Add test for parallel compiler reproducible build

tests/run-make/parallel-reproducible-build/rmake.rs

@@ -0,0 +1,33 @@
+//@ ignore-windows-gnu
+// GNU Linker for Windows is non-deterministic. (from `reproducible-build-2` test in this suite)
+
+use std::rc::Rc;
+
+use run_make_support::{bin_name, is_windows_msvc, rfs, run_in_tmpdir, rustc};
+
+/// Test that parallel compiler produces identical binaries.
+fn main() {
+    const FILE_NAME: &str = "static-muts-issue-140413";
+    let bin_name = bin_name(FILE_NAME);
+
+    let mut reference = None;
+
+    for _ in 0..100 {
+        // Tmp dir as previous runs affect output binary on windows.
+        run_in_tmpdir(|| {
+            let mut rustc = rustc();
+            rustc.input(format!("{FILE_NAME}.rs")).arg("-Zthreads=50").output(&bin_name);
+
+            if is_windows_msvc() {
+                rustc.arg("-Clink-arg=/Brepro");
+            }
+
+            rustc.run();
+
+            let current = Rc::new(rfs::read(&bin_name));
+            reference.get_or_insert(Rc::clone(&current));
+
+            assert_eq!(Some(current), reference);
+        });
+    }
+}

tests/run-make/parallel-reproducible-build/static-muts-issue-140413.rs

@@ -0,0 +1,20 @@
+// Checks that mutable static items can have mutable slices and other references
+
+pub static mut TEST: &'static mut [isize] = &mut [1];
+pub static mut EMPTY: &'static mut [isize] = &mut [];
+pub static mut INT: &'static mut isize = &mut 1;
+
+// And the same for raw pointers.
+
+pub static mut TEST_RAW: *mut [isize] = &mut [1isize] as *mut _;
+pub static mut EMPTY_RAW: *mut [isize] = &mut [] as *mut _;
+pub static mut INT_RAW: *mut isize = &mut 1isize as *mut _;
+
+pub fn main() {
+    unsafe {
+        TEST[0] += 1;
+        assert_eq!(TEST[0], 2);
+        *INT_RAW += 1;
+        assert_eq!(*INT_RAW, 2);
+    }
+}