since __key will be used as
+      // local variable.
+      void
+      __delete_min_insert(_Tp __key, bool)
+      {
+        using std::swap;
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
 
-      int _M_source = _M_losers[0]._M_source;
-      for (unsigned int __pos = (_M_k + _M_source) / 2; __pos > 0; __pos /= 2)
-       {
-         // The smaller one gets promoted.
-         if (_M_comp(_M_losers[__pos]._M_key, _M_key))
-           {
-             // The other one is smaller.
-             std::swap(_M_losers[__pos]._M_source, _M_source);
-             std::swap(_M_losers[__pos]._M_key, _M_key);
-           }
-       }
-
-      _M_losers[0]._M_source = _M_source;
-      _M_losers[0]._M_key = _M_key;
-    }
-  };
-
-/** @brief Unguarded loser tree, keeping only pointers to the
-* elements in the tree structure.
-*
-*  No guarding is done, therefore not a single input sequence must
-*  run empty.  This is a very fast variant.
-*/
-template<typename _Tp, typename _Compare>
-  class LoserTreePointerUnguardedBase
-  {
-  protected:
-    struct _Loser
-    {
-      int _M_source;
-      const _Tp* _M_keyp;
+       int __source = _M_losers[0]._M_source;
+       for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+            __pos /= 2)
+         {
+           // The smaller one gets promoted.
+           if (_M_comp(_M_losers[__pos]._M_key, __key))
+             {
+               // The other one is smaller.
+               std::swap(_M_losers[__pos]._M_source, __source);
+               swap(_M_losers[__pos]._M_key, __key);
+             }
+         }
+
+       _M_losers[0]._M_source = __source;
+       _M_losers[0]._M_key = __key;
+      }
     };
 
-    unsigned int _M_ik, _M_k, _M_offset;
-    _Loser* _M_losers;
-    _Compare _M_comp;
-
-  public:
-
-    LoserTreePointerUnguardedBase(unsigned int __k, const _Tp& _sentinel,
-                                 _Compare __comp = std::less<_Tp>())
-    : _M_comp(__comp)
-    {
-      _M_ik = __k;
-
-      // Next greater power of 2.
-      _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
-      _M_offset = _M_k;
-      // Avoid default-constructing _M_losers[]._M_key
-      _M_losers = new _Loser[2 * _M_k];
-
-      for (unsigned int __i = _M_k + _M_ik - 1; __i < (2 * _M_k); ++__i)
-       {
-         _M_losers[__i]._M_keyp = &_sentinel;
-         _M_losers[__i]._M_source = -1;
-       }
-    }
-
-    ~LoserTreePointerUnguardedBase()
-    { delete[] _M_losers; }
-
-    int
-    __get_min_source()
+  /** @brief Unguarded loser tree, keeping only pointers to the
+  * elements in the tree structure.
+  *
+  *  No guarding is done, therefore not a single input sequence must
+  *  run empty.  This is a very fast variant.
+  */
+  template<typename _Tp, typename _Compare>
+    class _LoserTreePointerUnguardedBase
     {
+    protected:
+      struct _Loser
+      {
+       int _M_source;
+       const _Tp* _M_keyp;
+      };
+
+      unsigned int _M_ik, _M_k, _M_offset;
+      _Loser* _M_losers;
+      _Compare _M_comp;
+
+    public:
+
+      _LoserTreePointerUnguardedBase(unsigned int __k, const _Tp& __sentinel,
+                                    _Compare __comp = std::less<_Tp>())
+      : _M_comp(__comp)
+      {
+       _M_ik = __k;
+
+       // Next greater power of 2.
+       _M_k = 1 << (__rd_log2(_M_ik - 1) + 1);
+       _M_offset = _M_k;
+       // Avoid default-constructing _M_losers[]._M_key
+       _M_losers = new _Loser[2 * _M_k];
+
+       for (unsigned int __i = _M_k + _M_ik - 1; __i < (2 * _M_k); ++__i)
+         {
+           _M_losers[__i]._M_keyp = &__sentinel;
+           _M_losers[__i]._M_source = -1;
+         }
+      }
+
+      ~_LoserTreePointerUnguardedBase()
+      { delete[] _M_losers; }
+
+      int
+      __get_min_source()
+      {
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
-      return _M_losers[0]._M_source;
-    }
+       return _M_losers[0]._M_source;
+      }
 
