diff --git a/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt b/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
--- a/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
+++ b/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
@@ -1,3 +1,7 @@
+if (NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB)
+  set (atomic_lib atomic)
+endif()
+
 if( CMAKE_HOST_UNIX AND HAVE_LIBRT )
   set(rt_lib rt)
 endif()
@@ -53,6 +57,7 @@
   LINK_LIBS
   ${LLVM_PTHREAD_LIB}
   ${rt_lib}
+  ${atomic_lib}
 
   LINK_COMPONENTS
   Core