Value array element size represented as log2

[David Simms]

For copying to/from instance alignment would need to follow klass layout 
rules, i.e. HeapWord alignment, unless we specialize 
"valueKlass::value_store()". "value_store" needs to fix barrier rules 
for as is, so could be done.

/D


On 3/10/2018 12:16 a.m., John Rose wrote:
> On Oct 2, 2018, at 10:00 AM, Ioi Lam <ioi.lam at oracle.com> wrote:
>> Are we sure this is needed? C++ packs arrays with alignment of sizeof(elem), and it seems to do fine …
> That's not true; C++ packs to alignof(elem) which can be much smaller.
> A struct of 5 bytes has no padding, no fragmentation.  That is the standard for C.
>
>> For performance, do we worry about random access to arrays, or counted loops?
> Counted loops dominate, as your example shows.
>
> — John