diff --git a/crates/core_arch/src/x86_64/cmpxchg16b.rs b/crates/core_arch/src/x86_64/cmpxchg16b.rs index a4fc0e7321..46a008245b 100644 --- a/crates/core_arch/src/x86_64/cmpxchg16b.rs +++ b/crates/core_arch/src/x86_64/cmpxchg16b.rs @@ -48,34 +48,8 @@ pub unsafe fn cmpxchg16b( success: Ordering, failure: Ordering, ) -> u128 { - use crate::{intrinsics, sync::atomic::Ordering::*}; - debug_assert!(dst as usize % 16 == 0); - // Copied from `atomic_compare_exchange` in `core`. - // https://github.com/rust-lang/rust/blob/f8a2e49/library/core/src/sync/atomic.rs#L3046-L3079 - let (val, _ok) = match (success, failure) { - (Relaxed, Relaxed) => intrinsics::atomic_cxchg_relaxed_relaxed(dst, old, new), - (Relaxed, Acquire) => intrinsics::atomic_cxchg_relaxed_acquire(dst, old, new), - (Relaxed, SeqCst) => intrinsics::atomic_cxchg_relaxed_seqcst(dst, old, new), - (Acquire, Relaxed) => intrinsics::atomic_cxchg_acquire_relaxed(dst, old, new), - (Acquire, Acquire) => intrinsics::atomic_cxchg_acquire_acquire(dst, old, new), - (Acquire, SeqCst) => intrinsics::atomic_cxchg_acquire_seqcst(dst, old, new), - (Release, Relaxed) => intrinsics::atomic_cxchg_release_relaxed(dst, old, new), - (Release, Acquire) => intrinsics::atomic_cxchg_release_acquire(dst, old, new), - (Release, SeqCst) => intrinsics::atomic_cxchg_release_seqcst(dst, old, new), - (AcqRel, Relaxed) => intrinsics::atomic_cxchg_acqrel_relaxed(dst, old, new), - (AcqRel, Acquire) => intrinsics::atomic_cxchg_acqrel_acquire(dst, old, new), - (AcqRel, SeqCst) => intrinsics::atomic_cxchg_acqrel_seqcst(dst, old, new), - (SeqCst, Relaxed) => intrinsics::atomic_cxchg_seqcst_relaxed(dst, old, new), - (SeqCst, Acquire) => intrinsics::atomic_cxchg_seqcst_acquire(dst, old, new), - (SeqCst, SeqCst) => intrinsics::atomic_cxchg_seqcst_seqcst(dst, old, new), - (_, AcqRel) => panic!("there is no such thing as an acquire-release failure ordering"), - (_, Release) => panic!("there is no such thing as a release failure ordering"), - - // `atomic::Ordering` is non_exhaustive. It warns when `core_arch` is built as a part of `core`. - #[allow(unreachable_patterns)] - (_, _) => unreachable!(), - }; - val + let res = crate::sync::atomic::atomic_compare_exchange(dst, old, new, success, failure); + res.unwrap_or_else(|x| x) }