Index: libcxx/include/experimental/simd
===================================================================
--- libcxx/include/experimental/simd
+++ libcxx/include/experimental/simd
@@ -18,14 +18,14 @@
 inline namespace parallelism_v2 {
 
 namespace simd_abi {
-
-struct scalar {};
-template <int N> struct fixed_size {};
-template <typename T> inline constexpr int max_fixed_size = implementation-defined;
-template <typename T> using compatible = implementation-defined;
-template <typename T> using native = implementation-defined;
-
-} // simd_abi
+  struct scalar {};
+  template <int N> struct fixed_size {};
+  template <typename T> inline constexpr int max_fixed_size = implementation-defined;
+  template <typename T> using compatible = implementation-defined;
+  template <typename T> using native = implementation-defined;
+  template <class T, size_t N> struct deduce { using type = see below ; };
+  template <class T, size_t N> using deduce_t = typename deduce<T, N>::type;
+}
 
 struct element_aligned_tag {};
 struct vector_aligned_tag {};
@@ -37,17 +37,20 @@
 // traits [simd.traits]
 template <class T> struct is_abi_tag;
 template <class T> inline constexpr bool is_abi_tag_v = is_abi_tag<T>::value;
+
 template <class T> struct is_simd;
 template <class T> inline constexpr bool is_simd_v = is_simd<T>::value;
+
 template <class T> struct is_simd_mask;
 template <class T> inline constexpr bool is_simd_mask_v = is_simd_mask<T>::value;
+
 template <class T> struct is_simd_flag_type;
 template <class T> inline constexpr bool is_simd_flag_type_v = is_simd_flag_type<T>::value;
-template <class T, size_t N> struct abi_for_size { using type = see below ; };
-template <class T, size_t N> using abi_for_size_t = typename abi_for_size<T, N>::type;
+
 template <class T, class Abi = simd_abi::compatible<T>> struct simd_size;
 template <class T, class Abi = simd_abi::compatible<T>>
 inline constexpr size_t simd_size_v = simd_size<T, Abi>::value;
+
 template <class T, class U = typename T::value_type> struct memory_alignment;
 template <class T, class U = typename T::value_type>
 inline constexpr size_t memory_alignment_v = memory_alignment<T, U>::value;
@@ -64,43 +67,32 @@
 
 // casts [simd.casts]
 template <class T, class U, class Abi> see below simd_cast(const simd<U, Abi>&);
-
 template <class T, class U, class Abi> see below static_simd_cast(const simd<U, Abi>&);
 
 template <class T, class Abi>
 fixed_size_simd<T, simd_size_v<T, Abi>> to_fixed_size(const simd<T, Abi>&) noexcept;
-
 template <class T, class Abi>
 fixed_size_simd_mask<T, simd_size_v<T, Abi>> to_fixed_size(const simd_mask<T, Abi>&) noexcept;
-
-template <class T, size_t N> native_simd<T> to_native(const fixed_size_simd<T, N>&) noexcept;
-
-template <class T, size_t N>
-native_simd_mask<T> to_native(const fixed_size_simd_mask<T, N>> &) noexcept;
-
-template <class T, size_t N> simd<T> to_compatible(const fixed_size_simd<T, N>&) noexcept;
-
-template <class T, size_t N> simd_mask<T> to_compatible(const fixed_size_simd_mask<T, N>&) noexcept;
+template <class T, int N> native_simd<T> to_native(const fixed_size_simd<T, N>&) noexcept;
+template <class T, int N> native_simd_mask<T> to_native(const fixed_size_simd_mask<T, N>&) noexcept;
+template <class T, int N> simd<T> to_compatible(const fixed_size_simd<T, N>&) noexcept;
+template <class T, int N> simd_mask<T> to_compatible(const fixed_size_simd_mask<T, N>&) noexcept;
 
 template <size_t... Sizes, class T, class Abi>
-tuple<simd<T, abi_for_size_t<Sizes>>...> split(const simd<T, Abi>&);
-
+tuple<simd<T, simd_abi::deduce_t<T, Sizes>>...> split(const simd<T, Abi>&);
 template <size_t... Sizes, class T, class Abi>
-tuple<simd_mask<T, abi_for_size_t<Sizes>>...> split(const simd_mask<T, Abi>&);
-
+tuple<simd_mask<T, simd_abi::deduce_t<T, Sizes>>...> split(const simd_mask<T, Abi>&);
 template <class V, class Abi>
 array<V, simd_size_v<typename V::value_type, Abi> / V::size()> split(
 const simd<typename V::value_type, Abi>&);
-
 template <class V, class Abi>
 array<V, simd_size_v<typename V::value_type, Abi> / V::size()> split(
 const simd_mask<typename V::value_type, Abi>&);
 
 template <class T, class... Abis>
-simd<T, abi_for_size_t<T, (simd_size_v<T, Abis> + ...)>> concat(const simd<T, Abis>&...);
-
+simd<T, simd_abi::deduce_t<T, (simd_size_v<T, Abis> + ...)>> concat(const simd<T, Abis>&...);
 template <class T, class... Abis>
-simd_mask<T, abi_for_size_t<T, (simd_size_v<T, Abis> + ...)>> concat(const simd_mask<T, Abis>&...);
+simd_mask<T, simd_abi::deduce_t<T, (simd_size_v<T, Abis> + ...)>> concat(const simd_mask<T, Abis>&...);
 
