Auto merge of #67362 - Mark-Simulacrum:par-4-default, r=alexcrichton

4 thread parallelism by default

The Session default here is super unusual but seems to both compile and do what we expect as best as I can tell.

2 files changed, 4 insertions, 1 deletions

diff --git a/src/librustc_data_structures/lib.rs b/src/librustc_data_structures/lib.rs
index fb541637e5f..02611a36aae 100644
--- a/src/librustc_data_structures/lib.rs
+++ b/src/librustc_data_structures/lib.rs
@@ -24,6 +24,7 @@
 #![feature(integer_atomics)]
 #![feature(test)]
 #![feature(associated_type_bounds)]
+#![feature(cfg_target_has_atomic)]
 
 #![cfg_attr(unix, feature(libc))]
 
diff --git a/src/librustc_data_structures/sync.rs b/src/librustc_data_structures/sync.rs
index 6a19f52897e..c4aed0628ba 100644
--- a/src/librustc_data_structures/sync.rs
+++ b/src/librustc_data_structures/sync.rs
@@ -317,7 +317,9 @@ cfg_if! {
         pub use parking_lot::MutexGuard as LockGuard;
         pub use parking_lot::MappedMutexGuard as MappedLockGuard;
 
-        pub use std::sync::atomic::{AtomicBool, AtomicUsize, AtomicU32, AtomicU64};
+        pub use std::sync::atomic::{AtomicBool, AtomicUsize, AtomicU32};
+        #[cfg(target_has_atomic = "64")]
+        pub use std::sync::atomic::{AtomicU64};
 
         pub use crossbeam_utils::atomic::AtomicCell;