Revert "[libcxx] implement <simd> ABI for Clang/GCC vector extension, constructors, copy_from and copy_to."

This reverts commit r338309.

llvm-svn: 338316

2 files changed, 48 insertions, 336 deletions

diff --git a/libcxx/include/experimental/__config b/libcxx/include/experimental/__config
index c6f17762022..55ae31b8aea 100644
--- a/libcxx/include/experimental/__config
+++ b/libcxx/include/experimental/__config
@@ -64,11 +64,4 @@
 #define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD_ABI \
     } _LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD
 
-// TODO: support more targets
-#if defined(__AVX__)
-#define _LIBCPP_NATIVE_SIMD_WIDTH_IN_BYTES 32
-#else
-#define _LIBCPP_NATIVE_SIMD_WIDTH_IN_BYTES 16
-#endif
-
 #endif
diff --git a/libcxx/include/experimental/simd b/libcxx/include/experimental/simd
index 2cc0d8debab..4876ccb82d2 100644
--- a/libcxx/include/experimental/simd
+++ b/libcxx/include/experimental/simd
@@ -651,7 +651,6 @@ public:
 */
 
 #include <experimental/__config>
-#include <algorithm>
 #include <array>
 #include <cstddef>
 #include <functional>
@@ -665,241 +664,23 @@ _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD
 enum class _StorageKind {
   _Scalar,
   _Array,
-  _VecExt,
 };
 
 template <_StorageKind __kind, int _Np>
 struct __simd_abi {};
 
 template <class _Tp, class _Abi>
-class __simd_storage {};
+struct __simd_storage_traits {};
 
 template <class _Tp, int __num_element>
-class __simd_storage<_Tp, __simd_abi<_StorageKind::_Array, __num_element>> {
-  std::array<_Tp, __num_element> __storage_;
-
-  template <class, class>
-  friend struct simd;
-
-  template <class, class>
-  friend struct simd_mask;
-
-public:
-  _Tp __get(size_t __index) const noexcept { return __storage_[__index]; };
-  void __set(size_t __index, _Tp __val) noexcept {
-    __storage_[__index] = __val;
-  }
+struct __simd_storage_traits<_Tp,
+                             __simd_abi<_StorageKind::_Array, __num_element>> {
+  using type = std::array<_Tp, __num_element>;
 };
 
