PR67085 pass comparison functions by reference in heap algorithms

	PR libstdc++/67085
	* include/bits/predefined_ops.h (_Iter_less_val, _Val_less_iter): Add
	converting constructors from _Iter_less_iter.
	(_Iter_comp_val, _Val_comp_iter): Add converting constructors from
	_Iter_comp_iter.
	(__iter_comp_val(_Iter_comp_iter<C>): Use converting constructor.
	(__val_comp_iter(_Iter_comp_iter<C>): Likewise.
	* include/bits/stl_heap.h (__is_heap_until, __push_heap, __pop_heap)
	(__make_heap, __sort_heap): Change _Compare parameters to references.
	(__is_heap, push_heap, __adjust_heap, __pop_heap, pop_heap)
	(__make_heap, make_heap, sort_heap, is_heap_until): Pass comparison
	functions as lvalues.
	(is_heap): Call __is_heap_until directly to avoid copying __comp.
	* testsuite/23_containers/priority_queue/67085.cc: Adjust test to
	count copies during construction with empty sequence.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@244656 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 109 insertions, 47 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 0106c23a3ef..fde7f341444 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,6 +1,22 @@
 2017-01-19  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/67085
+	* include/bits/predefined_ops.h (_Iter_less_val, _Val_less_iter): Add
+	converting constructors from _Iter_less_iter.
+	(_Iter_comp_val, _Val_comp_iter): Add converting constructors from
+	_Iter_comp_iter.
+	(__iter_comp_val(_Iter_comp_iter<C>): Use converting constructor.
+	(__val_comp_iter(_Iter_comp_iter<C>): Likewise.
+	* include/bits/stl_heap.h (__is_heap_until, __push_heap, __pop_heap)
+	(__make_heap, __sort_heap): Change _Compare parameters to references.
+	(__is_heap, push_heap, __adjust_heap, __pop_heap, pop_heap)
+	(__make_heap, make_heap, sort_heap, is_heap_until): Pass comparison
+	functions as lvalues.
+	(is_heap): Call __is_heap_until directly to avoid copying __comp.
+	* testsuite/23_containers/priority_queue/67085.cc: Adjust test to
+	count copies during construction with empty sequence.
+
+	PR libstdc++/67085
 	* include/bits/stl_heap.h (__is_heap): Use _GLIBCXX_MOVE.
 	(__make_heap, __sort_heap): Don't use _GLIBCXX_MOVE inside loops.
 	* testsuite/23_containers/priority_queue/67085.cc: Adjust expected
diff --git a/libstdc++-v3/include/bits/predefined_ops.h b/libstdc++-v3/include/bits/predefined_ops.h
index 2742984b647..a5a7694501a 100644
--- a/libstdc++-v3/include/bits/predefined_ops.h
+++ b/libstdc++-v3/include/bits/predefined_ops.h
@@ -50,6 +50,15 @@ namespace __ops
 
   struct _Iter_less_val
   {
+#if __cplusplus >= 201103L
+    constexpr _Iter_less_val() = default;
+#else
+    _Iter_less_val() { }
+#endif
+
+    explicit
+    _Iter_less_val(_Iter_less_iter) { }
+
     template<typename _Iterator, typename _Value>
       bool
       operator()(_Iterator __it, _Value& __val) const
@@ -66,6 +75,15 @@ namespace __ops
 
   struct _Val_less_iter
   {
+#if __cplusplus >= 201103L
+    constexpr _Val_less_iter() = default;
+#else
+    _Val_less_iter() { }
+#endif
+
+    explicit
+    _Val_less_iter(_Iter_less_iter) { }
+
     template<typename _Value, typename _Iterator>
       bool
       operator()(_Value& __val, _Iterator __it) const
@@ -141,6 +159,18 @@ namespace __ops
 	: _M_comp(_GLIBCXX_MOVE(__comp))
       { }
 
