[all-commits] [llvm/llvm-project] 635199: [libc] Simplifies multi implementations

[Guillaume Chatelet via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6351993da72e298b3f79218e4f129a9bbde3e679
      https://github.com/llvm/llvm-project/commit/6351993da72e298b3f79218e4f129a9bbde3e679
  Author: Guillaume Chatelet <gchatelet at google.com>
  Date:   2021-05-12 (Wed, 12 May 2021)

  Changed paths:
    M libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake
    M libc/src/string/CMakeLists.txt
    R libc/src/string/aarch64/CMakeLists.txt
    R libc/src/string/x86_64/CMakeLists.txt
    M libc/test/src/string/CMakeLists.txt

  Log Message:
  -----------
  [libc] Simplifies multi implementations

This is a roll forward of D101895 with two additional fixes:

Original Patch description:
> This is a follow up on D101524 which:
>
> - simplifies cpu features detection and usage,
> - flattens target dependent optimizations so it's obvious which implementations are generated,
> - provides an implementation targeting the host (march/mtune=native) for the mem* functions,
> - makes sure all implementations are unittested (provided the host can run them).

Additional fixes:
 - Fix uninitialized ALL_CPU_FEATURES
 - Use non pseudo microarch as it is only supported from Clang 12 on

Differential Revision: https://reviews.llvm.org/D102233