[libcxx] implement <simd> ABI for Clang/GCC vector extension, constructors…

Authored by timshen on Jul 30 2018, 2:23 PM.


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

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

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