diff --git a/clang/test/utils/update-verify-tests/lit.local.cfg b/clang/test/utils/update-verify-tests/lit.local.cfg
index a0b6afccc2501..b0eebf337da5c 100644
--- a/clang/test/utils/update-verify-tests/lit.local.cfg
+++ b/clang/test/utils/update-verify-tests/lit.local.cfg
@@ -23,3 +23,6 @@ else:
             "%s %s" % (python, shell_quote(script_path)),
         )
     )
+    # AIX 'diff' command doesn't support --strip-trailing-cr, but the internal
+    # python implementation does, so use that for cross platform compatibility
+    config.test_format = lit.formats.ShTest()