[all-commits] [llvm/llvm-project] a9cb29: [libc] Add intrinsic for thread fence to the atomi...

[Joseph Huber via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a9cb298b394034856f88aebe66523c4a61c0df2e
      https://github.com/llvm/llvm-project/commit/a9cb298b394034856f88aebe66523c4a61c0df2e
  Author: Joseph Huber <jhuber6 at vols.utk.edu>
  Date:   2023-03-09 (Thu, 09 Mar 2023)

  Changed paths:
    M libc/src/__support/CPP/atomic.h

  Log Message:
  -----------
  [libc] Add intrinsic for thread fence to the atomic support

This function mimics the std::atomic_thread_fence function from
<atomic>. This has no uses in source currently, but this will be used by
the proposed RPC client for the GPU mode support. There is varying
support for direct memory ordering for the GPU atomics on shared memory
resources. So the implementation will use relaxed atomics and explicit
memory fences.

Some additional work may need to be done to map this to `NVPTX` system
level fences.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D145608