diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 54ec1a5..cfbc40b 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1467,7 +1467,7 @@
     Opts.AddVFSOverlayFile(A->getValue());
 }
 
-bool isOpenCL(LangStandard::Kind LangStd) {
+static bool isOpenCL(LangStandard::Kind LangStd) {
   return LangStd == LangStandard::lang_opencl ||
          LangStd == LangStandard::lang_opencl11 ||
          LangStd == LangStandard::lang_opencl12 ||