 // reductions [simd.mask.reductions]
 template <class T, class Abi> bool all_of(const simd_mask<T, Abi>&) noexcept;
@@ -110,6 +102,7 @@
 template <class T, class Abi> int popcount(const simd_mask<T, Abi>&) noexcept;
 template <class T, class Abi> int find_first_set(const simd_mask<T, Abi>&);
 template <class T, class Abi> int find_last_set(const simd_mask<T, Abi>&);
+
 bool all_of(see below ) noexcept;
 bool any_of(see below ) noexcept;
 bool none_of(see below ) noexcept;
@@ -124,113 +117,107 @@
 
 // masked assignment [simd.mask.where]
 template <class T> struct nodeduce { using type = T; }; // exposition only
-
 template <class T> using nodeduce_t = typename nodeduce<T>::type; // exposition only
 
 template <class T, class Abi>
 where_expression<simd_mask<T, Abi>, simd<T, Abi>>
 where(const typename simd<T, Abi>::mask_type&, simd<T, Abi>&) noexcept;
-
 template <class T, class Abi>
-const_where_expression<simd_mask<T, Abi>, const simd<T, Abi>>
+const_where_expression<simd_mask<T, Abi>, simd<T, Abi>>
 where(const typename simd<T, Abi>::mask_type&, const simd<T, Abi>&) noexcept;
 
 template <class T, class Abi>
 where_expression<simd_mask<T, Abi>, simd_mask<T, Abi>>
 where(const nodeduce_t<simd_mask<T, Abi>>&, simd_mask<T, Abi>&) noexcept;
-
 template <class T, class Abi>
-const_where_expression<simd_mask<T, Abi>, const simd_mask<T, Abi>>
+const_where_expression<simd_mask<T, Abi>, simd_mask<T, Abi>>
 where(const nodeduce_t<simd_mask<T, Abi>>&, const simd_mask<T, Abi>&) noexcept;
 
 template <class T> where_expression<bool, T> where(see below k, T& d) noexcept;
-
 template <class T>
-const_where_expression<bool, const T> where(see below k, const T& d) noexcept;
+const_where_expression<bool, T> where(see below k, const T& d) noexcept;
 
 // reductions [simd.reductions]
-template <class T, class Abi, class BinaryOperation = std::plus<>>
-T reduce(const simd<T, Abi>&, BinaryOperation = BinaryOperation());
+template <class T, class Abi, class BinaryOperation = plus<>>
+T reduce(const simd<T, Abi>&, BinaryOperation = {});
 
 template <class M, class V, class BinaryOperation>
 typename V::value_type reduce(const const_where_expression<M, V>& x,
-typename V::value_type neutral_element, BinaryOperation binary_op);
-
+typename V::value_type identity_element, BinaryOperation binary_op);
 template <class M, class V>
-typename V::value_type reduce(const const_where_expression<M, V>& x, plus<> binary_op = plus<>());
-
+typename V::value_type reduce(const const_where_expression<M, V>& x, plus<> binary_op = {});
 template <class M, class V>
 typename V::value_type reduce(const const_where_expression<M, V>& x, multiplies<> binary_op);
-
 template <class M, class V>
 typename V::value_type reduce(const const_where_expression<M, V>& x, bit_and<> binary_op);
-
 template <class M, class V>
 typename V::value_type reduce(const const_where_expression<M, V>& x, bit_or<> binary_op);
-
 template <class M, class V>
 typename V::value_type reduce(const const_where_expression<M, V>& x, bit_xor<> binary_op);
 
 template <class T, class Abi> T hmin(const simd<T, Abi>&);
-template <class M, class V> T hmin(const const_where_expression<M, V>&);
+template <class M, class V> typename V::value_type hmin(const const_where_expression<M, V>&);
 template <class T, class Abi> T hmax(const simd<T, Abi>&);
-template <class M, class V> T hmax(const const_where_expression<M, V>&);
+template <class M, class V> typename V::value_type hmax(const const_where_expression<M, V>&);
 
 // algorithms [simd.alg]
 template <class T, class Abi> simd<T, Abi> min(const simd<T, Abi>&, const simd<T, Abi>&) noexcept;
-
 template <class T, class Abi> simd<T, Abi> max(const simd<T, Abi>&, const simd<T, Abi>&) noexcept;
-
 template <class T, class Abi>
-std::pair<simd<T, Abi>, simd<T, Abi>> minmax(const simd<T, Abi>&, const simd<T, Abi>&) noexcept;
-
+pair<simd<T, Abi>, simd<T, Abi>> minmax(const simd<T, Abi>&, const simd<T, Abi>&) noexcept;
 template <class T, class Abi>
 simd<T, Abi> clamp(const simd<T, Abi>& v, const simd<T, Abi>& lo, const simd<T, Abi>& hi);
 
