[project @ 2000-03-27 13:24:12 by simonpj]

[ghc-hetmet.git] / ghc / compiler / simplCore / Simplify.lhs

diff --git a/ghc/compiler/simplCore/Simplify.lhs b/ghc/compiler/simplCore/Simplify.lhs
index 2f88b17..9febaa7 100644 (file)
--- a/ghc/compiler/simplCore/Simplify.lhs
+++ b/ghc/compiler/simplCore/Simplify.lhs
@@ -48,10 +48,10 @@ import CoreFVs              ( exprFreeVars )
 import CoreUnfold      ( Unfolding, mkOtherCon, mkUnfolding, otherCons, maybeUnfoldingTemplate,
                          callSiteInline, hasSomeUnfolding, noUnfolding
                        )
-import CoreUtils       ( cheapEqExpr, exprIsDupable, exprIsCheap, exprIsTrivial,
+import CoreUtils       ( cheapEqExpr, exprIsDupable, exprIsCheap, exprIsTrivial, exprIsConApp_maybe,
                          exprType, coreAltsType, exprArity, exprIsValue, idAppIsCheap,
                          exprOkForSpeculation, etaReduceExpr,
-                         mkCoerce, mkSCC, mkInlineMe
+                         mkCoerce, mkSCC, mkInlineMe, mkAltExpr
                        )
 import Rules           ( lookupRule )
 import CostCentre      ( isSubsumedCCS, currentCCS, isEmptyCC )
@@ -1141,26 +1141,9 @@ rebuild_case scrut bndr alts se cont
   = complete_case scrut bndr alts se cont
 
   where
-    maybe_con_app    = analyse (collectArgs scrut)
+    maybe_con_app    = exprIsConApp_maybe scrut
     Just (con, args) = maybe_con_app
 
-    analyse (Var fun, args)
-       | maybeToBool maybe_con_app = maybe_con_app
-       where
-         maybe_con_app = case isDataConId_maybe fun of
-                               Just con | length args >= dataConRepArity con 
-                                       -- Might be > because the arity excludes type args
-                                        -> Just (con, args)
-                               other    -> Nothing
-
-    analyse (Var fun, [])
-       = case maybeUnfoldingTemplate (idUnfolding fun) of
-               Nothing  -> Nothing
-               Just unf -> analyse (collectArgs unf)
-
-    analyse other = Nothing
- 
-
        -- See if we can get rid of the case altogether
        -- See the extensive notes on case-elimination above
 canEliminateCase scrut bndr alts
@@ -1297,7 +1280,7 @@ If we eliminate the inner case, we trap it inside the I# v -> arm,
 which might prevent some full laziness happening.  I've seen this
 in action in spectral/cichelli/Prog.hs:
         [(m,n) | m <- [1..max], n <- [1..max]]
-Hence the add_eval_info argument
+Hence the no_case_of_case argument
 
 
 If we do this, then we have to nuke any occurrence info (eg IAmDead)
@@ -1316,8 +1299,8 @@ Urk! b is alive!  Reason: the scrutinee was a variable, and case elimination
 happened.  Hence the zap_occ_info function returned by simplCaseBinder
 
 \begin{code}
-simplCaseBinder add_eval_info (Var v) case_bndr thing_inside
-  | add_eval_info
+simplCaseBinder no_case_of_case (Var v) case_bndr thing_inside
+  | not no_case_of_case
   = simplBinder (zap case_bndr)                                        $ \ case_bndr' ->
     modifyInScope v case_bndr'                                 $
        -- We could extend the substitution instead, but it would be