cmpxchg16b: use atomic_compare_exchange from libcore
diff --git a/crates/core_arch/src/x86_64/cmpxchg16b.rs b/crates/core_arch/src/x86_64/cmpxchg16b.rs
index a4fc0e7..46a0082 100644
--- a/crates/core_arch/src/x86_64/cmpxchg16b.rs
+++ b/crates/core_arch/src/x86_64/cmpxchg16b.rs
@@ -48,34 +48,8 @@
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)
}
