[llvm-branch-commits] [libcxx] release/22.x: [libc++][test] Use loop with compare_exchange_weak calls (#185953) (PR #194642)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libcxx

Author: llvmbot

<details>
<summary>Changes</summary>

Backport 3fea2f61652e10c7f3abc17f0542e8bc0dd0ea25

Requested by: @<!-- -->alexrp

---
Full diff: https://github.com/llvm/llvm-project/pull/194642.diff


1 Files Affected:

- (modified) libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp (+10-10) 


``````````diff
diff --git a/libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp b/libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp
index 99c1385a2fe0b..0d9ccd93533a0 100644
--- a/libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.ref/compare_exchange_weak.pass.cpp
@@ -32,11 +32,11 @@ struct TestCompareExchangeWeak {
       std::atomic_ref<T> const a(x);
 
       T t(T(1));
-      std::same_as<bool> decltype(auto) y = a.compare_exchange_weak(t, T(2));
-      assert(y == true);
+      while (!a.compare_exchange_weak(t, T(2))) {
+      }
       assert(a == T(2));
       assert(t == T(1));
-      y = a.compare_exchange_weak(t, T(3));
+      std::same_as<bool> decltype(auto) y = a.compare_exchange_weak(t, T(3));
       assert(y == false);
       assert(a == T(2));
       assert(t == T(2));
@@ -48,11 +48,11 @@ struct TestCompareExchangeWeak {
       std::atomic_ref<T> const a(x);
 
       T t(T(1));
-      std::same_as<bool> decltype(auto) y = a.compare_exchange_weak(t, T(2), std::memory_order_seq_cst);
-      assert(y == true);
+      while (!a.compare_exchange_weak(t, T(2), std::memory_order_seq_cst)) {
+      }
       assert(a == T(2));
       assert(t == T(1));
-      y = a.compare_exchange_weak(t, T(3), std::memory_order_seq_cst);
+      std::same_as<bool> decltype(auto) y = a.compare_exchange_weak(t, T(3), std::memory_order_seq_cst);
       assert(y == false);
       assert(a == T(2));
       assert(t == T(2));
@@ -64,12 +64,12 @@ struct TestCompareExchangeWeak {
       std::atomic_ref<T> const a(x);
 
       T t(T(1));
-      std::same_as<bool> decltype(auto) y =
-          a.compare_exchange_weak(t, T(2), std::memory_order_release, std::memory_order_relaxed);
-      assert(y == true);
+      while (!a.compare_exchange_weak(t, T(2), std::memory_order_release, std::memory_order_relaxed)) {
+      }
       assert(a == T(2));
       assert(t == T(1));
-      y = a.compare_exchange_weak(t, T(3), std::memory_order_release, std::memory_order_relaxed);
+      std::same_as<bool> decltype(auto) y =
+          a.compare_exchange_weak(t, T(3), std::memory_order_release, std::memory_order_relaxed);
       assert(y == false);
       assert(a == T(2));
       assert(t == T(2));

``````````

</details>


https://github.com/llvm/llvm-project/pull/194642