This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Recent libstdc++ regression on i686-linux: abi/cxx_runtime_only_linkage.cc
On Wed, Aug 27, 2008 at 10:15 AM, Joseph S. Myers
> > glibc has certainly required -march=i486 or greater for some time to build
> > for IA32; it will fail to link for -march=i386 because of missing atomic
On Wed, Aug 27, 2008 at 10:26:32AM -0700, H.J. Lu wrote:
> Given that glibc requires -march=i486, I think Linux/ia32 should default
> to i486.
Agreed; defaulting to i386 just causes problems (with both glibc and
Boost), so since i486 is effectively a requirement imposed by glibc,
it might as well be the default. Embedded apps might use the Linux
kernel and newlib or uClibc and work on an i386 equivalent, but it's
not too much of a burden to ask the developer to give an -march flag
in that case.
On the embedded issue: does anyone know which *currently shipping*
embedded x86-compatible processors are not i486-compatible?
Joseph again:
> > operations. (And I hold that i686-* should mean -march=i686 default not
> > -mcpu=i386 and similarly x86_64-* -m32 should default to -march=x86_64,
> > subject to --with-arch etc. in both cases.)
I'm not keen on moving the default -march all the way to i686, as there
are still enough old machines out there that this could cause
inconvenience.