It's in the tree for quite a while, it could get some stabilization.
====amd64==== Installs. All tests fine in test directory. Portage 2.1.2.12 (default-linux/amd64/2007.0/desktop, gcc-4.1.2, glibc-2.5-r4, 2.6.22-gentoo-r2 x86_64) ================================================================= System uname: 2.6.22-gentoo-r2 x86_64 AMD Athlon(tm) 64 Processor 3400+ Gentoo Base System release 1.12.9 Timestamp of tree: Sun, 02 Sep 2007 17:00:01 +0000 distcc 2.18.3 x86_64-pc-linux-gnu (protocols 1 and 2) (default port 3632) [disabled] ccache version 2.4 [disabled] app-shells/bash: 3.2_p17 dev-lang/python: 2.4.4-r4 dev-python/pycrypto: 2.0.1-r6 dev-util/ccache: 2.4-r7 sys-apps/baselayout: 1.12.9-r2 sys-apps/sandbox: 1.2.17 sys-devel/autoconf: 2.13, 2.61 sys-devel/automake: 1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2, 1.10 sys-devel/binutils: 2.17 sys-devel/gcc-config: 1.3.16 sys-devel/libtool: 1.5.24 virtual/os-headers: 2.6.21 ACCEPT_KEYWORDS="amd64" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=athlon64 -O2 -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/X11/xkb /usr/share/config" CONFIG_PROTECT_MASK="/etc/env.d /etc/gconf /etc/terminfo" CXXFLAGS="-march=athlon64 -O2 -pipe" DISTDIR="/distfiles" FEATURES="distlocks metadata-transfer parallel-fetch sandbox sfperms strict test" GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/linux/distributions/gentoo" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --filter=H_**/files/digest-*" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/overlay /usr/portage/local/kde" SYNC="rsync://kv80/gentoo-portage" USE="X acl acpi aiglx aim alsa amd64 arts berkdb bitmap-fonts branding cairo cli cracklib crypt cups dbus dri dvd dvdread emboss encode esd evo fam firefox fortran gdbm gif gpm gstreamer gtk hal iconv imap ipv6 isdnlog jpeg kde kerberos mad midi mikmod mmx mp3 mpeg mpeg3 mqsli mudflap mysql ncurses nls nptl nptlonly nvidia ogg opengl openmp oss pam pcre pdf perl png pppd python qt3 qt3support quicktime readline reflection sdl session sockets spell spl sqlite3 sse sse2 ssl svg tcpd test tiff truetype truetype-fonts type1-fonts unicode vim vorbis xcomposite xine xml xorg xv zlib" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mulaw multi null plug rate route share shm softvol" ELIBC="glibc" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" USERLAND="GNU" VIDEO_CARDS="nvidia" Unset: CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LC_ALL, LDFLAGS, LINGUAS, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS
amd64 stable
x86 stable, closing