PR libstdc++/80064 make heap algorithms work with function types

	PR libstdc++/80064
	* include/bits/stl_heap.h (__is_heap, push_heap, __adjust_heap)
	(pop_heap, make_heap, sort_heap, is_heap_until, is_heap): Cope with
	invalid instantiations using function types for _Compare argument.
	* testsuite/25_algorithms/make_heap/80064.cc: New test.

From-SVN: r246197

libstdc++-v3/ChangeLog

 2017-03-16  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/80064
+	* include/bits/stl_heap.h (__is_heap, push_heap, __adjust_heap)
+	(pop_heap, make_heap, sort_heap, is_heap_until, is_heap): Cope with
+	invalid instantiations using function types for _Compare argument.
+	* testsuite/25_algorithms/make_heap/80064.cc: New test.
+
 	PR libstdc++/67440
 	* python/libstdcxx/v6/printers.py (find_type): Avoid gdb.Type.name
 	for GDB 7.6 compatibility, use gdb.Type.unqualified instead.

libstdc++-v3/include/bits/stl_heap.h

@@ -100,7 +100,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     inline bool
     __is_heap(_RandomAccessIterator __first, _Compare __comp, _Distance __n)
     {
-      __gnu_cxx::__ops::_Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
       return std::__is_heap_until(__first, __n, __cmp) == __n;
     }
 
@@ -313,8 +314,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       if (__last - __first > 1)
 	{
-	  using __gnu_cxx::__ops::_Iter_comp_iter;
-	  _Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
+	  typedef __decltype(__comp) _Cmp;
+	  __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
 	  --__last;
 	  std::__pop_heap(__first, __last, __last, __cmp);
 	}
@@ -391,7 +392,8 @@ _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));
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
       std::__make_heap(__first, __last, __cmp);
     }
 
@@ -454,7 +456,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
       __glibcxx_requires_heap_pred(__first, __last, __comp);
 
-      __gnu_cxx::__ops::_Iter_comp_iter<_Compare> __cmp(_GLIBCXX_MOVE(__comp));
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
       std::__sort_heap(__first, __last, __cmp);
     }
 
@@ -508,7 +511,8 @@ _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));
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
       return __first
 	+ std::__is_heap_until(__first, std::distance(__first, __last), __cmp);
     }
@@ -545,7 +549,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __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));
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
       return std::__is_heap_until(__first, __dist, __cmp) == __dist;
     }
 #endif

libstdc++-v3/testsuite/25_algorithms/make_heap/80064.cc

+// Copyright (C) 2017 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/>.
+
+// { dg-do compile }
+
+#include <algorithm>
+
+void
+test01(int* first, int* last)
+{
+  extern bool cmp(int, int);
+  // PR libstdc++/80064
+  // This is undefined, because [alg.sorting] requires the template argument
+  // Compare to be a function object type, and bool(int, int) is not an
+  // object type. We previously accepted it by accident, so keep doing so.
+  std::make_heap<int*, bool(int, int)>(first, last, cmp);
+}