aco: miscellaneous IR clean up
pretty arbitrary small simplifications and clean ups, I came across.
aco: simplify Definition constructors
aco/lower_to_hw: don't allocate new temporaries
are a prerequisite for !31387 (merged) so that we clearly distinguish between pre and post SSA. With SSA, we want to create Temporaries which might or might not be precolored to certain registers. After SSA elimination, we shouldn't create new temporaries but work on registers. The other patches are just to make things a bit easier.
no fossil changes.
Edited by Daniel Schürmann