 // [simd.whereexpr]
 template <class M, class T>
 class const_where_expression {
-  const M& mask; // exposition only
+  const M mask; // exposition only
   T& data; // exposition only
+
 public:
   const_where_expression(const const_where_expression&) = delete;
   const_where_expression& operator=(const const_where_expression&) = delete;
-  remove_const_t<T> operator-() const &&;
+
+  T operator-() const &&;
+  T operator+() const &&;
+  T operator~() const &&;
+
   template <class U, class Flags> void copy_to(U* mem, Flags f) const &&;
 };
 
 template <class M, class T>
 class where_expression : public const_where_expression<M, T> {
 public:
-  where_expression(const where_expression&) = delete;
-  where_expression& operator=(const where_expression&) = delete;
-  template <class U> void operator=(U&& x);
-  template <class U> void operator+=(U&& x);
-  template <class U> void operator-=(U&& x);
-  template <class U> void operator*=(U&& x);
-  template <class U> void operator/=(U&& x);
-  template <class U> void operator%=(U&& x);
-  template <class U> void operator&=(U&& x);
-  template <class U> void operator|=(U&& x);
-  template <class U> void operator^=(U&& x);
-  template <class U> void operator<<=(U&& x);
-  template <class U> void operator>>=(U&& x);
-  void operator++();
-  void operator++(int);
-  void operator--();
-  void operator--(int);
-  template <class U, class Flags> void copy_from(const U* mem, Flags);
+  template <class U> void operator=(U&& x) &&;
+  template <class U> void operator+=(U&& x) &&;
+  template <class U> void operator-=(U&& x) &&;
+  template <class U> void operator*=(U&& x) &&;
+  template <class U> void operator/=(U&& x) &&;
+  template <class U> void operator%=(U&& x) &&;
+  template <class U> void operator&=(U&& x) &&;
+  template <class U> void operator|=(U&& x) &&;
+  template <class U> void operator^=(U&& x) &&;
+  template <class U> void operator<<=(U&& x) &&;
+  template <class U> void operator>>=(U&& x) &&;
+  void operator++() &&;
+  void operator++(int) &&;
+  void operator--() &&;
+  void operator--(int) &&;
+
+  template <class U, class Flags> void copy_from(const U* mem, Flags) &&;
 };
 
 // [simd.class]
-template <class T, class Abi> class simd {
+template <class T, class Abi>
+class simd {
 public:
   using value_type = T;
   using reference = see below ;
   using mask_type = simd_mask<T, Abi>;
-
   using abi_type = Abi;
+
   static constexpr size_t size() noexcept;
+
   simd() = default;
 
   // implicit type conversion constructor
@@ -285,7 +272,6 @@
   friend simd& operator*= (simd&, const simd&);
   friend simd& operator/= (simd&, const simd&);
   friend simd& operator%= (simd&, const simd&);
-
   friend simd& operator&= (simd&, const simd&);
   friend simd& operator|= (simd&, const simd&);
   friend simd& operator^= (simd&, const simd&);
@@ -303,237 +289,36 @@
   friend mask_type operator< (const simd&, const simd&);
 };
 
