review (M) for 4809552: Optimize Arrays.fill(...)

[Tom Rodriguez]

On Aug 20, 2010, at 3:30 AM, Ulf Zibis wrote:

> Couldn't we intrinsify loops like? :
>        for (int i = fromIndex; i < toIndex; i++)
>            a[i] = val;
>        for (int i = 0, len = a.length; i < len; i++)
>            a[i] = val;

It will.

tom

> 
> So all similar Java-coded loops would benefit from the performance gain of using REP STOS operation, especially in case of client compiler and maybe interpreter too.
> 
> -Ulf
> 
> 
> Am 20.08.2010 00:11, schrieb Tom Rodriguez:
>> 4809552: Optimize Arrays.fill(...)
>> Reviewed-by:
>> 
>> This adds new logic to recognize fill idioms and convert them into a
>> call to an optimized fill routine.  Loop predication creates easily
>> matched loops that are simply replaced with calls to the new assembly
>> stubs.  Currently only 1,2 and 4 byte primitive types are supported.
>> Objects and longs/double will be supported in a later putback.  Tested
>> with runthese, nsk and ctw plus jbb2005.
>> 
>> http://cr.openjdk.java.net/~never/4809552
>> 
>> 
>>   
>