[Bug tree-optimization/122629] [16 Regression] ICE at -O2/O3 during GIMPLE pass: ifcvt

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122629

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is a reduced testcase which fails with a different ICE but the same issue
really:
```
typedef int ix4 __attribute__((vector_size(4*sizeof(int))));

int f(ix4 *a, int l, int *b)
{
  for (int i =0 ;i < l; i++)
  {
    int t;
    ix4 tt = a[i];
    if(*b) t = tt[1]; else t = tt[0];
    *b = t;
  }
}
```