-// [simd.math]
-template <class Abi> using scharv = simd<signed char, Abi>; // exposition only
-template <class Abi> using shortv = simd<short, Abi>; // exposition only
-template <class Abi> using intv = simd<int, Abi>; // exposition only
-template <class Abi> using longv = simd<long int, Abi>; // exposition only
-template <class Abi> using llongv = simd<long long int, Abi>; // exposition only
-template <class Abi> using floatv = simd<float, Abi>; // exposition only
-template <class Abi> using doublev = simd<double, Abi>; // exposition only
-template <class Abi> using ldoublev = simd<long double, Abi>; // exposition only
-template <class T, class V> using samesize = fixed_size_simd<T, V::size()>; // exposition only
-template <class Abi> floatv<Abi> acos(floatv<Abi> x);
-template <class Abi> doublev<Abi> acos(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> acos(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> asin(floatv<Abi> x);
-template <class Abi> doublev<Abi> asin(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> asin(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> atan(floatv<Abi> x);
-template <class Abi> doublev<Abi> atan(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> atan(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> atan2(floatv<Abi> y, floatv<Abi> x);
-template <class Abi> doublev<Abi> atan2(doublev<Abi> y, doublev<Abi> x);
-template <class Abi> ldoublev<Abi> atan2(ldoublev<Abi> y, ldoublev<Abi> x);
-template <class Abi> floatv<Abi> cos(floatv<Abi> x);
-template <class Abi> doublev<Abi> cos(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> cos(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> sin(floatv<Abi> x);
-template <class Abi> doublev<Abi> sin(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> sin(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> tan(floatv<Abi> x);
-template <class Abi> doublev<Abi> tan(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> tan(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> acosh(floatv<Abi> x);
-template <class Abi> doublev<Abi> acosh(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> acosh(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> asinh(floatv<Abi> x);
-template <class Abi> doublev<Abi> asinh(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> asinh(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> atanh(floatv<Abi> x);
-template <class Abi> doublev<Abi> atanh(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> atanh(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> cosh(floatv<Abi> x);
-template <class Abi> doublev<Abi> cosh(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> cosh(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> sinh(floatv<Abi> x);
-template <class Abi> doublev<Abi> sinh(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> sinh(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> tanh(floatv<Abi> x);
-template <class Abi> doublev<Abi> tanh(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> tanh(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> exp(floatv<Abi> x);
-template <class Abi> doublev<Abi> exp(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> exp(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> exp2(floatv<Abi> x);
-template <class Abi> doublev<Abi> exp2(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> exp2(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> expm1(floatv<Abi> x);
-template <class Abi> doublev<Abi> expm1(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> expm1(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> frexp(floatv<Abi> value, samesize<int, floatv<Abi>>* exp);
-template <class Abi> doublev<Abi> frexp(doublev<Abi> value, samesize<int, doublev<Abi>>* exp);
-template <class Abi> ldoublev<Abi> frexp(ldoublev<Abi> value, samesize<int, ldoublev<Abi>>* exp);
-template <class Abi> samesize<int, floatv<Abi>> ilogb(floatv<Abi> x);
-template <class Abi> samesize<int, doublev<Abi>> ilogb(doublev<Abi> x);
-template <class Abi> samesize<int, ldoublev<Abi>> ilogb(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> ldexp(floatv<Abi> x, samesize<int, floatv<Abi>> exp);
-template <class Abi> doublev<Abi> ldexp(doublev<Abi> x, samesize<int, doublev<Abi>> exp);
-template <class Abi> ldoublev<Abi> ldexp(ldoublev<Abi> x, samesize<int, ldoublev<Abi>> exp);
-template <class Abi> floatv<Abi> log(floatv<Abi> x);
-template <class Abi> doublev<Abi> log(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> log(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> log10(floatv<Abi> x);
-template <class Abi> doublev<Abi> log10(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> log10(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> log1p(floatv<Abi> x);
-template <class Abi> doublev<Abi> log1p(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> log1p(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> log2(floatv<Abi> x);
-template <class Abi> doublev<Abi> log2(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> log2(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> logb(floatv<Abi> x);
-template <class Abi> doublev<Abi> logb(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> logb(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> modf(floatv<Abi> value, floatv<Abi>* iptr);
-template <class Abi> doublev<Abi> modf(doublev<Abi> value, doublev<Abi>* iptr);
-template <class Abi> ldoublev<Abi> modf(ldoublev<Abi> value, ldoublev<Abi>* iptr);
-template <class Abi> floatv<Abi> scalbn(floatv<Abi> x, samesize<int, floatv<Abi>> n);
-template <class Abi> doublev<Abi> scalbn(doublev<Abi> x, samesize<int, doublev<Abi>> n);
-template <class Abi> ldoublev<Abi> scalbn(ldoublev<Abi> x, samesize<int, ldoublev<Abi>> n);
-template <class Abi> floatv<Abi> scalbln(floatv<Abi> x, samesize<long int, floatv<Abi>> n);
-template <class Abi> doublev<Abi> scalbln(doublev<Abi> x, samesize<long int, doublev<Abi>> n);
-template <class Abi> ldoublev<Abi> scalbln(ldoublev<Abi> x, samesize<long int, ldoublev<Abi>> n);
-template <class Abi> floatv<Abi> cbrt(floatv<Abi> x);
-template <class Abi> doublev<Abi> cbrt(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> cbrt(ldoublev<Abi> x);
-template <class Abi> scharv<Abi> abs(scharv<Abi> j);
-template <class Abi> shortv<Abi> abs(shortv<Abi> j);
-template <class Abi> intv<Abi> abs(intv<Abi> j);
-template <class Abi> longv<Abi> abs(longv<Abi> j);
-template <class Abi> llongv<Abi> abs(llongv<Abi> j);
-template <class Abi> floatv<Abi> abs(floatv<Abi> j);
-template <class Abi> doublev<Abi> abs(doublev<Abi> j);
-template <class Abi> ldoublev<Abi> abs(ldoublev<Abi> j);
-template <class Abi> floatv<Abi> hypot(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> hypot(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> hypot(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> floatv<Abi> hypot(floatv<Abi> x, floatv<Abi> y, floatv<Abi> z);
-template <class Abi> doublev<Abi> hypot(doublev<Abi> x, doublev<Abi> y, doublev<Abi> z);
-template <class Abi> ldoublev<Abi> hypot(ldoublev<Abi> x, ldoublev<Abi> y, ldoublev<Abi> z);
-template <class Abi> floatv<Abi> pow(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> pow(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> pow(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> floatv<Abi> sqrt(floatv<Abi> x);
-template <class Abi> doublev<Abi> sqrt(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> sqrt(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> erf(floatv<Abi> x);
-template <class Abi> doublev<Abi> erf(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> erf(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> erfc(floatv<Abi> x);
-template <class Abi> doublev<Abi> erfc(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> erfc(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> lgamma(floatv<Abi> x);
-template <class Abi> doublev<Abi> lgamma(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> lgamma(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> tgamma(floatv<Abi> x);
-template <class Abi> doublev<Abi> tgamma(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> tgamma(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> ceil(floatv<Abi> x);
-template <class Abi> doublev<Abi> ceil(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> ceil(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> floor(floatv<Abi> x);
-template <class Abi> doublev<Abi> floor(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> floor(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> nearbyint(floatv<Abi> x);
