Vendor import of libc++ trunk r305575:vendor/libc++/libc++-trunk-r305575

https://llvm.org/svn/llvm-project/libcxx/trunk@305575

50 files changed, 1188 insertions, 162 deletions

diff --git a/benchmarks/stringstream.bench.cpp b/benchmarks/stringstream.bench.cpp
new file mode 100644
index 000000000000..6023cf775bc8
--- /dev/null
+++ b/benchmarks/stringstream.bench.cpp
@@ -0,0 +1,38 @@
+#include "benchmark/benchmark_api.h"
+
+#include <sstream>
+double __attribute__((noinline)) istream_numbers();
+
+double istream_numbers() {
+  const char *a[] = {
+    "-6  69 -71  2.4882e-02 -100 101 -2.00005 5000000 -50000000",
+    "-25 71   7 -9.3262e+01 -100 101 -2.00005 5000000 -50000000",
+    "-14 53  46 -6.7026e-02 -100 101 -2.00005 5000000 -50000000"
+  };
+
+  int a1, a2, a3, a4, a5, a6, a7;
+  double f1 = 0.0, f2 = 0.0, q = 0.0;
+  for (int i=0; i < 3; i++) {
+    std::istringstream s(a[i]);
+    s >> a1
+      >> a2
+      >> a3
+      >> f1
+      >> a4
+      >> a5
+      >> f2
+      >> a6
+      >> a7;
+    q += (a1 + a2 + a3 + a4 + a5 + a6 + a7 + f1 + f2)/1000000;
+  }
+  return q;
+}
+
+static void BM_Istream_numbers(benchmark::State &state) {
+  double i = 0;
+  while (state.KeepRunning())
+    benchmark::DoNotOptimize(i += istream_numbers());
+}
+
+BENCHMARK(BM_Istream_numbers)->RangeMultiplier(2)->Range(1024, 4096);
+BENCHMARK_MAIN()
diff --git a/include/__bsd_locale_fallbacks.h b/include/__bsd_locale_fallbacks.h
index 3425ce659b7e..9489452905c1 100644
--- a/include/__bsd_locale_fallbacks.h
+++ b/include/__bsd_locale_fallbacks.h
@@ -15,6 +15,7 @@
 #define _LIBCPP_BSD_LOCALE_FALLBACKS_DEFAULTS_H
 
 #include <stdlib.h>
+#include <stdarg.h>
 #include <memory>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/include/__config b/include/__config
index 212a2d53136b..fc24a3bc9ba9 100644
--- a/include/__config
+++ b/include/__config
@@ -76,6 +76,9 @@
 // its vtable and typeinfo to libc++ rather than having all other libraries
 // using that class define their own copies.
 #define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
+
+// Enable optimized version of __do_get_(un)signed which avoids redundant copies.
+#define _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
 #elif _LIBCPP_ABI_VERSION == 1
 #if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
 // Enable compiling copies of now inline methods into the dylib to support
@@ -289,7 +292,7 @@
 # endif
 #endif  // !defined(_LIBCPP_LITTLE_ENDIAN) || !defined(_LIBCPP_BIG_ENDIAN)
 
-#if __has_attribute(__no_sanitize__)
+#if __has_attribute(__no_sanitize__) && !defined(_LIBCPP_COMPILER_GCC)
 #define _LIBCPP_NO_CFI __attribute__((__no_sanitize__("cfi")))
 #else
 #define _LIBCPP_NO_CFI
@@ -1132,8 +1135,6 @@ _LIBCPP_FUNC_VIS extern "C" void __sanitizer_annotate_contiguous_container(
 # define _LIBCPP_HAS_NO_COROUTINES
 #endif
 
-#endif // __cplusplus
-
 // Decide whether to use availability macros.
 #if !defined(_LIBCPP_BUILDING_LIBRARY) &&                                      \
     !defined(_LIBCPP_DISABLE_AVAILABILITY) &&                                  \
@@ -1237,4 +1238,7 @@ _LIBCPP_FUNC_VIS extern "C" void __sanitizer_annotate_contiguous_container(
 # endif
 #endif // defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
 
+
+#endif // __cplusplus
+
 #endif // _LIBCPP_CONFIG
diff --git a/include/__functional_03 b/include/__functional_03
index 1db7082eb3d6..13d8a3d96009 100644
--- a/include/__functional_03
+++ b/include/__functional_03
@@ -704,7 +704,7 @@ function<_Rp()>::target()
 {
     if (__f_ == 0)
         return (_Tp*)0;
-    return (_Tp*)__f_->target(typeid(_Tp));
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
 }
 
 template<class _Rp>
@@ -980,7 +980,7 @@ function<_Rp(_A0)>::target()
 {
     if (__f_ == 0)
         return (_Tp*)0;
-    return (_Tp*)__f_->target(typeid(_Tp));
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
 }
 
 template<class _Rp, class _A0>
@@ -1256,7 +1256,7 @@ function<_Rp(_A0, _A1)>::target()
 {
     if (__f_ == 0)
         return (_Tp*)0;
-    return (_Tp*)__f_->target(typeid(_Tp));
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
 }
 
 template<class _Rp, class _A0, class _A1>
@@ -1532,7 +1532,7 @@ function<_Rp(_A0, _A1, _A2)>::target()
 {
     if (__f_ == 0)
         return (_Tp*)0;
-    return (_Tp*)__f_->target(typeid(_Tp));
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
 }
 
 template<class _Rp, class _A0, class _A1, class _A2>
diff --git a/include/__functional_base b/include/__functional_base
index 0d2c2fc65015..79017fe759b4 100644
--- a/include/__functional_base
+++ b/include/__functional_base
@@ -548,16 +548,13 @@ template <class _Tp> void cref(const _Tp&&) = delete;
 #endif
 
 #if _LIBCPP_STD_VER > 11
-template <class _Tp1, class _Tp2 = void>
-struct __is_transparent
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::is_transparent* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp1>(0)) == 1;
-};
+template <class _Tp, class, class = void>
+struct __is_transparent : false_type {};
+
+template <class _Tp, class _Up>
+struct __is_transparent<_Tp, _Up,  
+                        typename __void_t<typename _Tp::is_transparent>::type>
+   : true_type {};
 #endif
 
 // allocator_arg_t
diff --git a/include/array b/include/array
index 79f7e0d62c56..12780992e5c4 100644
--- a/include/array
+++ b/include/array
@@ -296,6 +296,7 @@ class _LIBCPP_TEMPLATE_VIS tuple_size<array<_Tp, _Size> >
 template <size_t _Ip, class _Tp, size_t _Size>
 class _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, array<_Tp, _Size> >
 {
+    static_assert(_Ip < _Size, "Index out of bounds in std::tuple_element<> (std::array)");
 public:
     typedef _Tp type;
 };
diff --git a/include/experimental/coroutine b/include/experimental/coroutine
index 21c1ea566403..ce795ad452c0 100644
--- a/include/experimental/coroutine
+++ b/include/experimental/coroutine
@@ -250,9 +250,11 @@ public:
 
     _LIBCPP_ALWAYS_INLINE
     static coroutine_handle from_promise(_Promise& __promise) _NOEXCEPT {
+        typedef typename remove_cv<_Promise>::type _RawPromise;
         coroutine_handle __tmp;
-        __tmp.__handle_ = __builtin_coro_promise(_VSTD::addressof(__promise),
-                                                 __alignof(_Promise), true);
+        __tmp.__handle_ = __builtin_coro_promise(
+            _VSTD::addressof(const_cast<_RawPromise&>(__promise)),
+             __alignof(_Promise), true);
         return __tmp;
     }
 };
diff --git a/include/fstream b/include/fstream
index e41a53af4a0c..ffd569839bd4 100644
--- a/include/fstream
+++ b/include/fstream
@@ -617,7 +617,7 @@ basic_filebuf<_CharT, _Traits>::underflow()
                                  static_cast<size_t>(__extbufend_ - __extbufnext_));
             codecvt_base::result __r;
             __st_last_ = __st_;
-            size_t __nr = fread((void*)__extbufnext_, 1, __nmemb, __file_);
+            size_t __nr = fread((void*) const_cast<char *>(__extbufnext_), 1, __nmemb, __file_);
             if (__nr != 0)
             {
                 if (!__cv_)
@@ -630,7 +630,8 @@ basic_filebuf<_CharT, _Traits>::underflow()
                                        this->eback() + __ibs_, __inext);
                 if (__r == codecvt_base::noconv)
                 {
-                    this->setg((char_type*)__extbuf_, (char_type*)__extbuf_, (char_type*)__extbufend_);
+                    this->setg((char_type*)__extbuf_, (char_type*)__extbuf_, 
+                                          (char_type*)const_cast<char *>(__extbufend_));
                     __c = traits_type::to_int_type(*this->gptr());
                 }
                 else if (__inext != this->eback() + __unget_sz)
@@ -722,7 +723,7 @@ basic_filebuf<_CharT, _Traits>::overflow(int_type __c)
                         return traits_type::eof();
                     if (__r == codecvt_base::partial)
                     {
-                        this->setp((char_type*)__e, this->pptr());
+                        this->setp(const_cast<char_type*>(__e), this->pptr());
                         this->pbump(this->epptr() - this->pbase());
                     }
                 }
diff --git a/include/functional b/include/functional
index ea35697d3bbf..83a2e5a39a88 100644
--- a/include/functional
+++ b/include/functional
@@ -1941,8 +1941,8 @@ _Tp*
 function<_Rp(_ArgTypes...)>::target() _NOEXCEPT
 {
     if (__f_ == 0)
-        return (_Tp*)0;
-    return (_Tp*)__f_->target(typeid(_Tp));
+        return nullptr;
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
 }
 
