Hello Rafael, hello all! > Would you mind reporting a bug in llvm.org/bugs? I have already done so, see the following entries: http://llvm.org/bugs/show_bug.cgi?id=18347 http://llvm.org/bugs/show_bug.cgi?id=18348 http://llvm.org/bugs/show_bug.cgi?id=18349 Best regards Jasper Neumann
Some of the behavior seen there was for a purpose, like the heuristics to overcome different problems. I have to remember all the details :) On Sat, Jan 11, 2014 at 3:26 AM, Jasper Neumann <jasper.neumann at web.de> wrote:> Hello Rafael, hello all! > > >> Would you mind reporting a bug in llvm.org/bugs? > > I have already done so, see the following entries: > http://llvm.org/bugs/show_bug.cgi?id=18347 > http://llvm.org/bugs/show_bug.cgi?id=18348 > http://llvm.org/bugs/show_bug.cgi?id=18349 > > > Best regards > Jasper Neumann > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev-- With best regards, Anton Korobeynikov Faculty of Mathematics and Mechanics, Saint Petersburg State University
Hello Anton! > Some of the behavior seen there was for a purpose, > like the heuristics to overcome different problems. > I have to remember all the details :) I have read your article "Improving Switch Lowering for The LLVM Compiler System" and thought that the selection mechanism works out well; by chance however I found that this mechanism does not work as designed if labels are sufficiently sparse and can effectively create an else-if chain because separated (single) marginal (i.e. first and last) labels have a too high weight. The central point might be: What is the density of a single label? It might also be that the logarithmic metric is not always working well. My simple modification however seems to be a solution to this special problem; until now I have not found any malicious secondary effects (collateral damages). By the way: I have submitted the patch to llvm-commits at cs.uiuc.edu few minutes ago; perhaps you are the person with the best knowledge for this problem. I'm currently working on switch lowering using hashing which can fully replace the jump table method. It works quite good by now but I will have to prepare a ton of documentation and test stuff. Some of the remaining problems can easily be solved later. Is anybody interested in beta-testing my patches therefor? Best regards Jasper Neumann