+--------------------------------------------------------------------------------
+-- | Convert a NatCmmTop to a LiveCmmTop, with empty liveness information
+{-
+natCmmTopToLive
+ :: NatCmmTop instr
+ -> LiveCmmTop instr
+
+natCmmTopToLive cmm@(CmmData _ _)
+ = cmm
+
+natCmmTopToLive (CmmProc info lbl params (ListGraph []))
+ = CmmProc (LiveInfo info Nothing emptyBlockEnv)
+ lbl params (ListGraph []))
+
+natCmmTopToLive (CmmProc info lbl params (ListGraph blocks))
+ = let first_id = blockId first
+ sccs = sccBlocks blocks
+
+ liveBlocks
+ = map (\scc -> case scc of
+ AcyclicSCC b@(BasicBlock l _) -> BasicBlock l [cmmBlockToLive b]
+ CyclicSCC bs@(BasicBlock l _ : _) -> BasicBlock l (map cmmBlockToLive bs)
+ CyclicSCC []
+ -> panic "RegLiveNess.natCmmTopToLive: no blocks in scc list")
+ sccs
+
+ in CmmProc (LiveInfo info (Just first_id) ???
+-}
+