James,

Since other members of the "tune_params" structure were signed integers, 
even though negative numbers would make no sense for most either, I 
followed the same pattern.

Regardless, here's a patch with unsigned integers as you requested:

    [AArch64] Add extra tuning parameters for target processors

    2015-11-05  Evandro Menezes  <e.menezes@samsung.com>

    gcc/

        * config/aarch64/aarch64-protos.h (tune_params): Add new members
        "max_case_values" and "cache_line_size".
        * config/aarch64/aarch64.c (aarch64_case_values_threshold): New
        function.
        (aarch64_override_options_internal): Tune heuristics based on new
        members in "tune_params".
        (TARGET_CASE_VALUES_THRESHOLD): Define macro.

Please, commit if it's alright.

Thank you,

-- 
Evandro Menezes

On 11/05/2015 03:22 AM, James Greenhalgh wrote:
> On Wed, Nov 04, 2015 at 05:21:03PM -0600, Evandro Menezes wrote:
>> Please, ignore the previous patch.  This is the intended patch.
>>
>> Sorry.
>>
>> -- 
>> Evandro Menezes
>>
>> On 11/04/2015 05:18 PM, Evandro Menezes wrote:
>>> This patch adds extra tuning information about AArch64 targets:
>>>
>>> * Maximum number of case values before resorting to a jump table
>>>    The default values assumed independently of the specific backends
>>>    may be rather low for modern processors, which sport quite efficient
>>>    direct branch prediction, whereas indirect branch prediction is
>>>    still typically not so efficient.  This value may be specifically
>>>    set for a processor or left at zero to use the default values.
>>> * L1 cache line size
>>>    The auto-prefetcher uses this information when emitting software
>>>    prefetch insns.
>>>
>>> Please, commit if it's alright.
>>>
>>> Thank you,
>>>
> Thanks for the patch,
>
>> diff --git a/gcc/config/aarch64/aarch64-protos.h b/gcc/config/aarch64/aarch64-protos.h
>> index 81792bc..ecf4685 100644
>> --- a/gcc/config/aarch64/aarch64-protos.h
>> +++ b/gcc/config/aarch64/aarch64-protos.h
>> @@ -195,6 +195,9 @@ struct tune_params
>>     int vec_reassoc_width;
>>     int min_div_recip_mul_sf;
>>     int min_div_recip_mul_df;
>> +  int max_case_values; /* Case values threshold; or 0 for the default.  */
> If we're using an int, how about -1 as the sentinel value? (Maybe someone
> really likes jump tables!). Otherwise, make this an unsigned int?
>
>> +
>> +  int cache_line_size; /* Cache line size; or 0 for the default.  */
> unsigned int?
>
> The patch is otherwise OK, though it needs a ChangeLog.
>
> Thanks,
> James
>
>