Or else the test returns garbage since it loads after
moving SP. Prior bad disassembly:

    # Block: bb0(v0, v1, v2, v3, v4, v5, v6, v7, v8)
    stp x29, x30, [sp, #-0x10]!
    mov x29, sp
    # bump C stack pointer
    sub sp, sp, #0x10
    # Insn: v10 Return v8
    # pop stack frame
    adds x19, x19, #0x38
    stur x19, [x20, #0x10]
    # restore C stack pointer
    add sp, sp, #0x10
    mov sp, x29
    ldp x29, x30, [sp], #0x10
    ldur x0, [sp]
    ret