'loop_unroll' - unroll loops
Loop unrolling expands the loop body by combining several iterations into one removing intermediate loop-exit checks.
The optimization reduces number of instructions executed per loop iteration and expands scope for optimizations inside of the loop body.
implementation file: http://svn.apache.org/viewvc/harmony/enhanced/drlvm/trunk/vm/jitrino/src/optimizer/loop_unroll.cpp