[SYCLomatic]Fix incorrect return value of atomic_compare_exchange_strong (#694)

Signed-off-by: Ni, Wenhui <[email protected]>

Author: wenhuiNi

clang/runtime/dpct-rt/include/atomic.hpp.inc

@@ -714,7 +714,7 @@ T1 atomic_compare_exchange_strong(
       sycl::atomic_ref<T1, memoryOrder, memoryScope, addressSpace>(*addr);
   T1 expected_value = expected;
   atm.compare_exchange_strong(expected_value, desired, success, fail);
-  return expected;
+  return expected_value;
 }
 
 /// Atomically compare the value at \p addr to the value expected and exchange
@@ -754,7 +754,7 @@ T1 atomic_compare_exchange_strong(
   auto atm =
       sycl::atomic_ref<T1, memoryOrder, memoryScope, addressSpace>(addr[0]);
   atm.compare_exchange_strong(expected_value, desired, success, fail);
-  return expected;
+  return expected_value;
 }
 // DPCT_LABEL_END
 

clang/test/dpct/helper_files_ref/include/atomic.hpp

@@ -637,7 +637,7 @@ T1 atomic_compare_exchange_strong(
       sycl::atomic_ref<T1, memoryOrder, memoryScope, addressSpace>(*addr);
   T1 expected_value = expected;
   atm.compare_exchange_strong(expected_value, desired, success, fail);
-  return expected;
+  return expected_value;
 }
 
 /// Atomically compare the value at \p addr to the value expected and exchange
@@ -677,7 +677,7 @@ T1 atomic_compare_exchange_strong(
   auto atm =
       sycl::atomic_ref<T1, memoryOrder, memoryScope, addressSpace>(addr[0]);
   atm.compare_exchange_strong(expected_value, desired, success, fail);
-  return expected;
+  return expected_value;
 }
 
 /// Atomic extension to implement standard APIs in std::atomic