[Bug rtl-optimization/87507] IRA unnecessarily uses non-volatile registers during register assignment

[bergner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87507

--- Comment #6 from Peter Bergner <bergner at gcc dot gnu.org> ---
(In reply to Peter Bergner from comment #2)
> Seems to work fine on BE, so probably a LE only issue.

So this is a generic problem, not related to LE.  I can get this to fail on BE
as well if I strategically remove some hard regs via using -ffixed-r6
-ffixed-r9 -ffixed-r11.