On Wed, Jun 4, 2014 at 8:46 AM, Jeff Law <l...@redhat.com> wrote:
> On 06/03/14 03:29, Richard Biener wrote:
>>
>> On Tue, Jun 3, 2014 at 7:55 AM, Ilya Enkovich <enkovich....@gmail.com>
>> wrote:
>>>
>>> 2014-06-02 21:27 GMT+04:00 Jeff Law <l...@redhat.com>:
>>>>
>>>> On 06/02/14 04:48, Ilya Enkovich wrote:
>>>>>>
>>>>>>
>>>>>> Hmm, so if I understand things correctly, src_fun has no loop
>>>>>> structures attached, thus there's nothing to copy. Presumably at
>>>>>> some later point we build loop structures for the copy from scratch?
>>>>>
>>>>>
>>>>> I suppose it is just a simple bug with absent NULL pointer check. Here
>>>>> is
>>>>> original code:
>>>>>
>>>>> /* Duplicate the loop tree, if available and wanted. */
>>>>> if (loops_for_fn (src_cfun) != NULL
>>>>> && current_loops != NULL)
>>>>> {
>>>>> copy_loops (id, entry_block_map->loop_father,
>>>>> get_loop (src_cfun, 0));
>>>>> /* Defer to cfgcleanup to update loop-father fields of
>>>>> basic-blocks. */
>>>>> loops_state_set (LOOPS_NEED_FIXUP);
>>>>> }
>>>>>
>>>>> /* If the loop tree in the source function needed fixup, mark the
>>>>> destination loop tree for fixup, too. */
>>>>> if (loops_for_fn (src_cfun)->state & LOOPS_NEED_FIXUP)
>>>>> loops_state_set (LOOPS_NEED_FIXUP);
>>>>>
>>>>> As you may see we have check for absent loops structure in the first
>>>>> if-statement and no check in the second one. I hit segfault and added
>>>>> the
>>>>> check.
>>>>
>>>>
>>>> Downthread you indicated you're not in SSA form which might explain the
>>>> inconsistency here. If so, then we need to make sure that the loop & df
>>>> structures do get set up properly later.
>>>
>>>
>>> That is what init_data_structures pass will do for us as Richard pointed.
>>> Right?
>>
>>
>> loops are set up during the CFG construction and thus are available
>> everywhere.
>
> Which would argue that the hunk that checks for the loop tree's existence
> before accessing it should not be needed. Ilya -- is it possible you hit
> this prior to Richi's work to build the loop structures as part of CFG
> construction and maintain them throughout compilation.
That's likely. It's still on my list of janitor things to do to remove all
those if (current_loops) checks ...
>> the df structures are set up in init_data_structures pass which is run
>> before
>> going into SSA form (I'd like to somehow cleanup that area).
>
> OK. So this part should be approved since we've established this code is
> running prior to going into SSA form.
Agreed.
Thanks,
Richard.
> jeff
>
