[libc++] <experimental/simd> Add implicit type conversion constructor for class simd/simd_mask (#71132)

libcxx/docs/Status/ParallelismProjects.csv

@@ -20,6 +20,7 @@ Section,Description,Dependencies,Assignee,Complete
 | `[parallel.simd.class] <https://wg21.link/N4808>`_, "`simd<>::size() <https://reviews.llvm.org/D144363>`_", [parallel.simd.traits] simd_size[_v], Yin Zhang, |Complete|
 | `[parallel.simd.class] <https://wg21.link/N4808>`_, "`simd default constructor <https://github.com/llvm/llvm-project/pull/70424>`_", None, Yin Zhang, |Complete|
 | `[parallel.simd.class] <https://wg21.link/N4808>`_, "`simd broadcast constructor <https://reviews.llvm.org/D156225>`_", None, Yin Zhang, |Complete|
+| `[parallel.simd.class] <https://wg21.link/N4808>`_, "`simd implicit type conversion constructor <https://github.com/llvm/llvm-project/pull/71132>`_", None, Yin Zhang, |Complete|
 | `[parallel.simd.class] <https://wg21.link/N4808>`_, "`simd generate constructor <https://reviews.llvm.org/D159442>`_", None, Yin Zhang, |Complete|
 | `[parallel.simd.class] <https://wg21.link/N4808>`_, "`simd subscript operators <https://github.com/llvm/llvm-project/pull/68960>`_", None, Yin Zhang, |Complete|
 | `[parallel.simd.class] <https://wg21.link/N4808>`_, "Class template simd implementation", None, Yin Zhang, |In Progress|
@@ -28,6 +29,7 @@ Section,Description,Dependencies,Assignee,Complete
 | `[parallel.simd.mask.class] <https://wg21.link/N4808>`_, "`simd_mask<>::size() <https://reviews.llvm.org/D144363>`_", [parallel.simd.class] simd<>::size(), Yin Zhang, |Complete|
 | `[parallel.simd.mask.class] <https://wg21.link/N4808>`_, "`simd_mask default constructor <https://github.com/llvm/llvm-project/pull/70424>`_", None, Yin Zhang, |Complete|
 | `[parallel.simd.mask.class] <https://wg21.link/N4808>`_, "`simd_mask broadcast constructor <https://reviews.llvm.org/D156225>`_", None, Yin Zhang, |Complete|
+| `[parallel.simd.mask.class] <https://wg21.link/N4808>`_, "`simd_mask implicit type conversion constructor <https://github.com/llvm/llvm-project/pull/71132>`_", None, Yin Zhang, |Complete|
 | `[parallel.simd.mask.class] <https://wg21.link/N4808>`_, "`simd_mask subscript operators <https://github.com/llvm/llvm-project/pull/68960>`_", None, Yin Zhang, |Complete|
 | `[parallel.simd.mask.class] <https://wg21.link/N4808>`_, "Class template simd_mask implementation", None, Yin Zhang, |In Progress|
 | `[parallel.simd.mask.nonmembers] <https://wg21.link/N4808>`_, "simd_mask non-member operations", None, Yin Zhang, |In Progress|

libcxx/include/experimental/__simd/simd.h

@@ -46,6 +46,17 @@ public:
   template <class _Up, enable_if_t<__can_broadcast_v<value_type, __remove_cvref_t<_Up>>, int> = 0>
   _LIBCPP_HIDE_FROM_ABI simd(_Up&& __v) noexcept : __s_(_Impl::__broadcast(static_cast<value_type>(__v))) {}
 
+  // implicit type conversion constructor
+  template <class _Up,
+            enable_if_t<!is_same_v<_Up, _Tp> && is_same_v<abi_type, simd_abi::fixed_size<size()>> &&
+                            __is_non_narrowing_convertible_v<_Up, value_type>,
+                        int> = 0>
+  _LIBCPP_HIDE_FROM_ABI simd(const simd<_Up, simd_abi::fixed_size<size()>>& __v) noexcept {
+    for (size_t __i = 0; __i < size(); __i++) {
+      (*this)[__i] = static_cast<value_type>(__v[__i]);
+    }
+  }
+
   // generator constructor
   template <class _Generator, enable_if_t<__can_generate_v<value_type, _Generator, size()>, int> = 0>
   explicit _LIBCPP_HIDE_FROM_ABI simd(_Generator&& __g) noexcept

libcxx/include/experimental/__simd/simd_mask.h

@@ -43,6 +43,14 @@ public:
   // broadcast constructor
   _LIBCPP_HIDE_FROM_ABI explicit simd_mask(value_type __v) noexcept : __s_(_Impl::__broadcast(__v)) {}
 
+  // implicit type conversion constructor
+  template <class _Up, enable_if_t<!is_same_v<_Up, _Tp> && is_same_v<abi_type, simd_abi::fixed_size<size()>>, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI simd_mask(const simd_mask<_Up, simd_abi::fixed_size<size()>>& __v) noexcept {
+    for (size_t __i = 0; __i < size(); __i++) {
+      (*this)[__i] = __v[__i];
+    }
+  }
+
   // scalar access [simd.mask.subscr]
   _LIBCPP_HIDE_FROM_ABI reference operator[](size_t __i) noexcept { return reference(__s_, __i); }
   _LIBCPP_HIDE_FROM_ABI value_type operator[](size_t __i) const noexcept { return __s_.__get(__i); }