-    void
-    __insert_start(const _Tp& _M_key, int _M_source, bool)
-    {
-      unsigned int __pos = _M_k + _M_source;
-
-      _M_losers[__pos]._M_keyp = &_M_key;
-      _M_losers[__pos]._M_source = _M_source;
-    }
-  };
-
-/**
- * @brief Stable unguarded _LoserTree variant storing pointers.
- *
- * Unstable variant is implemented below using partial specialization.
- */
-template<bool __stable/* default == true */, typename _Tp, typename _Compare>
-  class _LoserTreePointerUnguarded
-  : public LoserTreePointerUnguardedBase<_Tp, _Compare>
-  {
-    typedef LoserTreePointerUnguardedBase<_Tp, _Compare> _Base;
-    using _Base::_M_k;
-    using _Base::_M_losers;
+      void
+      __insert_start(const _Tp& __key, int __source, bool)
+      {
+       unsigned int __pos = _M_k + __source;
 
-  public:
-    _LoserTreePointerUnguarded(unsigned int __k, const _Tp& _sentinel,
-                              _Compare __comp = std::less<_Tp>())
-    : _Base::LoserTreePointerUnguardedBase(__k, _sentinel, __comp)
-    { }
+       _M_losers[__pos]._M_keyp = &__key;
+       _M_losers[__pos]._M_source = __source;
+      }
+    };
 
-    unsigned int
-    __init_winner(unsigned int __root)
-    {
-      if (__root >= _M_k)
-       return __root;
-      else
-       {
-         unsigned int __left = __init_winner (2 * __root);
-         unsigned int __right = __init_winner (2 * __root + 1);
-         if (!_M_comp(*_M_losers[__right]._M_keyp,
-                      *_M_losers[__left]._M_keyp))
-           {
-             // Left one is less or equal.
-             _M_losers[__root] = _M_losers[__right];
-             return __left;
-           }
-         else
-           {
-             // Right one is less.
-             _M_losers[__root] = _M_losers[__left];
-             return __right;
-           }
-       }
-    }
-    
-    void
-    __init()
+  /**
+   * @brief Stable unguarded _LoserTree variant storing pointers.
+   *
+   * Unstable variant is implemented below using partial specialization.
+   */
+  template<bool __stable/* default == true */, typename _Tp, typename _Compare>
+    class _LoserTreePointerUnguarded
+    : public _LoserTreePointerUnguardedBase<_Tp, _Compare>
     {
-      _M_losers[0] = _M_losers[__init_winner(1)];
+      typedef _LoserTreePointerUnguardedBase<_Tp, _Compare> _Base;
+      using _Base::_M_k;
+      using _Base::_M_losers;
+
+    public:
+      _LoserTreePointerUnguarded(unsigned int __k, const _Tp& __sentinel,
+                                _Compare __comp = std::less<_Tp>())
+      : _Base::_LoserTreePointerUnguardedBase(__k, __sentinel, __comp)
+      { }
+
+      unsigned int
+      __init_winner(unsigned int __root)
+      {
+       if (__root >= _M_k)
+         return __root;
+       else
+         {
+           unsigned int __left = __init_winner(2 * __root);
+           unsigned int __right = __init_winner(2 * __root + 1);
+           if (!_M_comp(*_M_losers[__right]._M_keyp,
+                        *_M_losers[__left]._M_keyp))
+             {
+               // Left one is less or equal.
+               _M_losers[__root] = _M_losers[__right];
+               return __left;
+             }
+           else
+             {
+               // Right one is less.
+               _M_losers[__root] = _M_losers[__left];
+               return __right;
+             }
+         }
+      }
+
+      void
+      __init()
+      {
+       _M_losers[0] = _M_losers[__init_winner(1)];
 