 template<class _Rp, class ..._ArgTypes>
@@ -1951,7 +1951,7 @@ const _Tp*
 function<_Rp(_ArgTypes...)>::target() const _NOEXCEPT
 {
     if (__f_ == 0)
-        return (const _Tp*)0;
+        return nullptr;
     return (const _Tp*)__f_->target(typeid(_Tp));
 }
 
diff --git a/include/locale b/include/locale
index 6aaa22ccaa15..d30d950c7f85 100644
--- a/include/locale
+++ b/include/locale
@@ -372,19 +372,57 @@ template <class _CharT>
 struct __num_get
     : protected __num_get_base
 {
-    static string __stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& __thousands_sep);
     static string __stage2_float_prep(ios_base& __iob, _CharT* __atoms, _CharT& __decimal_point,
                                       _CharT& __thousands_sep);
-    static int __stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
-                  unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
-                  unsigned* __g, unsigned*& __g_end, _CharT* __atoms);
+
     static int __stage2_float_loop(_CharT __ct, bool& __in_units, char& __exp,
                                    char* __a, char*& __a_end,
                                    _CharT __decimal_point, _CharT __thousands_sep,
                                    const string& __grouping, unsigned* __g,
                                    unsigned*& __g_end, unsigned& __dc, _CharT* __atoms);
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+    static string __stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& __thousands_sep);
+    static int __stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+                  unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+                  unsigned* __g, unsigned*& __g_end, _CharT* __atoms);
+
+#else
+    static string __stage2_int_prep(ios_base& __iob, _CharT& __thousands_sep)
+    {
+        locale __loc = __iob.getloc();
+        const numpunct<_CharT>& __np = use_facet<numpunct<_CharT> >(__loc);
+        __thousands_sep = __np.thousands_sep();
+        return __np.grouping();
+    }
+
+    const _CharT* __do_widen(ios_base& __iob, _CharT* __atoms) const
+    {
+      return __do_widen_p(__iob, __atoms);
+    }
+
+
+    static int __stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+                  unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+                  unsigned* __g, unsigned*& __g_end, const _CharT* __atoms);
+private:
+    template<typename T>
+    const T* __do_widen_p(ios_base& __iob, T* __atoms) const
+    {
+      locale __loc = __iob.getloc();
+      use_facet<ctype<T> >(__loc).widen(__src, __src + 26, __atoms);
+      return __atoms;
+    }
+
+    const char* __do_widen_p(ios_base& __iob, char* __atoms) const
+    {
+      (void)__iob;
+      (void)__atoms;
+      return __src;
+    }
+#endif
 };
 
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
 template <class _CharT>
 string
 __num_get<_CharT>::__stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& __thousands_sep)
@@ -395,6 +433,7 @@ __num_get<_CharT>::__stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& _
     __thousands_sep = __np.thousands_sep();
     return __np.grouping();
 }
+#endif
 
 template <class _CharT>
 string
@@ -411,9 +450,16 @@ __num_get<_CharT>::__stage2_float_prep(ios_base& __iob, _CharT* __atoms, _CharT&
 
 template <class _CharT>
 int
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
 __num_get<_CharT>::__stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
                   unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
                   unsigned* __g, unsigned*& __g_end, _CharT* __atoms)
+#else
+__num_get<_CharT>::__stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+                  unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+                  unsigned* __g, unsigned*& __g_end, const _CharT* __atoms)
+
+#endif
 {
     if (__a_end == __a && (__ct == __atoms[24] || __ct == __atoms[25]))
     {
@@ -849,9 +895,16 @@ num_get<_CharT, _InputIterator>::__do_get_signed(iter_type __b, iter_type __e,
     // Stage 1
     int __base = this->__get_base(__iob);
     // Stage 2
-    char_type __atoms[26];
     char_type __thousands_sep;
+    const int __atoms_size = 26;
+#ifdef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+    char_type __atoms1[__atoms_size];
+    const char_type *__atoms = this->__do_widen(__iob, __atoms1);
+    string __grouping = this->__stage2_int_prep(__iob, __thousands_sep);
+#else
+    char_type __atoms[__atoms_size];
     string __grouping = this->__stage2_int_prep(__iob, __atoms, __thousands_sep);
+#endif
     string __buf;
     __buf.resize(__buf.capacity());
     char* __a = &__buf[0];
@@ -899,9 +952,16 @@ num_get<_CharT, _InputIterator>::__do_get_unsigned(iter_type __b, iter_type __e,
     // Stage 1
     int __base = this->__get_base(__iob);
     // Stage 2
-    char_type __atoms[26];
     char_type __thousands_sep;
+    const int __atoms_size = 26;
+#ifdef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+    char_type __atoms1[__atoms_size];
+    const char_type *__atoms = this->__do_widen(__iob, __atoms1);
+    string __grouping = this->__stage2_int_prep(__iob, __thousands_sep);
+#else
+    char_type __atoms[__atoms_size];
     string __grouping = this->__stage2_int_prep(__iob, __atoms, __thousands_sep);
+#endif
     string __buf;
     __buf.resize(__buf.capacity());
     char* __a = &__buf[0];
@@ -3960,7 +4020,8 @@ wbuffer_convert<_Codecvt, _Elem, _Tr>::underflow()
                                        this->egptr(), __inext);
                 if (__r == codecvt_base::noconv)
                 {
-                    this->setg((char_type*)__extbuf_, (char_type*)__extbuf_, (char_type*)__extbufend_);
+                    this->setg((char_type*)__extbuf_, (char_type*)__extbuf_, 
+                               (char_type*) const_cast<char *>(__extbufend_));
                     __c = *this->gptr();
                 }
                 else if (__inext != this->eback() + __unget_sz)
@@ -4048,7 +4109,7 @@ wbuffer_convert<_Codecvt, _Elem, _Tr>::overflow(int_type __c)
                         return traits_type::eof();
                     if (__r == codecvt_base::partial)
                     {
-                        this->setp((char_type*)__e, this->pptr());
+                        this->setp(const_cast<char_type *>(__e), this->pptr());
                         this->pbump(this->epptr() - this->pbase());
                     }
                 }
diff --git a/include/memory b/include/memory
index 711551d5732d..22706d029d5f 100644
--- a/include/memory
+++ b/include/memory
@@ -720,16 +720,12 @@ public:
 
 // pointer_traits
 
+template <class _Tp, class = void>
+struct __has_element_type : false_type {};
+
 template <class _Tp>
-struct __has_element_type
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::element_type* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_element_type<_Tp, 
+              typename __void_t<typename _Tp::element_type>::type> : true_type {};
 
 template <class _Ptr, bool = __has_element_type<_Ptr>::value>
 struct __pointer_traits_element_type;
@@ -808,16 +804,12 @@ struct __pointer_traits_element_type<_Sp<_Tp, _A0, _A1, _A2>, false>
 
 #endif  // _LIBCPP_HAS_NO_VARIADICS
 
+template <class _Tp, class = void>
+struct __has_difference_type : false_type {};
+
 template <class _Tp>
-struct __has_difference_type
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::difference_type* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_difference_type<_Tp, 
+            typename __void_t<typename _Tp::difference_type>::type> : true_type {};
 
 template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
 struct __pointer_traits_difference_type
@@ -998,17 +990,12 @@ struct __rebind_pointer {
 
 // allocator_traits
 
-struct __has_pointer_type_imp
-{
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::pointer* = 0);
-};
+template <class _Tp, class = void>
+struct __has_pointer_type : false_type {};
 
 template <class _Tp>
-struct __has_pointer_type
-    : public integral_constant<bool, sizeof(__has_pointer_type_imp::__test<_Tp>(0)) == 1>
-{
-};
+struct __has_pointer_type<_Tp, 
+          typename __void_t<typename _Tp::pointer>::type> : true_type {};
 
 namespace __pointer_type_imp
 {
@@ -1033,16 +1020,12 @@ struct __pointer_type
     typedef typename __pointer_type_imp::__pointer_type<_Tp, typename remove_reference<_Dp>::type>::type type;
 };
 
+template <class _Tp, class = void>
+struct __has_const_pointer : false_type {};
+
 template <class _Tp>
-struct __has_const_pointer
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::const_pointer* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_const_pointer<_Tp, 
+            typename __void_t<typename _Tp::const_pointer>::type> : true_type {};
 
 template <class _Tp, class _Ptr, class _Alloc, bool = __has_const_pointer<_Alloc>::value>
 struct __const_pointer
@@ -1060,16 +1043,12 @@ struct __const_pointer<_Tp, _Ptr, _Alloc, false>
 #endif
 };
 
+template <class _Tp, class = void>
+struct __has_void_pointer : false_type {};
+
 template <class _Tp>
-struct __has_void_pointer
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::void_pointer* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_void_pointer<_Tp, 
+               typename __void_t<typename _Tp::void_pointer>::type> : true_type {};
 
 template <class _Ptr, class _Alloc, bool = __has_void_pointer<_Alloc>::value>
 struct __void_pointer
@@ -1087,16 +1066,12 @@ struct __void_pointer<_Ptr, _Alloc, false>
 #endif
 };
 