+      explicit
+      _Iter_comp_val(const _Iter_comp_iter<_Compare>& __comp)
+	: _M_comp(__comp._M_comp)
+      { }
+
+#if __cplusplus >= 201103L
+      explicit
+      _Iter_comp_val(_Iter_comp_iter<_Compare>&& __comp)
+	: _M_comp(std::move(__comp._M_comp))
+      { }
+#endif
+
       template<typename _Iterator, typename _Value>
 	bool
 	operator()(_Iterator __it, _Value& __val)
@@ -155,7 +185,7 @@ namespace __ops
   template<typename _Compare>
     inline _Iter_comp_val<_Compare>
     __iter_comp_val(_Iter_comp_iter<_Compare> __comp)
-    { return _Iter_comp_val<_Compare>(_GLIBCXX_MOVE(__comp._M_comp)); }
+    { return _Iter_comp_val<_Compare>(_GLIBCXX_MOVE(__comp)); }
 
   template<typename _Compare>
     struct _Val_comp_iter
@@ -167,6 +197,18 @@ namespace __ops
 	: _M_comp(_GLIBCXX_MOVE(__comp))
       { }
 
+      explicit
+      _Val_comp_iter(const _Iter_comp_iter<_Compare>& __comp)
+	: _M_comp(__comp._M_comp)
+      { }
+
+#if __cplusplus >= 201103L
+      explicit
+      _Val_comp_iter(_Iter_comp_iter<_Compare>&& __comp)
+	: _M_comp(std::move(__comp._M_comp))
+      { }
+#endif
+
       template<typename _Value, typename _Iterator>
 	bool
 	operator()(_Value& __val, _Iterator __it)
@@ -181,7 +223,7 @@ namespace __ops
   template<typename _Compare>
     inline _Val_comp_iter<_Compare>
     __val_comp_iter(_Iter_comp_iter<_Compare> __comp)
-    { return _Val_comp_iter<_Compare>(_GLIBCXX_MOVE(__comp._M_comp)); }
+    { return _Val_comp_iter<_Compare>(_GLIBCXX_MOVE(__comp)); }
 
   template<typename _Value>
     struct _Iter_equals_val
diff --git a/libstdc++-v3/include/bits/stl_heap.h b/libstdc++-v3/include/bits/stl_heap.h
index b19c9f499b8..3c102f136e6 100644
--- a/libstdc++-v3/include/bits/stl_heap.h
+++ b/libstdc++-v3/include/bits/stl_heap.h
@@ -72,7 +72,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	   typename _Compare>
     _Distance
     __is_heap_until(_RandomAccessIterator __first, _Distance __n,
-		    _Compare __comp)
+		    _Compare& __comp)
     {
       _Distance __parent = 0;
       for (_Distance __child = 1; __child < __n; ++__child)
@@ -91,8 +91,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     inline bool
     __is_heap(_RandomAccessIterator __first, _Distance __n)
     {
-      return std::__is_heap_until(__first, __n,
-			__gnu_cxx::__ops::__iter_less_iter()) == __n;
+      __gnu_cxx::__ops::_Iter_less_iter __comp;
+      return std::__is_heap_until(__first, __n, __comp) == __n;
     }
 
   template<typename _RandomAccessIterator, typename _Compare,
@@ -100,8 +100,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     inline bool
     __is_heap(_RandomAccessIterator __first, _Compare __comp, _Distance __n)
     {
-      return std::__is_heap_until(__first, __n,
-	__gnu_cxx::__ops::__iter_comp_iter(__comp)) == __n;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
+      return std::__is_heap_until(__first, __n, __cmp) == __n;
     }
 
   template<typename _RandomAccessIterator>
@@ -126,7 +126,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     void
     __push_heap(_RandomAccessIterator __first,
 		_Distance __holeIndex, _Distance __topIndex, _Tp __value,
-		_Compare __comp)
+		_Compare& __comp)
     {
       _Distance __parent = (__holeIndex - 1) / 2;
       while (__holeIndex > __topIndex && __comp(__first + __parent, __value))
@@ -165,10 +165,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_irreflexive(__first, __last);
       __glibcxx_requires_heap(__first, __last - 1);
 
