Run simplifier before SpecConstr

[ghc-hetmet.git] / compiler / main / DynFlags.hs

diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 9a7de07..2d28ae6 100644 (file)
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -722,19 +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
        ]
      ]