[PATCH GCC][10/13]Compute and cache data dependence relation

[Richard Biener]

On Fri, Jun 23, 2017 at 12:22 PM, Bin.Cheng <amker.cheng@gmail.com> wrote:
> On Tue, Jun 20, 2017 at 12:32 PM, Richard Biener
> <richard.guenther@gmail.com> wrote:
>> On Tue, Jun 20, 2017 at 11:15 AM, Bin.Cheng <amker.cheng@gmail.com> wrote:
>>> On Fri, Jun 16, 2017 at 11:03 AM, Richard Biener
>>> <richard.guenther@gmail.com> wrote:
>>>> On Mon, Jun 12, 2017 at 7:03 PM, Bin Cheng <Bin.Cheng@arm.com> wrote:
>>>>> Hi,
>>>>> This patch computes and caches data dependence relation in a hash table
>>>>> so that it can be queried multiple times later for partition dependence
>>>>> check.
>>>>> Bootstrap and test on x86_64 and AArch64.  Is it OK?
>>>>
>>>> +/* Vector of data dependence relations.  */
>>>> +static vec<ddr_p> *ddrs_vec;
>>>> +
>>>> +/* Hash table for data dependence relation in the loop to be distributed.  */
>>>> +static hash_table<ddr_entry_hasher> *ddrs_table;
>>>>
>>>> avoid the extra indirection.
>>>>
>>>> +/* Hashtable entry for data reference relation.  */
>>>> +struct ddr_entry
>>>> +{
>>>> +  data_reference_p a;
>>>> +  data_reference_p b;
>>>> +  ddr_p ddr;
>>>> +  hashval_t hash;
>>>> +};
>>>> ...
>>>> +/* Hash table equality function for data reference relation.  */
>>>> +
>>>> +inline bool
>>>> +ddr_entry_hasher::equal (const ddr_entry *entry1, const ddr_entry *entry2)
>>>> +{
>>>> +  return (entry1->hash == entry2->hash
>>>> +         && DR_STMT (entry1->a) == DR_STMT (entry2->a)
>>>> +         && DR_STMT (entry1->b) == DR_STMT (entry2->b)
>>>> +         && operand_equal_p (DR_REF (entry1->a), DR_REF (entry2->a), 0)
>>>> +         && operand_equal_p (DR_REF (entry1->b), DR_REF (entry2->b), 0));
>>>> +}
>>>>
>>>> what's the issue with using hash_table <ddr_p> with a custom hasher?
>>>> That is, simply key on the dataref pointers (hash them, compare those
>>>> for equality)?
>>>>
>>>> Your scheme looks too complicated / expensive to me ...
>>>>
>>>> You can drop ddrs_vec needed only for memory removal if you traverse
>>>> the hashtable.
>>> Thanks for reviewing.  Patch simplified as suggested.  Is it OK?
>>
>> +inline hashval_t
>> +ddr_hasher::hash (const data_dependence_relation *ddr)
>> +{
>> +  return iterative_hash_object (DDR_A (ddr),
>> +                               iterative_hash_object (DDR_B (ddr), 0));
>> +}
>> +
>>
>> please use
>>
>>     inchash::hash h;
>>     h.add_ptr (DDR_A (ddr));
>>     h.add_ptr (DDR_B (ddr));
>>     return h.end ();
>>
>> Ok with that change.
> Done, patch updated.

Ok.

> Thanks,
> bin
>>
>> Richard.
>>
>>> Thanks,
>>> bin
>>> 2017-06-17  Bin Cheng  <bin.cheng@arm.com>
>>>
>>>     * tree-loop-distribution.c (struct ddr_hasher): New.
>>>     (ddr_hasher::hash, ::equal, get_data_dependence): New function.
>>>     (ddrs_table): New.
>>>     (classify_partition): Call get_data_dependence.
>>>     (pg_add_dependence_edges): Ditto.
>>>     (distribute_loop): Release data dependence hash table.