Re: [PATCH 3/3] Enhance dumps of IVOPTS

["H.J. Lu" <hjl.tools@gmail.com>]

On Fri, May 13, 2016 at 3:44 AM, Martin Liška <mliska@suse.cz> wrote:
> On 05/13/2016 11:43 AM, Bin.Cheng wrote:
>> On Thu, May 12, 2016 at 5:41 PM, Martin Liška <mliska@suse.cz> wrote:
>>> On 05/12/2016 03:51 PM, Bin.Cheng wrote:
>>>> On Thu, May 12, 2016 at 1:13 PM, Martin Liška <mliska@suse.cz> wrote:
>>>>> On 05/10/2016 03:16 PM, Bin.Cheng wrote:
>>>>>> Another way is to remove the use of id for struct iv_inv_expr_ent once
>>>>>> for all.  We can change iv_ca.used_inv_expr and cost_pair.inv_expr_id
>>>>>> to pointers, and rename iv_inv_expr_ent.id to count and use this to
>>>>>> record reference number in iv_ca.  This if-statement on dump_file can
>>>>>> be saved.  Also I think it simplifies current code a bit.  For now,
>>>>>> there are id <-> struct maps for different structures in IVOPT which
>>>>>> make it not straightforward.
>>>>>
>>>>> Hi.
>>>>>
>>>>> I'm sending second version of the patch. I tried to follow your advices, but
>>>>> because of a iv_inv_expr_ent can simultaneously belong to multiply iv_cas,
>>>>> putting counter to iv_inv_expr_ent does not works. Instead of that, I've
>>>>> decided to replace used_inv_expr with a hash_map that contains used inv_exps
>>>>> and where value of the map is # of usages.
>>>>>
>>>>> Further questions:
>>>>> + iv_inv_expr_ent::id can be now removed as it's used just for purpose of dumps
>>>>> Group 0:
>>>>>   cand  cost    scaled  freq    compl.  depends on
>>>>>   5     2       2.00    1.000
>>>>>   6     4       4.00    1.001    inv_expr:0
>>>>>   7     4       4.00    1.001    inv_expr:1
>>>>>   8     4       4.00    1.001    inv_expr:2
>>>>>
>>>>> That can be replaced with print_generic_expr, but I think using ids makes the dump
>>>>> output more clear.
>>>> I am okay with keeping id.  Could you please dump all inv_exprs in a
>>>> single section like
>>>> <Invariant Exprs>:
>>>> inv_expr 0: print_generic_expr
>>>> inv_expr 1: ...
>>>>
>>>> Then only dump the id afterwards?
>>>>
>>>
>>> Sure, it would be definitely better:
>>>
>>> The new dump format looks:
>>>
>>> <Invariant Expressions>:
>>> inv_expr 0:     sudoku_351(D) + (sizetype) S.833_774 * 4
>>> inv_expr 1:     sudoku_351(D) + ((sizetype) S.833_774 * 4 + 18446744073709551580)
>>> inv_expr 2:     sudoku_351(D) + ((sizetype) S.833_774 + 72) * 4
>>> inv_expr 3:     sudoku_351(D) + ((sizetype) S.833_774 + 81) * 4
>>> inv_expr 4:     &A.832 + (sizetype) _377 * 4
>>> inv_expr 5:     &A.832 + ((sizetype) _377 * 4 + 18446744073709551612)
>>> inv_expr 6:     &A.832 + ((sizetype) _377 + 8) * 4
>>> inv_expr 7:     &A.832 + ((sizetype) _377 + 9) * 4
>>>
>>> <Group-candidate Costs>:
>>> Group 0:
>>>   cand  cost    scaled  freq    compl.  depends on
>>>
>>> ...
>>>
>>> Improved to:
>>>   cost: 27 (complexity 2)
>>>   cand_cost: 11
>>>   cand_group_cost: 10 (complexity 2)
>>>   candidates: 3, 5
>>>    group:0 --> iv_cand:5, cost=(2,0)
>>>    group:1 --> iv_cand:5, cost=(4,1)
>>>    group:2 --> iv_cand:5, cost=(4,1)
>>>    group:3 --> iv_cand:3, cost=(0,0)
>>>    group:4 --> iv_cand:3, cost=(0,0)
>>>   invariants 1, 6
>>>   invariant expressions 6, 3
>>>
>>> The only question here is that as used_inv_exprs are stored in a hash_map,
>>> order of dumped invariants would not be stable. Is it problem?
>> It is okay.
>>
>> Only nitpicking on this version.
>>
>>>
>>>>>
>>>>> + As check_GNU_style.sh reported multiple 8 spaces issues in hunks I've touched, I decided
>>>>> to fix all 8 spaces issues. Hope it's fine.
>>>>>
>>>>> I'm going to test the patch.
>>>>> Thoughts?
>>>>
>>>> Some comments on the patch embedded.
>>>>
>>>>>
>>>>> +/* Forward declaration.  */
>>>> Not necessary.
>>>>> +struct iv_inv_expr_ent;
>>>>> +
>>>
>>> I think it's needed because struct cost_pair uses a pointer to iv_inv_expr_ent.
