[project @ 2002-02-07 12:51:34 by simonpj]

[ghc-hetmet.git] / ghc / compiler / codeGen / CgRetConv.lhs

diff --git a/ghc/compiler/codeGen/CgRetConv.lhs b/ghc/compiler/codeGen/CgRetConv.lhs
index 6108567..f3ef813 100644 (file)
--- a/ghc/compiler/codeGen/CgRetConv.lhs
+++ b/ghc/compiler/codeGen/CgRetConv.lhs
@@ -1,7 +1,7 @@
 %
 % (c) The GRASP Project, Glasgow University, 1992-1998
 %
-% $Id: CgRetConv.lhs,v 1.30 2001/08/17 17:18:52 apt Exp $
+% $Id: CgRetConv.lhs,v 1.31 2002/01/28 16:52:37 simonpj Exp $
 %
 \section[CgRetConv]{Return conventions for the code generator}
 
@@ -58,12 +58,16 @@ ctrlReturnConvAlg :: TyCon -> CtrlReturnConvention
 
 ctrlReturnConvAlg tycon
   = case (tyConFamilySize tycon) of
-      0 -> pprPanic "ctrlRetConvAlg" (ppr tycon)
       size -> -- we're supposed to know...
        if (size > (1::Int) && size <= mAX_FAMILY_SIZE_FOR_VEC_RETURNS) then
            VectoredReturn size
        else
-           UnvectoredReturn size
+           UnvectoredReturn size       
+  -- NB: unvectored returns Include size 0 (no constructors), so that
+  --     the following perverse code compiles (it crashed GHC in 5.02)
+  --       data T1
+  --       data T2 = T2 !T1 Int
+  --     The only value of type T1 is bottom, which never returns anyway.
 \end{code}
 
 %************************************************************************