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Re: [PATCH] Fix PR56521


On Tue, Mar 05, 2013 at 12:51:09PM +0100, Richard Biener wrote:
> VN now inserts all sorts of calls into the references hashtable,
> not only those which produce a value.  This results in missing
> initializations of ->value_id which eventually PRE ends up
> accessing.
> 
> The following fixes that.
> 
> Bootstrap and regtest pending on x86_64-unknown-linux-gnu.
> 
> Richard.
> 
> 2013-03-05  Richard Biener  <rguenther@suse.de>
> 
> 	* tree-ssa-sccvn.c (set_value_id_for_result): For a NULL
> 	result set a new value-id.
> 
> --- gcc/tree-ssa-sccvn.c	(revision 196451)
> +++ gcc/tree-ssa-sccvn.c	(working copy)
> @@ -3954,7 +3962,7 @@ free_scc_vn (void)
>    XDELETE (optimistic_info);
>  }
>  
> -/* Set *ID if we computed something useful in RESULT.  */
> +/* Set *ID according to RESULT.  */
>  
>  static void
>  set_value_id_for_result (tree result, unsigned int *id)
> @@ -3966,6 +3974,8 @@ set_value_id_for_result (tree result, un
>        else if (is_gimple_min_invariant (result))
>  	*id = get_or_alloc_constant_value_id (result);

This still won't initialize *id if result is non-NULL, but isn't
SSA_NAME nor is_gimple_min_invariant.  Can't you do the same for that case
too, just in case (perhaps we can't trigger that right now, but still
it would make me feel safer about that).

>      }
> +  else
> +    *id = get_next_value_id ();
>  }
>  
>  /* Set the value ids in the valid hash tables.  */

Otherwise looks good to me, thanks.

	Jakub


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