[Bug middle-end/68664] [6/7 Regression] Speculative sqrt in c-ray main loop causes large slow down

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68664

--- Comment #16 from David Edelsohn <dje at gcc dot gnu.org> ---
> That isn't an argument for -fno-sched-spec, it is an argument for a cost 
> model which better matches the cost of the transformation, using the 
> information available, without bloating the automaton.

And that's what Segher proposed with the patch for the hook on the mailing
list.