## Submitted by Kate Clark Assigned to **Nobody** **[Link to original bugzilla bug (#1555)](https://eigen.tuxfamily.org/bz/show_bug.cgi?id=1555)** **Version**: 3.3 (current stable) ## Description Compiling Eigen 3.3.4 (the latest release) with xlc++ 16.0.3 gives this error message: In file included from .../eigen/src/Eigen/Eigen/Core:376: .../eigen/src/Eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:1025:13: error: cannot initialize a variable of type 'Packet2bl' (aka 'Packet2ul') with an rvalue of type '__vector __bool unsigned long long' (vector of 2 'unsigned long long' values) ...mask = vec_cmpeq(reinterpret_cast(select), reinterpret_cast(p2l_ONE)); 1 error generated. However, compiling an earlier version of Eigen (3.2.10) has no such error. Can this error be fixed for compilation with Eigen? Now that the POWER9 Summit/Sierra supercomputer has gone online, the use of XLC for HPC codes is expected to increase dramatically. Thank you ### Depends on #1494 ### Blocking #814