+template <class _Tp, class = void>
+struct __has_const_void_pointer : false_type {};
+
 template <class _Tp>
-struct __has_const_void_pointer
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::const_void_pointer* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_const_void_pointer<_Tp, 
+            typename __void_t<typename _Tp::const_void_pointer>::type> : true_type {};
 
 template <class _Ptr, class _Alloc, bool = __has_const_void_pointer<_Alloc>::value>
 struct __const_void_pointer
@@ -1130,16 +1105,12 @@ __to_raw_pointer(_Pointer __p) _NOEXCEPT
     return _VSTD::__to_raw_pointer(__p.operator->());
 }
 
+template <class _Tp, class = void>
+struct __has_size_type : false_type {};
+
 template <class _Tp>
-struct __has_size_type
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::size_type* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_size_type<_Tp,
+               typename __void_t<typename _Tp::size_type>::type> : true_type {};
 
 template <class _Alloc, class _DiffType, bool = __has_size_type<_Alloc>::value>
 struct __size_type
@@ -1153,16 +1124,13 @@ struct __size_type<_Alloc, _DiffType, true>
     typedef typename _Alloc::size_type type;
 };
 
+template <class _Tp, class = void>
+struct __has_propagate_on_container_copy_assignment : false_type {};
+
 template <class _Tp>
-struct __has_propagate_on_container_copy_assignment
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::propagate_on_container_copy_assignment* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_propagate_on_container_copy_assignment<_Tp,
+    typename __void_t<typename _Tp::propagate_on_container_copy_assignment>::type>
+        : true_type {};
 
 template <class _Alloc, bool = __has_propagate_on_container_copy_assignment<_Alloc>::value>
 struct __propagate_on_container_copy_assignment
@@ -1176,16 +1144,13 @@ struct __propagate_on_container_copy_assignment<_Alloc, true>
     typedef typename _Alloc::propagate_on_container_copy_assignment type;
 };
 
+template <class _Tp, class = void>
+struct __has_propagate_on_container_move_assignment : false_type {};
+
 template <class _Tp>
-struct __has_propagate_on_container_move_assignment
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::propagate_on_container_move_assignment* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_propagate_on_container_move_assignment<_Tp, 
+           typename __void_t<typename _Tp::propagate_on_container_move_assignment>::type>
+               : true_type {};
 
 template <class _Alloc, bool = __has_propagate_on_container_move_assignment<_Alloc>::value>
 struct __propagate_on_container_move_assignment
@@ -1199,16 +1164,13 @@ struct __propagate_on_container_move_assignment<_Alloc, true>
     typedef typename _Alloc::propagate_on_container_move_assignment type;
 };
 
+template <class _Tp, class = void>
+struct __has_propagate_on_container_swap : false_type {};
+
 template <class _Tp>
-struct __has_propagate_on_container_swap
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::propagate_on_container_swap* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_propagate_on_container_swap<_Tp, 
+           typename __void_t<typename _Tp::propagate_on_container_swap>::type>
+               : true_type {};
 
 template <class _Alloc, bool = __has_propagate_on_container_swap<_Alloc>::value>
 struct __propagate_on_container_swap
@@ -1222,16 +1184,13 @@ struct __propagate_on_container_swap<_Alloc, true>
     typedef typename _Alloc::propagate_on_container_swap type;
 };
 
+template <class _Tp, class = void>
+struct __has_is_always_equal : false_type {};
+
 template <class _Tp>
-struct __has_is_always_equal
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::is_always_equal* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp>(0)) == 1;
-};
+struct __has_is_always_equal<_Tp, 
+           typename __void_t<typename _Tp::is_always_equal>::type>
+               : true_type {};
 
 template <class _Alloc, bool = __has_is_always_equal<_Alloc>::value>
 struct __is_always_equal
@@ -1884,7 +1843,7 @@ public:
         return static_cast<pointer>(_VSTD::__allocate(__n * sizeof(_Tp)));
     }
     _LIBCPP_INLINE_VISIBILITY void deallocate(pointer __p, size_type) _NOEXCEPT
-        {_VSTD::__libcpp_deallocate((void*)__p);}
+        {_VSTD::__libcpp_deallocate((void*) const_cast<_Tp *>(__p));}
     _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT
         {return size_type(~0) / sizeof(_Tp);}
 #if !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
@@ -1900,7 +1859,7 @@ public:
         void
         construct(pointer __p)
         {
-            ::new((void*)__p) _Tp();
+            ::new((void*) const_cast<_Tp *>(__p)) _Tp();
         }
 # if defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
 
@@ -1909,14 +1868,14 @@ public:
         void
         construct(pointer __p, _A0& __a0)
         {
-            ::new((void*)__p) _Tp(__a0);
+            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0);
         }
     template <class _A0>
         _LIBCPP_INLINE_VISIBILITY
         void
         construct(pointer __p, const _A0& __a0)
         {
-            ::new((void*)__p) _Tp(__a0);
+            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0);
         }
 # endif  // defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
     template <class _A0, class _A1>
@@ -1924,28 +1883,28 @@ public:
         void
         construct(pointer __p, _A0& __a0, _A1& __a1)
         {
-            ::new((void*)__p) _Tp(__a0, __a1);
+            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0, __a1);
         }
     template <class _A0, class _A1>
         _LIBCPP_INLINE_VISIBILITY
         void
         construct(pointer __p, const _A0& __a0, _A1& __a1)
         {
-            ::new((void*)__p) _Tp(__a0, __a1);
+            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0, __a1);
         }
     template <class _A0, class _A1>
         _LIBCPP_INLINE_VISIBILITY
         void
         construct(pointer __p, _A0& __a0, const _A1& __a1)
         {
-            ::new((void*)__p) _Tp(__a0, __a1);
+            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0, __a1);
         }
     template <class _A0, class _A1>
         _LIBCPP_INLINE_VISIBILITY
         void
         construct(pointer __p, const _A0& __a0, const _A1& __a1)
         {
-            ::new((void*)__p) _Tp(__a0, __a1);
+            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0, __a1);
         }
 #endif  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
     _LIBCPP_INLINE_VISIBILITY void destroy(pointer __p) {__p->~_Tp();}
@@ -3890,7 +3849,9 @@ public:
     template <class _Dp>
         _LIBCPP_INLINE_VISIBILITY
         _Dp* __get_deleter() const _NOEXCEPT
-            {return (_Dp*)(__cntrl_ ? __cntrl_->__get_deleter(typeid(_Dp)) : 0);}
+            {return static_cast<_Dp*>(__cntrl_
+                    ? const_cast<void *>(__cntrl_->__get_deleter(typeid(_Dp))) 
+                      : nullptr);}
 #endif  // _LIBCPP_NO_RTTI
 
 #ifndef _LIBCPP_HAS_NO_VARIADICS
diff --git a/include/numeric b/include/numeric
index a84fb862b667..39e81934dfa1 100644
--- a/include/numeric
+++ b/include/numeric
@@ -25,6 +25,18 @@ template <class InputIterator, class T, class BinaryOperation>
     T
     accumulate(InputIterator first, InputIterator last, T init, BinaryOperation binary_op);
 
+template<class InputIterator>
+    typename iterator_traits<InputIterator>::value_type
+    reduce(InputIterator first, InputIterator last);  // C++17
+
+template<class InputIterator, class T>
+    T
+    reduce(InputIterator first, InputIterator last, T init);  // C++17
+
+template<class InputIterator, class T, class BinaryOperation>
+    T
+    reduce(InputIterator first, InputIterator last, T init, BinaryOperation binary_op);  // C++17
+
 template <class InputIterator1, class InputIterator2, class T>
     T
     inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init);
@@ -34,6 +46,23 @@ template <class InputIterator1, class InputIterator2, class T, class BinaryOpera
     inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
                   T init, BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);
 
+
+template<class InputIterator1, class InputIterator2, class T>
+    T
+    transform_reduce(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, T init);  // C++17
+                     
+template<class InputIterator1, class InputIterator2, class T, class BinaryOperation1, class BinaryOperation2>
+    T
+    transform_reduce(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, T init,
+                     BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);  // C++17
+
+template<class InputIterator, class T, class BinaryOperation, class UnaryOperation>
+    T
+    transform_reduce(InputIterator first, InputIterator last, T init,
+                     BinaryOperation binary_op, UnaryOperation unary_op);  // C++17
+
 template <class InputIterator, class OutputIterator>
     OutputIterator
     partial_sum(InputIterator first, InputIterator last, OutputIterator result);
@@ -114,6 +143,35 @@ accumulate(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOpe
     return __init;
 }
 
+#if _LIBCPP_STD_VER > 14
+template <class _InputIterator, class _Tp, class _BinaryOp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOp __b)
+{
+    for (; __first != __last; ++__first)
+        __init = __b(__init, *__first);
+    return __init;
+}
+
+template <class _InputIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init)
+{
+    return _VSTD::reduce(__first, __last, __init, _VSTD::plus<>());
+}
+
+template <class _InputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename iterator_traits<_InputIterator>::value_type
+reduce(_InputIterator __first, _InputIterator __last)
+{
+    return _VSTD::reduce(__first, __last, 
+       typename iterator_traits<_InputIterator>::value_type{});
+}
+#endif
+
 template <class _InputIterator1, class _InputIterator2, class _Tp>
 inline _LIBCPP_INLINE_VISIBILITY
 _Tp
@@ -135,6 +193,41 @@ inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2
     return __init;
 }
 
