no known regressions, and -r1 is a minor fix over -r0 which has been in the tree for long enough. should fix a few known bugs w/2.24 though.
amd64 stable
Stable on alpha.
x86 stable
sparc stable
ppc stable
ppc64 stable
Stable for HPPA.
done arm now: http://gitweb.gentoo.org/repo/gentoo.git/commit/?id=f1db98b9e7ea7a8fcef96f863f1377823100e893