On Tue, Dec 1, 2009 at 2:25 AM, Paolo Bonzini <bonz...@gnu.org> wrote: > > On 11/30/2009 09:47 PM, Michael Witten wrote: >> >> On Mon, Nov 30, 2009 at 12:04 AM, Kaveh R. GHAZI<gh...@caip.rutgers.edu> >> wrote: >>> >>> The patch which makes the MPC library a hard requirement for GCC >>> bootstrapping has been approved today. >> >> Out of curiosity and ignorance: Why, specifically, is MPC going to be >> a hard requirement? >> >> On the prerequisites page, MPC is currently described with: "Having >> this library will enable additional optimizations on complex numbers." >> >> Does that mean that such optimizations are now an important >> requirement? or is MPC being used for something else? > > They are a requirement for Fortran, but it's (much) simpler to do them for > all front-ends. > > Paolo >
On the flip side, it's not necessarily easy to get it to work. On my build system, apt-get doesn't find it. Downloading and installing the .deb manually triggers 3 missing deps. ftp://gcc.gnu.org/pub/gcc/infrastructure/ is unresponsive, so I had to look around for the source. Installing from source fails with a libgmp abi message during configuration, so now I need to fiddle with it. Like many, I don't use fortran much, so this is pure overhead at this point. It could be just that my build system is such that it's more difficult to bring in this change than is in the average case. I'm not arguing against change, especially when it brings improved performance, but I think it's worth reinforcing that bringing in a library dependence is not free. (Looking at this issue oblivious of the maintenance and development burden, it would have been nice to have a transitional --no-mpc configure option.) Silvius