 template <class _Tp>
-class __simd_storage<_Tp, __simd_abi<_StorageKind::_Scalar, 1>> {
-  _Tp __storage_;
-
-  template <class, class>
-  friend struct simd;
-
-  template <class, class>
-  friend struct simd_mask;
-
-public:
-  _Tp __get(size_t __index) const noexcept { return (&__storage_)[__index]; };
-  void __set(size_t __index, _Tp __val) noexcept {
-    (&__storage_)[__index] = __val;
-  }
-};
-
-#ifndef _LIBCPP_HAS_NO_VECTOR_EXTENSION
-
-constexpr size_t __floor_pow_of_2(size_t __val) {
-  return ((__val - 1) & __val) == 0 ? __val
-                                    : __floor_pow_of_2((__val - 1) & __val);
-}
-
-constexpr size_t __ceil_pow_of_2(size_t __val) {
-  return __val == 1 ? 1 : __floor_pow_of_2(__val - 1) << 1;
-}
-
-template <class _Tp, size_t __bytes>
-struct __vec_ext_traits {
-#if !defined(_LIBCPP_COMPILER_CLANG)
-  typedef _Tp type __attribute__((vector_size(__ceil_pow_of_2(__bytes))));
-#endif
-};
-
-#if defined(_LIBCPP_COMPILER_CLANG)
-#define _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, _NUM_ELEMENT)                        \
-  template <>                                                                  \
-  struct __vec_ext_traits<_TYPE, sizeof(_TYPE) * _NUM_ELEMENT> {               \
-    using type =                                                               \
-        _TYPE __attribute__((vector_size(sizeof(_TYPE) * _NUM_ELEMENT)));      \
-  }
-
-#define _LIBCPP_SPECIALIZE_VEC_EXT_32(_TYPE)                                   \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 1);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 2);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 3);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 4);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 5);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 6);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 7);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 8);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 9);                                        \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 10);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 11);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 12);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 13);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 14);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 15);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 16);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 17);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 18);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 19);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 20);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 21);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 22);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 23);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 24);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 25);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 26);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 27);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 28);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 29);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 30);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 31);                                       \
-  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 32);
-
-_LIBCPP_SPECIALIZE_VEC_EXT_32(char);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(char16_t);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(char32_t);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(wchar_t);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(signed char);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(signed short);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(signed int);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(signed long);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(signed long long);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned char);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned short);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned int);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned long);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned long long);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(float);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(double);
-_LIBCPP_SPECIALIZE_VEC_EXT_32(long double);
-
-#undef _LIBCPP_SPECIALIZE_VEC_EXT_32
-#undef _LIBCPP_SPECIALIZE_VEC_EXT
-#endif
-
-template <class _Tp, int __num_element>
-class __simd_storage<_Tp, __simd_abi<_StorageKind::_VecExt, __num_element>> {
-  using _StorageType =
-      typename __vec_ext_traits<_Tp, sizeof(_Tp) * __num_element>::type;
-
-  _StorageType __storage_;
-
-  template <class, class>
-  friend struct simd;
-
-  template <class, class>
-  friend struct simd_mask;
-
-public:
-  _Tp __get(size_t __index) const noexcept { return __storage_[__index]; };
-  void __set(size_t __index, _Tp __val) noexcept {
-    __storage_[__index] = __val;
-  }
-};
-
-#endif // _LIBCPP_HAS_NO_VECTOR_EXTENSION
-
-template <class _Vp, class _Tp, class _Abi>
-class __simd_reference {
-  static_assert(std::is_same<_Vp, _Tp>::value, "");
-
-  template <class, class>
-  friend struct simd;
-
-  template <class, class>
-  friend struct simd_mask;
-
-  __simd_storage<_Tp, _Abi>* __ptr_;
-  size_t __index_;
-
-  __simd_reference(__simd_storage<_Tp, _Abi>* __ptr, size_t __index)
-      : __ptr_(__ptr), __index_(__index) {}
-
-  __simd_reference(const __simd_reference&) = default;
-
-public:
-  __simd_reference() = delete;
-  __simd_reference& operator=(const __simd_reference&) = delete;
-
-  operator _Vp() const { return __ptr_->__get(__index_); }
-
-  __simd_reference operator=(_Vp __value) && {
-    __ptr_->__set(__index_, __value);
-    return *this;
-  }
-
-  __simd_reference operator++() && {
-    return std::move(*this) = __ptr_->__get(__index_) + 1;
-  }
-
-  _Vp operator++(int) && {
-    auto __val = __ptr_->__get(__index_);
-    __ptr_->__set(__index_, __val + 1);
-    return __val;
-  }
-
-  __simd_reference operator--() && {
-    return std::move(*this) = __ptr_->__get(__index_) - 1;
-  }
-
-  _Vp operator--(int) && {
-    auto __val = __ptr_->__get(__index_);
-    __ptr_->__set(__index_, __val - 1);
-    return __val;
-  }
-
-  __simd_reference operator+=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) + __value;
-  }
-
-  __simd_reference operator-=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) - __value;
-  }
-
-  __simd_reference operator*=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) * __value;
-  }
-
-  __simd_reference operator/=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) / __value;
-  }
-
-  __simd_reference operator%=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) % __value;
-  }
-
-  __simd_reference operator>>=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) >> __value;
-  }
-
-  __simd_reference operator<<=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) << __value;
-  }
-
-  __simd_reference operator&=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) & __value;
-  }
-
-  __simd_reference operator|=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) | __value;
-  }
-
-  __simd_reference operator^=(_Vp __value) && {
-    return std::move(*this) = __ptr_->__get(__index_) ^ __value;
-  }
+struct __simd_storage_traits<_Tp, __simd_abi<_StorageKind::_Scalar, 1>> {
+  using type = _Tp;
 };
 
 template <class _To, class _From>
@@ -939,17 +720,6 @@ constexpr _Tp __variadic_sum(_Up __first, _Args... __rest) {
   return static_cast<_Tp>(__first) + __variadic_sum<_Tp>(__rest...);
 }
 
-template <class _Tp>
-struct __nodeduce {
-  using type = _Tp;
-};
-
-template <class _Tp>
-constexpr bool __vectorizable() {
-  return std::is_arithmetic<_Tp>::value && !std::is_const<_Tp>::value &&
-         !std::is_volatile<_Tp>::value && !std::is_same<_Tp, bool>::value;
-}
-
 _LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD
 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD_ABI
 
@@ -958,21 +728,14 @@ using scalar = __simd_abi<_StorageKind::_Scalar, 1>;
 template <int _Np>
 using fixed_size = __simd_abi<_StorageKind::_Array, _Np>;
 
