https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88535
--- Comment #8 from Eric Botcazou <ebotcazou at gcc dot gnu.org> --- > Yes, same for a bootstrap. You can bootstrap the latter with the former if > you correctly configure the bootstrap, with explicit --build and CC="gcc > -m32". To be more explicit: if you want to bootstrap the 32-bit compiler with the 64-bit system compiler, you must configure like this: CC="gcc -m32" CXX="g++ -m32" ./configure --build=sparc-sun-solaris2.11 Conversely, if you want to bootstrap the 64-bit compiler with the 32-bit one: CC="gcc -m64" CXX="g++ -m64" ./configure --build=sparcv9-sun-solaris2.11