For the curious, reload was written by Richard Kenner, who, while a wonderful guy, was not generally familiar with modern compiler architecture (graph coloring register allocation goes back to 1982, reload was started in the late 80's).
It essentially took the place of spill placement/code/legalization. Over the years, it grew rematerialization, instruction combination, copy coalescing, stack slot sharing and all sorts of other interesting scope creep.
While i believe it has finally been replaced by LRA for some targets, there were many people who spent years of their life trying to replace reload with separate, smaller pieces of architecture. No one has yet completely succeeded.
It is essentially an interesting object lesson in what happens when you just incrementally improve architecture to achieve performance goals without a stop-loss point for requiring new design.