http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47460
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-01-25 16:59:49 UTC --- (In reply to comment #3) > > Versions 4.4 and 4.5 were built with the same parameters (modulo some > libraries), so my question is: Why are the __sync_fetch* builtins not found in > 4.4 by default? Is this related to the configure parameters? > > --with-cloog=/group/agabi/software/i686/gcc-4.4.5 > --with-ppl=/group/agabi/software/i686/gcc-4.4.5 No, it's because (as I already said) the default for -march is implied by the target in 4.5, but not in 4.4 So your 4.5.1 build with i686 target defaults to -march=i686. Your 4.4.5 build does not.
