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

[jgreenhalgh at gcc dot gnu.org]

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

--- Comment #17 from James Greenhalgh <jgreenhalgh at gcc dot gnu.org> ---
(In reply to David Edelsohn from comment #16)
> > 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.

I totally missed the proposal!
https://gcc.gnu.org/ml/gcc-patches/2017-01/msg02101.html for others following
this thread.