Rollup merge of #74449 - tmiasko:cmpxchg-test, r=nikomatsakis

Test codegen of compare_exchange operations

Add a codegen test for compare_exchange to verify that rustc emits expected LLVM IR.

src/test/codegen/atomic-operations.rs

@@ -0,0 +1,60 @@
+// Code generation of atomic operations.
+//
+// compile-flags: -O
+#![crate_type = "lib"]
+
+use std::sync::atomic::{AtomicI32, Ordering::*};
+
+// CHECK-LABEL: @compare_exchange
+#[no_mangle]
+pub fn compare_exchange(a: &AtomicI32) {
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 10 monotonic monotonic
+    let _ = a.compare_exchange(0, 10, Relaxed, Relaxed);
+
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 20 release monotonic
+    let _ = a.compare_exchange(0, 20, Release, Relaxed);
+
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 30 acquire monotonic
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 31 acquire acquire
+    let _ = a.compare_exchange(0, 30, Acquire, Relaxed);
+    let _ = a.compare_exchange(0, 31, Acquire, Acquire);
+
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 40 acq_rel monotonic
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 41 acq_rel acquire
+    let _ = a.compare_exchange(0, 40, AcqRel, Relaxed);
+    let _ = a.compare_exchange(0, 41, AcqRel, Acquire);
+
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 50 seq_cst monotonic
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 51 seq_cst acquire
+    // CHECK: cmpxchg i32* %{{.*}}, i32 0, i32 52 seq_cst seq_cst
+    let _ = a.compare_exchange(0, 50, SeqCst, Relaxed);
+    let _ = a.compare_exchange(0, 51, SeqCst, Acquire);
+    let _ = a.compare_exchange(0, 52, SeqCst, SeqCst);
+}
+
+// CHECK-LABEL: @compare_exchange_weak
+#[no_mangle]
+pub fn compare_exchange_weak(w: &AtomicI32) {
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 10 monotonic monotonic
+    let _ = w.compare_exchange_weak(1, 10, Relaxed, Relaxed);
+
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 20 release monotonic
+    let _ = w.compare_exchange_weak(1, 20, Release, Relaxed);
+
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 30 acquire monotonic
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 31 acquire acquire
+    let _ = w.compare_exchange_weak(1, 30, Acquire, Relaxed);
+    let _ = w.compare_exchange_weak(1, 31, Acquire, Acquire);
+
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 40 acq_rel monotonic
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 41 acq_rel acquire
+    let _ = w.compare_exchange_weak(1, 40, AcqRel, Relaxed);
+    let _ = w.compare_exchange_weak(1, 41, AcqRel, Acquire);
+
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 50 seq_cst monotonic
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 51 seq_cst acquire
+    // CHECK: cmpxchg weak i32* %{{.*}}, i32 1, i32 52 seq_cst seq_cst
+    let _ = w.compare_exchange_weak(1, 50, SeqCst, Relaxed);
+    let _ = w.compare_exchange_weak(1, 51, SeqCst, Acquire);
+    let _ = w.compare_exchange_weak(1, 52, SeqCst, SeqCst);
+}