diff options
Diffstat (limited to 'compiler/codeGen')
| -rw-r--r-- | compiler/codeGen/StgCmmExpr.hs | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/compiler/codeGen/StgCmmExpr.hs b/compiler/codeGen/StgCmmExpr.hs index c9b67bd2ff..50d500bc8c 100644 --- a/compiler/codeGen/StgCmmExpr.hs +++ b/compiler/codeGen/StgCmmExpr.hs @@ -40,6 +40,7 @@ import SMRep import TyCon import Type import CostCentre ( CostCentreStack, currentCCS ) +import Control.Monad (when) import Maybes import Util import FastString @@ -304,9 +305,10 @@ cgCase (OpApp ) bndr srt AlgAlt [(DataAlt flase, a2] 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 } @@ -314,15 +316,12 @@ cgCase (StgApp v []) bndr _ alt_type@(PrimAlt _) 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 |