The latest currently stable version of mpich is =sys-cluster/mpich-3.0.4, which is blocked by the recently-stabilized =virtual/mpi-2.0-r4. Stabilization of =sys-cluster/mpich-3.2-r1 would resolve this conflict.
Adding archs.
amd64 stable
x86 stable
ppc ppc64 stable.
Stable for HPPA. Closing.