NCG: Handle stripping of liveness info from procs with no blocks (like stg_split_marker)

[ghc-hetmet.git] / compiler / nativeGen / RegAlloc / Liveness.hs

diff --git a/compiler/nativeGen/RegAlloc/Liveness.hs b/compiler/nativeGen/RegAlloc/Liveness.hs
index 18dd01a..a4eeafc 100644 (file)
--- a/compiler/nativeGen/RegAlloc/Liveness.hs
+++ b/compiler/nativeGen/RegAlloc/Liveness.hs
@@ -447,9 +447,8 @@ slurpReloadCoalesce live
 
 
 -- | Strip away liveness information, yielding NatCmmTop
-
 stripLive 
-       :: Instruction instr
+       :: (Outputable instr, Instruction instr)
        => LiveCmmTop instr 
        -> NatCmmTop instr
 
@@ -470,8 +469,14 @@ stripLive live
           in   CmmProc info label params
                           (ListGraph $ map stripLiveBlock $ first' : rest')
 
-       stripCmm _
-                = panic "RegAlloc.Liveness.stripLive: no first_id on proc"     
+       -- procs used for stg_split_markers don't contain any blocks, and have no first_id.
+       stripCmm (CmmProc (LiveInfo info Nothing _) label params [])
+        =      CmmProc info label params (ListGraph [])
+
+       -- If the proc has blocks but we don't know what the first one was, then we're dead.
+       stripCmm proc
+                = pprPanic "RegAlloc.Liveness.stripLive: no first_id on proc" (ppr proc)
+                       
 
 -- | Strip away liveness information from a basic block,
 --     and make real spill instructions out of SPILL, RELOAD pseudos along the way.