Reported here:
 http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2015-September/019093.html

Indeed, running that simple benchmark on current JDK 9 and under -prof perfasm yields an ineffective code (see comments in the code):
 http://cr.openjdk.java.net/~shade/8137049/LoopReduceBench.java

Full perfasm log:
 http://cr.openjdk.java.net/~shade/8137049/loop-reduce.perfasm

Runnable benchmark:
 http://cr.openjdk.java.net/~shade/8137049/benchmarks.jar (-prof perfasm to produce output)