[PATCH] Fix unstable sort, PR28964

[Paolo Bonzini]

Ian Lance Taylor wrote:
> Richard Guenther <rguenther@suse.de> writes:
> 
>> 2006-09-22  Richard Guenther  <rguenther@suse.de>
>>
>> 	PR middle-end/28964
>> 	* cfgexpand.c (stack_var_size_cmp): Use DECL_UID to make
>> 	sort of stack variables stable.
> 
> OK for mainline.
> 
> For the release branches, it seems to me that this introduces a
> potential if rather unlikely regression from the gcc_unreachable call.
> And this is not a significant user visible problem.  So I'll say that
> it is OK for the release branches without the gcc_unreachable--just
> return 0 if the UIDs are the same.

OTOH, on mainline if you have gcc_reachable don't return 0.

Paolo