Implement -fexpose-all-unfoldings, and fix a non-termination bug

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

diff --git a/compiler/simplCore/Simplify.lhs b/compiler/simplCore/Simplify.lhs
index 5e63221..eb2884c 100644 (file)
--- a/compiler/simplCore/Simplify.lhs
+++ b/compiler/simplCore/Simplify.lhs
@@ -35,8 +35,7 @@ import BasicTypes       ( isMarkedStrict, Arity )
 import CostCentre       ( currentCCS, pushCCisNop )
 import TysPrim          ( realWorldStatePrimTy )
 import PrelInfo         ( realWorldPrimId )
-import BasicTypes       ( TopLevelFlag(..), isTopLevel,
-                          RecFlag(..), isNonRuleLoopBreaker )
+import BasicTypes       ( TopLevelFlag(..), isTopLevel, RecFlag(..) )
 import MonadUtils      ( foldlM, mapAccumLM )
 import Maybes           ( orElse )
 import Data.List        ( mapAccumL )
@@ -680,11 +679,14 @@ simplUnfolding env top_lvl _ _ _
                                  (guide { ir_info = mb_wkr' })) }
                -- See Note [Top-level flag on inline rules] in CoreUnfold
 
-simplUnfolding _ top_lvl _ occ_info new_rhs _
-  | omit_unfolding = return NoUnfolding        
-  | otherwise     = return (mkUnfolding (isTopLevel top_lvl) new_rhs)
-  where
-    omit_unfolding = isNonRuleLoopBreaker occ_info
+simplUnfolding _ top_lvl _ _occ_info new_rhs _
+  = return (mkUnfolding (isTopLevel top_lvl) new_rhs)
+  -- We make an  unfolding *even for loop-breakers*.
+  -- Reason: (a) It might be useful to know that they are WHNF
+  --        (b) In TidyPgm we currently assume that, if we want to
+  --            expose the unfolding then indeed we *have* an unfolding
+  --            to expose.  (We could instead use the RHS, but currently
+  --            we don't.)  The simple thing is always to have one.
 \end{code}
 
 Note [Arity decrease]