-template <class Abi> doublev<Abi> nearbyint(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> nearbyint(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> rint(floatv<Abi> x);
-template <class Abi> doublev<Abi> rint(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> rint(ldoublev<Abi> x);
-template <class Abi> samesize<long int, floatv<Abi>> lrint(floatv<Abi> x);
-template <class Abi> samesize<long int, doublev<Abi>> lrint(doublev<Abi> x);
-template <class Abi> samesize<long int, ldoublev<Abi>> lrint(ldoublev<Abi> x);
-template <class Abi> samesize<long long int, floatv<Abi>> llrint(floatv<Abi> x);
-template <class Abi> samesize<long long int, doublev<Abi>> llrint(doublev<Abi> x);
-template <class Abi> samesize<long long int, ldoublev<Abi>> llrint(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> round(floatv<Abi> x);
-template <class Abi> doublev<Abi> round(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> round(ldoublev<Abi> x);
-template <class Abi> samesize<long int, floatv<Abi>> lround(floatv<Abi> x);
-template <class Abi> samesize<long int, doublev<Abi>> lround(doublev<Abi> x);
-template <class Abi> samesize<long int, ldoublev<Abi>> lround(ldoublev<Abi> x);
-template <class Abi> samesize<long long int, floatv<Abi>> llround(floatv<Abi> x);
-template <class Abi> samesize<long long int, doublev<Abi>> llround(doublev<Abi> x);
-template <class Abi> samesize<long long int, ldoublev<Abi>> llround(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> trunc(floatv<Abi> x);
-template <class Abi> doublev<Abi> trunc(doublev<Abi> x);
-template <class Abi> ldoublev<Abi> trunc(ldoublev<Abi> x);
-template <class Abi> floatv<Abi> fmod(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> fmod(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> fmod(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> floatv<Abi> remainder(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> remainder(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> remainder(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> floatv<Abi> remquo(floatv<Abi> x, floatv<Abi> y, samesize<int, floatv<Abi>>* quo);
-template <class Abi> doublev<Abi> remquo(doublev<Abi> x, doublev<Abi> y, samesize<int, doublev<Abi>>* quo);
-template <class Abi> ldoublev<Abi> remquo(ldoublev<Abi> x, ldoublev<Abi> y, samesize<int, ldoublev<Abi>>* quo);
-template <class Abi> floatv<Abi> copysign(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> copysign(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> copysign(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> doublev<Abi> nan(const char* tagp);
-template <class Abi> floatv<Abi> nanf(const char* tagp);
-template <class Abi> ldoublev<Abi> nanl(const char* tagp);
-template <class Abi> floatv<Abi> nextafter(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> nextafter(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> nextafter(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> floatv<Abi> nexttoward(floatv<Abi> x, ldoublev<Abi> y);
-template <class Abi> doublev<Abi> nexttoward(doublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> ldoublev<Abi> nexttoward(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> floatv<Abi> fdim(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> fdim(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> fdim(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> floatv<Abi> fmax(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> fmax(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> fmax(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> floatv<Abi> fmin(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> doublev<Abi> fmin(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> ldoublev<Abi> fmin(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> floatv<Abi> fma(floatv<Abi> x, floatv<Abi> y, floatv<Abi> z);
-template <class Abi> doublev<Abi> fma(doublev<Abi> x, doublev<Abi> y, doublev<Abi> z);
-template <class Abi> ldoublev<Abi> fma(ldoublev<Abi> x, ldoublev<Abi> y, ldoublev<Abi> z);
-template <class Abi> samesize<int, floatv<Abi>> fpclassify(floatv<Abi> x);
-template <class Abi> samesize<int, doublev<Abi>> fpclassify(doublev<Abi> x);
-template <class Abi> samesize<int, ldoublev<Abi>> fpclassify(ldoublev<Abi> x);
-template <class Abi> simd_mask<float, Abi> isfinite(floatv<Abi> x);
-template <class Abi> simd_mask<double, Abi> isfinite(doublev<Abi> x);
-template <class Abi> simd_mask<long double, Abi> isfinite(ldoublev<Abi> x);
-template <class Abi> simd_mask<float, Abi> isinf(floatv<Abi> x);
-template <class Abi> simd_mask<double, Abi> isinf(doublev<Abi> x);
-template <class Abi> simd_mask<long double, Abi> isinf(ldoublev<Abi> x);
-template <class Abi> simd_mask<float, Abi> isnan(floatv<Abi> x);
-template <class Abi> simd_mask<double, Abi> isnan(doublev<Abi> x);
-template <class Abi> simd_mask<long double, Abi> isnan(ldoublev<Abi> x);
-template <class Abi> simd_mask<float, Abi> isnormal(floatv<Abi> x);
-template <class Abi> simd_mask<double, Abi> isnormal(doublev<Abi> x);
-template <class Abi> simd_mask<long double, Abi> isnormal(ldoublev<Abi> x);
-template <class Abi> simd_mask<float, Abi> signbit(floatv<Abi> x);
-template <class Abi> simd_mask<double, Abi> signbit(doublev<Abi> x);
-template <class Abi> simd_mask<long double, Abi> signbit(ldoublev<Abi> x);
-template <class Abi> simd_mask<float, Abi> isgreater(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> simd_mask<double, Abi> isgreater(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> simd_mask<long double, Abi> isgreater(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> simd_mask<float, Abi> isgreaterequal(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> simd_mask<double, Abi> isgreaterequal(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> simd_mask<long double, Abi> isgreaterequal(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> simd_mask<float, Abi> isless(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> simd_mask<double, Abi> isless(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> simd_mask<long double, Abi> isless(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> simd_mask<float, Abi> islessequal(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> simd_mask<double, Abi> islessequal(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> simd_mask<long double, Abi> islessequal(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> simd_mask<float, Abi> islessgreater(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> simd_mask<double, Abi> islessgreater(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> simd_mask<long double, Abi> islessgreater(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class Abi> simd_mask<float, Abi> isunordered(floatv<Abi> x, floatv<Abi> y);
-template <class Abi> simd_mask<double, Abi> isunordered(doublev<Abi> x, doublev<Abi> y);
-template <class Abi> simd_mask<long double, Abi> isunordered(ldoublev<Abi> x, ldoublev<Abi> y);
-template <class V> struct simd_div_t { V quot, rem; };
-template <class Abi> simd_div_t<scharv<Abi>> div(scharv<Abi> numer, scharv<Abi> denom);
-template <class Abi> simd_div_t<shortv<Abi>> div(shortv<Abi> numer, shortv<Abi> denom);
-template <class Abi> simd_div_t<intv<Abi>> div(intv<Abi> numer, intv<Abi> denom);
-template <class Abi> simd_div_t<longv<Abi>> div(longv<Abi> numer, longv<Abi> denom);
-template <class Abi> simd_div_t<llongv<Abi>> div(llongv<Abi> numer, llongv<Abi> denom);
+class reference // exposition only
+{
+public:
+  reference() = delete;
+  reference(const reference &) = delete;
+
+  operator value_type() const noexcept;
+
+  template <class U> reference operator=(U&& x) &&;
+
+  template <class U> reference operator+=(U&& x) &&;
+  template <class U> reference operator-=(U&& x) &&;
+  template <class U> reference operator*=(U&& x) &&;
+  template <class U> reference operator/=(U&& x) &&;
+  template <class U> reference operator%=(U&& x) &&;
+  template <class U> reference operator|=(U&& x) &&;
+  template <class U> reference operator&=(U&& x) &&;
+  template <class U> reference operator^=(U&& x) &&;
+  template <class U> reference operator<<=(U&& x) &&;
+  template <class U> reference operator>>=(U&& x) &&;
+
+  reference operator++() &&;
+  value_type operator++(int) &&;
+  reference operator--() &&;
+  value_type operator--(int) &&;
+
+  friend void swap(reference&& a, reference&& b) noexcept;
+  friend void swap(value_type& a, reference&& b) noexcept;
+  friend void swap(reference&& a, value_type& b) noexcept;
+};
 
