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

Summary:
This patch adds a new macro _LIBCPP_HAS_NO_VECTOR_EXTENSION for detecting
whether a vector extension (\_\_attribute\_\_((vector_size(num_bytes)))) is
available.

On the top of that, this patch implements the following API:
* all constructors
* operator[]
* copy_from
* copy_to

It also defines simd_abi::native to use vector extension, if available.
In GCC and Clang, certain values with vector extension are passed by registers,
instead of memory.

Based on D41148.

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits, MaskRay, lichray, sanjoy

Differential Revision: https://reviews.llvm.org/D41376

llvm-svn: 338309

1 files changed, 15 insertions, 12 deletions

diff --git a/libcxx/test/std/experimental/simd/simd.casts/static_simd_cast.pass.cpp b/libcxx/test/std/experimental/simd/simd.casts/static_simd_cast.pass.cpp
index eb1fa55e0a4..b734664770e 100644
--- a/libcxx/test/std/experimental/simd/simd.casts/static_simd_cast.pass.cpp
+++ b/libcxx/test/std/experimental/simd/simd.casts/static_simd_cast.pass.cpp
@@ -7,32 +7,35 @@
 //
 //===----------------------------------------------------------------------===//
 
-// UNSUPPORTED: c++98, c++03
+// UNSUPPORTED: c++98, c++03, c++11, c++14
 
 // <experimental/simd>
 //
 // [simd.casts]
-// template <class T, class U, class Abi> see below static_simd_cast(const simd<U, Abi>&);
+// template <class T, class U, class Abi> see below ex::static_simd_cast<(const
+// ex::simd<U, Abi>&);
 
 #include <experimental/simd>
 #include <cstdint>
 
-using namespace std::experimental::parallelism_v2;
+namespace ex = std::experimental::parallelism_v2;
 
 static_assert(
-    std::is_same<decltype(static_simd_cast<float>(native_simd<int>())),
-                 native_simd<float>>::value,
+    std::is_same<decltype(ex::static_simd_cast<float>(ex::native_simd<int>())),
+                 ex::native_simd<float>>::value,
     "");
 
-static_assert(std::is_same<decltype(static_simd_cast<fixed_size_simd<float, 1>>(
-                               simd<int, simd_abi::scalar>())),
-                           fixed_size_simd<float, 1>>::value,
-              "");
+static_assert(
+    std::is_same<decltype(ex::static_simd_cast<ex::fixed_size_simd<float, 1>>(
+                     ex::simd<int, ex::simd_abi::scalar>())),
+                 ex::fixed_size_simd<float, 1>>::value,
+    "");
 
 static_assert(
-    std::is_same<decltype(static_simd_cast<simd<float, simd_abi::scalar>>(
-                     fixed_size_simd<int, 1>())),
-                 simd<float, simd_abi::scalar>>::value,
+    std::is_same<
+        decltype(ex::static_simd_cast<ex::simd<float, ex::simd_abi::scalar>>(
+            ex::fixed_size_simd<int, 1>())),
+        ex::simd<float, ex::simd_abi::scalar>>::value,
     "");
 
 int main() {}