On Tue, 10 Jun 2008, Paolo Carlini wrote: > Luke Dalessandro wrote: > > I'm making some modifications to exception handling inside of > > unwind-dw2-fde.c that I'd like to use __sync_bool_compare_and_swap for, > > unfortunately I can't seem to figure out how to correctly use builtins in > > the context of libgcc. > > > > I've tried a bunch of different things, but I consistently get the error > > > > bin/../lib/gcc/i686-pc-linux-gnu/4.3.1/../../../libgcc_s.so: undefined > > reference to `__sync_bool_compare_and_swap_4' > > > > so clearly I'm not getting this symbol included correctly when I build. Any > > advice would be appreciated. > Isn't this the well know, annoying, issue that the default sub-architecture is > i386 and the builtins are only available on i486 and later?
I hold that it is a bug that i686-* tools default to -march=i386 instead of -march=i686 (whereas e.g. sparcv9-* tools default to -mcpu=sparcv9, and -mcpu means -march for SPARC). My --with-arch-32 etc. patch <http://gcc.gnu.org/ml/gcc-patches/2008-06/msg00124.html> (config/i386 part pending review) would facilitate fixing this bug by making i686-* imply --with-arch-32=i686 instead of --with-cpu-32=i686, while leaving the 64-bit defaults (for which mode -march=i686 is invalid) unaffected. -- Joseph S. Myers [EMAIL PROTECTED]
