Stack allocation prototype for C2

[Sergey Kuksenko]

I am just curious.

For each benchmark you show allocation reduce size in general. Do you 
have statistics which stack allocated objects gives major impact? And 
which code patterns fail scalar replacement except well know Integer 
cache flow merge?

On 6/29/20 2:05 PM, Charlie Gracie wrote:
> Hi hotspot-compiler-dev community,
>
> Here is the prototype code for our work on adding stack allocation to the HotSpot C2 compiler. We are looking for any and all feedback
> as we hope to move from a prototype to something that could be contributed. A change of this size is difficult to review so we
> understand the process will be thorough and will take time to complete. Any suggestions on how to allow for collaboration with others,
> if they wanted to, would also be appreciated (i.e., a repo somewhere).
>
> For a quick refresher here is a link to Nikola’s talk at FOSDEM:
> https://fosdem.org/2020/schedule/event/reducing_gc_times/
>
> Here is a link to our initial webrev:
> http://cr.openjdk.java.net/~adityam/charlie/stack_alloc/
>
> Expecting that a change like this will require a JEP, we have prepared a document describing our work based off of the JEP submission
> form. Our document has a few extra sections at the end discussing areas that we are looking for guidance on and some initial
> performance results. This document can be found here:
> https://github.com/microsoft/openjdk-proposals/blob/master/stack_allocation/Stack_Allocation_JEP.md
>
> Thanks in advance for reviews, suggestions, concerns, comments and issues.
> Charlie and Nikola
>