[tree-ssa]: PRE updates and note on bug

[Daniel Berlin]

>
>>
>> I was getting an empty stmt for end of bb using last_stmt and
>> last_stmt_ptr, but if i replace it with:
>>
>>        {
>>          block_stmt_iterator bsi2;
>>          block_stmt_iterator bsi3;
>>          for (bsi2 = bsi3 = bsi_start (bb);
>>         !bsi_end_p (bsi2);
>>         bsi_next (&bsi2))
>>            bsi3 = bsi2;
>>          endtree = bsi_stmt (bsi3);
>>          endtreep = bsi_stmt_ptr (bsi3);
>>        }
>>
>> (which is the code that bsi_last falls back on), it works fine and
>> gives the correct statement.
>
>
> last_stmt and last_stmt_ptr will do that, but bsi_last() should give 
> you
> the correct thing.
>

Errr, that would be strange, since:

tree
last_stmt (basic_block bb)
{
   block_stmt_iterator b;

   b = bsi_last (bb);
   return (!bsi_end_p (b)) ? bsi_stmt (b) : NULL_TREE;
}

last_stmt will only return an empty_stmt iff bsi_last does.

> Andrew

>