Re: [PATCH][ARM] Add debug dumping of cost table fields

[Andrew Pinski <pinskia@gmail.com>]

On Wed, May 27, 2015 at 4:38 PM, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
> Ping.
> https://gcc.gnu.org/ml/gcc-patches/2015-05/msg00054.html

This and the one in AARCH64 is too noisy.  Can we have an option to
turn this on and default to turning them off.

Thanks,
Andrew

>
> Thanks,
> Kyrill
>
> On 01/05/15 15:31, Kyrill Tkachov wrote:
>>
>> Hi all,
>>
>> This patch adds a macro to wrap cost field accesses into a helpful debug
>> dump,
>> saying which field is being accessed at what line and with what values.
>> This helped me track down cases where the costs were doing the wrong thing
>> by allowing me to see which path in arm_new_rtx_costs was taken.
>> For example, the combine log might now contain:
>>
>> Trying 2 -> 6:
>> Successfully matched this instruction:
>> (set (reg:SI 115 [ D.5348 ])
>>       (neg:SI (reg:SI 0 r0 [ a ])))
>> using extra_cost->alu.arith with cost 0 from line 10506
>>
>> which can be useful in debugging the rtx costs.
>>
>> Bootstrapped and tested on arm.
>>
>> Ok for trunk?
>>
>> Thanks,
>> Kyrill
>>
>>
>> 2015-05-01  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>>
>>       * config/arm/arm.c (DBG_COST): New macro.
>>       (arm_new_rtx_costs): Use above.
>
>