RFR: 8162865 Implementation of SPARC lzcnt

[Vladimir Kozlov]

Hi Trevor

Do you have performance numbers?

UseVIS is too wide flag to control only these instructions generation.

To be consistent with x86 code please add 
UseCountLeadingZerosInstruction flag to globals_sparc.hpp and its 
setting in vm_version_sparc.cpp (based on has_vis3()) similar to what is 
done for x86.

May be name new instructions *ZerosIvis instead of *ZerosI1 to be clear 
that VIS is used.

Indention in the new test is all over place. Please, fix.

Thanks,
Vladimir

On 11/15/16 3:57 AM, Trevor Watson wrote:
> I have implemented the code to use the lzcnt instruction for both
> integer and long countLeadingZeros() methods on SPARC platforms
> supporting the vis3 instruction set.
>
> Current "bmi" tests for the above are updated so that they run on both
> SPARC and x86 platforms.
>
> I've also implemented a test to ensure that Integer.countLeadingZeros()
> and Long.countLeadingZeros() return the correct values when C2 runs.
> This test is currently under the intrinsics "bmi" tests for want of
> somewhere better (they do apply to both SPARC and x86 though).
>
> http://cr.openjdk.java.net/~alanbur/8162865/
>
> Thanks,
> Trevor