loongarch64: wrong implementation of `xvldi` instruction

Host environment

• Operating system: Debian
• QEMU flavor: qemu-user-static
• QEMU version: qemu-loongarch64 version 9.2.2 (Debian 1:9.2.2+ds-1+b2)

Emulated/Virtualized environment

• Architecture: loongarch64 (default one)

Description of problem

Consider this sample program.

#include <cstdio>
#include <cstdint>
#include <lsxintrin.h>
#include <lasxintrin.h>

void dump_u32(__m256i x) {
    uint32_t tmp[32/4];
    __lasx_xvst(x, tmp, 0);
    putchar('[');
    for (int i=0; i < 32/4; i++) {
        if (i > 0) {
            putchar(' ');
        }

        printf("%08x", tmp[i]);
    }
    puts("]");
}

int main() {
    __m256i const1 = __lasx_xvldi(-3832);
    dump_u32(const1);
}

The magic constants here means: replicate in 32-bit words a byte (0x4) shifted left by 8. We should have a vector of words 0x800, and indeed, the program run on a real hardware prints expected:

[00000800 00000800 00000800 00000800 00000800 00000800 00000800 00000800]

The same program run under Qemu prints:

[08000800 00000000 08000800 00000000 08000800 00000000 08000800 00000000]

Additional information

I grabbed the latest sources, it seems there's bug in target/loongarch/tcg/insn_trans/trans_vec.c.inc, in function vldi_get_value.

    case 1:
        /* data: {2{16'0, imm[7:0], 8'0}} */
        data = (t << 24) | (t << 8);
        break;

There should be (t << (8+32)) | t << 8.