On Wed, Mar 9, 2016 at 8:43 PM, Jack Howarth <howarth.at.macpo...@gmail.com> wrote: > On Wed, Mar 9, 2016 at 6:36 PM, René J.V. <rjvber...@gmail.com> wrote: >> On Wednesday March 09 2016 18:00:07 Jack Howarth wrote: >> >>> Have you checked to make sure that the installed llvm packages aren't >>> built as the +assertions variant? The use of assertions will have a >> >> Oh yes. With that variant active the performance hit is much worse from what >> I recall, so I've been making a point of it only to install release >> versions, without assertions active. >> >>> 3.8.0. However, port isn't smart enough to honor that change for >>> previous installations of llvm-3.8 so the +assertions variant will >> >> I wouldn't call the user who doesn't notice that all of a sudden a >> clang/llvm upgrade takes hours because built from source particularly bright >> either ;) >> >>> slower than the same under the fink packaging of llvm38/clang38 but >>> the fink packaging uses the default -O3 optimization whereas MacPorts >>> resets the build to use -Os instead, >> >> Frankly I'd be surprised if that leads to a 10% performance difference! > > Why? My understanding is that the optimizations for -Os are equivalent > to -O2 with the emphasis on size reduction. The additional > optimizations from -O2 to -O3 would seem sufficient to produce a 10% > execution optimization, no?
The only other difference I see between the fink and MacPorts packaging is the use of -DLLVM_ENABLE_RTTI=ON in MacPorts. My understanding is that these additional virtual functions can introduce overhead in c++. > >> >>> Also, keep in mind that each release of clang has been getting slower >>> over time as discussed in this thread... >> >> Indeed, which is why I compared comparable versions in the past; my "up to >> 50%" estimate is based on that. >> >>> > Is there a reason the LLVM ports build a shared libLLVM? >> >> ? >> >> R. _______________________________________________ macports-dev mailing list macports-dev@lists.macosforge.org https://lists.macosforge.org/mailman/listinfo/macports-dev