Official MinGW installation reminds me of the old Xvid.org site before its new website... so back around in the pre-2007 years... Also reminds me of how annoying installing and using Cygwin can be. Interesting thread!
2010/3/10 Przemysław Czerpak <dru...@acn.waw.pl> > On Wed, 10 Mar 2010, Szak�ts Viktor wrote: > > Hi, > > > > It's interesting to check if there are any speed differences in MSVC C > and > > > C++ builds. > > > Can you check it? > > I checked mingw-tdm-2 4.4.1, and C++ turned out to be consistently > > faster by 5% than plain C. Calculated by 4-4 speedtst runs, dropping > > min/max and averaging rest 2-2 results. > > Env: MBP iC2D/2.8 -> OS X 10.6 (64-bit kernel) -> VMWare 3.0.2 -> Win7 > x64 > > It's similar to mine results. > GCC4 in C++ mode for sure uses more extensively strict aliasing > optimization. At least it was reporting more errors and warnings > for Harbour core code which was using casting ignoring aliasing > rules. > > BTW this ones are still reported: > > ../../../hb_btree.c: In function ‘ioOneBufferAlloc’: > ../../../hb_btree.c:275:3: warning: dereferencing type-punned pointer will > break strict-aliasing rules > > This seems to be also real bug which may cause GPF on some platforms but > I'm not familiar enough with this code to fix it myself. > > ../../../sddfb.c: In function ‘fbDisconnect’: > ../../../sddfb.c:181:4: warning: dereferencing type-punned pointer will > break strict-aliasing rules > ../../../sddfb.c: In function ‘fbOpen’: > ../../../sddfb.c:209:4: warning: dereferencing type-punned pointer will > break strict-aliasing rules > ../../../sddfb.c:219:4: warning: dereferencing type-punned pointer will > break strict-aliasing rules > > This is also danger casting though it should work if void * is large enough > to hold FB handlers. Anyhow it's potential problem so it should be fixed. > > BTW it would be good to check what GCC does when it detects such code or > even real problems (it can report also: "dereferencing pointer ... does > break strict-aliasing rules"). > Does it disable optimization or generates potentially wrong code. > > Can you compare C and C++ mode in MSVC too? > > best regards, > Przemek > _______________________________________________ > Harbour mailing list (attachment size limit: 40KB) > Harbour@harbour-project.org > http://lists.harbour-project.org/mailman/listinfo/harbour > -- smu johnson <smujohn...@gmail.com>
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