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Re: [PATCH] postreload: Invalidate reg_state info at barrier/volatile insns


> With the patch from http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49452
> the regstate information is resetted at the unspec_volatile instead of
> invalidated!

You're right.  This wouldn't have happened if the code had been properly 
commented.

> 2011-11-14  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>
>
> 	* postreload.c (reload_combine): Mark reg_state as invalid at a
> 	barrier if there has been a use already.

Let's be conservative instead and distinguish the two cases: in the barrier 
case, we don't change anything and just add the missing comment, along the 
lines of "Crossing a barrier resets all the use information".  In the volatile 
case, we unconditionally invalidate with a similar comment.

-- 
Eric Botcazou


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