+#if _LIBCPP_STD_VER > 14
+template <class _InputIterator, class _Tp, class _BinaryOp, class _UnaryOp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+transform_reduce(_InputIterator __first, _InputIterator __last, 
+           _Tp __init,  _BinaryOp __b, _UnaryOp __u)
+{
+    for (; __first != __last; ++__first)
+        __init = __b(__init, __u(*__first));
+    return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, 
+          class _Tp, class _BinaryOp1, class _BinaryOp2>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _Tp __init,  _BinaryOp1 __b1, _BinaryOp2 __b2)
+{
+    for (; __first1 != __last1; ++__first1, (void) ++__first2)
+        __init = __b1(__init, __b2(*__first1, *__first2));
+    return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1, 
+                 _InputIterator2 __first2, _Tp __init)
+{
+    return _VSTD::transform_reduce(__first1, __last1, __first2, __init, 
+                                   _VSTD::plus<>(), _VSTD::multiplies<>());
+}
+#endif
+
 template <class _InputIterator, class _OutputIterator>
 inline _LIBCPP_INLINE_VISIBILITY
 _OutputIterator
diff --git a/include/support/newlib/xlocale.h b/include/support/newlib/xlocale.h
index 4e4b23be8d6b..4b7e9b7495a0 100644
--- a/include/support/newlib/xlocale.h
+++ b/include/support/newlib/xlocale.h
@@ -16,7 +16,10 @@
 #include <clocale>
 #include <cwctype>
 #include <ctype.h>
+#if !defined(__NEWLIB__) || __NEWLIB__ < 2 || \
+    __NEWLIB__ == 2 && __NEWLIB_MINOR__ < 5
 #include <support/xlocale/__nop_locale_mgmt.h>
+#endif
 #include <support/xlocale/__posix_l_fallback.h>
 #include <support/xlocale/__strtonum_fallback.h>
 
diff --git a/include/utility b/include/utility
index be73207133b5..00e3cd208ecb 100644
--- a/include/utility
+++ b/include/utility
@@ -653,6 +653,12 @@ template <class _T1, class _T2>
   class _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
     : public integral_constant<size_t, 2> {};
 
+template <size_t _Ip, class _T1, class _T2>
+class _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, pair<_T1, _T2> >
+{
+    static_assert(_Ip < 2, "Index out of bounds in std::tuple_element<std::pair<T1, T2>>");
+};
+
 template <class _T1, class _T2>
 class _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
 {
@@ -924,6 +930,12 @@ template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_t
 template <class _Tp>
 using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
 
+template <class _Tp> struct __is_inplace_index_imp : false_type {};
+template <size_t _Idx> struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
+
+template <class _Tp>
+using __is_inplace_index = __is_inplace_index_imp<__uncvref_t<_Tp>>;
+
 #endif // _LIBCPP_STD_VER > 14
 
 template <class _Arg, class _Result>
diff --git a/include/variant b/include/variant
index 8505f3262a18..8711ef6eb387 100644
--- a/include/variant
+++ b/include/variant
@@ -278,7 +278,7 @@ struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp>
 
 template <size_t _Ip, class... _Types>
 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> {
-  static_assert(_Ip < sizeof...(_Types));
+  static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>");
   using type = __type_pack_element<_Ip, _Types...>;
 };
 
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index fe45f5ac0fe5..f04ef82a83d6 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -1,6 +1,7 @@
 set(LIBCXX_LIB_CMAKEFILES_DIR "${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}"  PARENT_SCOPE)
 
 # Get sources
+# FIXME: Don't use glob here
 file(GLOB LIBCXX_SOURCES ../src/*.cpp)
 if(WIN32)
   file(GLOB LIBCXX_WIN32_SOURCES ../src/support/win32/*.cpp)
diff --git a/src/experimental/filesystem/operations.cpp b/src/experimental/filesystem/operations.cpp
index 2856ae453a6b..e9bc0eb6e30e 100644
--- a/src/experimental/filesystem/operations.cpp
+++ b/src/experimental/filesystem/operations.cpp
@@ -842,7 +842,7 @@ void __rename(const path& from, const path& to, std::error_code *ec) {
 }
 
 void __resize_file(const path& p, std::uintmax_t size, std::error_code *ec) {
-    if (::truncate(p.c_str(), static_cast<long>(size)) == -1)
+    if (::truncate(p.c_str(), static_cast<::off_t>(size)) == -1)
         set_or_throw(ec, "resize_file", p);
     else if (ec)
         ec->clear();
diff --git a/src/locale.cpp b/src/locale.cpp
index 3d61fbede58a..3b4c83a09007 100644
--- a/src/locale.cpp
+++ b/src/locale.cpp
@@ -6158,6 +6158,4 @@ template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<wchar_t,
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char16_t, char, mbstate_t>;
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char32_t, char, mbstate_t>;
 
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __vector_base_common<true>;
-
 _LIBCPP_END_NAMESPACE_STD
diff --git a/src/vector.cpp b/src/vector.cpp
new file mode 100644
index 000000000000..300adaed5f47
--- /dev/null
+++ b/src/vector.cpp
@@ -0,0 +1,16 @@
+//===------------------------- vector.cpp ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "vector"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __vector_base_common<true>;
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/test/libcxx/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.cxx1z.pass.cpp b/test/libcxx/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.cxx1z.pass.cpp
index ef3ef7519d69..28a9281b49c2 100644
--- a/test/libcxx/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.cxx1z.pass.cpp
+++ b/test/libcxx/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle.cxx1z.pass.cpp
@@ -23,6 +23,7 @@
 //  However, for backwards compatibility, if _LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE
 //  is defined before including <algorithm>, then random_shuffle will be restored.
 
+// MODULES_DEFINES: _LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE
 #define _LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE
 
 #include <algorithm>
diff --git a/test/libcxx/depr/depr.function.objects/depr.adaptors.cxx1z.pass.cpp b/test/libcxx/depr/depr.function.objects/depr.adaptors.cxx1z.pass.cpp
index 9b846939313b..f06dbb927acb 100644
--- a/test/libcxx/depr/depr.function.objects/depr.adaptors.cxx1z.pass.cpp
+++ b/test/libcxx/depr/depr.function.objects/depr.adaptors.cxx1z.pass.cpp
@@ -14,6 +14,7 @@
 //  However, for backwards compatibility, if _LIBCPP_ENABLE_CXX17_REMOVED_BINDERS
 //  is defined before including <functional>, then they will be restored.
 
