  We present the implementation of twisted mass fermion operators for the QPhiX
library. We analyze the performance on the Intel Xeon Phi (Knights Corner)
coprocessor as well as on Intel Xeon Haswell CPUs. In particular, we
demonstrate that on the Xeon Phi 7120P the Dslash kernel is able to reach 80\%
of the theoretical peak bandwidth, while on a Xeon Haswell E5-2630 CPU our
generated code for the Dslash operator with AVX2 instructions outperforms the
corresponding implementation in the tmLQCD library by a factor of $\sim
5\times$ in single precision. We strong scale the code up to 6.8 (14.1) Tflops
in single (half) precision on 64 Xeon Haswell CPUs.
