The JVM IR backend code seems saner to me. The string concatenation
lowering for JVM IR calls the stringPlus intrinsic if there are
only two arguments. That leads to a lot less code:
```
load string
load argument
box argument
call Intrinsics.stringPlus
```
instead of
```
allocate StringBuilder
call StringBuilder.<init>
load string
call StringBuilder.append
load argument
call StringBuilder.append
call StringBuilder.toString
```
This will lead to more boxing, but a lot smaller code. We still
use StringBuilders in JVM IR if there are more than two strings
being concatenated.
Mads Ager
baf1f56859