+// MODULES_DEFINES: _LIBCPP_ENABLE_CXX17_REMOVED_BINDERS
 #define _LIBCPP_ENABLE_CXX17_REMOVED_BINDERS
 
 #include <functional>
diff --git a/test/libcxx/include_as_c.sh.cpp b/test/libcxx/include_as_c.sh.cpp
new file mode 100644
index 000000000000..db50d835ec1f
--- /dev/null
+++ b/test/libcxx/include_as_c.sh.cpp
@@ -0,0 +1,37 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// Test that the C wrapper headers can be included when compiling them as C.
+
+// NOTE: It's not common or recommended to have libc++ in the header search
+// path when compiling C files, but it does happen often enough.
+
+// RUN: %cxx -c -xc %s -fsyntax-only %flags %compile_flags -std=c99
+
+#include <complex.h>
+#include <ctype.h>
+#include <errno.h>
+#include <float.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <setjmp.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <tgmath.h>
+#include <wchar.h>
+#include <wctype.h>
+
+int main() {}
diff --git a/test/libcxx/utilities/utility/__is_inplace_index.pass.cpp b/test/libcxx/utilities/utility/__is_inplace_index.pass.cpp
new file mode 100644
index 000000000000..073cfac075f3
--- /dev/null
+++ b/test/libcxx/utilities/utility/__is_inplace_index.pass.cpp
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template <class _Tp> using __is_inplace_index
+
+#include <utility>
+
+struct S {};
+
+int main() {
+  using I = std::in_place_index_t<0>;
+  static_assert( std::__is_inplace_index<I>::value, "");
+  static_assert( std::__is_inplace_index<const I>::value, "");
+  static_assert( std::__is_inplace_index<const volatile I>::value, "");
+  static_assert( std::__is_inplace_index<I&>::value, "");
+  static_assert( std::__is_inplace_index<const I&>::value, "");
+  static_assert( std::__is_inplace_index<const volatile I&>::value, "");
+  static_assert( std::__is_inplace_index<I&&>::value, "");
+  static_assert( std::__is_inplace_index<const I&&>::value, "");
+  static_assert( std::__is_inplace_index<const volatile I&&>::value, "");
+  static_assert(!std::__is_inplace_index<std::in_place_type_t<int>>::value, "");
+  static_assert(!std::__is_inplace_index<std::in_place_t>::value, "");
+  static_assert(!std::__is_inplace_index<void>::value, "");
+  static_assert(!std::__is_inplace_index<int>::value, "");
+  static_assert(!std::__is_inplace_index<S>::value, "");
+}
diff --git a/test/libcxx/utilities/utility/__is_inplace_type.pass.cpp b/test/libcxx/utilities/utility/__is_inplace_type.pass.cpp
new file mode 100644
index 000000000000..54e22a0939da
--- /dev/null
+++ b/test/libcxx/utilities/utility/__is_inplace_type.pass.cpp
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template <class _Tp> using __is_inplace_type
+
+#include <utility>
+
+struct S {};
+
+int main() {
+  using T = std::in_place_type_t<int>;
+  static_assert( std::__is_inplace_type<T>::value, "");
+  static_assert( std::__is_inplace_type<const T>::value, "");
+  static_assert( std::__is_inplace_type<const volatile T>::value, "");
+  static_assert( std::__is_inplace_type<T&>::value, "");
+  static_assert( std::__is_inplace_type<const T&>::value, "");
+  static_assert( std::__is_inplace_type<const volatile T&>::value, "");
+  static_assert( std::__is_inplace_type<T&&>::value, "");
+  static_assert( std::__is_inplace_type<const T&&>::value, "");
+  static_assert( std::__is_inplace_type<const volatile T&&>::value, "");
+  static_assert(!std::__is_inplace_type<std::in_place_index_t<0>>::value, "");
+  static_assert(!std::__is_inplace_type<std::in_place_t>::value, "");
+  static_assert(!std::__is_inplace_type<void>::value, "");
+  static_assert(!std::__is_inplace_type<int>::value, "");
+  static_assert(!std::__is_inplace_type<S>::value, "");
+}
diff --git a/test/libcxx/utilities/utility/pairs/pairs.pair/pair.tuple_element.fail.cpp b/test/libcxx/utilities/utility/pairs/pairs.pair/pair.tuple_element.fail.cpp
new file mode 100644
index 000000000000..2a92240a63d2
--- /dev/null
+++ b/test/libcxx/utilities/utility/pairs/pairs.pair/pair.tuple_element.fail.cpp
@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <utility>
+
+// template <class T1, class T2> struct pair
+
+// tuple_element<I, pair<T1, T2> >::type
+
+#include <utility>
+
+int main()
+{
+    {
+    typedef std::pair<int, double> P;
+    std::tuple_element<2, P>::type foo; // expected-note {{requested here}}
+        // expected-error@utility:* {{static_assert failed "Index out of bounds in std::tuple_element<std::pair<T1, T2>>"}}
+    }
+}
diff --git a/test/libcxx/utilities/variant/variant.variant/variant.helper/variant_alternative.fail.cpp b/test/libcxx/utilities/variant/variant.variant/variant.helper/variant_alternative.fail.cpp
new file mode 100644
index 000000000000..f39a445b98af
--- /dev/null
+++ b/test/libcxx/utilities/variant/variant.variant/variant.helper/variant_alternative.fail.cpp
@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <variant>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+
+// template <size_t I, class T> struct variant_alternative; // undefined
+// template <size_t I, class T> struct variant_alternative<I, const T>;
+// template <size_t I, class T> struct variant_alternative<I, volatile T>;
+// template <size_t I, class T> struct variant_alternative<I, const volatile T>;
+// template <size_t I, class T>
+//   using variant_alternative_t = typename variant_alternative<I, T>::type;
+//
+// template <size_t I, class... Types>
+//    struct variant_alternative<I, variant<Types...>>;
+
+
+#include <variant>
+#include <cassert>
+
+
+int main()
+{
+    {
+        typedef std::variant<int, double> T;
+        std::variant_alternative<2, T>::type foo; // expected-note {{requested here}}
+        // expected-error@variant:* {{static_assert failed "Index out of bounds in std::variant_alternative<>"}}
+    }
+}
diff --git a/test/std/containers/associative/map/map.ops/count0.pass.cpp b/test/std/containers/associative/map/map.ops/count0.pass.cpp
index 0278343006a8..1fa8c4a70bd9 100644
--- a/test/std/containers/associative/map/map.ops/count0.pass.cpp
+++ b/test/std/containers/associative/map/map.ops/count0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::map<int, double, transparent_less> M;
-
     M().count(C2Int{5});
+    }
+    {
+    typedef std::map<int, double, transparent_less_not_referenceable> M;
+    M().count(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/map/map.ops/equal_range0.pass.cpp b/test/std/containers/associative/map/map.ops/equal_range0.pass.cpp
index 3b98426868e4..c254fb6a7db7 100644
--- a/test/std/containers/associative/map/map.ops/equal_range0.pass.cpp
+++ b/test/std/containers/associative/map/map.ops/equal_range0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::map<int, double, transparent_less> M;
-
     M().equal_range(C2Int{5});
+    }
+    {
+    typedef std::map<int, double, transparent_less_not_referenceable> M;
+    M().equal_range(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/map/map.ops/find0.pass.cpp b/test/std/containers/associative/map/map.ops/find0.pass.cpp
index d7de579d8b44..76fe9242a476 100644
--- a/test/std/containers/associative/map/map.ops/find0.pass.cpp
+++ b/test/std/containers/associative/map/map.ops/find0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::map<int, double, transparent_less> M;
-
     M().find(C2Int{5});
+    }
+    {
+    typedef std::map<int, double, transparent_less_not_referenceable> M;
+    M().find(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/map/map.ops/lower_bound0.pass.cpp b/test/std/containers/associative/map/map.ops/lower_bound0.pass.cpp
index ea121df73002..de7a545b6497 100644
--- a/test/std/containers/associative/map/map.ops/lower_bound0.pass.cpp
+++ b/test/std/containers/associative/map/map.ops/lower_bound0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::map<int, double, transparent_less> M;
-
     M().lower_bound(C2Int{5});
+    }
+    {
+    typedef std::map<int, double, transparent_less_not_referenceable> M;
+    M().lower_bound(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/map/map.ops/upper_bound0.pass.cpp b/test/std/containers/associative/map/map.ops/upper_bound0.pass.cpp
index 2e597b85cf0c..94508d284fd2 100644
--- a/test/std/containers/associative/map/map.ops/upper_bound0.pass.cpp
+++ b/test/std/containers/associative/map/map.ops/upper_bound0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::map<int, double, transparent_less> M;
-
     M().upper_bound(C2Int{5});
+    }
+    {
+    typedef std::map<int, double, transparent_less_not_referenceable> M;
+    M().upper_bound(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/multimap/multimap.ops/count0.pass.cpp b/test/std/containers/associative/multimap/multimap.ops/count0.pass.cpp
index b993f4f89087..289d405739ac 100644
--- a/test/std/containers/associative/multimap/multimap.ops/count0.pass.cpp
+++ b/test/std/containers/associative/multimap/multimap.ops/count0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::multimap<int, double, transparent_less> M;
-
     M().count(C2Int{5});
+    }
+    {
+    typedef std::multimap<int, double, transparent_less_not_referenceable> M;
+    M().count(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/multimap/multimap.ops/equal_range0.pass.cpp b/test/std/containers/associative/multimap/multimap.ops/equal_range0.pass.cpp
index a3a51e6ccbf9..8cdd3c03372f 100644
--- a/test/std/containers/associative/multimap/multimap.ops/equal_range0.pass.cpp
+++ b/test/std/containers/associative/multimap/multimap.ops/equal_range0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::multimap<int, double, transparent_less> M;
-
     M().equal_range(C2Int{5});
+    }
+    {
+    typedef std::multimap<int, double, transparent_less_not_referenceable> M;
+    M().equal_range(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/multimap/multimap.ops/find0.pass.cpp b/test/std/containers/associative/multimap/multimap.ops/find0.pass.cpp
index 03a6e1883051..a06ec4d702d5 100644
--- a/test/std/containers/associative/multimap/multimap.ops/find0.pass.cpp
+++ b/test/std/containers/associative/multimap/multimap.ops/find0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::multimap<int, double, transparent_less> M;
-
     M().find(C2Int{5});
+    }
+    {
+    typedef std::multimap<int, double, transparent_less_not_referenceable> M;
+    M().find(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/multimap/multimap.ops/lower_bound0.pass.cpp b/test/std/containers/associative/multimap/multimap.ops/lower_bound0.pass.cpp
index 77927bb5abed..1000aa772b31 100644
--- a/test/std/containers/associative/multimap/multimap.ops/lower_bound0.pass.cpp
+++ b/test/std/containers/associative/multimap/multimap.ops/lower_bound0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::multimap<int, double, transparent_less> M;
-
     M().lower_bound(C2Int{5});
+    }
+    {
+    typedef std::multimap<int, double, transparent_less_not_referenceable> M;
+    M().lower_bound(C2Int{5});
+    }
 }
diff --git a/test/std/containers/associative/multimap/multimap.ops/upper_bound0.pass.cpp b/test/std/containers/associative/multimap/multimap.ops/upper_bound0.pass.cpp
index 3f6852d085c3..1a572e9c5070 100644
--- a/test/std/containers/associative/multimap/multimap.ops/upper_bound0.pass.cpp
+++ b/test/std/containers/associative/multimap/multimap.ops/upper_bound0.pass.cpp
@@ -28,7 +28,12 @@
 
 int main()
 {
+    {
     typedef std::multimap<int, double, transparent_less> M;
-
     M().upper_bound(C2Int{5});
+    }
+    {
+    typedef std::multimap<int, double, transparent_less_not_referenceable> M;
+    M().upper_bound(C2Int{5});
+    }
 }
diff --git a/test/std/containers/sequences/array/array.tuple/tuple_element.fail.cpp b/test/std/containers/sequences/array/array.tuple/tuple_element.fail.cpp
new file mode 100644
index 000000000000..c9fe695f9cbd
--- /dev/null
+++ b/test/std/containers/sequences/array/array.tuple/tuple_element.fail.cpp
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+
+// tuple_element<I, array<T, N> >::type
+
+// Prevent -Warray-bounds from issuing a diagnostic when testing with clang verify.
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Warray-bounds"
+#endif
+
+#include <array>
+#include <cassert>
+
+
+// std::array is explicitly allowed to be initialized with A a = { init-list };.
+// Disable the missing braces warning for this reason.
+#include "disable_missing_braces_warning.h"
+
+int main()
+{
+    {
+        typedef double T;
+        typedef std::array<T, 3> C;
+        std::tuple_element<3, C> foo; // expected-note {{requested here}}
+        // expected-error@array:* {{static_assert failed "Index out of bounds in std::tuple_element<> (std::array)"}}
+    }
+}
diff --git a/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp b/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
index 4a61047a830a..f996886c4ca7 100644
--- a/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
+++ b/test/std/experimental/language.support/support.coroutines/coroutine.handle/coroutine.handle.prom/promise.pass.cpp
@@ -28,6 +28,39 @@
 
 namespace coro = std::experimental;
 
