[PATCH] Performance improvement of StringBuilder.append(CharSerquence, int, int)

[Stuart Marks]

It seems to me rather odd and surprising to introduce a code path into 
sb.append(cs,int,int) that allocates memory in order to get at an intrinsic that 
only sometimes makes things run faster. As you observed, the performance 
tradeoffs aren't obvious.

Instead, if we want to optimize sb.append(cs,int,int) maybe we should just go 
ahead and do that, possibly by adding or rearranging the intrinsics. I've filed 
JDK-8217675 to cover this. Jim Laskey said he might be able to look at it.

https://bugs.openjdk.java.net/browse/JDK-8217675

s'marks