On Tue, Apr 26, 2016 at 7:15 AM, Ilya Enkovich <enkovich....@gmail.com> wrote:
> 2016-04-26 17:07 GMT+03:00 H.J. Lu <hjl.to...@gmail.com>:
>> On Mon, Apr 25, 2016 at 9:13 AM, Ilya Enkovich <enkovich....@gmail.com>
>> wrote:
>>> 2016-04-25 18:27 GMT+03:00 H.J. Lu <hjl.to...@gmail.com>:
>>>>
>>>> Ilya, can you take a look?
>>>>
>>>> Thanks.
>>>>
>>>> --
>>>> H.J.
>>>
>>> Hi,
>>>
>>> Algorithmic part of the patch looks OK to me except the following piece of
>>> code.
>>>
>>> +/* Check REF's chain to add new insns into a queue
>>> + and find registers requiring conversion. */
>>>
>>> Comment is wrong because you don't have any conversions required for
>>> your candidates.
>>
>> I will fix it.
>>
>>> +
>>> +void
>>> +scalar_chain_64::analyze_register_chain (bitmap candidates, df_ref ref)
>>> +{
>>> + df_link *chain;
>>> +
>>> + gcc_assert (bitmap_bit_p (insns, DF_REF_INSN_UID (ref))
>>> + || bitmap_bit_p (candidates, DF_REF_INSN_UID (ref)));
>>> + add_to_queue (DF_REF_INSN_UID (ref));
>>> +
>>> + for (chain = DF_REF_CHAIN (ref); chain; chain = chain->next)
>>> + {
>>> + unsigned uid = DF_REF_INSN_UID (chain->ref);
>>> +
>>> + if (!NONDEBUG_INSN_P (DF_REF_INSN (chain->ref)))
>>> + continue;
>>> +
>>> + if (!DF_REF_REG_MEM_P (chain->ref))
>>> + continue;
>>>
>>> I believe here you wrongly jump to the next ref intead of actually adding it
>>> to a queue. You may just use
>>>
>>> gcc_assert (!DF_REF_REG_MEM_P (chain->ref));
>>>
>>> because you should'n have a candidate used in address operand.
>>
>> I will update.
>>
>>> +
>>> + if (bitmap_bit_p (insns, uid))
>>> + continue;
>>> +
>>> + if (bitmap_bit_p (candidates, uid))
>>> + add_to_queue (uid);
>>>
>>> Probably gcc_assert (bitmap_bit_p (candidates, uid)) since no uses and defs
>>> out of candidates list are allowed?
>>
>> That would be wrong since there are
>>
>> while (!bitmap_empty_p (queue))
>> {
>> insn_uid = bitmap_first_set_bit (queue);
>> bitmap_clear_bit (queue, insn_uid);
>> bitmap_clear_bit (candidates, insn_uid);
>> add_insn (candidates, insn_uid);
>> }
>>
>> An instruction is a candidate and the bit is cleared when
>> analyze_register_chain is called.
>
> You clear candidates bit but the first thing you do in add_insn is set
> insns bit.
> Thus you should hit:
>
> if (bitmap_bit_p (insns, uid))
> continue;
>
> For handled candidates.
>
> Probably it would be more clear if we keep this clear/set pair
> together? E.g. move
> bitmap_clear_bit (candidates, insn_uid) to scalar_chain::add_insn.
>
After we started processing candidates, we only use candidates
to check if an instruction is a candidate, not to check if an
instruction is NOT a candidate.
--
H.J.
