[Bug rtl-optimization/87047] [7/8/9 Regression] performance regression because of if-conversion

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87047

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I suspect it is treating cost 0 as being free rather than unknown cost.  And
the x86 backend is returning 0 cost for the upper multiple.