On Fri, Jun 23, 2017 at 12:25 PM, Bin.Cheng <amker.ch...@gmail.com> wrote:
> And the patch.
>
> On Fri, Jun 23, 2017 at 11:24 AM, Bin.Cheng <amker.ch...@gmail.com> wrote:
>> On Tue, Jun 20, 2017 at 12:34 PM, Richard Biener
>> <richard.guent...@gmail.com> wrote:
>>> On Tue, Jun 20, 2017 at 11:18 AM, Bin.Cheng <amker.ch...@gmail.com> wrote:
>>>> On Fri, Jun 16, 2017 at 11:10 AM, Richard Biener
>>>> <richard.guent...@gmail.com> wrote:
>>>>> On Mon, Jun 12, 2017 at 7:03 PM, Bin Cheng <bin.ch...@arm.com> wrote:
>>>>>> Hi,
>>>>>> This patch checks and records if partition can be executed in parallel by
>>>>>> looking if there exists data dependence cycles. The information is
>>>>>> needed
>>>>>> for distribution because the idea is to distribute parallel type
>>>>>> partitions
>>>>>> away from sequential ones. I believe current distribution doesn't work
>>>>>> very well because it does blind distribution/fusion.
>>>>>> Bootstrap and test on x86_64 and AArch64. Is it OK?
>>>>>
>>>>> + /* In case of no data dependence. */
>>>>> + if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
>>>>> + return false;
>>>>> + /* Or the data dependence can be resolved by compilation time alias
>>>>> + check. */
>>>>> + else if (!alias_sets_conflict_p (get_alias_set (DR_REF (dr1)),
>>>>> + get_alias_set (DR_REF (dr2))))
>>>>> + return false;
>>>>>
>>>>> dependence analysis should use TBAA already, in which cases do you need
>>>>> this?
>>>>> It seems to fall foul of the easy mistake of not honoring GCCs memory
>>>>> model
>>>>> as well ... see dr_may_alias_p.
>>>> I see. Patch updated with this branch removed.
>>>>
>>>>>
>>>>> + /* Further check if any data dependence prevents us from executing the
>>>>> + partition parallelly. */
>>>>> + EXECUTE_IF_SET_IN_BITMAP (partition->reads, 0, i, bi)
>>>>> + {
>>>>> + dr1 = (*datarefs_vec)[i];
>>>>> + EXECUTE_IF_SET_IN_BITMAP (partition->writes, 0, j, bj)
>>>>> + {
>>>>>
>>>>> what about write-write dependences?
>>>>>
>>>>> + EXECUTE_IF_SET_IN_BITMAP (partition->reads, 0, i, bi)
>>>>> + {
>>>>> + dr1 = (*datarefs_vec)[i];
>>>>> + EXECUTE_IF_SET_IN_BITMAP (partition->writes, i + 1, j, bj)
>>>>> + {
>>>>> + dr2 = (*datarefs_vec)[j];
>>>>> + /* Partition can only be executed sequentially if there is any
>>>>> + data dependence cycle. */
>>>>>
>>>>> exact copy of the loop nest follows?! Maybe you meant to iterate
>>>>> over writes in the first loop.
>>>> Yes, this is a copy-paste typo. Patch is also simplified because
>>>> read/write are recorded together now. Is it OK?
>>>
>>> Ok.
>> Sorry I have to update this patch because one of my mistake. I didn't
>> update partition type when fusing them. For some partition fusion,
>> the update is necessary otherwise we end up with inaccurate type and
>> inaccurate fusion later. Is it Ok?
Ok.
>> Thanks,
>> bin
>> 2017-06-20 Bin Cheng <bin.ch...@arm.com>
>>
>> * tree-loop-distribution.c (enum partition_type): New.
>> (struct partition): New field type.
>> (partition_merge_into): Add parameter. Update partition type.
>> (data_dep_in_cycle_p, update_type_for_merge): New functions.
>> (build_rdg_partition_for_vertex): Compute partition type.
>> (rdg_build_partitions): Dump partition type.
>> (distribute_loop): Update calls to partition_merge_into.
