On Wed, Nov 16, 2011 at 07:52:27AM -0800, Ted Dunning wrote: > The JVM is likely to in-line dummy, realize it does nothing and then > coalesce your other code. > > It isn't any wonder that this produces the same results.
I'm not sure I understand what you mean: Does "coalesce" means that x + delta - x will be equal to delta ? The issue is whether an optimization could do that transformation. [Note that I did not implement any "dummy" function but rather called the quite non-dummy "doubleToLongBits" and "longBitsToDouble".] Gilles > On Wed, Nov 16, 2011 at 5:28 AM, Gilles Sadowski < > gil...@harfang.homelinux.org> wrote: > > > Besides > > x + delta - x > > being strange-looking and running the risk of being manually (and > > incorrectly) changed to just > > delta > > the reference (not) cited above suggests to use a two- or three-steps > > procedure to ensure that some optimizing compiler will not do the same: > > ---CUT--- > > double sum = x + delta; > > dummy(sum); // function "dummy" does nothing. > > delta = sum - x; > > ---CUT--- > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
