[Bug target/69613] [6 Regression] wrong code with -O and simple 128bit arithmetics and vectors @ aarch64

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69613

--- Comment #2 from ktkachov at gcc dot gnu.org ---
Bisection shows this started with r226901, the big copyrename dropping patch.
I didn't investigate whether it's actually the cause of the bug or just exposes
another latent one.