 // [simd.mask.class]
 template <class T, class Abi>
@@ -543,7 +328,9 @@
   using reference = see below ;
   using simd_type = simd<T, Abi>;
   using abi_type = Abi;
+
   static constexpr size_t size() noexcept;
+
   simd_mask() = default;
 
   // broadcast constructor
Index: libcxx/test/std/experimental/simd/simd.horizontal/concat.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.horizontal/concat.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.horizontal/concat.pass.cpp
@@ -12,7 +12,7 @@
 // <experimental/simd>
 //
 // template <class T, class... Abis>
-// simd<T, abi_for_size_t<T, (simd_size_v<T, Abis> + ...)>>
+// simd<T, simd_abi::deduce_t<T, (simd_size_v<T, Abis> + ...)>>
 // concat(const simd<T, Abis>&...);
 //
 // template <class T, class Abi, size_t N>
@@ -20,7 +20,7 @@
 // concat(const std::array<simd<T, Abi>, N>& __v);
 //
 // template <class T, class... Abis>
-// simd_mask<T, abi_for_size_t<T, (simd_size_v<T, Abis> + ...)>>
+// simd_mask<T, simd_abi::deduce_t<T, (simd_size_v<T, Abis> + ...)>>
 // concat(const simd_mask<T, Abis>&...);
 //
 // template <class T, class Abi, size_t N>
Index: libcxx/test/std/experimental/simd/simd.horizontal/hmax.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.horizontal/hmax.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.horizontal/hmax.pass.cpp
@@ -12,7 +12,8 @@
 // <experimental/simd>
 //
 // template <class T, class Abi> T hmax(const simd<T, Abi>&);
-// template <class M, class V> T hmax(const const_where_expression<M, V>&);
+// template <class M, class V> typename V::value_type
+// hmax(const const_where_expression<M, V>&);
 
 #include <experimental/simd>
 #include <cassert>
Index: libcxx/test/std/experimental/simd/simd.horizontal/hmin.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.horizontal/hmin.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.horizontal/hmin.pass.cpp
@@ -12,7 +12,8 @@
 // <experimental/simd>
 //
 // template <class T, class Abi> T hmin(const simd<T, Abi>&);
-// template <class M, class V> T hmin(const const_where_expression<M, V>&);
+// template <class M, class V> typename V::value_type
+// hmin(const const_where_expression<M, V>&);
 
