[aarch64-port-dev ] RFR: 8129426: aarch64: add support for PopCount in C2

[Andrew Dinn]

On 23/06/15 11:10, Andrew Haley wrote:
> On 22/06/15 17:14, Andrew Dinn wrote:
>> . . .
>> Well, you might not want to take this risk and instead add an explicit
>> zero of the upper half. But I think we need to be clear what risk we are
>> taking.
> 
> It's this: if we don't explicitly zero the upper half we'll have to
> audit all the code which might present a sign-extended value (instead
> of a zero-extended one) in a register that's supposed to contain a
> jint.

Ok, let's play safe. If Ed tweaks the patch to zero the upper word we
can always revise that later if/when we decide we are feeling lucky.

regards,


Andrew Dinn
-----------