RFR: 8232165: Reduce allocations in ValueStack copying constructor

[Vladimir Kozlov]

Looks good.

thanks,
Vladimir

On 10/11/19 4:42 AM, Claes Redestad wrote:
> Hi,
> 
> this patch optimizes C1 ValueStack copying, which reduces unnecessary
> allocations and has a small but measurable impact on compilation speed.
> 
> Webrev: http://cr.openjdk.java.net/~redestad/8232165/open.00/
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8232165
> 
> Testing: tier1-2 (tier3-4 ongoing)
> 
> Thanks!
> 
> /Claes