 #include <experimental/simd>
 #include <cassert>
Index: libcxx/test/std/experimental/simd/simd.horizontal/reduce.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.horizontal/reduce.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.horizontal/reduce.pass.cpp
@@ -12,15 +12,15 @@
 // <experimental/simd>
 //
 // // reductions [simd.reductions]
-// template <class T, class Abi, class BinaryOperation = std::plus<>>
-// T reduce(const simd<T, Abi>&, BinaryOperation = BinaryOperation());
+// template <class T, class Abi, class BinaryOperation = plus<>>
+// T reduce(const simd<T, Abi>&, BinaryOperation = {});
 //
 // template <class M, class V, class BinaryOperation>
 // typename V::value_type reduce(const const_where_expression<M, V>& x,
-// typename V::value_type neutral_element, BinaryOperation binary_op);
+// typename V::value_type identity_element, BinaryOperation binary_op);
 //
 // template <class M, class V>
-// typename V::value_type reduce(const const_where_expression<M, V>& x, plus<> binary_op = plus<>());
+// typename V::value_type reduce(const const_where_expression<M, V>& x, plus<> binary_op = {});
 //
 // template <class M, class V>
 // typename V::value_type reduce(const const_where_expression<M, V>& x, multiplies<> binary_op);
Index: libcxx/test/std/experimental/simd/simd.horizontal/split.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.horizontal/split.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.horizontal/split.pass.cpp
@@ -12,10 +12,10 @@
 // <experimental/simd>
 //
 // template <size_t... Sizes, class T, class Abi>
-// tuple<simd<T, abi_for_size_t<Sizes>>...> split(const simd<T, Abi>&);
+// tuple<simd<T, simd_abi::deduce_t<T, Sizes>>...> split(const simd<T, Abi>&);
 //
 // template <size_t... Sizes, class T, class Abi>
-// tuple<simd_mask<T, abi_for_size_t<Sizes>>...> split(const simd_mask<T, Abi>&);
+// tuple<simd_mask<T, simd_abi::deduce_t<T, Sizes>>...> split(const simd_mask<T, Abi>&);
 //
 // template <class V, class Abi>
 // array<V, simd_size_v<typename V::value_type, Abi> / V::size()> split(
Index: libcxx/test/std/experimental/simd/simd.access/default.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.access/default.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.access/default.pass.cpp
@@ -11,9 +11,36 @@
 
 // <experimental/simd>
 //
-// scalar access [simd.subscr]
-// reference operator[](size_t);
-// value_type operator[](size_t) const;
+// class reference // exposition only
+// {
+// public:
+//   reference() = delete;
+//   reference(const reference &) = delete;
+//
+//   operator value_type() const noexcept;
+//
+//   template <class U> reference operator=(U&& x) &&;
+//
+//   template <class U> reference operator+=(U&& x) &&;
+//   template <class U> reference operator-=(U&& x) &&;
+//   template <class U> reference operator*=(U&& x) &&;
+//   template <class U> reference operator/=(U&& x) &&;
+//   template <class U> reference operator%=(U&& x) &&;
+//   template <class U> reference operator|=(U&& x) &&;
+//   template <class U> reference operator&=(U&& x) &&;
+//   template <class U> reference operator^=(U&& x) &&;
+//   template <class U> reference operator<<=(U&& x) &&;
+//   template <class U> reference operator>>=(U&& x) &&;
+//
+//   reference operator++() &&;
+//   value_type operator++(int) &&;
+//   reference operator--() &&;
+//   value_type operator--(int) &&;
+//
+//   friend void swap(reference&& a, reference&& b) noexcept;
+//   friend void swap(value_type& a, reference&& b) noexcept;
+//   friend void swap(reference&& a, value_type& b) noexcept;
+// };
 
 #include <experimental/simd>
 #include <cassert>
Index: libcxx/test/std/experimental/simd/simd.casts/to_compatible.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.casts/to_compatible.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.casts/to_compatible.pass.cpp
@@ -12,12 +12,8 @@
 // <experimental/simd>
 //
 // [simd.casts]
-//
-// template <class T, size_t N> simd<T>
-// to_compatible(const fixed_size_simd<T, N>&) noexcept;
-//
-// template <class T, size_t N> simd_mask<T>
-// to_compatible(const fixed_size_simd_mask<T, N>&) noexcept;
+// template <class T, int N> simd<T> to_compatible(const fixed_size_simd<T, N>&) noexcept;
+// template <class T, int N> simd_mask<T> to_compatible(const fixed_size_simd_mask<T, N>&) noexcept;
 
 #include <experimental/simd>
 #include <cstdint>
Index: libcxx/test/std/experimental/simd/simd.casts/to_native.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.casts/to_native.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.casts/to_native.pass.cpp
@@ -12,12 +12,8 @@
 // <experimental/simd>
 //
 // [simd.casts]
-//
-// template <class T, size_t N>
-// native_simd<T> to_native(const fixed_size_simd<T, N>&) noexcept;
-//
-// template <class T, size_t N>
-// native_simd_mask<T> to_native(const fixed_size_simd_mask<T, N>&) noexcept;
+// template <class T, int N> native_simd<T> to_native(const fixed_size_simd<T, N>&) noexcept;
+// template <class T, int N> native_simd_mask<T> to_native(const fixed_size_simd_mask<T, N>&) noexcept;
 
 #include <experimental/simd>
 #include <cstdint>
Index: libcxx/test/std/experimental/simd/simd.elementwise/minmax.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.elementwise/minmax.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.elementwise/minmax.pass.cpp
@@ -12,7 +12,7 @@
 // <experimental/simd>
 //
 // template <class T, class Abi>
-// std::pair<simd<T, Abi>, simd<T, Abi>>
+// pair<simd<T, Abi>, simd<T, Abi>>
 // minmax(const simd<T, Abi>&, const simd<T, Abi>&) noexcept;
 