+      __gnu_cxx::__ops::_Iter_less_val __comp;
       _ValueType __value = _GLIBCXX_MOVE(*(__last - 1));
       std::__push_heap(__first, _DistanceType((__last - __first) - 1),
-		       _DistanceType(0), _GLIBCXX_MOVE(__value),
-		       __gnu_cxx::__ops::__iter_less_val());
+		       _DistanceType(0), _GLIBCXX_MOVE(__value), __comp);
     }
 
   /**
@@ -200,11 +200,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
       __glibcxx_requires_heap_pred(__first, __last - 1, __comp);
 
+      __decltype(__gnu_cxx::__ops::__iter_comp_val(_GLIBCXX_MOVE(__comp)))
+	__cmp(_GLIBCXX_MOVE(__comp));
       _ValueType __value = _GLIBCXX_MOVE(*(__last - 1));
       std::__push_heap(__first, _DistanceType((__last - __first) - 1),
-		       _DistanceType(0), _GLIBCXX_MOVE(__value),
-		       __gnu_cxx::__ops::
-		       __iter_comp_val(_GLIBCXX_MOVE(__comp)));
+		       _DistanceType(0), _GLIBCXX_MOVE(__value), __cmp);
     }
 
   template<typename _RandomAccessIterator, typename _Distance,
@@ -231,16 +231,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 						     + (__secondChild - 1)));
 	  __holeIndex = __secondChild - 1;
 	}
-      std::__push_heap(__first, __holeIndex, __topIndex, 
-		       _GLIBCXX_MOVE(__value),
-		       __gnu_cxx::__ops::
-		       __iter_comp_val(_GLIBCXX_MOVE(__comp)));
+      __decltype(__gnu_cxx::__ops::__iter_comp_val(_GLIBCXX_MOVE(__comp)))
+	__cmp(_GLIBCXX_MOVE(__comp));
+      std::__push_heap(__first, __holeIndex, __topIndex,
+		       _GLIBCXX_MOVE(__value), __cmp);
     }
 
   template<typename _RandomAccessIterator, typename _Compare>
     inline void
     __pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
-	       _RandomAccessIterator __result, _Compare __comp)
+	       _RandomAccessIterator __result, _Compare& __comp)
     {
       typedef typename iterator_traits<_RandomAccessIterator>::value_type
 	_ValueType;
@@ -251,7 +251,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       *__result = _GLIBCXX_MOVE(*__first);
       std::__adjust_heap(__first, _DistanceType(0),
 			 _DistanceType(__last - __first),
-			 _GLIBCXX_MOVE(__value), _GLIBCXX_MOVE(__comp));
+			 _GLIBCXX_MOVE(__value), __comp);
     }
 
   /**
@@ -282,8 +282,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       if (__last - __first > 1)
 	{
 	  --__last;
-	  std::__pop_heap(__first, __last, __last,
-			  __gnu_cxx::__ops::__iter_less_iter());
+	  __gnu_cxx::__ops::_Iter_less_iter __comp;
+	  std::__pop_heap(__first, __last, __last, __comp);
 	}
     }
 
@@ -313,17 +313,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       if (__last - __first > 1)
 	{
+	  using __gnu_cxx::__ops::_Iter_comp_iter;
+	  _Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
 	  --__last;
-	  std::__pop_heap(__first, __last, __last,
-			  __gnu_cxx::__ops::
-			  __iter_comp_iter(_GLIBCXX_MOVE(__comp)));
+	  std::__pop_heap(__first, __last, __last, __cmp);
 	}
     }
 
   template<typename _RandomAccessIterator, typename _Compare>
     void
     __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
-		_Compare __comp)
+		_Compare& __comp)
     {
       typedef typename iterator_traits<_RandomAccessIterator>::value_type
 	  _ValueType;
@@ -366,8 +366,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_valid_range(__first, __last);
       __glibcxx_requires_irreflexive(__first, __last);
 
