[Bug tree-optimization/86965] nios2 optimizer forgets about known upper bits of register

[sandra at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86965

--- Comment #2 from sandra at gcc dot gnu.org ---
Also see PR86975, which is specifically about that negative constant operand to
the AND expression being generated by the range optimizer.