 #include <cassert>
Index: libcxx/test/std/experimental/simd/simd.traits/simd_abi_deduce.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.traits/simd_abi_deduce.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.traits/simd_abi_deduce.pass.cpp
@@ -10,10 +10,8 @@
 // UNSUPPORTED: c++98, c++03
 
 // <experimental/simd>
-//
-// [simd.traits]
-// template <class T, size_t N> struct abi_for_size { using type = see below ; };
-// template <class T, size_t N> using abi_for_size_t = typename abi_for_size<T, N>::type;
+// template <class T, size_t N> struct deduce { using type = see below ; };
+// template <class T, size_t N> using deduce_t = typename deduce<T, N>::type;
 
 #include <cstdint>
 #include <experimental/simd>
Index: libcxx/test/std/experimental/simd/simd.whereexpr/const_where_expression.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.whereexpr/const_where_expression.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.whereexpr/const_where_expression.pass.cpp
@@ -14,12 +14,17 @@
 // // [simd.whereexpr]
 // template <class M, class T>
 // class const_where_expression {
-//   const M& mask; // exposition only
+//   const M mask; // exposition only
 //   T& data; // exposition only
+//
 // public:
 //   const_where_expression(const const_where_expression&) = delete;
 //   const_where_expression& operator=(const const_where_expression&) = delete;
-//   remove_const_t<T> operator-() const &&;
+//
+//   T operator-() const &&;
+//   T operator+() const &&;
+//   T operator~() const &&;
+//
 //   template <class U, class Flags> void copy_to(U* mem, Flags f) const &&;
 // };
 
Index: libcxx/test/std/experimental/simd/simd.whereexpr/where.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.whereexpr/where.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.whereexpr/where.pass.cpp
@@ -17,7 +17,7 @@
 // where(const typename simd<T, Abi>::mask_type&, simd<T, Abi>&) noexcept;
 //
 // template <class T, class Abi>
-// const_where_expression<simd_mask<T, Abi>, const simd<T, Abi>>
+// const_where_expression<simd_mask<T, Abi>, simd<T, Abi>>
 // where(const typename simd<T, Abi>::mask_type&, const simd<T, Abi>&) noexcept;
 //
 // template <class T, class Abi>
@@ -25,13 +25,13 @@
 // where(const nodeduce_t<simd_mask<T, Abi>>&, simd_mask<T, Abi>&) noexcept;
 //
 // template <class T, class Abi>
-// const_where_expression<simd_mask<T, Abi>, const simd_mask<T, Abi>>
+// const_where_expression<simd_mask<T, Abi>, simd_mask<T, Abi>>
 // where(const nodeduce_t<simd_mask<T, Abi>>&, const simd_mask<T, Abi>&) noexcept;
 //
 // template <class T> where_expression<bool, T> where(see below k, T& d) noexcept;
 //
 // template <class T>
-// const_where_expression<bool, const T> where(see below k, const T& d) noexcept;
+// const_where_expression<bool, T> where(see below k, const T& d) noexcept;
 
 #include <experimental/simd>
 #include <cassert>
Index: libcxx/test/std/experimental/simd/simd.whereexpr/where_expression.pass.cpp
===================================================================
--- libcxx/test/std/experimental/simd/simd.whereexpr/where_expression.pass.cpp
+++ libcxx/test/std/experimental/simd/simd.whereexpr/where_expression.pass.cpp
@@ -15,24 +15,23 @@
 // template <class M, class T>
 // class where_expression : public const_where_expression<M, T> {
 // public:
-//   where_expression(const where_expression&) = delete;
-//   where_expression& operator=(const where_expression&) = delete;
-//   template <class U> void operator=(U&& x);
-//   template <class U> void operator+=(U&& x);
-//   template <class U> void operator-=(U&& x);
-//   template <class U> void operator*=(U&& x);
-//   template <class U> void operator/=(U&& x);
-//   template <class U> void operator%=(U&& x);
-//   template <class U> void operator&=(U&& x);
-//   template <class U> void operator|=(U&& x);
-//   template <class U> void operator^=(U&& x);
-//   template <class U> void operator<<=(U&& x);
-//   template <class U> void operator>>=(U&& x);
-//   void operator++();
-//   void operator++(int);
-//   void operator--();
-//   void operator--(int);
-//   template <class U, class Flags> void copy_from(const U* mem, Flags);
+//  template <class U> void operator=(U&& x) &&;
+//  template <class U> void operator+=(U&& x) &&;
+//  template <class U> void operator-=(U&& x) &&;
+//  template <class U> void operator*=(U&& x) &&;
+//  template <class U> void operator/=(U&& x) &&;
+//  template <class U> void operator%=(U&& x) &&;
+//  template <class U> void operator&=(U&& x) &&;
+//  template <class U> void operator|=(U&& x) &&;
+//  template <class U> void operator^=(U&& x) &&;
+//  template <class U> void operator<<=(U&& x) &&;
+//  template <class U> void operator>>=(U&& x) &&;
+//  void operator++() &&;
+//  void operator++(int) &&;
+//  void operator--() &&;
+//  void operator--(int) &&;
+//
+//  template <class U, class Flags> void copy_from(const U* mem, Flags) &&;
 // };
 
 #include <experimental/simd>