OptimizeStringConcat option

[David Dabbs]

Hello. 

I see that a bug related to OptimizeStringConcat will land in 6u21 and I guess is also in jdk7-94 (or earlier).
>From what I can tell OptimizeStringConcat is now product, but disabled by default. What behavior does it enable?
Is this related to issue "C2 should optimize some stringbuilder patterns?" If not, does a separate option enable/disable that optimization?

Other questions:

Does the closing of the SSE4.2 intrinsics issue mean that they are re-enabled?

Release 6u14? introduced some options that I think have been in and out. Specifically, 

-XX:+DoEscapeAnalysis
-XX:+UseCompressedOops 
-XX:+UseG1GC
TreeMap Iteration Improvement (via -XX:+AggressiveOpts)

At this point is the options.cpp (sic) the most accurate source for all options, product or otherwise, and their defaults?


Thank you,

David Dabbs