move nopreempt sync tests to their own file

Author: RalfJung

tests/pass/concurrency/sync.rs

@@ -1,6 +1,5 @@
 // ignore-windows: Concurrency on Windows is not supported yet.
-// We are making scheduler assumptions here.
-// compile-flags: -Zmiri-disable-isolation -Zmiri-strict-provenance -Zmiri-preemption-rate=0
+// compile-flags: -Zmiri-disable-isolation -Zmiri-strict-provenance
 
 use std::sync::{Arc, Barrier, Condvar, Mutex, Once, RwLock};
 use std::thread;
@@ -53,35 +52,6 @@ fn check_conditional_variables_notify_one() {
     }
 }
 
-fn check_conditional_variables_notify_all() {
-    let pair = Arc::new(((Mutex::new(())), Condvar::new()));
-
-    // Spawn threads and block them on the conditional variable.
-    let handles: Vec<_> = (0..5)
-        .map(|_| {
-            let pair2 = pair.clone();
-            thread::spawn(move || {
-                let (lock, cvar) = &*pair2;
-                let guard = lock.lock().unwrap();
-                // Block waiting on the conditional variable.
-                let _ = cvar.wait(guard).unwrap();
-            })
-        })
-        .inspect(|_| {
-            thread::yield_now();
-            thread::yield_now();
-        })
-        .collect();
-
-    let (_, cvar) = &*pair;
-    // Unblock all threads.
-    cvar.notify_all();
-
-    for handle in handles {
-        handle.join().unwrap();
-    }
-}
-
 /// Test that waiting on a conditional variable with a timeout does not
 /// deadlock.
 fn check_conditional_variables_timed_wait_timeout() {
@@ -301,7 +271,6 @@ fn check_condvar() {
 fn main() {
     check_barriers();
     check_conditional_variables_notify_one();
-    check_conditional_variables_notify_all();
     check_conditional_variables_timed_wait_timeout();
     check_conditional_variables_timed_wait_notimeout();
     check_mutex();

tests/pass/concurrency/sync_nopreempt.rs

@@ -0,0 +1,40 @@
+// ignore-windows: Concurrency on Windows is not supported yet.
+// We are making scheduler assumptions here.
+// compile-flags: -Zmiri-strict-provenance -Zmiri-preemption-rate=0
+
+use std::sync::{Condvar, Mutex, Arc};
+use std::thread;
+
+fn check_conditional_variables_notify_all() {
+    let pair = Arc::new(((Mutex::new(())), Condvar::new()));
+
+    // Spawn threads and block them on the conditional variable.
+    let handles: Vec<_> = (0..5)
+        .map(|_| {
+            let pair2 = pair.clone();
+            thread::spawn(move || {
+                let (lock, cvar) = &*pair2;
+                let guard = lock.lock().unwrap();
+                // Block waiting on the conditional variable.
+                let _ = cvar.wait(guard).unwrap();
+            })
+        })
+        .inspect(|_| {
+            // Ensure the other threads all run and block on the `wait`.
+            thread::yield_now();
+            thread::yield_now();
+        })
+        .collect();
+
+    let (_, cvar) = &*pair;
+    // Unblock all threads.
+    cvar.notify_all();
+
+    for handle in handles {
+        handle.join().unwrap();
+    }
+}
+
+fn main() {
+    check_conditional_variables_notify_all();
+}