[Bug tree-optimization/121830] [16 regression] ice in vect_build_slp_tree_2, again ?

[sjames at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121830

--- Comment #3 from Sam James <sjames at gcc dot gnu.org> ---
The testcase from the dupe is cleaned up a bit:
```
int a, b;
short c;
short d(short e) { return e - 1; }
int main() {
  for (; c; c++)
    for (a = 2; a != 0; a = d(a)) {
      int *i = &b;
      *i &= a;
    }
  return 0;
}
```