https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108990
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- Consolidating these kind of duplicates would be nice. Note in this particular case we should order the more specific pattern earlier (diagnosing that with -v would be nice). Implementing order preserving differently, for example by expressing 'A must be matched before B' explicitely would be a good improvement as well. If you add -v to the genmatch command-line you'll see 273 cases where we forcefully re-start matching because of intermediate "more specific" patterns.
