[llvm-branch-commits] [clang] [release/18.x][COFF][Aarch64] Add _InterlockedAdd64 intrinsic (#81849) (PR #89951)

[Tom Stellard via llvm-branch-commits]

tstellar wrote:

> > I think BuiltinsAArch64.def is part of clang's ABI, so changing it violates the backport rules.
> > Otherwise, I'd be inclined to accept; it's kind of late to request, but it's low risk.
> 
> @tstellar can you please advise if this change is ok to backport?

@efriedma-quic Is right, changing the builtin list changes the enum values which breaks the ABI.

https://github.com/llvm/llvm-project/pull/89951