diff -up a/lib/Frontend/InitPreprocessor.cpp b/lib/Frontend/InitPreprocessor.cpp
--- a/lib/Frontend/InitPreprocessor.cpp	2021-02-06 05:47:20.000000000 +0100
+++ b/lib/Frontend/InitPreprocessor.cpp	2021-02-08 19:16:07.894088125 +0100
@@ -626,7 +626,10 @@ static void InitializePredefinedMacros(c
     Builder.defineMacro("__GNUC__", Twine(GNUCMajor));
     Builder.defineMacro("__GNUC_MINOR__", Twine(GNUCMinor));
     Builder.defineMacro("__GNUC_PATCHLEVEL__", Twine(GNUCPatch));
-    Builder.defineMacro("__GXX_ABI_VERSION", "1002");
+    if (GNUCMajor < 6)
+      Builder.defineMacro("__GXX_ABI_VERSION", "1002");
+    else
+      Builder.defineMacro("__GXX_ABI_VERSION", "1016");
 
     if (LangOpts.CPlusPlus) {
       Builder.defineMacro("__GNUG__", Twine(GNUCMajor));