Hi Peter,
On 2019-04-28 23:34, Claes Redestad wrote:
What do you think?
This is what I meant by "simplified wiring logic":
http://cr.openjdk.java.net/~plevart/jdk-dev/8222852_StringConcatOpt/webrev.02p/
I haven't tried this though, but if it works correctly and if JIT
inlines the strategy for each call site, it should also eliminate the
dead code paths that are detected from null/non-null bound constants
and the end result should be equivalent machine code. But that's just
in theory...
thanks for picking this up and experimenting further with it!
having run the numbers on your patch, I'm warming to this approach:
- It seems the branches testing for null do get eliminated (no
regressions in neither existing nor new micro trying to provoke
pollution between LFs)
- Startup numbers generally a bit better, and the amortized/repeated
bootstrap cost of always binding in prefix and suffix appears to be
insignificant
- The logic for handling constants is nicer and less spread out; bonus
points for folding successive suffix constants!
http://cr.openjdk.java.net/~redestad/8222852/open.03/
I merged some of the cleanups and comments and think this is good to
go rather than splitting it up into a follow-up RFE.
Thanks!
/Claes