+struct MyCoro {
+  struct promise_type {
+    void unhandled_exception() {}
+    void return_void() {}
+    coro::suspend_never initial_suspend() { return {}; }
+    coro::suspend_never final_suspend() { return {}; }
+    MyCoro get_return_object() {
+      do_runtime_test();
+      return {};
+    }
+    void do_runtime_test() {
+      // Test that a coroutine_handle<const T> can be created from a const
+      // promise_type and that it represents the same coroutine as
+      // coroutine_handle<T>
+      using CH = coro::coroutine_handle<promise_type>;
+      using CCH = coro::coroutine_handle<const promise_type>;
+      const auto &cthis = *this;
+      CH h = CH::from_promise(*this);
+      CCH h2 = CCH::from_promise(*this);
+      CCH h3 = CCH::from_promise(cthis);
+      assert(&h.promise() == this);
+      assert(&h2.promise() == this);
+      assert(&h3.promise() == this);
+      assert(h.address() == h2.address());
+      assert(h2.address() == h3.address());
+    }
+  };
+};
+
+MyCoro do_runtime_test() {
+  co_await coro::suspend_never{};
+}
+
 template <class Promise>
 void do_test(coro::coroutine_handle<Promise>&& H) {
 
@@ -46,4 +79,6 @@ void do_test(coro::coroutine_handle<Promise>&& H) {
 int main()
 {
   do_test(coro::coroutine_handle<int>{});
+  do_test(coro::coroutine_handle<const int>{});
+  do_runtime_test();
 }
diff --git a/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_iter_iter_iter.pass.cpp b/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan.pass.cpp
index 6fdd288e2d6a..6fdd288e2d6a 100644
--- a/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_iter_iter_iter.pass.cpp
+++ b/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan.pass.cpp
diff --git a/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_iter_iter_iter_init_op.pass.cpp b/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_init_op.pass.cpp
index ba1673fe467f..ba1673fe467f 100644
--- a/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_iter_iter_iter_init_op.pass.cpp
+++ b/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_init_op.pass.cpp
diff --git a/test/std/numerics/numeric.ops/reduce/reduce.pass.cpp b/test/std/numerics/numeric.ops/reduce/reduce.pass.cpp
new file mode 100644
index 000000000000..aa055e70d4f8
--- /dev/null
+++ b/test/std/numerics/numeric.ops/reduce/reduce.pass.cpp
@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <numeric>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template<class InputIterator>
+//     typename iterator_traits<InputIterator>::value_type
+//     reduce(InputIterator first, InputIterator last);
+
+#include <numeric>
+#include <cassert>
+
+#include "test_iterators.h"
+
+template <class Iter, class T>
+void
+test(Iter first, Iter last, T x)
+{
+    static_assert( std::is_same_v<typename std::iterator_traits<decltype(first)>::value_type,
+                                decltype(std::reduce(first, last))> );
+    assert(std::reduce(first, last) == x);
+}
+
+template <class Iter>
+void
+test()
+{
+    int ia[] = {1, 2, 3, 4, 5, 6};
+    unsigned sa = sizeof(ia) / sizeof(ia[0]);
+    test(Iter(ia), Iter(ia), 0);
+    test(Iter(ia), Iter(ia+1), 1);
+    test(Iter(ia), Iter(ia+2), 3);
+    test(Iter(ia), Iter(ia+sa), 21);
+}
+
+template <typename T>
+void test_return_type()
+{
+    T *p = nullptr;
+    static_assert( std::is_same_v<T, decltype(std::reduce(p, p))> );
+}
+
+int main()
+{
+    test_return_type<char>();
+    test_return_type<int>();
+    test_return_type<unsigned long>();
+    test_return_type<float>();
+    test_return_type<double>();
+
+    test<input_iterator<const int*> >();
+    test<forward_iterator<const int*> >();
+    test<bidirectional_iterator<const int*> >();
+    test<random_access_iterator<const int*> >();
+    test<const int*>();
+}
diff --git a/test/std/numerics/numeric.ops/reduce/reduce_init.pass.cpp b/test/std/numerics/numeric.ops/reduce/reduce_init.pass.cpp
new file mode 100644
index 000000000000..480ead11c734
--- /dev/null
+++ b/test/std/numerics/numeric.ops/reduce/reduce_init.pass.cpp
@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <numeric>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template<class InputIterator, class T>
+//   T reduce(InputIterator first, InputIterator last, T init);
+
+#include <numeric>
+#include <cassert>
+
+#include "test_iterators.h"
+
+template <class Iter, class T>
+void
+test(Iter first, Iter last, T init, T x)
+{
+    static_assert( std::is_same_v<T, decltype(std::reduce(first, last, init))> );
+    assert(std::reduce(first, last, init) == x);
+}
+
+template <class Iter>
+void
+test()
+{
+    int ia[] = {1, 2, 3, 4, 5, 6};
+    unsigned sa = sizeof(ia) / sizeof(ia[0]);
+    test(Iter(ia), Iter(ia), 0, 0);
+    test(Iter(ia), Iter(ia), 1, 1);
+    test(Iter(ia), Iter(ia+1), 0, 1);
+    test(Iter(ia), Iter(ia+1), 2, 3);
+    test(Iter(ia), Iter(ia+2), 0, 3);
+    test(Iter(ia), Iter(ia+2), 3, 6);
+    test(Iter(ia), Iter(ia+sa), 0, 21);
+    test(Iter(ia), Iter(ia+sa), 4, 25);
+}
+
+template <typename T, typename Init>
+void test_return_type()
+{
+    T *p = nullptr;
+    static_assert( std::is_same_v<Init, decltype(std::reduce(p, p, Init{}))> );
+}
+
+int main()
+{
+    test_return_type<char, int>();
+    test_return_type<int, int>();
+    test_return_type<int, unsigned long>();
+    test_return_type<float, int>();
+    test_return_type<short, float>();
+    test_return_type<double, char>();
+    test_return_type<char, double>();
+
+    test<input_iterator<const int*> >();
+    test<forward_iterator<const int*> >();
+    test<bidirectional_iterator<const int*> >();
+    test<random_access_iterator<const int*> >();
+    test<const int*>();
+}
diff --git a/test/std/numerics/numeric.ops/reduce/reduce_init_op.pass.cpp b/test/std/numerics/numeric.ops/reduce/reduce_init_op.pass.cpp
new file mode 100644
index 000000000000..5238a1f2ed5b
--- /dev/null
+++ b/test/std/numerics/numeric.ops/reduce/reduce_init_op.pass.cpp
@@ -0,0 +1,74 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <numeric>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template<class InputIterator, class T, class BinaryOperation>
+//   T reduce(InputIterator first, InputIterator last, T init, BinaryOperation op);
+  
+#include <numeric>
+#include <cassert>
+
+#include "test_iterators.h"
+
+template <class Iter, class T, class Op>
+void
+test(Iter first, Iter last, T init, Op op, T x)
+{
+    static_assert( std::is_same_v<T, decltype(std::reduce(first, last, init, op))>, "" );
+    assert(std::reduce(first, last, init, op) == x);
+}
+
+template <class Iter>
+void
+test()
+{
+    int ia[] = {1, 2, 3, 4, 5, 6};
+    unsigned sa = sizeof(ia) / sizeof(ia[0]);
+    test(Iter(ia), Iter(ia), 0, std::plus<>(), 0);
+    test(Iter(ia), Iter(ia), 1, std::multiplies<>(), 1);
+    test(Iter(ia), Iter(ia+1), 0, std::plus<>(), 1);
+    test(Iter(ia), Iter(ia+1), 2, std::multiplies<>(), 2);
+    test(Iter(ia), Iter(ia+2), 0, std::plus<>(), 3);
+    test(Iter(ia), Iter(ia+2), 3, std::multiplies<>(), 6);
+    test(Iter(ia), Iter(ia+sa), 0, std::plus<>(), 21);
+    test(Iter(ia), Iter(ia+sa), 4, std::multiplies<>(), 2880);
+}
+
+template <typename T, typename Init>
+void test_return_type()
+{
+    T *p = nullptr;
+    static_assert( std::is_same_v<Init, decltype(std::reduce(p, p, Init{}, std::plus<>()))>, "" );
+}
+
+int main()
+{
+    test_return_type<char, int>();
+    test_return_type<int, int>();
+    test_return_type<int, unsigned long>();
+    test_return_type<float, int>();
+    test_return_type<short, float>();
+    test_return_type<double, char>();
+    test_return_type<char, double>();
+
+    test<input_iterator<const int*> >();
+    test<forward_iterator<const int*> >();
+    test<bidirectional_iterator<const int*> >();
+    test<random_access_iterator<const int*> >();
+    test<const int*>();
+
+//	Make sure the math is done using the correct type
+    {
+    auto v = {1, 2, 3, 4, 5, 6, 7, 8};
+    unsigned res = std::reduce(v.begin(), v.end(), 1U, std::multiplies<>());
+    assert(res == 40320);		// 8! will not fit into a char
+    }
+}
diff --git a/test/std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_iter_iter_iter_init_bop_uop.pass.cpp b/test/std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_init_bop_uop.pass.cpp
index 3bfb336a03f9..2370e9ea9137 100644
--- a/test/std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_iter_iter_iter_init_bop_uop.pass.cpp
+++ b/test/std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_init_bop_uop.pass.cpp
@@ -122,6 +122,12 @@ void basic_tests()
         assert(v[i] == 40 + triangle(i));
     }
 
