  Based on $k\cdot p$ analysis and realistic tight-binding calculations, we
find that time-reversal-breaking Weyl semimetals can be realized in
magnetically-doped (Mn, Eu, Cr etc.) Sn$_{1-x}$Pb$_x$(Te,Se) class of
topological crystalline insulators. All the Weyl points are well separated in
momentum space and possess nearly the same energy due to high crystalline
symmetry. Moreover, both the Weyl points and Fermi arcs are highly tunable by
varying Pb/Sn composition, pressure, magnetization, temperature, surface
potential etc., opening up the possibility of manipulating Weyl points and
rewiring the Fermi arcs.
