Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld.  LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by:	The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by:	Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by:	emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124.  The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by:	dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509).  The release will follow soon.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64.  See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes:	yes
Exp-run:	antoine
PR:		215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it.  An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by:	mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

  [SCEV] Decrease the recursion threshold for CompareValueComplexity

  Fixes PR32142.

  r287232 accidentally increased the recursion threshold for
  CompareValueComplexity from 2 to 32.  This change reverses that
  change by introducing a separate flag for CompareValueComplexity's
  threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes:	yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

  builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

  Summary:
  Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
  mode (-mthumb, -marm), it reflect's capability of given CPU.

  Due to this:
   - use  __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
   - use '.thumb' directive consistently  in all affected files
   - decorate all thumb functions using
     DEFINE_COMPILERRT_THUMB_FUNCTION()

  ---------
  Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

  Reviewers: weimingz, rengolin, compnerd

  Subscribers: aemerson, dim

  Differential Revision: https://reviews.llvm.org/D30938

Discussed with:	mmel

1 files changed, 132 insertions, 91 deletions

diff --git a/contrib/libc++/include/algorithm b/contrib/libc++/include/algorithm
index 7a6db7a..5eec80c 100644
--- a/contrib/libc++/include/algorithm
+++ b/contrib/libc++/include/algorithm
@@ -89,7 +89,7 @@ template <class InputIterator1, class InputIterator2>
 
 template <class InputIterator1, class InputIterator2>
     pair<InputIterator1, InputIterator2>
-    mismatch(InputIterator1 first1, InputIterator1 last1, 
+    mismatch(InputIterator1 first1, InputIterator1 last1,
              InputIterator2 first2, InputIterator2 last2); // **C++14**
 
 template <class InputIterator1, class InputIterator2, class BinaryPredicate>
@@ -109,7 +109,7 @@ template <class InputIterator1, class InputIterator2>
 
 template <class InputIterator1, class InputIterator2>
     bool
-    equal(InputIterator1 first1, InputIterator1 last1, 
+    equal(InputIterator1 first1, InputIterator1 last1,
           InputIterator2 first2, InputIterator2 last2); // **C++14**
 
 template <class InputIterator1, class InputIterator2, class BinaryPredicate>
@@ -288,6 +288,12 @@ template <class RandomAccessIterator, class RandomNumberGenerator>
     random_shuffle(RandomAccessIterator first, RandomAccessIterator last,
                    RandomNumberGenerator& rand);  // deprecated in C++14
 
+template<class PopulationIterator, class SampleIterator,
+         class Distance, class UniformRandomBitGenerator>
+    SampleIterator sample(PopulationIterator first, PopulationIterator last,
+                          SampleIterator out, Distance n,
+                          UniformRandomBitGenerator&& g); // C++17
+
 template<class RandomAccessIterator, class UniformRandomNumberGenerator>
     void shuffle(RandomAccessIterator first, RandomAccessIterator last,
                  UniformRandomNumberGenerator&& g);
@@ -688,7 +694,7 @@ struct __equal_to<_T1, const _T1>
 template <class _T1, class _T2 = _T1>
 struct __less
 {
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
@@ -749,14 +755,28 @@ struct __debug_less
 {
     _Compare __comp_;
     __debug_less(_Compare& __c) : __comp_(__c) {}
+
     template <class _Tp, class _Up>
     bool operator()(const _Tp& __x, const _Up& __y)
     {
         bool __r = __comp_(__x, __y);
         if (__r)
-            _LIBCPP_ASSERT(!__comp_(__y, __x), "Comparator does not induce a strict weak ordering");
+            __do_compare_assert(0, __y, __x);
         return __r;
     }
+
+    template <class _LHS, class _RHS>
+    inline _LIBCPP_INLINE_VISIBILITY
+    decltype((void)_VSTD::declval<_Compare&>()(
+        _VSTD::declval<_LHS const&>(), _VSTD::declval<_RHS const&>()))
+    __do_compare_assert(int, _LHS const& __l, _RHS const& __r) {
+        _LIBCPP_ASSERT(!__comp_(__l, __r),
+            "Comparator does not induce a strict weak ordering");
+    }
+
+    template <class _LHS, class _RHS>
+    inline _LIBCPP_INLINE_VISIBILITY
+    void __do_compare_assert(long, _LHS const&, _RHS const&) {}
 };
 