+    {
+    std::vector<int> v, res;
+    std::transform_exclusive_scan(v.begin(), v.end(), std::back_inserter(res), 40, std::plus<>(), identity<>());
+    assert(res.empty());
+    }
+
 //  Make sure that the calculations are done using the init typedef
     {
     std::vector<unsigned char> v(10);
diff --git a/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_init_bop_uop.pass.cpp b/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_init_bop_uop.pass.cpp
new file mode 100644
index 000000000000..c283f3e29722
--- /dev/null
+++ b/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_init_bop_uop.pass.cpp
@@ -0,0 +1,124 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <numeric>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template <class InputIterator1, class T,
+//           class BinaryOperation, class UnaryOperation>
+//    T transform_reduce(InputIterator1 first1, InputIterator1 last1,
+//                       T init, BinaryOperation binary_op, UnaryOperation unary_op);
+//                      
+  
+#include <numeric>
+#include <cassert>
+
+#include "test_iterators.h"
+
+template <class _Tp = void>
+struct identity : std::unary_function<_Tp, _Tp>
+{
+    constexpr const _Tp& operator()(const _Tp& __x) const { return __x;}
+};
+
+template <>
+struct identity<void>
+{
+    template <class _Tp>
+    constexpr auto operator()(_Tp&& __x) const
+    _NOEXCEPT_(noexcept(_VSTD::forward<_Tp>(__x)))
+    -> decltype        (_VSTD::forward<_Tp>(__x))
+        { return        _VSTD::forward<_Tp>(__x); }
+};
+
+
+template <class _Tp = void>
+struct twice
+{
+  	constexpr const _Tp operator()(const _Tp& __x) const noexcept { return 2 * __x; }
+};
+
+template <>
+struct twice<void>
+{
+    template <class _Tp>
+    constexpr auto operator()(const _Tp& __x) const
+    _NOEXCEPT_(noexcept(2 * __x))
+    -> decltype        (2 * __x)
+        { return        2 * __x; }
+};
+
+template <class Iter1, class T, class BOp, class UOp>
+void
+test(Iter1 first1, Iter1 last1, T init, BOp bOp, UOp uOp, T x)
+{
+    static_assert( std::is_same_v<T, 
+                    decltype(std::transform_reduce(first1, last1, init, bOp, uOp))> );
+    assert(std::transform_reduce(first1, last1, init, bOp, uOp) == x);
+}
+
+template <class Iter>
+void
+test()
+{
+    int ia[]          = {1, 2, 3, 4, 5, 6};
+    unsigned sa = sizeof(ia) / sizeof(ia[0]);
+
+    test(Iter(ia), Iter(ia),    0, std::plus<>(),       identity<>(),       0);
+    test(Iter(ia), Iter(ia),    1, std::multiplies<>(), identity<>(),       1);
+    test(Iter(ia), Iter(ia+1),  0, std::multiplies<>(), identity<>(),       0);
+    test(Iter(ia), Iter(ia+1),  2, std::plus<>(),       identity<>(),       3);
+    test(Iter(ia), Iter(ia+2),  0, std::plus<>(),       identity<>(),       3);
+    test(Iter(ia), Iter(ia+2),  3, std::multiplies<>(), identity<>(),       6);
+    test(Iter(ia), Iter(ia+sa), 4, std::multiplies<>(), identity<>(),    2880);
+    test(Iter(ia), Iter(ia+sa), 4, std::plus<>(),       identity<>(),      25);
+
+    test(Iter(ia), Iter(ia),    0, std::plus<>(),       twice<>(),       0);
+    test(Iter(ia), Iter(ia),    1, std::multiplies<>(), twice<>(),       1);
+    test(Iter(ia), Iter(ia+1),  0, std::multiplies<>(), twice<>(),       0);
+    test(Iter(ia), Iter(ia+1),  2, std::plus<>(),       twice<>(),       4);
+    test(Iter(ia), Iter(ia+2),  0, std::plus<>(),       twice<>(),       6);
+    test(Iter(ia), Iter(ia+2),  3, std::multiplies<>(), twice<>(),      24);
+    test(Iter(ia), Iter(ia+sa), 4, std::multiplies<>(), twice<>(),  184320); // 64 * 2880
+    test(Iter(ia), Iter(ia+sa), 4, std::plus<>(),       twice<>(),      46);
+}
+
+template <typename T, typename Init>
+void test_return_type()
+{
+    T *p = nullptr;
+    static_assert( std::is_same_v<Init, 
+         decltype(std::transform_reduce(p, p, Init{}, std::plus<>(), identity<>()))> );
+}
+
+int main()
+{
+    test_return_type<char, int>();
+    test_return_type<int, int>();
+    test_return_type<int, unsigned long>();
+    test_return_type<float, int>();
+    test_return_type<short, float>();
+    test_return_type<double, char>();
+    test_return_type<char, double>();
+
+//  All the iterator categories
+    test<input_iterator        <const int*> >();
+    test<forward_iterator      <const int*> >();
+    test<bidirectional_iterator<const int*> >();
+    test<random_access_iterator<const int*> >();
+    test<const int*>();
+    test<      int*>();
+
+//	Make sure the math is done using the correct type
+    {
+    auto v = {1, 2, 3, 4, 5, 6};
+    unsigned res = std::transform_reduce(v.begin(), v.end(), 1U, std::multiplies<>(), twice<>());
+    assert(res == 46080);		// 6! * 64 will not fit into a char
+    }
+}
diff --git a/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init.pass.cpp b/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init.pass.cpp
new file mode 100644
index 000000000000..f36b7d49410b
--- /dev/null
+++ b/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init.pass.cpp
@@ -0,0 +1,95 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <numeric>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template <class InputIterator1, class InputIterator2, class T>
+//   T transform_reduce(InputIterator1 first1, InputIterator1 last1,
+//                      InputIterator2 first2, T init);
+
+
+#include <numeric>
+#include <cassert>
+
+#include "test_iterators.h"
+
+template <class Iter1, class Iter2, class T>
+void
+test(Iter1 first1, Iter1 last1, Iter2 first2, T init, T x)
+{
+    static_assert( std::is_same_v<T, 
+            decltype(std::transform_reduce(first1, last1, first2, init))> );
+    assert(std::transform_reduce(first1, last1, first2, init) == x);
+}
+
+template <class SIter, class UIter>
+void
+test()
+{
+    int ia[]          = {1, 2, 3, 4, 5, 6};
+    unsigned int ua[] = {2, 4, 6, 8, 10,12};
+    unsigned sa = sizeof(ia) / sizeof(ia[0]);
+    assert(sa == sizeof(ua) / sizeof(ua[0]));       // just to be sure
+
+    test(SIter(ia), SIter(ia),    UIter(ua), 0,   0);
+    test(UIter(ua), UIter(ua),    SIter(ia), 1,   1);
+    test(SIter(ia), SIter(ia+1),  UIter(ua), 0,   2);
+    test(UIter(ua), UIter(ua+1),  SIter(ia), 2,   4);
+    test(SIter(ia), SIter(ia+2),  UIter(ua), 0,  10);
+    test(UIter(ua), UIter(ua+2),  SIter(ia), 3,  13);
+    test(SIter(ia), SIter(ia+sa), UIter(ua), 0, 182);
+    test(UIter(ua), UIter(ua+sa), SIter(ia), 4, 186);
+}
+
+template <typename T, typename Init>
+void test_return_type()
+{
+    T *p = nullptr;
+    static_assert( std::is_same_v<Init, 
+                       decltype(std::transform_reduce(p, p, p, Init{}))> );
+}
+
+int main()
+{
+    test_return_type<char, int>();
+    test_return_type<int, int>();
+    test_return_type<int, unsigned long>();
+    test_return_type<float, int>();
+    test_return_type<short, float>();
+    test_return_type<double, char>();
+    test_return_type<char, double>();
+
+//  All the iterator categories
+    test<input_iterator        <const int*>, input_iterator        <const unsigned int*> >();
+    test<input_iterator        <const int*>, forward_iterator      <const unsigned int*> >();
+    test<input_iterator        <const int*>, bidirectional_iterator<const unsigned int*> >();
+    test<input_iterator        <const int*>, random_access_iterator<const unsigned int*> >();
+
+    test<forward_iterator      <const int*>, input_iterator        <const unsigned int*> >();
+    test<forward_iterator      <const int*>, forward_iterator      <const unsigned int*> >();
+    test<forward_iterator      <const int*>, bidirectional_iterator<const unsigned int*> >();
+    test<forward_iterator      <const int*>, random_access_iterator<const unsigned int*> >();
+
+    test<bidirectional_iterator<const int*>, input_iterator        <const unsigned int*> >();
+    test<bidirectional_iterator<const int*>, forward_iterator      <const unsigned int*> >();
+    test<bidirectional_iterator<const int*>, bidirectional_iterator<const unsigned int*> >();
+    test<bidirectional_iterator<const int*>, random_access_iterator<const unsigned int*> >();
+
+    test<random_access_iterator<const int*>, input_iterator        <const unsigned int*> >();
+    test<random_access_iterator<const int*>, forward_iterator      <const unsigned int*> >();
+    test<random_access_iterator<const int*>, bidirectional_iterator<const unsigned int*> >();
+    test<random_access_iterator<const int*>, random_access_iterator<const unsigned int*> >();
+
+//  just plain pointers (const vs. non-const, too)
+    test<const int*, const unsigned int *>();
+    test<const int*,       unsigned int *>();
+    test<      int*, const unsigned int *>();
+    test<      int*,       unsigned int *>();
+}
diff --git a/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init_op_op.pass.cpp b/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init_op_op.pass.cpp
new file mode 100644
index 000000000000..b1b53293b991
--- /dev/null
+++ b/test/std/numerics/numeric.ops/transform.reduce/transform_reduce_iter_iter_iter_init_op_op.pass.cpp
@@ -0,0 +1,97 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <numeric>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template <class InputIterator1, class InputIterator2, class T,
+//           class BinaryOperation1, class BinaryOperation2>
+//    T transform_reduce(InputIterator1 first1, InputIterator1 last1,
+//                       InputIterator2 first2, T init,
+//                       BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);
+//                      
+  
+#include <numeric>
+#include <cassert>
+
+#include "test_iterators.h"
+
+template <class Iter1, class Iter2, class T, class Op1, class Op2>
+void
+test(Iter1 first1, Iter1 last1, Iter2 first2, T init, Op1 op1, Op2 op2, T x)
+{
+    static_assert( std::is_same_v<T, 
+         decltype(std::transform_reduce(first1, last1, first2, init, op1, op2))> );
+    assert(std::transform_reduce(first1, last1, first2, init, op1, op2) == x);
+}
+
+template <class SIter, class UIter>
+void
+test()
+{
+    int ia[]          = {1, 2, 3, 4, 5, 6};
+    unsigned int ua[] = {2, 4, 6, 8, 10,12};
+    unsigned sa = sizeof(ia) / sizeof(ia[0]);
+    assert(sa == sizeof(ua) / sizeof(ua[0]));       // just to be sure
+
+    test(SIter(ia), SIter(ia),    UIter(ua), 0, std::plus<>(), std::multiplies<>(),       0);
+    test(UIter(ua), UIter(ua),    SIter(ia), 1, std::multiplies<>(), std::plus<>(),       1);
+    test(SIter(ia), SIter(ia+1),  UIter(ua), 0, std::multiplies<>(), std::plus<>(),       0);
+    test(UIter(ua), UIter(ua+1),  SIter(ia), 2, std::plus<>(), std::multiplies<>(),       4);
+    test(SIter(ia), SIter(ia+2),  UIter(ua), 0, std::plus<>(), std::multiplies<>(),      10);
+    test(UIter(ua), UIter(ua+2),  SIter(ia), 3, std::multiplies<>(), std::plus<>(),      54);
+    test(SIter(ia), SIter(ia+sa), UIter(ua), 4, std::multiplies<>(), std::plus<>(), 2099520);
+    test(UIter(ua), UIter(ua+sa), SIter(ia), 4, std::plus<>(), std::multiplies<>(),     186);
+}
+
+template <typename T, typename Init>
+void test_return_type()
+{
+    T *p = nullptr;
+    static_assert( std::is_same_v<Init, 
+       decltype(std::transform_reduce(p, p, p, Init{}, std::plus<>(), std::multiplies<>()))> );
+}
+
+int main()
+{
+    test_return_type<char, int>();
+    test_return_type<int, int>();
+    test_return_type<int, unsigned long>();
+    test_return_type<float, int>();
+    test_return_type<short, float>();
+    test_return_type<double, char>();
+    test_return_type<char, double>();
+
+//  All the iterator categories
+    test<input_iterator        <const int*>, input_iterator        <const unsigned int*> >();
+    test<input_iterator        <const int*>, forward_iterator      <const unsigned int*> >();
+    test<input_iterator        <const int*>, bidirectional_iterator<const unsigned int*> >();
+    test<input_iterator        <const int*>, random_access_iterator<const unsigned int*> >();
+
+    test<forward_iterator      <const int*>, input_iterator        <const unsigned int*> >();
+    test<forward_iterator      <const int*>, forward_iterator      <const unsigned int*> >();
+    test<forward_iterator      <const int*>, bidirectional_iterator<const unsigned int*> >();
+    test<forward_iterator      <const int*>, random_access_iterator<const unsigned int*> >();
+
+    test<bidirectional_iterator<const int*>, input_iterator        <const unsigned int*> >();
+    test<bidirectional_iterator<const int*>, forward_iterator      <const unsigned int*> >();
+    test<bidirectional_iterator<const int*>, bidirectional_iterator<const unsigned int*> >();
+    test<bidirectional_iterator<const int*>, random_access_iterator<const unsigned int*> >();
+
+    test<random_access_iterator<const int*>, input_iterator        <const unsigned int*> >();
+    test<random_access_iterator<const int*>, forward_iterator      <const unsigned int*> >();
+    test<random_access_iterator<const int*>, bidirectional_iterator<const unsigned int*> >();
+    test<random_access_iterator<const int*>, random_access_iterator<const unsigned int*> >();
+
+//  just plain pointers (const vs. non-const, too)
+    test<const int*, const unsigned int *>();
+    test<const int*,       unsigned int *>();
+    test<      int*, const unsigned int *>();
+    test<      int*,       unsigned int *>();
+}
diff --git a/test/support/allocators.h b/test/support/allocators.h
index b1eea8d0b683..00e9a0c13ce7 100644
--- a/test/support/allocators.h
+++ b/test/support/allocators.h
@@ -104,7 +104,7 @@ public:
     T* allocate(std::size_t, const void* hint)
     {
         allocate_called = true;
-        return (T*)hint;
+        return (T*) const_cast<void *>(hint);
     }
 };
 
