HotSpot folds FP constants in a few rare cases, and I don't thing Math.log is one of them. For instance you can't fold "x+0.0" into "x" in case "x" happens to be negative 0. Math.log is a pure function so it would be possible, but I don't think it made the short-list of hot FP functions to optimize.
Otherwise, the JDK is total specified and JVMs routinely optimize popular JDK calls. e.g. various String compare calls or x.getClass are totally inlined. Cliff On Dec 31 2008, 12:00 pm, "Mark H." <mark.hoem...@gmail.com> wrote: > Folding constants in nontrivial floating-point expressions is an > aggressive optimization that can break some subtle code. For example, > when building LAPACK, the file that tries to determine parameters of > the floating-point units generally has to be compiled with no > optimization. I'd much rather keep that part of the optimization > turned off, or be very selective about when it gets turned on. > Furthermore, in some cases (FFTs on the Cell processor is the modern > example, if I recall correctly), it's better to recompute constants on > the fly then to look them up in a table. > > mfh --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