-      std::__make_heap(__first, __last,
-		       __gnu_cxx::__ops::__iter_less_iter());
+      __gnu_cxx::__ops::_Iter_less_iter __comp;
+      std::__make_heap(__first, __last, __comp);
     }
 
   /**
@@ -391,15 +391,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_valid_range(__first, __last);
       __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
 
-      std::__make_heap(__first, __last,
-		       __gnu_cxx::__ops::
-		       __iter_comp_iter(_GLIBCXX_MOVE(__comp)));
+      __gnu_cxx::__ops::_Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
+      std::__make_heap(__first, __last, __cmp);
     }
 
   template<typename _RandomAccessIterator, typename _Compare>
     void
     __sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
-		_Compare __comp)
+		_Compare& __comp)
     {
       while (__last - __first > 1)
 	{
@@ -429,8 +428,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_irreflexive(__first, __last);
       __glibcxx_requires_heap(__first, __last);
 
-      std::__sort_heap(__first, __last,
-		       __gnu_cxx::__ops::__iter_less_iter());
+      __gnu_cxx::__ops::_Iter_less_iter __comp;
+      std::__sort_heap(__first, __last, __comp);
     }
 
   /**
@@ -455,9 +454,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
       __glibcxx_requires_heap_pred(__first, __last, __comp);
 
-      std::__sort_heap(__first, __last,
-		       __gnu_cxx::__ops::
-		       __iter_comp_iter(_GLIBCXX_MOVE(__comp)));
+      __gnu_cxx::__ops::_Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
+      std::__sort_heap(__first, __last, __cmp);
     }
 
 #if __cplusplus >= 201103L
@@ -483,9 +481,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_valid_range(__first, __last);
       __glibcxx_requires_irreflexive(__first, __last);
 
+      __gnu_cxx::__ops::_Iter_less_iter __comp;
       return __first + 
-	std::__is_heap_until(__first, std::distance(__first, __last),
-			     __gnu_cxx::__ops::__iter_less_iter());
+	std::__is_heap_until(__first, std::distance(__first, __last), __comp);
     }
 
   /**
@@ -510,10 +508,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_valid_range(__first, __last);
       __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
 
+      __gnu_cxx::__ops::_Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
       return __first
-	+ std::__is_heap_until(__first, std::distance(__first, __last),
-			       __gnu_cxx::__ops::
-			       __iter_comp_iter(std::move(__comp)));
+	+ std::__is_heap_until(__first, std::distance(__first, __last), __cmp);
     }
 
   /**
@@ -541,8 +538,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
 	    _Compare __comp)
     {
-      return std::is_heap_until(__first, __last, std::move(__comp))
-	== __last;
+      // concept requirements
+      __glibcxx_function_requires(_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      const auto __dist = std::distance(__first, __last);
+      __gnu_cxx::__ops::_Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
+      return std::__is_heap_until(__first, __dist, __cmp) == __dist;
     }
 #endif
 
diff --git a/libstdc++-v3/testsuite/23_containers/priority_queue/67085.cc b/libstdc++-v3/testsuite/23_containers/priority_queue/67085.cc
index 4ccea309fcf..9f4da585dd8 100644
--- a/libstdc++-v3/testsuite/23_containers/priority_queue/67085.cc
+++ b/libstdc++-v3/testsuite/23_containers/priority_queue/67085.cc
@@ -32,11 +32,11 @@ struct CopyCounter : std::less<int>
 void
 test01()
 {
-  int v[] = {1, 2, 3, 4};
-  std::priority_queue<int, std::vector<int>, CopyCounter> q{v, v+4};
-  VERIFY(count == 4);
+  int i;
+  std::priority_queue<int, std::vector<int>, CopyCounter> q{&i, &i};
+  VERIFY(count == 2);
   q.push(1);
-  VERIFY(count == 5);
+  VERIFY(count == 3);
 }
 
 int