Factor cmmToRawCmm completely out of CPS

This patch also fixes how the CPS handles functions with an empty body.
Factoring cmmToRawCmm out of the CPS pass made that fix easier.

compiler/cmm/CmmCPS.hs

@@ -43,7 +43,7 @@ import Data.List
 -----------------------------------------------------------------------------
 cmmCPS :: DynFlags -- ^ Dynamic flags: -dcmm-lint -ddump-cps-cmm
        -> [GenCmm CmmStatic CmmInfo CmmStmt]    -- ^ Input C-- with Proceedures
-       -> IO [GenCmm CmmStatic [CmmStatic] CmmStmt] -- ^ Output CPS transformed C--
+       -> IO [GenCmm CmmStatic CmmInfo CmmStmt] -- ^ Output CPS transformed C--
 cmmCPS dflags abstractC = do
   when (dopt Opt_DoCmmLinting dflags) $
        do showPass dflags "CmmLint"
@@ -112,9 +112,17 @@ force_gc_block old_info stack_use block_id fun_label formals =
 
 cpsProc :: UniqSupply 
         -> GenCmmTop CmmStatic CmmInfo CmmStmt     -- ^Input proceedure
-        -> [GenCmmTop CmmStatic [CmmStatic] CmmStmt]   -- ^Output proceedure and continuations
-cpsProc uniqSupply (CmmData sec dat) = [CmmData sec dat]
-cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs
+        -> [GenCmmTop CmmStatic CmmInfo CmmStmt]   -- ^Output proceedure and continuations
+
+-- Data blocks don't need to be CPS transformed
+cpsProc uniqSupply proc@(CmmData _ _) = [proc]
+
+-- Empty functions just don't work with the CPS algorithm, but
+-- they don't need the transformation anyway so just output them directly
+cpsProc uniqSupply proc@(CmmProc _ _ _ []) = [proc]
+
+-- CPS transform for those procs that actually need it
+cpsProc uniqSupply (CmmProc info ident params blocks) = cps_procs
     where
       (uniqSupply1, uniqSupply2) = splitUniqSupply uniqSupply
       uniques :: [[Unique]]
@@ -203,11 +211,6 @@ cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs
       cps_procs :: [CmmTop]
       cps_procs = zipWith (continuationToProc formats' stack_use) proc_uniques continuations'
 
-      -- Convert the info tables from CmmInfo to [CmmStatic]
-      -- We might want to put this in another pass eventually
-      info_procs :: [RawCmmTop]
-      info_procs = concat (zipWith mkInfoTable info_uniques cps_procs)
-
 -----------------------------------------------------------------------------
 
 collectNonProcPointTargets ::