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

["juzhe.zhong at rivai dot ai" <gcc-bugzilla@gcc.gnu.org>]

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

            Bug ID: 111720
           Summary: RISC-V: Ugly codegen in RVV
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: juzhe.zhong at rivai dot ai
  Target Milestone: ---

Reference: https://godbolt.org/z/YqW7Y5Yve

#include<riscv_vector.h>
vbool8_t fn() {

    uint8_t arr[32] = {1, 2, 7, 1, 3, 4, 5, 3, 1, 0, 1, 2, 4, 4, 9, 9, 1, 2, 7,
1, 3, 4, 5, 3, 1, 0, 1, 2, 4, 4, 9, 9};
    uint8_t m = 1;

    vuint8m1_t varr = __riscv_vle8_v_u8m1(arr, 32);
    vuint8m1_t vand_m = __riscv_vand_vx_u8m1(varr, m, 32);
    vbool8_t vmask = __riscv_vreinterpret_v_u8m1_b8(vand_m);

    return vmask;
}

GCC asm:

fn:
        lui     a5,%hi(.LANCHOR0)
        addi    sp,sp,-32
        vsetivli        zero,4,e64,m2,ta,ma
        addi    a5,a5,%lo(.LANCHOR0)
        li      a4,32
        vle64.v v2,0(a5)
        vse64.v v2,0(sp)
        vsetvli zero,a4,e8,m1,ta,ma
        vle8.v  v1,0(sp)
        vand.vi v1,v1,1
        vsetvli a5,zero,e8,m1,ta,ma
        vsm.v   v1,0(a0)
        addi    sp,sp,32
        jr      ra

LLVM ASM:

fn:                                     # @fn
.Lpcrel_hi0:
        auipc   a0, %pcrel_hi(.L__const.fn.arr)
        addi    a0, a0, %pcrel_lo(.Lpcrel_hi0)
        li      a1, 32
        vsetvli zero, a1, e8, m1, ta, ma
        vle8.v  v8, (a0)
        vand.vi v0, v8, 1
        ret
.L__const.fn.arr:
        .ascii 
"\001\002\007\001\003\004\005\003\001\000\001\002\004\004\t\t\001\002\007\001\003\004\005\003\001\000\001\002\004\004\t\t"