[Bug rtl-optimization/64081] [5 Regression] r217827 prevents RTL loop unroll

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64081

--- Comment #10 from David Edelsohn <dje at gcc dot gnu.org> ---
Unfortunately the attached patch causes the same failure demonstrating a
miscompilation of the stage 2 compiler.