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top at the beginning
-      // (0 sequences!)
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top at the beginning
+       // (0 sequences!)
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
-    }
+      }
 
-    void
-    __delete_min_insert(const _Tp& _M_key, bool _M_sup)
-    {
+      void
+      __delete_min_insert(const _Tp& __key, bool __sup)
+      {
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
 
-      const _Tp* _M_keyp = &_M_key;
-      int _M_source = _M_losers[0]._M_source;
-      for (unsigned int __pos = (_M_k + _M_source) / 2; __pos > 0; __pos /= 2)
-       {
-         // The smaller one gets promoted, ties are broken by _M_source.
-         if (_M_comp(*_M_losers[__pos]._M_keyp, *_M_keyp)
-             || (!_M_comp(*_M_keyp, *_M_losers[__pos]._M_keyp)
-                 && _M_losers[__pos]._M_source < _M_source))
-           {
-             // The other one is smaller.
-             std::swap(_M_losers[__pos]._M_source, _M_source);
-             std::swap(_M_losers[__pos]._M_keyp, _M_keyp);
-           }
-       }
-
-      _M_losers[0]._M_source = _M_source;
-      _M_losers[0]._M_keyp = _M_keyp;
-    }
-  };
-
-/**
- * @brief Unstable unguarded _LoserTree variant storing pointers.
- *
- * Stable variant is above.
- */
-template<typename _Tp, typename _Compare>
-  class _LoserTreePointerUnguarded</* __stable == */false, _Tp, _Compare>
-  : public LoserTreePointerUnguardedBase<_Tp, _Compare>
-  {
-    typedef LoserTreePointerUnguardedBase<_Tp, _Compare> _Base;
-    using _Base::_M_k;
-    using _Base::_M_losers;
-
-public:
-    _LoserTreePointerUnguarded(unsigned int __k, const _Tp& _sentinel,
-                              _Compare __comp = std::less<_Tp>())
-    : _Base::LoserTreePointerUnguardedBase(__k, _sentinel, __comp)
-    { }
-
-    unsigned int
-    __init_winner(unsigned int __root)
+       const _Tp* __keyp = &__key;
+       int __source = _M_losers[0]._M_source;
+       for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+            __pos /= 2)
+         {
+           // The smaller one gets promoted, ties are broken by _M_source.
+           if (_M_comp(*_M_losers[__pos]._M_keyp, *__keyp)
+               || (!_M_comp(*__keyp, *_M_losers[__pos]._M_keyp)
+                   && _M_losers[__pos]._M_source < __source))
+             {
+               // The other one is smaller.
+               std::swap(_M_losers[__pos]._M_source, __source);
+               std::swap(_M_losers[__pos]._M_keyp, __keyp);
+             }
+         }
+
+       _M_losers[0]._M_source = __source;
+       _M_losers[0]._M_keyp = __keyp;
+      }
+    };
+
+  /**
+   * @brief Unstable unguarded _LoserTree variant storing pointers.
+   *
+   * Stable variant is above.
+   */
+  template<typename _Tp, typename _Compare>
+    class _LoserTreePointerUnguarded</* __stable == */false, _Tp, _Compare>
+    : public _LoserTreePointerUnguardedBase<_Tp, _Compare>
     {
-      if (__root >= _M_k)
-       return __root;
-      else
-       {
-         unsigned int __left = __init_winner (2 * __root);
-         unsigned int __right = __init_winner (2 * __root + 1);
+      typedef _LoserTreePointerUnguardedBase<_Tp, _Compare> _Base;
+      using _Base::_M_k;
+      using _Base::_M_losers;
+
+  public:
+      _LoserTreePointerUnguarded(unsigned int __k, const _Tp& __sentinel,
+                                _Compare __comp = std::less<_Tp>())
+      : _Base::_LoserTreePointerUnguardedBase(__k, __sentinel, __comp)
+      { }
+
+      unsigned int
+      __init_winner(unsigned int __root)
+      {
+       if (__root >= _M_k)
+         return __root;
+       else
+         {
+           unsigned int __left = __init_winner(2 * __root);
+           unsigned int __right = __init_winner(2 * __root + 1);
 