 #endif  // _LIBCPP_DEBUG
@@ -857,7 +877,7 @@ for_each(_InputIterator __first, _InputIterator __last, _Function __f)
 {
     for (; __first != __last; ++__first)
         __f(*__first);
-    return _LIBCPP_EXPLICIT_MOVE(__f);  // explicitly moved for (emulated) C++03
+    return __f;
 }
 
 // find
@@ -1215,7 +1235,7 @@ equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first
 template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
 inline _LIBCPP_INLINE_VISIBILITY
 bool
-__equal(_InputIterator1 __first1, _InputIterator1 __last1, 
+__equal(_InputIterator1 __first1, _InputIterator1 __last1,
         _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred,
         input_iterator_tag, input_iterator_tag )
 {
@@ -1228,8 +1248,8 @@ __equal(_InputIterator1 __first1, _InputIterator1 __last1,
 template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
 inline _LIBCPP_INLINE_VISIBILITY
 bool
-__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, 
-        _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred, 
+__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+        _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
       random_access_iterator_tag, random_access_iterator_tag )
 {
     if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
@@ -1242,11 +1262,11 @@ __equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
 inline _LIBCPP_INLINE_VISIBILITY
 bool
-equal(_InputIterator1 __first1, _InputIterator1 __last1, 
+equal(_InputIterator1 __first1, _InputIterator1 __last1,
       _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred )
 {
     return _VSTD::__equal<typename add_lvalue_reference<_BinaryPredicate>::type>
-       (__first1, __last1, __first2, __last2, __pred, 
+       (__first1, __last1, __first2, __last2, __pred,
         typename iterator_traits<_InputIterator1>::iterator_category(),
         typename iterator_traits<_InputIterator2>::iterator_category());
 }
@@ -1254,7 +1274,7 @@ equal(_InputIterator1 __first1, _InputIterator1 __last1,
 template <class _InputIterator1, class _InputIterator2>
 inline _LIBCPP_INLINE_VISIBILITY
 bool
-equal(_InputIterator1 __first1, _InputIterator1 __last1, 
+equal(_InputIterator1 __first1, _InputIterator1 __last1,
       _InputIterator2 __first2, _InputIterator2 __last2)
 {
     typedef typename iterator_traits<_InputIterator1>::value_type __v1;
@@ -1328,7 +1348,7 @@ is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
 template<class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
 bool
 __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
-                 _ForwardIterator2 __first2, _ForwardIterator2 __last2, 
+                 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
                  _BinaryPredicate __pred,
                  forward_iterator_tag, forward_iterator_tag )
 {
@@ -1379,7 +1399,7 @@ __next_iter:;
 template<class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
 bool
 __is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
-               _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2, 
+               _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2,
                _BinaryPredicate __pred,
                random_access_iterator_tag, random_access_iterator_tag )
 {
@@ -1458,7 +1478,7 @@ __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
 }
 
