https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79201
--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #6)
> here is a testcase where DOM does not mess with the loop but we should still
> be able to sink the function out and do when adding -fno-tree-pre:
>
> int f(int n, int t) {
> int i,j=0;
> if (t >=31 || t < 0) return 100;
>
> for (i = 0; i < t; i++) {
> j = __builtin_ffs(i);
> }
> return j;
> }
Note in GCC 12+, you need -fno-tree-vectorize to get the bad behavior back.