 #if _GLIBCXX_ASSERTIONS
-         // If __left one is sentinel then __right one must be, too.
-         if (_M_losers[__left]._M_source == -1)
-           _GLIBCXX_PARALLEL_ASSERT(_M_losers[__right]._M_source == -1);
+           // If __left one is sentinel then __right one must be, too.
+           if (_M_losers[__left]._M_source == -1)
+             _GLIBCXX_PARALLEL_ASSERT(_M_losers[__right]._M_source == -1);
 #endif
 
-         if (!_M_comp(*_M_losers[__right]._M_keyp,
-                      *_M_losers[__left]._M_keyp))
-           {
-             // Left one is less or equal.
-             _M_losers[__root] = _M_losers[__right];
-             return __left;
-           }
-         else
-           {
-             // Right one is less.
-             _M_losers[__root] = _M_losers[__left];
-             return __right;
-           }
-       }
-    }
-
-    void
-    __init()
-    {
-      _M_losers[0] = _M_losers[__init_winner(1)];
+           if (!_M_comp(*_M_losers[__right]._M_keyp,
+                        *_M_losers[__left]._M_keyp))
+             {
+               // Left one is less or equal.
+               _M_losers[__root] = _M_losers[__right];
+               return __left;
+             }
+           else
+             {
+               // Right one is less.
+               _M_losers[__root] = _M_losers[__left];
+               return __right;
+             }
+         }
+      }
+
+      void
+      __init()
+      {
+       _M_losers[0] = _M_losers[__init_winner(1)];
 
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top at the beginning
-      // (0 sequences!)
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top at the beginning
+       // (0 sequences!)
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
-    }
+      }
 
-    void
-    __delete_min_insert(const _Tp& _M_key, bool _M_sup)
-    {
+      void
+      __delete_min_insert(const _Tp& __key, bool __sup)
+      {
 #if _GLIBCXX_ASSERTIONS
-      // no dummy sequence can ever be at the top!
-      _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
+       // no dummy sequence can ever be at the top!
+       _GLIBCXX_PARALLEL_ASSERT(_M_losers[0]._M_source != -1);
 #endif
 
-      const _Tp* _M_keyp = &_M_key;
-      int _M_source = _M_losers[0]._M_source;
-      for (unsigned int __pos = (_M_k + _M_source) / 2; __pos > 0; __pos /= 2)
-       {
-         // The smaller one gets promoted.
-         if (_M_comp(*(_M_losers[__pos]._M_keyp), *_M_keyp))
-           {
-             // The other one is smaller.
-             std::swap(_M_losers[__pos]._M_source, _M_source);
-             std::swap(_M_losers[__pos]._M_keyp, _M_keyp);
-           }
-       }
-
-      _M_losers[0]._M_source = _M_source;
-      _M_losers[0]._M_keyp = _M_keyp;
-    }
-  };
+       const _Tp* __keyp = &__key;
+       int __source = _M_losers[0]._M_source;
+       for (unsigned int __pos = (_M_k + __source) / 2; __pos > 0;
+            __pos /= 2)
+         {
+           // The smaller one gets promoted.
+           if (_M_comp(*(_M_losers[__pos]._M_keyp), *__keyp))
+             {
+               // The other one is smaller.
+               std::swap(_M_losers[__pos]._M_source, __source);
+               std::swap(_M_losers[__pos]._M_keyp, __keyp);
+             }
+         }
+
+       _M_losers[0]._M_source = __source;
+       _M_losers[0]._M_keyp = __keyp;
+      }
+    };
 } // namespace __gnu_parallel
 
 #endif /* _GLIBCXX_PARALLEL_LOSERTREE_H */