[Bug rtl-optimization/85899] [8/9 Regression] ICE in find_fallthru_edge_from, at haifa-sched.c:8059

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85899

--- Comment #4 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
It appears that fallthru edges to the exit block are unusual in that they don't
obey the invariant e->dest == e->src->next_bb (i.e. next_bb may be anything).

If so, the assert in haifa-sched needs to be relaxed, so I'm going to
bootstrap/regtest the following:

--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -8082,7 +8082,7 @@ find_fallthru_edge_from (basic_block pred)

       if (e)
        {
-         gcc_assert (e->dest == succ);
+         gcc_assert (e->dest == succ || e->dest->index == EXIT_BLOCK);
          return e;
        }
     }