https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100934
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #8)
> --- a/gcc/tree-ssa-threadupdate.c
> +++ b/gcc/tree-ssa-threadupdate.c
> @@ -2379,12 +2379,15 @@ jump_thread_path_registry::duplicate_thread_path
> (edge entry,
> missuses of the functions. I.e. if you ask to copy something weird,
> it will work, but the state of structures probably will not be
> correct. */
> + bool loop_header_duplicated = false;
> for (i = 0; i < n_region; i++)
> {
> /* We do not handle subloops, i.e. all the blocks must belong to the
> same loop. */
> if (region[i]->loop_father != loop)
> return false;
> + if (region[i]->loop_father == loop)
> + loop_header_duplicated = true;
The if right above this returns false if loop_father is not loop, so
wouldn't be loop_header_duplicated == true whenever n_region != 0 (or always)?
