Index: llvm/utils/update_mir_test_checks.py
===================================================================
--- llvm/utils/update_mir_test_checks.py
+++ llvm/utils/update_mir_test_checks.py
@@ -235,9 +235,9 @@
                 break
             if not func_dict[prefix][func_name]:
                 continue
-            # if printed_prefixes:
-            #     # Add some space between different check prefixes.
-            #     output_lines.append('')
+            if printed_prefixes:
+                # Add some space between different check prefixes.
+                output_lines.append('')
             printed_prefixes.add(prefix)
             log("Adding {} lines for {}".format(prefix, func_name), args.verbose)
             add_check_lines(