[Bug target/111720] RISC-V: Ugly codegen in RVV

[pan2.li at intel dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111720

--- Comment #31 from Li Pan <pan2.li at intel dot com> ---
We still have some unnecessary code here, which is stack-related, will take
care of it in another PATCH.

    After this patch:
    test:
      lui     a5,%hi(.LANCHOR0)
      addi    a5,a5,%lo(.LANCHOR0)
      li      a4,32
      addi    sp,sp,-32                   <== unnecessary insn
      vsetvli zero,a4,e8,m1,ta,ma
      vle8.v  v1,0(a5)
      vs1r.v  v1,0(a0)
      addi    sp,sp,32                    <== unnecessary insn
      jr      ra