case (elementOfUniqSet uq seen, fn blockid) of
(True, _) -> mkAsmTempLabel uq
(_, Nothing) -> mkAsmTempLabel uq
(_, Just (DestBlockId blockid')) -> shortBlockId fn (addOneToUniqSet seen uq) blockid'
(_, Just (DestImm (ImmCLbl lbl))) -> lbl
(_, _other) -> panic "shortBlockId"
case (elementOfUniqSet uq seen, fn blockid) of
(True, _) -> mkAsmTempLabel uq
(_, Nothing) -> mkAsmTempLabel uq
(_, Just (DestBlockId blockid')) -> shortBlockId fn (addOneToUniqSet seen uq) blockid'
(_, Just (DestImm (ImmCLbl lbl))) -> lbl
(_, _other) -> panic "shortBlockId"