 template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
-_LIBCPP_CONSTEXPR_AFTER_CXX11 
+_LIBCPP_CONSTEXPR_AFTER_CXX11
 pair<_RandomAccessIterator1, _RandomAccessIterator1>
 __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
          _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
@@ -1474,9 +1494,9 @@ __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
     if (__len1 < __len2)
         return make_pair(__last1, __last1);
     const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
+
     while (true)
     {
-#if !_LIBCPP_UNROLL_LOOPS
         while (true)
         {
             if (__first1 == __s)
@@ -1485,40 +1505,9 @@ __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
                 break;
             ++__first1;
         }
-#else  // !_LIBCPP_UNROLL_LOOPS
-        for (_D1 __loop_unroll = (__s - __first1) / 4; __loop_unroll > 0; --__loop_unroll)
-        {
-            if (__pred(*__first1, *__first2))
-                goto __phase2;
-            if (__pred(*++__first1, *__first2))
-                goto __phase2;
-            if (__pred(*++__first1, *__first2))
-                goto __phase2;
-            if (__pred(*++__first1, *__first2))
-                goto __phase2;
-            ++__first1;
-        }
-        switch (__s - __first1)
-        {
-        case 3:
-            if (__pred(*__first1, *__first2))
-                break;
-            ++__first1;
-        case 2:
-            if (__pred(*__first1, *__first2))
-                break;
-            ++__first1;
-        case 1:
-            if (__pred(*__first1, *__first2))
-                break;
-        case 0:
-            return make_pair(__last1, __last1);
-        }
-    __phase2:
-#endif  // !_LIBCPP_UNROLL_LOOPS
+
         _RandomAccessIterator1 __m1 = __first1;
         _RandomAccessIterator2 __m2 = __first2;
-#if !_LIBCPP_UNROLL_LOOPS
          while (true)
          {
              if (++__m2 == __last2)
@@ -1530,43 +1519,6 @@ __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
                  break;
              }
          }
-#else  // !_LIBCPP_UNROLL_LOOPS
-        ++__m2;
-        ++__m1;
-        for (_D2 __loop_unroll = (__last2 - __m2) / 4; __loop_unroll > 0; --__loop_unroll)
-        {
-            if (!__pred(*__m1, *__m2))
-                goto __continue;
-            if (!__pred(*++__m1, *++__m2))
-                goto __continue;
-            if (!__pred(*++__m1, *++__m2))
-                goto __continue;
-            if (!__pred(*++__m1, *++__m2))
-                goto __continue;
-            ++__m1;
-            ++__m2;
-        }
-        switch (__last2 - __m2)
-        {
-        case 3:
-            if (!__pred(*__m1, *__m2))
-                break;
-            ++__m1;
-            ++__m2;
-        case 2:
-            if (!__pred(*__m1, *__m2))
-                break;
-            ++__m1;
-            ++__m2;
-        case 1:
-            if (!__pred(*__m1, *__m2))
-                break;
-        case 0:
-            return make_pair(__first1, __first1 + __len2);
-        }
-    __continue:
-        ++__first1;
-#endif  // !_LIBCPP_UNROLL_LOOPS
     }
 }
 
@@ -1729,6 +1681,20 @@ __unwrap_iter(__wrap_iter<_Tp*> __i)
     return __i.base();
 }
 
+#else
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_trivially_copy_assignable<_Tp>::value,
+    __wrap_iter<_Tp*>
+>::type
+__unwrap_iter(__wrap_iter<_Tp*> __i)
+{
+    return __i;
+}
+
 #endif  // _LIBCPP_DEBUG_LEVEL < 2
 
 template <class _InputIterator, class _OutputIterator>
@@ -1802,7 +1768,9 @@ _BidirectionalIterator2
 copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
               _BidirectionalIterator2 __result)
 {
-    return _VSTD::__copy_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
+    return _VSTD::__copy_backward(__unwrap_iter(__first),
+                                  __unwrap_iter(__last),
+                                  __unwrap_iter(__result));
 }
 
 // copy_if
@@ -2417,7 +2385,7 @@ __rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIt
 template<typename _Integral>
 inline _LIBCPP_INLINE_VISIBILITY
 _Integral
-__gcd(_Integral __x, _Integral __y)
+__algo_gcd(_Integral __x, _Integral __y)
 {
     do
     {
@@ -2442,7 +2410,7 @@ __rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _Ran
         _VSTD::swap_ranges(__first, __middle, __middle);
         return __middle;
     }
-    const difference_type __g = _VSTD::__gcd(__m1, __m2);
+    const difference_type __g = _VSTD::__algo_gcd(__m1, __m2);
     for (_RandomAccessIterator __p = __first + __g; __p != __first;)
     {
         value_type __t(_VSTD::move(*--__p));
@@ -2785,7 +2753,7 @@ minmax(initializer_list<_Tp> __t, _Compare __comp)
             __result.second = *__first;
         ++__first;
     }
-    
+
     while (__first != __last)
     {
         _Tp __prev = *__first++;
@@ -2797,7 +2765,7 @@ minmax(initializer_list<_Tp> __t, _Compare __comp)
             if ( __comp(__prev, __result.first))    __result.first  = __prev;
             if (!__comp(*__first, __result.second)) __result.second = *__first;
             }
-                
+
         __first++;
     }
     return __result;
@@ -3128,6 +3096,78 @@ random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
     }
 }
 
