[Ping] [patch 0/3] New macro PREFERRED_RENAME_CLASS

[Eric Botcazou]

> Bootstrap and regression tested on x86_64-linux.  Committed.  Thanks a
> lot for your patient review.

You're welcome.  However, I've pondered some more on this and I now think that 
we went a little too far.  The problem is the sorting of DU chains.  Although 
this isn't explicit in the pass (lack of general comment at the top of the 
file among other things), it uses a round-robin algorithm to rename the 
registers (the 'tick' business); sorting the chains damages the algorithm.

So I think that we cannot sort the chains, at least not so abruptly.  The 
attached patch removes the sort, but in exchange forces the renaming of 
registers that don't belong to the preferred class to registers that do, even 
though they were used recently.  It also adds the missing general comment.

Could you give it a whirl on your favorite set of tests and see how it fares?

-- 
Eric Botcazou
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