import TyCon
import Type
import CostCentre ( CostCentreStack, currentCCS )
+import Control.Monad (when)
import Maybes
import Util
import FastString
cgCase (StgApp v []) bndr _ alt_type@(PrimAlt _) alts
| isUnLiftedType (idType v)
|| reps_compatible
- = -- assignment instruction suffices for unlifted types
- do { v_info <- getCgIdInfo v
- ; emit $ mkComment $ mkFastString "New case:"
+ = -- assignment suffices for unlifted types
+ do { when (not reps_compatible) $
+ panic "cgCase: reps do not match, perhaps a dodgy unsafeCoerce?"
+ ; v_info <- getCgIdInfo v
; emit (mkAssign (CmmLocal (idToReg (NonVoid bndr))) (idInfoToAmode v_info))
; _ <- bindArgsToRegs [NonVoid bndr]
; cgAlts NoGcInAlts (NonVoid bndr) alt_type alts }
reps_compatible = idCgRep v == idCgRep bndr
cgCase scrut@(StgApp v []) _ _ (PrimAlt _) _
- | lifted
= -- fail at run-time, not compile-time
do { mb_cc <- maybeSaveCostCentre True
; withSequel (AssignTo [idToReg (NonVoid v)] False) (cgExpr scrut)
; restoreCurrentCostCentre mb_cc
; emit $ mkComment $ mkFastString "should be unreachable code"
; emit $ withFreshLabel "l" (\l -> mkLabel l <*> mkBranch l)}
- where
- lifted = not (isUnLiftedType (idType v))
cgCase scrut bndr srt alt_type alts
= -- the general case