Generate slightly less crap to be cleaned up later

compiler/codeGen/StgCmmHeap.hs

@@ -45,6 +45,8 @@ import FastString( mkFastString, fsLit )
 import Constants
 import Util
 
+import Control.Monad (when)
+
 -----------------------------------------------------------
 --              Initialise dynamic heap objects
 -----------------------------------------------------------
@@ -491,20 +493,15 @@ do_checks :: Bool       -- Should we check the stack?
           -> FCode ()
 do_checks checkStack alloc do_gc = do
   gc_id <- newLabelC
-  hp_check <- if alloc == 0
-                 then return mkNop
-                 else do
-                   ifthen <- mkCmmIfThen hp_oflo (alloc_n <*> mkBranch gc_id)
-                   return (mkAssign hpReg bump_hp <*> ifthen)
 
-  if checkStack
-     then emit =<< mkCmmIfThenElse sp_oflo (mkBranch gc_id) hp_check
-     else emit hp_check
+  when checkStack $
+     emit =<< mkCmmIfGoto sp_oflo gc_id
 
-  emit $ mkComment (mkFastString "outOfLine should follow:")
+  when (alloc /= 0) $ do
+     emitAssign hpReg bump_hp
+     emit =<< mkCmmIfThen hp_oflo (alloc_n <*> mkBranch gc_id)
 
   emitOutOfLine gc_id $
-     mkComment (mkFastString "outOfLine here") <*>
      do_gc -- this is expected to jump back somewhere
 
                 -- Test for stack pointer exhaustion, then

compiler/codeGen/StgCmmMonad.hs

@@ -29,7 +29,8 @@ module StgCmmMonad (
 	getCmm, cgStmtsToBlocks,
 	getCodeR, getCode, getHeapUsage,
 
-        mkCmmIfThenElse, mkCmmIfThen, mkCall, mkCmmCall, mkSafeCall,
+        mkCmmIfThenElse, mkCmmIfThen, mkCmmIfGoto,
+        mkCall, mkCmmCall, mkSafeCall,
 
         forkClosureBody, forkStatics, forkAlts, forkProc, codeOnly,
 
@@ -676,6 +677,11 @@ mkCmmIfThenElse e tbranch fbranch = do
             mkLabel tid <*> tbranch <*> mkBranch endif <*>
             mkLabel fid <*> fbranch <*> mkLabel endif
 
+mkCmmIfGoto :: CmmExpr -> BlockId -> FCode CmmAGraph
+mkCmmIfGoto e tid = do
+  endif <- newLabelC
+  return $ mkCbranch e tid endif <*> mkLabel endif
+
 mkCmmIfThen :: CmmExpr -> CmmAGraph -> FCode CmmAGraph
 mkCmmIfThen e tbranch = do
   endif <- newLabelC