[Bug c/80775] -O3 produces ice in group_case_labels_stmt

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80775

--- Comment #1 from David Binderman <dcb314 at hotmail dot com> ---
Reduced code:

typedef struct { short a } b;
b c[10];
d, e, f, g, h;
i() {
  f = 0;
  for (; f < e; f++) {
    switch (g) {
    case 1:
      d = 1;
    case 2:
      c[2 + f].a = 1;
    }
    h += c[f].a;
  }
}