[Bug testsuite/84370] Invalid option used in test case gcc.target/powerpc/builtins-3-p9-runnable.c

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84370

--- Comment #1 from Segher Boessenkool <segher at gcc dot gnu.org> ---
That option was deleted in r250482 (last July) and now is on when VSX is on.
So in this testcase it can just be deleted (it already has -mcpu=power9 which
implies -mvsx).