https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100250
--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> --- This is a consequence of fixing pr97172 by clearing the VLA bounds encoded by the front end in function attributes before the IL enters the middle end: they VLA bounds aren't used to decide whether to diagnose code but they are used in the text of the warnings. That's why the originally submitted patches preserved them (v2 of the patch encoded them as strings: https://gcc.gnu.org/pipermail/gcc-patches/2020-December/562318.html)
