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Date: Thu, 16 Jun 2016 14:37:00 -0000
From: Alexander Monakov <amonakov@ispras.ru>
To: Jan Hubicka <hubicka@ucw.cz>
cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Handle undefined extern vars in output_in_order
In-Reply-To: <20160616142524.GA93274@kam.mff.cuni.cz>
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On Thu, 16 Jun 2016, Jan Hubicka wrote:
> > On Thu, 9 Jun 2016, Alexander Monakov wrote:
> +  FOR_EACH_VARIABLE (pv)
[snip]
> +      i = pv->order;
> +      gcc_assert (nodes[i].kind == ORDER_UNDEFINED);
> +      nodes[i].kind = pv->definition ? ORDER_VAR : ORDER_VAR_UNDEF;
> +      nodes[i].u.v = pv;
> 
> order for undefined variables is not computed, so it will be 0. Doesn't
> think overwrite existing entries of nodes array?

Hm, I've tried the following testcase:

extern int a, b;
int f()
{
  return a+b;
}

and in the above loop I see pv->order == 2 on the first iteration,
pv->order == 1 on the second. Under what circumstances wouldn't
order be computed?

Thanks.
Alexander