libcxx/test/std/experimental/simd/simd.class/simd_ctor_conversion.pass.cpp

@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// <experimental/simd>
+//
+// [simd.class]
+// template<class U> simd(const simd<U, simd_abi::fixed_size<size()>>&) noexcept;
+
+#include "../test_utils.h"
+#include <experimental/simd>
+
+namespace ex = std::experimental::parallelism_v2;
+
+template <class T, class SimdAbi, std::size_t array_size>
+struct ConversionHelper {
+  const std::array<T, array_size>& expected_value;
+
+  ConversionHelper(const std::array<T, array_size>& value) : expected_value(value) {}
+
+  template <class U>
+  void operator()() const {
+    if constexpr (!std::is_same_v<U, T> && std::is_same_v<SimdAbi, ex::simd_abi::fixed_size<array_size>> &&
+                  is_non_narrowing_convertible_v<U, T>) {
+      static_assert(noexcept(ex::simd<T, SimdAbi>(ex::simd<U, SimdAbi>{})));
+      ex::simd<U, SimdAbi> origin_simd([](U i) { return i; });
+      ex::simd<T, SimdAbi> simd_from_implicit_conversion(origin_simd);
+      assert_simd_values_equal<array_size>(simd_from_implicit_conversion, expected_value);
+    }
+  }
+};
+
+template <class T, std::size_t>
+struct CheckConversionSimdCtor {
+  template <class SimdAbi>
+  void operator()() {
+    constexpr std::size_t array_size = ex::simd_size_v<T, SimdAbi>;
+    std::array<T, array_size> expected_value;
+    for (size_t i = 0; i < array_size; ++i)
+      expected_value[i] = static_cast<T>(i);
+
+    types::for_each(arithmetic_no_bool_types(), ConversionHelper<T, SimdAbi, array_size>(expected_value));
+  }
+};
+
+template <class T, class SimdAbi, std::size_t array_size>
+struct CheckConversionSimdCtorTraitsHelper {
+  template <class U>
+  void operator()() {
+    if constexpr (!std::is_same_v<U, T>) {
+      if constexpr (std::is_same_v<SimdAbi, ex::simd_abi::fixed_size<array_size>> &&
+                    is_non_narrowing_convertible_v<U, T>)
+        static_assert(std::is_convertible_v<ex::simd<U, SimdAbi>, ex::simd<T, SimdAbi>>);
+      else
+        static_assert(!std::is_convertible_v<ex::simd<U, SimdAbi>, ex::simd<T, SimdAbi>>);
+    }
+  }
+};
+
+template <class T, std::size_t>
+struct CheckConversionSimdCtorTraits {
+  template <class SimdAbi>
+  void operator()() {
+    constexpr std::size_t array_size = ex::simd_size_v<T, SimdAbi>;
+
+    types::for_each(arithmetic_no_bool_types(), CheckConversionSimdCtorTraitsHelper<T, SimdAbi, array_size>());
+  }
+};
+
+int main(int, char**) {
+  test_all_simd_abi<CheckConversionSimdCtor>();
+  test_all_simd_abi<CheckConversionSimdCtorTraits>();
+  return 0;
+}

libcxx/test/std/experimental/simd/simd.mask.class/simd_mask_ctor_conversion.pass.cpp

@@ -0,0 +1,76 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// <experimental/simd>
+//
+// [simd.class]
+// template<class U> simd_mask(const simd_mask<U, simd_abi::fixed_size<size()>>&) noexcept;
+
+#include "../test_utils.h"
+#include <experimental/simd>
+
+namespace ex = std::experimental::parallelism_v2;
+
+template <class T, class SimdAbi, std::size_t array_size>
+struct ConversionHelper {
+  const std::array<bool, array_size>& expected_value;
+
+  ConversionHelper(const std::array<bool, array_size>& value) : expected_value(value) {}
+
+  template <class U>
+  void operator()() const {
+    if constexpr (!std::is_same_v<U, T> && std::is_same_v<SimdAbi, ex::simd_abi::fixed_size<array_size>>) {
+      static_assert(noexcept(ex::simd_mask<T, SimdAbi>(ex::simd_mask<U, SimdAbi>{})));
+      ex::simd_mask<U, SimdAbi> origin_mask(false);
+      ex::simd_mask<T, SimdAbi> mask_from_implicit_conversion(origin_mask);
+      assert_simd_mask_values_equal<array_size>(mask_from_implicit_conversion, expected_value);
+    }
+  }
+};
+
+template <class T, std::size_t>
+struct CheckConversionMaskCtor {
+  template <class SimdAbi>
+  void operator()() {
+    constexpr std::size_t array_size = ex::simd_size_v<T, SimdAbi>;
+    std::array<bool, array_size> expected_value{};
+
+    types::for_each(arithmetic_no_bool_types(), ConversionHelper<T, SimdAbi, array_size>(expected_value));
+  }
+};
+
+template <class T, class SimdAbi, std::size_t array_size>
+struct CheckConversionMaskCtorTraitsHelper {
+  template <class U>
+  void operator()() {
+    if constexpr (!std::is_same_v<U, T>) {
+      if constexpr (std::is_same_v<SimdAbi, ex::simd_abi::fixed_size<array_size>>)
+        static_assert(std::is_convertible_v<ex::simd_mask<U, SimdAbi>, ex::simd_mask<T, SimdAbi>>);
+      else
+        static_assert(!std::is_convertible_v<ex::simd_mask<U, SimdAbi>, ex::simd_mask<T, SimdAbi>>);
+    }
+  }
+};
+
+template <class T, std::size_t>
+struct CheckConversionMaskCtorTraits {
+  template <class SimdAbi>
+  void operator()() {
+    constexpr std::size_t array_size = ex::simd_size_v<T, SimdAbi>;
+
+    types::for_each(arithmetic_no_bool_types(), CheckConversionMaskCtorTraitsHelper<T, SimdAbi, array_size>());
+  }
+};
+
+int main(int, char**) {
+  test_all_simd_abi<CheckConversionMaskCtor>();
+  test_all_simd_abi<CheckConversionMaskCtorTraits>();
+  return 0;
+}