When using more than one installed OpenCL ICD, in my case
321232 -rw-r--r-- 1 root wheel - 33B 24 Nov. 14:24 intel-beignet.icd
321144 -rw-r--r-- 1 root wheel - 19B 10 Nov. 15:05 mesa.icd
321060 -rw-r--r-- 1 root wheel - 31B 24 Nov. 12:02 pocl.icd
a OpenCL client like clinfo (devel/clinfo) reports an error:
: CommandLine Error: Option 'enable-value-profiling' registered more than once!
LLVM ERROR: inconsistency in registered CommandLine options
This error occurs also with any software compiled with lang/pocl.
Searching the net for this specific error reveals problems going back to January of 2017, i.e.
Maintainer informed via mail
*** This bug has been marked as a duplicate of bug 223879 ***