X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fmain%2FDynFlags.hs;h=0bd669041fefefd19c2daec1c6e263ce95910677;hb=a5168e30f331c6fe912cca4f53be8544ce6800d5;hp=07698122bdde4f44ff1ff67def8626844bec424c;hpb=862106eb2518f437b9f10dc9367e99454ebd8072;p=ghc-hetmet.git

diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 0769812..0bd6690 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -641,9 +641,8 @@ getCoreToDo dflags
 			-- Similarly, don't apply any rules until after full 
 			-- laziness.  Notably, list fusion can prevent floating.
 
-            NoCaseOfCase,
-			-- Don't do case-of-case transformations.
-			-- This makes full laziness work better
+            NoCaseOfCase,	-- Don't do case-of-case transformations.
+				-- This makes full laziness work better
 	    MaxSimplifierIterations max_iter
 	],
 
@@ -723,19 +722,27 @@ getCoreToDo dflags
 -- Case-liberation for -O2.  This should be after
 -- strictness analysis and the simplification which follows it.
 
-	case rule_check of { Just pat -> CoreDoRuleCheck 0 pat; Nothing -> CoreDoNothing },
+	case rule_check of { Just pat -> CoreDoRuleCheck 0 pat; Nothing -> CoreDoNothing }
+     ]
+
+	++ 
 
-	if opt_level >= 2 then
-	   CoreLiberateCase
-	else
-	   CoreDoNothing,
-	if opt_level >= 2 then
-	   CoreDoSpecConstr
-	else
-	   CoreDoNothing,
+     (if opt_level >= 2 then
+	   [  CoreLiberateCase,
+	      CoreDoSimplify (SimplPhase 0) [
+		  MaxSimplifierIterations max_iter
+	      ],	-- Run the simplifier after LiberateCase to vastly 
+			-- reduce the possiblility of shadowing
+			-- Reason: see Note [Shadowing] in SpecConstr.lhs
+	     CoreDoSpecConstr
+	   ]
+      else
+	   [])
+
+	++
 
 	-- Final clean-up simplification:
-	CoreDoSimplify (SimplPhase 0) [
+     [	CoreDoSimplify (SimplPhase 0) [
 	  MaxSimplifierIterations max_iter
 	]
      ]