8159244: Partially initialized string object created by C2's string concat optimization may escape
Summary: Emit release barrier after String creation to prevent partially initialized object from escaping.
Reviewed-by: kvn
^build/
^dist/
^.idea/
nbproject/private/
^webrev
^.hgtip
^.bridge2
^.jib/
.DS_Store
.metadata/
.recommenders/