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+          class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+                         _PopulationIterator __last, _SampleIterator __output,
+                         _Distance __n,
+                         _UniformRandomNumberGenerator & __g,
+                         input_iterator_tag) {
+
+  _Distance __k = 0;
+  for (; __first != __last && __k < __n; ++__first, (void)++__k)
+    __output[__k] = *__first;
+  _Distance __sz = __k;
+  for (; __first != __last; ++__first, (void)++__k) {
+    _Distance __r = _VSTD::uniform_int_distribution<_Distance>(0, __k)(__g);
+    if (__r < __sz)
+      __output[__r] = *__first;
+  }
+  return __output + _VSTD::min(__n, __k);
+}
+
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+          class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+                         _PopulationIterator __last, _SampleIterator __output,
+                         _Distance __n,
+                         _UniformRandomNumberGenerator& __g,
+                         forward_iterator_tag) {
+  _Distance __unsampled_sz = _VSTD::distance(__first, __last);
+  for (__n = _VSTD::min(__n, __unsampled_sz); __n != 0; ++__first) {
+    _Distance __r =
+        _VSTD::uniform_int_distribution<_Distance>(0, --__unsampled_sz)(__g);
+    if (__r < __n) {
+      *__output++ = *__first;
+      --__n;
+    }
+  }
+  return __output;
+}
+
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+          class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+                         _PopulationIterator __last, _SampleIterator __output,
+                         _Distance __n, _UniformRandomNumberGenerator& __g) {
+  typedef typename iterator_traits<_PopulationIterator>::iterator_category
+        _PopCategory;
+  typedef typename iterator_traits<_PopulationIterator>::difference_type
+        _Difference;
+  static_assert(__is_forward_iterator<_PopulationIterator>::value ||
+                __is_random_access_iterator<_SampleIterator>::value,
+                "SampleIterator must meet the requirements of RandomAccessIterator");
+  typedef typename common_type<_Distance, _Difference>::type _CommonType;
+  _LIBCPP_ASSERT(__n >= 0, "N must be a positive number.");
+  return _VSTD::__sample(
+      __first, __last, __output, _CommonType(__n),
+      __g, _PopCategory());
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+          class _UniformRandomNumberGenerator>
+inline _LIBCPP_INLINE_VISIBILITY
+_SampleIterator sample(_PopulationIterator __first,
+                       _PopulationIterator __last, _SampleIterator __output,
+                       _Distance __n, _UniformRandomNumberGenerator&& __g) {
+    return _VSTD::__sample(__first, __last, __output, __n, __g);
+}
+#endif // _LIBCPP_STD_VER > 14
+
 template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
     void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
@@ -4423,7 +4463,7 @@ __buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator
             ::new(__p) value_type(_VSTD::move(*__i));
         typedef reverse_iterator<_BidirectionalIterator> _RBi;
         typedef reverse_iterator<value_type*> _Rv;
-        __half_inplace_merge(_Rv(__p), _Rv(__buff), 
+        __half_inplace_merge(_Rv(__p), _Rv(__buff),
                              _RBi(__middle), _RBi(__first),
                              _RBi(__last), __negate<_Compare>(__comp));
     }
@@ -4871,7 +4911,8 @@ push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
 
 template <class _Compare, class _RandomAccessIterator>
 void
-__sift_down(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+__sift_down(_RandomAccessIterator __first, _RandomAccessIterator /*__last*/,
+            _Compare __comp,
             typename iterator_traits<_RandomAccessIterator>::difference_type __len,
             _RandomAccessIterator __start)
 {