<p>Have a look at <a href="http://arxiv.org/abs/1412.6765" rel="nofollow">Performance comparison between Java and JNI for optimal implementation of computational micro-kernels</a>. They show that Java HotSpot VM server compiler supports auto-vectorization using Super-word Level Parallelism, which is limited to simple cases of inside the loop parallelism. This article will also give you some guidance whether your data size is large enough to justify going JNI route.</p>
Do any JVM's JIT compilers generate code that uses vectorized floating point instructions?
<p>Let's say the bottleneck of my Java program really is some tight loops to compute a bunch of vector dot products. Yes I've profiled, yes it's the bottleneck, yes it's significant, yes that's just how the algorithm is, yes I've run Proguard to optimize the byte code, etc.</p>

<p>The work is, essentially, dot products. As in, I have two <code>float[50]</code> and I need to compute the sum of pairwise products. I know processor instruction sets exist to perform these kind of operations quickly and in bulk, like SSE or MMX.</p>

<p>Yes I can probably access these by writing some native code in JNI. The JNI call turns out to  be pretty expensive.</p>

<p>I know you can't guarantee what a JIT will compile or not compile. Has anyone <em>ever</em> heard of a JIT generating code that uses these instructions? and if so, is there anything about the Java code that helps make it compilable this way?</p>

<p>Probably a "no"; worth asking.</p>