Auto merge of #1729 - RalfJung:rustup, r=RalfJung

rustup; fix tests for new MIR optimization

Somehow rust-lang/rust#78360 manages to mask UB. This would make sense if there were loops or things like that, but there are not, so really this is just very confusing...

rust-version

@@ -1 +1 @@
-d2731d8e9338d8fe844e19d3fbb39617753e65f4
+09db05762b283bed62d4f92729cfee4646519833

tests/compile-fail/data_race/dealloc_read_race_stack.rs

@@ -1,5 +1,6 @@
 // ignore-windows: Concurrency on Windows is not supported yet.
-// compile-flags: -Zmiri-disable-isolation
+// compile-flags: -Zmiri-disable-isolation -Zmir-opt-level=0
+// FIXME: Disabling optimizations since somehow #78360 broke this test.
 
 use std::thread::{spawn, sleep};
 use std::ptr::null_mut;
@@ -27,9 +28,6 @@ pub fn main() {
     //  3. stack-deallocate
     unsafe {
         let j1 = spawn(move || {
-            // Concurrent allocate the memory.
-            // Uses relaxed semantics to not generate
-            // a release sequence.
             let pointer = &*ptr.0;
             {
                 let mut stack_var = 0usize;
@@ -38,6 +36,8 @@ pub fn main() {
 
                 sleep(Duration::from_millis(200));
 
+                // Now `stack_var` gets deallocated.
+
             } //~ ERROR Data race detected between Deallocate on Thread(id = 1) and Read on Thread(id = 2)
         });
 

tests/compile-fail/data_race/dealloc_write_race_stack.rs

@@ -1,5 +1,6 @@
 // ignore-windows: Concurrency on Windows is not supported yet.
-// compile-flags: -Zmiri-disable-isolation
+// compile-flags: -Zmiri-disable-isolation -Zmir-opt-level=0
+// FIXME: Disabling optimizations since somehow #78360 broke this test.
 
 use std::thread::{spawn, sleep};
 use std::ptr::null_mut;
@@ -27,9 +28,6 @@ pub fn main() {
     //  3. stack-deallocate
     unsafe {
         let j1 = spawn(move || {
-            // Concurrent allocate the memory.
-            // Uses relaxed semantics to not generate
-            // a release sequence.
             let pointer = &*ptr.0;
             {
                 let mut stack_var = 0usize;
@@ -38,6 +36,8 @@ pub fn main() {
 
                 sleep(Duration::from_millis(200));
 
+                // Now `stack_var` gets deallocated.
+
             } //~ ERROR Data race detected between Deallocate on Thread(id = 1) and Write on Thread(id = 2)
         });
 

tests/compile-fail/sync/libc_pthread_rwlock_read_write_deadlock.rs → tests/compile-fail/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.rs

@@ -1,4 +1,6 @@
 // ignore-windows: No libc on Windows
+// compile-flags: -Zmir-opt-level=0
+// FIXME: Disabling optimizations since somehow #78360 broke this test.
 
 #![feature(rustc_private)]
 

tests/compile-fail/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.rs

@@ -1,4 +1,6 @@
 // ignore-windows: No libc on Windows
+// compile-flags: -Zmir-opt-level=0
+// FIXME: Disabling optimizations since somehow #78360 broke this test.
 
 #![feature(rustc_private)]
 

tests/compile-fail/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.rs

@@ -1,4 +1,6 @@
 // ignore-windows: No libc on Windows
+// compile-flags: -Zmir-opt-level=0
+// FIXME: Disabling optimizations since somehow #78360 broke this test.
 
 #![feature(rustc_private)]