[Bug tree-optimization/96920] [10/11 Regression] ICE segmentation fault in tree-vectorizer at -O3

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96920

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
It's similar to PR96698 where we had a nested cycle where a cycle PHI was fed
by an induction.  Here we're feeding the cycle PHI by another cycle PHI so the
fancy detection of computing a latch value doesn't work since the def is both
the PHI of a cycle _and_ the latch def (in PR96698 we were safe because the def
was an induction, not clashing with data structures).

I never liked the current code much but now have to think about sth more
reliable
and workable for SLP.