Rollup merge of rust-lang#82093 - bjorn3:more_atomic_tests, r=kennytm

Add tests for Atomic*::fetch_{min,max}

This ensures that all atomic operations except for fences are tested. This has been useful to test my work on using atomic instructions for atomic operations in cg_clif instead of a global lock.

library/core/tests/atomic.rs

@@ -59,6 +59,24 @@ fn uint_xor() {
     assert_eq!(x.load(SeqCst), 0xf731 ^ 0x137f);
 }
 
+#[test]
+fn uint_min() {
+    let x = AtomicUsize::new(0xf731);
+    assert_eq!(x.fetch_min(0x137f, SeqCst), 0xf731);
+    assert_eq!(x.load(SeqCst), 0x137f);
+    assert_eq!(x.fetch_min(0xf731, SeqCst), 0x137f);
+    assert_eq!(x.load(SeqCst), 0x137f);
+}
+
+#[test]
+fn uint_max() {
+    let x = AtomicUsize::new(0x137f);
+    assert_eq!(x.fetch_max(0xf731, SeqCst), 0x137f);
+    assert_eq!(x.load(SeqCst), 0xf731);
+    assert_eq!(x.fetch_max(0x137f, SeqCst), 0xf731);
+    assert_eq!(x.load(SeqCst), 0xf731);
+}
+
 #[test]
 fn int_and() {
     let x = AtomicIsize::new(0xf731);
@@ -87,6 +105,24 @@ fn int_xor() {
     assert_eq!(x.load(SeqCst), 0xf731 ^ 0x137f);
 }
 
+#[test]
+fn int_min() {
+    let x = AtomicIsize::new(0xf731);
+    assert_eq!(x.fetch_min(0x137f, SeqCst), 0xf731);
+    assert_eq!(x.load(SeqCst), 0x137f);
+    assert_eq!(x.fetch_min(0xf731, SeqCst), 0x137f);
+    assert_eq!(x.load(SeqCst), 0x137f);
+}
+
+#[test]
+fn int_max() {
+    let x = AtomicIsize::new(0x137f);
+    assert_eq!(x.fetch_max(0xf731, SeqCst), 0x137f);
+    assert_eq!(x.load(SeqCst), 0xf731);
+    assert_eq!(x.fetch_max(0x137f, SeqCst), 0xf731);
+    assert_eq!(x.load(SeqCst), 0xf731);
+}
+
 static S_FALSE: AtomicBool = AtomicBool::new(false);
 static S_TRUE: AtomicBool = AtomicBool::new(true);
 static S_INT: AtomicIsize = AtomicIsize::new(0);