https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104010
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> --- This is likely because of a similar issue as PR103941 and related to pattern recognition. We're trying to be more precise now but with patterns there are still issues and we are now erroring on the "safe" side (not vectorizing). The way we compute the "scalar cover" of the vectorized stmts is currently not correct and it probably needs another rewrite. Likely the fix for PR102176 regressed this. I do have a small fix for this particular testcase but I think it will then not cost pattern stmts with multiple scalar pieces correctly - basically the whole vect_bb_slp_scalar_cost needs a rewrite.
