[Bug target/71722] incorrect code for test pr64252.c for -mcpu=power9 -mpower9-vector -ftree-vectorize -O3

[acsawdey at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71722

--- Comment #2 from acsawdey at gcc dot gnu.org ---
adding -mno-power9-dform-vector does not help this one. So, likely not
dform-vector related.