[PATCH] Fix -fcompare-debug issue in reload1 (PR debug/46252)

[Eric Botcazou]

> So far I have done 3) from the above list, bootstrapped/regtested on
> x86_64-linux and i686-linux, getting tired so I've postponed the rest for
> later on, will try to get to it soon.  

While the 3rd use of prev_real_insn in the middle-end has disappeared in the 
meantime, it turns out that it is used in several back-ends.

-- 
Eric Botcazou