[Bug tree-optimization/108770] [12/13/14/15 regression] Spurious -Warray-bounds at -O2 (gcc >= 12)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108770

--- Comment #3 from qinzhao at gcc dot gnu.org ---
With my patch for new option -fdiagnostics-explain-harder, the output is:

t_108770.c: In function ‘init’:
t_108770.c:10:13: warning: array subscript 2 is above array bounds of ‘const
char *[2]’ [-Warray-bounds=]
   10 |   while (arr[check_idx(i)] != 0) {
      |          ~~~^~~~~~~~~~~~~~
  ‘init’: events 1-2
    3 |   if (i > 1)
      |      ^
      |      |
      |      (1) when the condition is evaluated to true
......
   10 |   while (arr[check_idx(i)] != 0) {
      |          ~~~~~~~~~~~~~~~~~
      |             |
      |             (2) out of array bounds here
t_108770.c:7:13: note: while referencing ‘arr’
    7 | const char *arr[] = {"A", 0};
      |             ^~~

this looks like a nice improvement to the diagnostic.