https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105451
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Ever confirmed|0 |1 Last reconfirmed| |2022-05-02 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- It's difficult to even spot the difference in the SLP tree, but the associatable multiplications make it somewhat random which of the valid SLP tree representations we'll pick. All of the SLP discovery is a heuristically greedy search for the _first_ match, not for the "best" even ("best" interpreted as "largest" in case of BB vectorization). The only thing that reliably happens at the moment is associating until the leafs are all from one load group (until we support multiple load groups in one leaf).