Does psVar[-6] refer to 6*sizeof(psVar) bytes before psVar? Can you avoid the negative index?

Question

In this decompiled code, does psVar8[-6] refer to 6*sizeof(psVar8) == 12 bytes before psVar8?

psVar8 = (short *)(&DAT_1412345b4 + named_index * 0x20);
do {
  if (psVar8[-6] == 0) break;
  // ...
} while (lVar10 < 6);

It would seem more intuitive to me if the position of psVar8 was earlier to avoid the negative index. Is there a way to change this in the decompiled code, or a reason not to?

I'm attaching the entire loop in case that is important to the question:

    do {
      if (psVar8[-6] == 0) break;
      if (psVar8[-6] == 4) {
        named_variable = 0;
        if (0 < *psVar8) {
          named_variable = (int)*psVar8;
        }
        iVar4 = 0x1d;
        if (named_variable < 0x1d) {
          iVar4 = named_variable;
        }
        *(undefined2 *)(&DAT_145678900 + (longlong)iVar4 * 2) = 1;
      }
      lVar10 += 1;
      psVar8 = psVar8 + 1;
    } while (lVar10 < 6);

Answer 1

I think you are running into a case of "shifted pointers". For various reasons the compiler might generate code where a pointer to the middle of a struct is returned. There is a Ghidra PR for this, but this isn't merged yet and still has various issues, IDA discusses this feature here