+#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
 template <class _Tp>
-_LIBCPP_INLINE_VAR constexpr size_t max_fixed_size = 32;
-
+_LIBCPP_INLINE_VAR constexpr int max_fixed_size = 32;
+#endif
 template <class _Tp>
 using compatible = fixed_size<16 / sizeof(_Tp)>;
-
-#ifndef _LIBCPP_HAS_NO_VECTOR_EXTENSION
-template <class _Tp>
-using native = __simd_abi<_StorageKind::_VecExt,
-                          _LIBCPP_NATIVE_SIMD_WIDTH_IN_BYTES / sizeof(_Tp)>;
-#else
 template <class _Tp>
-using native =
-    fixed_size<_Tp, _LIBCPP_NATIVE_SIMD_WIDTH_IN_BYTES / sizeof(_Tp)>;
-#endif // _LIBCPP_HAS_NO_VECTOR_EXTENSION
+using native = compatible<_Tp>;
 
 _LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD_ABI
 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD
@@ -986,10 +749,14 @@ struct element_aligned_tag {};
 struct vector_aligned_tag {};
 template <size_t>
 struct overaligned_tag {};
+#if _LIBCPP_STD_VER > 14
 _LIBCPP_INLINE_VAR constexpr element_aligned_tag element_aligned{};
 _LIBCPP_INLINE_VAR constexpr vector_aligned_tag vector_aligned{};
+#if !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
 template <size_t _Np>
 _LIBCPP_INLINE_VAR constexpr overaligned_tag<_Np> overaligned{};
+#endif
+#endif
 
 // traits [simd.traits]
 template <class _Tp>
@@ -1027,6 +794,7 @@ template <size_t _Align>
 struct is_simd_flag_type<overaligned_tag<_Align>>
     : std::integral_constant<bool, true> {};
 
+#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
 template <class _Tp>
 _LIBCPP_INLINE_VAR constexpr bool is_abi_tag_v = is_abi_tag<_Tp>::value;
 template <class _Tp>
@@ -1036,6 +804,7 @@ _LIBCPP_INLINE_VAR constexpr bool is_simd_mask_v = is_simd_mask<_Tp>::value;
 template <class _Tp>
 _LIBCPP_INLINE_VAR constexpr bool is_simd_flag_type_v =
     is_simd_flag_type<_Tp>::value;
+#endif
 template <class _Tp, size_t _Np>
 struct abi_for_size {
   using type = simd_abi::fixed_size<_Np>;
@@ -1055,16 +824,17 @@ struct simd_size<_Tp, __simd_abi<__kind, _Np>>
       "Element type should be vectorizable");
 };
 
-// TODO: implement it.
 template <class _Tp, class _Up = typename _Tp::value_type>
 struct memory_alignment;
 
+#if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
 template <class _Tp, class _Abi = simd_abi::compatible<_Tp>>
 _LIBCPP_INLINE_VAR constexpr size_t simd_size_v = simd_size<_Tp, _Abi>::value;
 
 template <class _Tp, class _Up = typename _Tp::value_type>
 _LIBCPP_INLINE_VAR constexpr size_t memory_alignment_v =
     memory_alignment<_Tp, _Up>::value;
+#endif
 
 // class template simd [simd.class]
 template <class _Tp>
@@ -1202,6 +972,11 @@ template <class _MaskType, class _Tp>
 class where_expression;
 
 // masked assignment [simd.mask.where]
+template <class _Tp>
+struct __nodeduce {
+  using type = _Tp;
+};
+
 template <class _Tp, class _Abi>
 where_expression<simd_mask<_Tp, _Abi>, simd<_Tp, _Abi>>
 where(const typename simd<_Tp, _Abi>::mask_type&, simd<_Tp, _Abi>&) noexcept;
@@ -1338,23 +1113,7 @@ public:
 // TODO: implement simd
 template <class _Tp, class _Abi>
 class simd {
-public:
-  using value_type = _Tp;
-  using reference = __simd_reference<_Tp, _Tp, _Abi>;
-  using mask_type = simd_mask<_Tp, _Abi>;
-  using abi_type = _Abi;
-
-  simd() = default;
-  simd(const simd&) = default;
-  simd& operator=(const simd&) = default;
-
-  static constexpr size_t size() noexcept {
-    return simd_size<_Tp, _Abi>::value;
-  }
-
 private:
-  __simd_storage<_Tp, _Abi> __s_;
-
   template <class _Up>
   static constexpr bool __can_broadcast() {
     return (std::is_arithmetic<_Up>::value &&
@@ -1367,97 +1126,57 @@ private:
             std::is_unsigned<_Tp>::value);
   }
 
