On 13.04.2016 18:38, Chris Pavlina wrote: > I would argue - quite strongly! - that it doesn't matter if it's faster in an > isolated test if it isn't used enough to actually affect the overall code > speed. Was this ever profiled in situ? This sort of thing just causes > headaches > when people misunderstand the usage and subtleties of the more limited > "optimized" replacement. I find it hard to believe that we call dynamic_cast > enough for it to be a performance issue.
Perhaps you're right, I'm not going to argue here. > > Also - *please* let me rename it. dynamic_cast vs dyn_cast is almost the > _textboox_ example of poor naming. It's absolutely 100% non-obvious to someone > reading code using the latter _why_ it was chosen, what its advantage is over > the normal one, and whether it has any subtle issues that can cause bugs. At > least it should be called something like dynamic_cast_fast so there's > justification for its use in the actual code using it. Go on with the renaming. Tom > > On Wed, Apr 13, 2016 at 06:34:28PM +0200, Tomasz Wlostowski wrote: >> On 13.04.2016 18:19, Simon Richter wrote: >>> Hi, >>> >>> On 13.04.2016 18:13, Chris Pavlina wrote: >>> >>>> What is the purpose of dyn_cast<> in include/core/typeinfo.h? Why don't we >>>> just >>>> use dynamic_cast<>? And can we either replace the former with the latter, >>>> or >>>> add a comment to the former explaining its purpose? >>> >>> It uses the parallel type system in EDA_ITEM rather than RTTI, so it >>> works if RTTI is broken, e.g. when compiling with gcc 2.95. >>> >> >> I wrote it inspired with Clang/LLVM design which uses a very similar >> pattern. Sorry Simon, I didn't consider compatibility with gcc 2.95 >> would be of an advantage. My reasons were: >> >> 1) Much faster (code in the attachment): >> - dynamic_cast<> : 9090437 usecs >> - dyn_cast<> : 1832433 usecs (5x improvement) >> >> 2) Lightweight & compatible with existing Kicad type system. >> >> Cheers, >> Tom > _______________________________________________ Mailing list: https://launchpad.net/~kicad-developers Post to : kicad-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~kicad-developers More help : https://help.launchpad.net/ListHelp
