On Wed, May 17, 2017 at 1:24 PM, Richard Biener
<richard.guent...@gmail.com> wrote:
> On Mon, May 15, 2017 at 5:50 PM, Bin.Cheng <amker.ch...@gmail.com> wrote:
>> On Thu, May 11, 2017 at 11:39 AM, Richard Biener
>> <richard.guent...@gmail.com> wrote:
>>> On Tue, Apr 18, 2017 at 12:53 PM, Bin Cheng <bin.ch...@arm.com> wrote:
>>>> Hi,
>>>> Currently IVOPTs shares the same register pressure computation with RTL
>>>> loop invariant pass,
>>>> which doesn't work very well. This patch introduces specific interface
>>>> for IVOPTs.
>>>> The general idea is described in the cover message as below:
>>>> C) Current implementation shares the same register pressure computation
>>>> with RTL loop
>>>> inv pass. It has difficulty in handling (especially large) loop
>>>> nest, and quite
>>>> often generating too many candidates (especially for outer loops).
>>>> This change
>>>> introduces new register pressure computation. The brief idea is to
>>>> differentiate
>>>> (hot) innermost loop and outer loop. for (possibly hot) inner most,
>>>> more registers
>>>> are allowed as long as the register pressure is within the range of
>>>> number of target
>>>> available registers.
>>>> It can also help to restrict number of candidates for outer loop.
>>>> Is it OK?
>>>
>>> +/* Determine if current loop is the innermost loop and maybe hot. */
>>> +
>>> +static void
>>> +determine_hot_innermost_loop (struct ivopts_data *data)
>>> +{
>>> + data->hot_innermost_loop_p = true;
>>> + if (!data->speed)
>>> + return;
>>>
>>> err, so when not optimizing for speed we assume all loops (even not
>>> innermost)
>>> are hot and innermost?!
>>>
>>> + HOST_WIDE_INT niter = avg_loop_niter (loop);
>>> + if (niter < PARAM_VALUE (PARAM_AVG_LOOP_NITER)
>>> + || loop_constraint_set_p (loop, LOOP_C_PROLOG)
>>> + || loop_constraint_set_p (loop, LOOP_C_EPILOG)
>>> + || loop_constraint_set_p (loop, LOOP_C_VERSION))
>>> + data->hot_innermost_loop_p = false;
>>>
>>> this needs adjustment for the constraint patch removal. Also looking at
>>> niter
>>> of the loop in question insn't a good metric for hotness. data->speed is
>>> the
>>> best guess you get I think (optimize_loop_for_speed_p).
>>>
>>> data->speed = optimize_loop_for_speed_p (loop);
>>> + determine_hot_innermost_loop (data);
>>>
>>> data->hot_innermost_loop_p = determine_hot_innermost_loop (data);
>>>
>>> would be more consistent here.
>> Hi,
>> I removed the hot innermost part and here is the updated version. Is it OK?
>
> Ok.
Sorry for the long time delay, I committed the patch @r248954
Thanks,
bin
>
>> Thanks,
>> bin
>>
>> 2017-05-11 Bin Cheng <bin.ch...@arm.com>
>>
>> * tree-ssa-loop-ivopts.c (ivopts_estimate_reg_pressure): New
>> reg_pressure model function.
>> (ivopts_global_cost_for_size): Delete.
>> (determine_set_costs, iv_ca_recount_cost): Call new model function
>> ivopts_estimate_reg_pressure.
>>
>>>
>>> Thanks,
>>> Richard.
>>>
>>>> Thanks,
>>>> bin
>>>> 2017-04-11 Bin Cheng <bin.ch...@arm.com>
>>>>
>>>> * tree-ssa-loop-ivopts.c (struct ivopts_data): New field.
>>>> (ivopts_estimate_reg_pressure): New reg_pressure model function.
>>>> (ivopts_global_cost_for_size): Delete.
>>>> (determine_set_costs, iv_ca_recount_cost): Call new model function
>>>> ivopts_estimate_reg_pressure.
>>>> (determine_hot_innermost_loop): New.
>>>> (tree_ssa_iv_optimize_loop): Call above function.