-  template <class _Generator, size_t... __indicies>
-  static constexpr decltype(
-      std::forward_as_tuple(std::declval<_Generator>()(
-          std::integral_constant<size_t, __indicies>())...),
-      bool())
-  __can_generate(std::index_sequence<__indicies...>) {
-    return !__variadic_sum<bool>(
-        !__can_broadcast<decltype(std::declval<_Generator>()(
-            std::integral_constant<size_t, __indicies>()))>()...);
-  }
+public:
+  using value_type = _Tp;
+  // TODO: this is strawman implementation. Turn it into a proxy type.
+  using reference = _Tp&;
+  using mask_type = simd_mask<_Tp, _Abi>;
 
-  template <class _Generator>
-  static bool __can_generate(...) {
-    return false;
-  }
+  using abi_type = _Abi;
 
-  template <class _Generator, size_t... __indicies>
-  void __generator_init(_Generator&& __g, std::index_sequence<__indicies...>) {
-    int __not_used[]{((*this)[__indicies] =
-                          __g(std::integral_constant<size_t, __indicies>()),
-                      0)...};
-    (void)__not_used;
+  static constexpr size_t size() noexcept {
+    return simd_size<_Tp, _Abi>::value;
   }
 
-public:
+  simd() = default;
+
   // implicit type conversion constructor
   template <class _Up,
             class = typename std::enable_if<
                 std::is_same<_Abi, simd_abi::fixed_size<size()>>::value &&
                 __is_non_narrowing_arithmetic_convertible<_Up, _Tp>()>::type>
-  simd(const simd<_Up, simd_abi::fixed_size<size()>>& __v) {
-    for (size_t __i = 0; __i < size(); __i++) {
-      (*this)[__i] = static_cast<_Tp>(__v[__i]);
-    }
-  }
+  simd(const simd<_Up, simd_abi::fixed_size<size()>>&) {}
 
   // implicit broadcast constructor
   template <class _Up,
             class = typename std::enable_if<__can_broadcast<_Up>()>::type>
-  simd(_Up&& __rv) {
-    auto __v = static_cast<_Tp>(__rv);
-    for (size_t __i = 0; __i < size(); __i++) {
-      (*this)[__i] = __v;
-    }
-  }
+  simd(_Up&&);
 
   // generator constructor
+  // TODO: for now only check for the index 0. This is because C++11 doesn't
+  // have index_sequence, and it's hard to check for all indicies without using
+  // index_sequence.
   template <class _Generator,
-            int = typename std::enable_if<
-                __can_generate<_Generator>(std::make_index_sequence<size()>()),
-                int>::type()>
-  explicit simd(_Generator&& __g) {
-    __generator_init(std::forward<_Generator>(__g),
-                     std::make_index_sequence<size()>());
-  }
+            int = decltype(simd(std::declval<_Generator>()(
+                               std::integral_constant<size_t, 0>())),
+                           int())()>
+  explicit simd(_Generator&&);
 
   // load constructor
-  template <
-      class _Up, class _Flags,
-      class = typename std::enable_if<__vectorizable<_Up>()>::type,
-      class = typename std::enable_if<is_simd_flag_type<_Flags>::value>::type>
-  simd(const _Up* __buffer, _Flags) {
-    // TODO: optimize for overaligned flags
-    for (size_t __i = 0; __i < size(); __i++) {
-      (*this)[__i] = static_cast<_Tp>(__buffer[__i]);
-    }
-  }
+  template <class _Up, class _Flags>
+  simd(const _Up*, _Flags);
 
   // loads [simd.load]
   template <class _Up, class _Flags>
-  typename std::enable_if<__vectorizable<_Up>() &&
-                          is_simd_flag_type<_Flags>::value>::type
-  copy_from(const _Up* __buffer, _Flags) {
-    *this = simd(__buffer, _Flags());
-  }
+  void copy_from(const _Up*, _Flags);
 
   // stores [simd.store]
   template <class _Up, class _Flags>
-  typename std::enable_if<__vectorizable<_Up>() &&
-                          is_simd_flag_type<_Flags>::value>::type
-  copy_to(_Up* __buffer, _Flags) const {
-    // TODO: optimize for overaligned flags
-    for (size_t __i = 0; __i < size(); __i++) {
-      __buffer[__i] = static_cast<_Up>((*this)[__i]);
-    }
-  }
+  void copy_to(_Up*, _Flags) const;
 
   // scalar access [simd.subscr]
-  reference operator[](size_t __i) { return reference(&__s_, __i); }
-
-  value_type operator[](size_t __i) const { return __s_.__get(__i); }
+  reference operator[](size_t);
+  value_type operator[](size_t) const;
 
   // unary operators [simd.unary]
   simd& operator++();