http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46186
--- Comment #7 from Julian Andres Klode <j...@jak-linux.org> 2010-10-26 15:00:37 UTC --- (In reply to comment #5) > (In reply to comment #4) > > GCC's output is significantly faster at -O3 or without the noinline > > attribute > > I just tested and at -O3, gcc-4.4 creates slow code and gcc-4.5 fast code. At > -O2, both are equally fast. The clang 1.1 code at -O2 is as fast as GCC 4.5's > code at -O3. Using gcc 4.5 with -O3 may work for the C code, but it does not optimize the C++ code posted at http://lwn.net/Articles/411776/: g++-4.5 -O3: real 0m1.608s clang++ -O2: real 0m0.003s clang++ -Os: real 0m0.003s But I guess the C++ problem might be a different one.