I just depcleaned dev-libs/ocl-icd on my system and got the following warning: !!! existing preserved libs: >>> package: dev-libs/ocl-icd-2.2.12 * - /usr/lib64/OpenCL/vendors/ocl-icd/libOpenCL.so.1 * - /usr/lib64/OpenCL/vendors/ocl-icd/libOpenCL.so.1.0.0 * used by /usr/lib64/libhwloc.so.15.0.1 (sys-apps/hwloc-2.0.2) * used by /usr/lib64/libmca_common_monitoring.so.50.10.0 (sys-cluster/openmpi-4.0.1) * used by /usr/lib64/libmca_common_ompio.so.41.19.1 (sys-cluster/openmpi-4.0.1) * used by 108 other files so it seems that openmpi has an automagic dependency on OpenCL.
*** This bug has been marked as a duplicate of bug 683216 ***