>> I mean the comment, clearly the declaration is self-documented.
>
> Hi.
>
> Yeah, removed.
>
>>
>>> @@ -6000,11 +6045,12 @@ iv_ca_set_no_cp (struct ivopts_data *data, struct iv_ca *ivs,
>>>
>>>    iv_ca_set_remove_invariants (ivs, cp->depends_on);
>>>
>>> -  if (cp->inv_expr_id != -1)
>>> +  if (cp->inv_expr != NULL)
>>>      {
>>> -      ivs->used_inv_expr[cp->inv_expr_id]--;
>>> -      if (ivs->used_inv_expr[cp->inv_expr_id] == 0)
>>> -        ivs->num_used_inv_expr--;
>>> +      unsigned *slot = ivs->used_inv_exprs->get (cp->inv_expr);
>>> +      --(*slot);
>>> +      if (*slot == 0)
>>> +    ivs->used_inv_exprs->remove (cp->inv_expr);
>> I suppose insertion/removal of hash_map are not expensive?  Because
>> the algorithm causes a lot of these operations.
>
> I think it should be ~ a constant operation.
>
>>
>>> @@ -6324,12 +6368,26 @@ iv_ca_dump (struct ivopts_data *data, FILE *file, struct iv_ca *ivs)
>>>      fprintf (file, "   group:%d --> ??\n", group->id);
>>>      }
>>>
>>> +  bool any_invariant = false;
>>>    for (i = 1; i <= data->max_inv_id; i++)
>>>      if (ivs->n_invariant_uses[i])
>>>        {
>>> +    const char *pref = any_invariant ? ", " : "  invariants ";
>>> +    any_invariant = true;
>>>      fprintf (file, "%s%d", pref, i);
>>> -    pref = ", ";
>>>        }
>>> +
>>> +  if (any_invariant)
>>> +    fprintf (file, "\n");
>>> +
>> To make dump easier to read, we can simply dump invariant
>> variables/expressions unconditionally.  Also keep invariant variables
>> and expressions in the same form.
>
> Sure, that's a good idea!
>
> Sample output:
>
>
> Initial set of candidates:
>   cost: 17 (complexity 0)
>   cand_cost: 11
>   cand_group_cost: 2 (complexity 0)
>   candidates: 1, 5
>    group:0 --> iv_cand:5, cost=(2,0)
>    group:1 --> iv_cand:1, cost=(0,0)
>   invariant variables: 1, 4
>   invariant expressions:
>
> Initial set of candidates:
>   cost: 42 (complexity 2)
>   cand_cost: 15
>   cand_group_cost: 12 (complexity 2)
>   candidates: 4, 15, 16
>    group:0 --> iv_cand:16, cost=(0,0)
>    group:1 --> iv_cand:15, cost=(-1,0)
>    group:2 --> iv_cand:4, cost=(0,0)
>    group:3 --> iv_cand:15, cost=(9,1)
>    group:4 --> iv_cand:15, cost=(4,1)
>   invariant variables:
>   invariant expressions:
>
>>    const char *pref = "";
>>    //...
>>    fprintf (file, "  invariant variables: "
>>    for (i = 1; i <= data->max_inv_id; i++)
>>      if (ivs->n_invariant_uses[i])
>>        {
>>      fprintf (file, "%s%d", pref, i);
>>     pref = ", ";
>>        }
>>    fprintf (file, "\n");
>>
>>> +  const char *pref = "  invariant expressions ";
>>> +  for (hash_map<iv_inv_expr_ent *, unsigned>::iterator it
>>> +       = ivs->used_inv_exprs->begin (); it != ivs->used_inv_exprs->end (); ++it)
>>> +    {
>>> +    fprintf (file, "%s%d", pref, (*it).first->id);
>>> +    pref = ", ";
>>> +    }
>>> +
>>>    fprintf (file, "\n\n");
>>>  }
>>>
>>
>> Okay with the dump change,  you may need to update Changelog entry too.
>
> There's no fundamental change, thus not changing the ChangeLog entry.
>
> Thanks for the review, installed as r236200.
>

It failed to build on 32-bit hosts:

../../src-trunk/gcc/tree-ssa-loop-ivopts.c: In function \u2018void
create_new_ivs(ivopts_data*, iv_ca*)\u2019:
../../src-trunk/gcc/tree-ssa-loop-ivopts.c:7050:44: error: format
\u2018%lu\u2019 expects argument of type \u2018long unsigned
int\u2019, but argument 3 has type \u2018long long int\u2019
[-Werror=format=]
         avg_loop_niter (data->current_loop));
                                            ^
../../src-trunk/gcc/tree-ssa-loop-ivopts.c:7052:41: error: format
\u2018%lu\u2019 expects argument of type \u2018long unsigned
int\u2019, but argument 3 has type \u2018size_t {aka unsigned
int}\u2019 [-Werror=format=]
         set->used_inv_exprs->elements ());
                                         ^



-- 
H.J.