[Bug target/90323] powerpc should convert equivalent sequences to vec_sel()

[slandden at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90323

--- Comment #3 from Shawn Landden <slandden at gmail dot com> ---
Instead:

        .globl without_sel
        .type   without_sel, @function
without_sel:
.LFB0:
        .cfi_startproc
        xxlxor 36,34,36
        xxland 36,36,35
        xxlxor 34,34,36
        blr
        .long 0
        .byte 0,0,0,0,0,0,0,0
        .cfi_endproc
.LFE0:
        .size   without_sel,.-without_sel
        .align 2
        .p2align 4,,15
        .globl with_sel
        .type   with_sel, @function
with_sel:
.LFB1:
        .cfi_startproc
        xxsel 34,34,36,35
        blr
        .long 0
        .byte 0,0,0,0,0,0,0,0
        .cfi_endproc
.LFE1:
        .size   with_sel,.-with_sel