[all-commits] [llvm/llvm-project] ed372d: [M68k] Add support for lowering atomic fence

[Min-Yih Hsu via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ed372d194f938b750855ad1297517d26f1102250
      https://github.com/llvm/llvm-project/commit/ed372d194f938b750855ad1297517d26f1102250
  Author: Min-Yih Hsu <minyihh at uci.edu>
  Date:   2023-04-01 (Sat, 01 Apr 2023)

  Changed paths:
    M llvm/lib/Target/M68k/M68kISelLowering.cpp
    M llvm/lib/Target/M68k/M68kISelLowering.h
    A llvm/test/CodeGen/M68k/Atomics/fence.ll

  Log Message:
  -----------
  [M68k] Add support for lowering atomic fence

Ideally we want to lower ATOMIC_FENCE into `__sync_synchronize`.
However, libgcc doesn't implement that builtin as GCC simply generates an
inline assembly barrier whenever there needs to be a fence.

We use a similar way to lower ATOMIC_FENCE.

Differential Revision: https://reviews.llvm.org/D146996