diff --git a/test/support/is_transparent.h b/test/support/is_transparent.h
index 541689314b8b..f7cdbbc14ccd 100644
--- a/test/support/is_transparent.h
+++ b/test/support/is_transparent.h
@@ -22,7 +22,17 @@ struct transparent_less
     noexcept(noexcept(std::forward<T>(t) < std::forward<U>(u)))
     -> decltype      (std::forward<T>(t) < std::forward<U>(u))
         { return      std::forward<T>(t) < std::forward<U>(u); }
-    typedef void is_transparent;  // correct
+    using is_transparent = void;  // correct
+};
+
+struct transparent_less_not_referenceable
+{
+    template <class T, class U>
+    constexpr auto operator()(T&& t, U&& u) const
+    noexcept(noexcept(std::forward<T>(t) < std::forward<U>(u)))
+    -> decltype      (std::forward<T>(t) < std::forward<U>(u))
+        { return      std::forward<T>(t) < std::forward<U>(u); }
+    using is_transparent = void () const &;  // it's a type; a weird one, but a type
 };
 
 struct transparent_less_no_type
@@ -33,7 +43,7 @@ struct transparent_less_no_type
     -> decltype      (std::forward<T>(t) < std::forward<U>(u))
         { return      std::forward<T>(t) < std::forward<U>(u); }
 private:
-//    typedef void is_transparent;  // error - should exist
+//    using is_transparent = void;  // error - should exist
 };
 
 struct transparent_less_private
@@ -44,7 +54,7 @@ struct transparent_less_private
     -> decltype      (std::forward<T>(t) < std::forward<U>(u))
         { return      std::forward<T>(t) < std::forward<U>(u); }
 private:
-    typedef void is_transparent;  // error - should be accessible
+    using is_transparent = void;  // error - should be accessible
 };
 
 struct transparent_less_not_a_type
diff --git a/utils/libcxx/test/config.py b/utils/libcxx/test/config.py
index 0fbc2cf4ea62..96b3df55ede7 100644
--- a/utils/libcxx/test/config.py
+++ b/utils/libcxx/test/config.py
@@ -108,6 +108,11 @@ class Configuration(object):
             return check_value(val, env_var)
         return check_value(conf_val, name)
 
+    def get_modules_enabled(self):
+        return self.get_lit_bool('enable_modules',
+                                default=False,
+                                env_var='LIBCXX_ENABLE_MODULES')
+
     def make_static_lib_name(self, name):
         """Return the full filename for the specified library name"""
         if self.is_windows:
@@ -631,9 +636,19 @@ class Configuration(object):
         # The __config_site header should be non-empty. Otherwise it should
         # have never been emitted by CMake.
         assert len(feature_macros) > 0
+        # FIXME: This is a hack that should be fixed using module maps (or something)
+        # If modules are enabled then we have to lift all of the definitions
+        # in __config_site onto the command line.
+        modules_enabled = self.get_modules_enabled()
+        self.cxx.compile_flags += ['-Wno-macro-redefined']
         # Transform each macro name into the feature name used in the tests.
         # Ex. _LIBCPP_HAS_NO_THREADS -> libcpp-has-no-threads
         for m in feature_macros:
+            if modules_enabled:
+                define = '-D%s' % m
+                if feature_macros[m]:
+                    define += '=%s' % (feature_macros[m])
+                self.cxx.compile_flags += [define]
             if m == '_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS':
                 continue
             if m == '_LIBCPP_ABI_VERSION':
@@ -976,9 +991,7 @@ class Configuration(object):
         if platform.system() != 'Darwin':
             modules_flags += ['-Xclang', '-fmodules-local-submodule-visibility']
         supports_modules = self.cxx.hasCompileFlag(modules_flags)
-        enable_modules = self.get_lit_bool('enable_modules',
-                                           default=False,
-                                           env_var='LIBCXX_ENABLE_MODULES')
+        enable_modules = self.get_modules_enabled()
         if enable_modules and not supports_modules:
             self.lit_config.fatal(
                 '-fmodules is enabled but not supported by the compiler')