https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115344
--- Comment #4 from Andi Kleen <andi-gcc at firstfloor dot org> --- Pedantry aside the basic problem is that doloop optimization depends on the target supporting doloop, but the loop reversal would be useful everywhere. So there are two options: add doloop to every target of interest or make the reversal optimization independent.
