diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 0e6b5ec..6d8d7f2 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -742,6 +742,11 @@
         << Ptr->getType() << Ptr->getSourceRange();
       return ExprError();
     }
+    if (AtomTy.isConstQualified()) {
+      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic)
+        << Ptr->getType() << Ptr->getSourceRange();
+      return ExprError();
+    }
     ValType = AtomTy->getAs<AtomicType>()->getValueType();
   }
 
@@ -6124,4 +6129,3 @@
         << ArgumentExpr->getSourceRange()
         << TypeTagExpr->getSourceRange();
 }
-