[Bug target/89271] [9 Regression] gcc.target/powerpc/vsx-simode2.c stopped working in GCC 9

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89271

--- Comment #20 from Segher Boessenkool <segher at gcc dot gnu.org> ---
I currently get (on BE; the testcase forces -mcpu=power8):

        std 3,-16(1)
        addi 9,1,-12
        lxsiwzx 32,0,9
#APP
 # 10 "vsx-simode2.c" 1
        xxlor 32,32,32  # v, v constraints
 # 0 "" 2
#NO_APP
        mfvsrwz 3,32
        blr

so yes this test _should_ fail, we do the wrong thing.  NO_REGS is
chosen for this reg class, no vector class is considered.