[Bug target/124454] [14/15/16 Regression] during RTL pass: sched2 ICE: in operator[], at vec.h:911 with custom flags since r14-4944

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124454

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Anyway, seems the cfg is in some non-cleaned-up state at that point, as
pre_and_rev_post_order_compute_fn for a function with n_basic_blocks_for_fn
(fn) 29 is about to return 20 (but before doing that it accesses rev_post_order
array on the uninitialized members and crashes even before reaching the assert
later on.