Try -XX:+PrintOptoAssembly See here: http://stackoverflow.com/questions/1551781/how-can-i-see-the-code-that-hotspot-generates-after-optimizing
and here: http://weblogs.java.net/blog/kohsuke/archive/2008/03/deep_dive_into.html 2011/11/17 Sébastien Brisard <sebastien.bris...@m4x.org> > Hi, > > Also, it is clear that (x+delta) - x != delta for > > some values of delta so I doubt that the optimization happens. > > > > > Is there a specification where this is clearly stated ? I am actually > strugggling to find what kind of optimizations are performed by --say-- > Oracle's JVM. One reason for this would be this issue, another would be: is > it possible to write the code in a way that would "help" the JIT (for > example to remove array bounds checks, and so on). If anyone could share > any hint about this, I would be grateful. > > Regarding Gilles's issue. If we were to define a private *class variable* > called dummy, then I think the JIT would *have to compute* dummy > {code} > dummy = x + h; > h = dummy - x; > {code} > > Now, this is not a perfect solution, because for the proposed (static) > method representableDelta, the class variable dummy woud need to be static > as well, which I think raises thread-safety issues? Do you think a solution > can be worked along those lines? > > Thank you beforehand, > Sébastien >
