[Bug target/119210] [SME] 'smstart za' seems not to dominate the block that uses za register

[xiezhiheng at huawei dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119210

--- Comment #7 from xiezhiheng at huawei dot com ---
For other information,
https://godbolt.org/z/xdPYGsjYd

LLVM seems always dominate block .LBB0_14

.LBB0_11:
        add     x23, x23, #1
        msr     TPIDR2_EL0, xzr
        cmp     x23, #64
        b.eq    .LBB0_14
.LBB0_12:
        ldr     d0, [x20, x23, lsl #3]
        ldr     d1, [x21, x23, lsl #3]
        mov     x0, x24
        mov     w1, w23
        sturh   w25, [x29, #-72]
        msr     TPIDR2_EL0, x26
        bl      printf
        smstart za           <== smstart za before cbnz
        mrs     x8, TPIDR2_EL0
        sub     x0, x29, #80
        cbnz    x8, .LBB0_11
        bl      __arm_tpidr2_restore
        b       .LBB0_11
.LBB0_14:
        smstart sm
        mov     x0, x20
        mov     x1, x21
        bl      example(double*, double*)
        mov     x0, x22
        bl      example0(double*)
        smstop  sm
        mov     x23, xzr
        rdsvl   x25, #1
        sub     x26, x29, #80
        adrp    x24, .L.str.1
        add     x24, x24, :lo12:.L.str.1
        b       .LBB0_16