On Tue, 25 Apr 2023 21:19:06 GMT, Vladimir Ivanov <vliva...@openjdk.org> wrote:
>> @iwanowww - may I ask why always allocating a fresh object might be better >> than returning a pointer to a previous "selected" object? > > I don't mind there's caching happening if it gives any noticeable benefit. As > of now, the code around doesn't care, probably, because it is allocated in > resource arena. > > What I'm against is repurposing existing instances: don't modify a candidate > object into a "real object", allocate a fresh one instead. Thanks for clarifying. There is one scenario where turning the candidate into a "real object" simplify the implementation _greatly_. The scenario is when the ObjectValue is not just a candidate. I.e., the ObjectValue is also used independently of the merge. Example: Point p = new Point(); Point q = new Point(); if (cond) p = q; trap(p, q); Second issue, is that allocating a fresh ObjectValue will require copying the array of field values from the candidate object to the newly allocated object. That's not a big issue, just pointing that out, though. I propose that we allocate a fresh ObjectValue if the candidate is just a candidate (not used independent of merge) and if the candidate is not just a candidate we return the existing ObjectValue (turned 'real object'). I have that implemented, I can push it for you to take a look. What do you think? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/12897#discussion_r1177087887
