On Fri, 2010-08-27 at 17:09 +0200, Richard Guenther wrote: > On Fri, Aug 27, 2010 at 5:02 PM, Corey Kasten > <co...@materialintelligencellc.com> wrote: > > On Fri, 2010-08-27 at 06:50 -0700, Nathan Froyd wrote: > >> On Fri, Aug 27, 2010 at 09:44:25AM -0400, Corey Kasten wrote: > >> > I find that the executable compiled on system A runs faster (on both > >> > systems) than the executable compiled on system B (on both system), by a > >> > factor about approximately 4 times. I have attempted to play with the > >> > GCC optimizer flags and have not been able to get System B (with the > >> > later GCC version) to compile code with any better performance. Could > >> > someone please help figure this out? > >> > >> It's almost impossible to tell what's going on without an actual > >> testcase. You might not be able to provide the actual code, but you > >> could try distilling it down to something you could release. > >> > >> -Nathan > > > > Thanks for the reply Nathan. > > > > I have attached an archive with the test case code. The code is built by > > build.sh and outputs the number of microseconds to complete the > > processing. > > > > Compiling with GCC version "4.1.2 20070925 (Red Hat 4.1.2-33)" produces > > code that runs in about 66% of the time than does GCC version "4.3.0 > > 20080428 (Red Hat 4.3.0-8)" > > -fcx-limited-range or -fcx-fortran-rules. 4.3 now is more conforming than > 4.1. > > Richard. > > > Thanks > > > > Corey > >
Richard, -fcx-limited-range worked great on both my real benchmark and my test achive. GCC didn't recognize -fcx-fortran-rules, but obviously I don't need it. Thanks so much, Corey
