instruction: 0.821
syscall: 0.096
runtime: 0.083



loongarch64: wrong implementation of `xvldi` instruction
Description of problem:
Consider this sample program.

```c++
#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`.

```c
    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`.