NCG: Emit a warning on unreachable code block instead of panicing

diff --git a/compiler/nativeGen/RegAlloc/Linear/Main.hs b/compiler/nativeGen/RegAlloc/Linear/Main.hs
index 29cc0e5..63f2814 100644 (file)
--- a/compiler/nativeGen/RegAlloc/Linear/Main.hs
+++ b/compiler/nativeGen/RegAlloc/Linear/Main.hs
@@ -206,15 +206,16 @@ linearRA_SCCs first_id block_live blocksAcc (CyclicSCC blocks : sccs)
    some reason then this function will loop. We should probably do some 
    more sanity checking to guard against this eventuality.
 -}
-               
+
 process _ _ [] []         accum _
        = return $ reverse accum
 
 process first_id block_live [] next_round accum madeProgress
        | not madeProgress
-       = pprPanic "RegAlloc.Linear.Main.process: no progress made, bailing out" 
-               (  text "stalled blocks:"
+       = pprTrace "RegAlloc.Linear.Main.process: no progress made, bailing out." 
+               (  text "Unreachable blocks:"
                $$ vcat (map ppr next_round))
+       $ return $ reverse accum
        
        | otherwise
        = process first_id block_live 
@@ -380,9 +381,9 @@ genRaInsn block_live new_instrs block_id instr r_dying w_dying =
     clobber_saves      <- saveClobberedTemps real_written r_dying
 
     -- debugging
-    freeregs <- getFreeRegsR
+{-    freeregs <- getFreeRegsR
     assig    <- getAssigR
-{-    pprTrace "genRaInsn" 
+    pprTrace "genRaInsn" 
        (ppr instr 
                $$ text "r_dying      = " <+> ppr r_dying 
                $$ text "w_dying      = " <+> ppr w_dying