OpenBSD disables jump tables in Clang on amd64 due to IBT, some architectures also had jump tables disabled as part of the switch to --execute-only ("xonly") binaries by default, e.g: powerpc64/sparc64/hppa.

https://marc.info/?l=openbsd-cvs&m=168254711511764&w=2

E.g: https://marc.info/?l=openbsd-cvs&m=167337396024167&w=2