Vincent Labrecque wrote:
> And as I'm writing this, with regards to optimization flags, maybe the > sage build system should provide an abstraction over -On. As I'm > sure you know, these have widely differing behaviors across > compilers. Sometimes -O3 will do nothing, sometimes it will break > your code. ``high'', ``medium'' and ``low'' can be translated by an > expert on the particular platform (os/compiler/compiler-version). > Then again I'm thinking in general terms and maybe in the case of sage > people don't build it or change flags so often and you can ignore this) > > --Vincent Yes, they do widely differ. On Solaris, with Sun's compiler, -O defaults to -O3, but Sun say that can change. I think an environment variable SAGE_OPTIMISATION, which the user can set, but which otherwise defaults to something reasonable might be sensible. * i.e, with GNU compilers it defaults to -O3 * With Sun Studio compiler it defaults to -O * With any other compilers I can work out, I'll default it to something reasonable. But in every case, the user could set SAGE_OPTIMISATION to whatever they want. So if they want "-fast -nobreakages" or whatever, they can set it. Of course, one issue is that not every configure script will My thoughts for a set of CFLAGS for a default build would be: -Wall -g -O3 Each of those would be changed where appropriate i.e. -Wall would not work with Sun compilers, or any other compiler that I know of. -O3 would be changed to -O with the Sun Studio compiler. -m64 would be added with the GNU or Sun compilers if SAGE64 was set to yes. SAGE64=yes would not be permitted with a native HP-UX compiler, as HP's Fortran compiler can't generate 64-bit code, which seems a bit stupid, as HP had 64-bit machines long before they were common place. Clearly the platforms which we use a lot (linux, OS X, Solaris), finding the right flags should be easy. For other platforms, lets take a quick stab at them, and leave it to someone more serious about porting to find them. Dave --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
