[Bug tree-optimization/81611] [8 Regression] gcc un-learned loop / post-increment optimization

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81611

--- Comment #13 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
We do have such constant propagation on such ports as x86* and arm, but not on
avr.  Presumably (I haven't checked) it has to do with available addressing
modes, and gimple's avoiding, even in MEM_REFs, address expressions that don't
fit its more stringent requirements.