A reload inheritance bug

[Joern Rennecke]

> In order to fix this I think that reload1.c:emit_reload_insns should,
> at the point of discovery of an input reload whose reload register is a
> non-spill hard register H, invalidate all previous reloads involving
> that hard register. 

If the reload is inherited, and there is no non-input part of the reload
that would destroy the value in the register, you should leave previous
reloads alone, so that they can be inherited multiple times.